kottke.org posts about science
The Cassini probe, launched from Earth in 1997 (six months before I started publishing kottke.org), has been taking photos of Saturn and its moons for 11 years now. The Wall Street Journal has a great feature that shows exactly what the probe has been looking at all that time. (Note: the video above features flashing images, so beware if that sort of thing is harmful to you.)
Randall Munroe has a new book coming out called Thing Explainer: Complicated Stuff in Simple Words in which he uses the 1000 most common English words to explain interesting mostly scientific stuff. In a preview of the book, Munroe has a piece in the New Yorker explaining Einstein's theory of relativity using the same constraint.
The problem was light. A few dozen years before the space doctor's time, someone explained with numbers how waves of light and radio move through space. Everyone checked those numbers every way they could, and they seemed to be right. But there was trouble. The numbers said that the wave moved through space a certain distance every second. (The distance is about seven times around Earth.) They didn't say what was sitting still. They just said a certain distance every second.
It took people a while to realize what a huge problem this was. The numbers said that everyone will see light going that same distance every second, but what happens if you go really fast in the same direction as the light? If someone drove next to a light wave in a really fast car, wouldn't they see the light going past them slowly? The numbers said no-they would see the light going past them just as fast as if they were standing still.
It's a fun read, but as Bill Gates observed in his review of Thing Explainer, sometimes the limited vocabulary gets in the way of true understanding:1
If I have a criticism of Thing Explainer, it's that the clever concept sometimes gets in the way of clarity. Occasionally I found myself wishing that Munroe had allowed himself a few more terms -- "Mars" instead of "red world," or "helium" instead of "funny voice air."
See also Albert Einstein's Theory of Relativity In Words of Four Letters or Less. You might prefer this explanation instead, in the form of a video by high school senior Ryan Chester:
This video recently won Chester a $250,000 Breakthrough Prize college scholarship.2 Nice work!
Michael Specter has a truly fascinating piece in the New Yorker about CRISPR, a relatively new genetic tool for editing genes that geneticists are very excited about.
With CRISPR, scientists can change, delete, and replace genes in any animal, including us. Working mostly with mice, researchers have already deployed the tool to correct the genetic errors responsible for sickle-cell anemia, muscular dystrophy, and the fundamental defect associated with cystic fibrosis. One group has replaced a mutation that causes cataracts; another has destroyed receptors that H.I.V. uses to infiltrate our immune system.
The story has everything: the cheap copy/paste of DNA, easily editable mice, pig Hitler, "destroyer of worlds" overtones, and an incredible tale of science that could actually revolutionize (or ruin, depending on who you talk to) the world. I was shocked at how easy it is to do genetic research nowadays.
Ordering the genetic parts required to tailor DNA isn't as easy as buying a pair of shoes from Zappos, but it seems to be headed in that direction. Yan turned on the computer at his lab station and navigated to an order form for a company called Integrated DNA Technologies, which synthesizes biological parts. "It takes orders online, so if I want a particular sequence I can have it here in a day or two," he said. That is not unusual. Researchers can now order online almost any biological component, including DNA, RNA, and the chemicals necessary to use them. One can buy the parts required to assemble a working version of the polio virus (it's been done) or genes that, when put together properly, can make feces smell like wintergreen. In Cambridge, I.D.T. often makes same-day deliveries. Another organization, Addgene, was established, more than a decade ago, as a nonprofit repository that houses tens of thousands of ready-made sequences, including nearly every guide used to edit genes with CRISPR. When researchers at the Broad, and at many other institutions, create a new guide, they typically donate a copy to Addgene.
And CRISPR in particular has quickened the pace. A scientist studying lung cancer mutations said of her research:
"In the past, this would have taken the field a decade, and would have required a consortium," Platt said. "With CRISPR, it took me four months to do it by myself."
Also recommended: Radiolab's podcast on CRISPR from back in June.
This is one of the freakiest atmospheric happenings I have ever seen: a fallstreak hole from Victoria, Aus.
It is believed that the introduction of large numbers of tiny ice crystals into the cloud layer sets off this domino effect of evaporation which creates the hole. The ice crystals can be formed by passing aircraft which often have a large reduction in pressure behind the wing- or propeller-tips. This cools the air very quickly, and can produce a ribbon of ice crystals trailing in the aircraft's wake. These ice crystals find themselves surrounded by droplets, grow quickly by the Bergeron process, causing the droplets to evaporate and creating a hole with brush-like streaks of ice crystals below it.
More photos of this particular hole can be found here.
Here's everything you need to know about the Earth, in a snappy 7-minute video. I am trying very hard not to watch the rest of Kurzgesagt's videos this afternoon, but I did make time for this one on the Big Bang -- key quote: "time itself becomes wibbly wobbly" -- and how evolution works.
A group in Wales is testing concrete that can heal itself. Three different techniques are being pursued:
The first technique uses shape-shifting materials, known as shape-memory polymers, to repair large cracks in concrete. When these materials are heated with a small current, they can transform into a different shape that the material has 'memorised'. The researchers believe that these materials can be embedded into concrete and used to close cracks or make them smaller.
In the second technique, researchers will pump both organic and inorganic healing agents through a network of thin tunnels in the concrete to help repair damage.
In the third technique, the team will embed tiny capsules, or lightweight aggregates, containing both bacteria and healing agents into the concrete. It is anticipated that once cracks occur, these capsules will release their cargos and, in the case of the bacteria, the nutrients that will enable them to function and produce calcium carbonate, which the researchers envisage will heal the cracks in the concrete.
Concrete-patching bacteria. Cool! (via @CharlesCMann)
A group called Kurzgesagt, in collaboration with author Johann Hari, made this video about taking a new approach to understanding addiction. You've probably heard of the experiments where rats in cages were given access to drugs. The rats quickly became addicted to them and used them heavily until overdosing. But perhaps the problem is not the drugs but the cage. Later experiments showed that if rats were given plenty of alternate activities, freedom, and room to roam, they were not likely to become heavy drugs users or overdose.
Human studies are more difficult to come by, but it still appears that when available, living life, family, and friends are more addictive than heroin. And so, according to Hari, who wrote a book about all this, what we should be doing is not isolating those who become addicted to drugs, alcohol, and other things. Instead, we should build a society that reconnects people to each other so that the drugs become unnecessary.
In addition to the video and the book, there's an interactive version of the video as well as an article by Hari on Huffington Post. (via @gavinpurcell)
Whoa, how have I not heard about this before today: the Cassini spacecraft is going to dive through a jet of water erupting from Enceladus, a Saturnian moon.
Discovering life was not on the agenda when Cassini was designed and launched two decades ago. Its instruments can't capture microbes or detect life, but in a couple of dozen passes through the plumes of Enceladus, it has detected various molecules associated with life: water vapor, carbon dioxide, methane, molecular nitrogen, propane, acetylene, formaldehyde and traces of ammonia.
Wednesday's dive will be the deepest Cassini will make through the plumes, only 30 miles above the icy surface. Scientists are especially interested in measuring the amount of hydrogen gas in the plume, which would tell them how much energy and heat are being generated by chemical reactions in hydrothermal vents at the bottom of the moon's ocean.
That's pretty crazy...it sounds like science fiction. NASA is doing a wonderful job producing great science with the lean budgets they are given.
Some recent science suggests that perhaps cats aren't as domesticated as some other animals like dogs, sheep, or horses.
It appears that, following the advent of agriculture, wildcats in the Near East and Asia likely began to congregate near farms and grain stores, where mice and rats were abundant. People tolerated the volunteer exterminators, and wildcats became increasingly comfortable with people. Whether this affiliation began five or ten millennia ago, the evidence suggests that cats have not been part of our domestic domain for nearly as long as dogs, which have been our companions for perhaps forty thousand years.
After all, true house cats are only 60-ish years old, dating roughly to the invention of kitty litter.
Or, as one of my favorite short talks (by Kevin Slavin) suggests, perhaps it is humans who have been domesticated by a protozoan parasite that lives within cats, which, when transmitted to humans, makes us want to share funny cat GIFs online.
A new study from scientists and economists at Stanford and Berkeley has taken a stab at determining how climate change will affect the world's economic activity. As part of their study, they look at which countries might benefit from climate change and which might lose out. As you might expect, countries in the Northern Hemisphere with cooler climates stand to benefit while the rest of the world will not. Here are some of the projected big winners (the Nordic countries) and losers (the Middle East):
Saudi Arabia -96%
United Arab Emirates -94%
Canada (+247%) is another one of the potential big winners while the US (-36%) stands to lose out...along with all of Africa, South America, India, and China. This quote by one of the study's lead authors, really grabbed me by the throat:
What climate change is doing is basically devaluing all the real estate south of the United States and making the whole planet less productive. Climate change is essentially a massive transfer of value from the hot parts of the world to the cooler parts of the world. This is like taking from the poor and giving to the rich.
Among other many things, anthropogenic climate change is an issue of discrimination.1 Rich, predominantly white countries caused the problem and can do the most to limit the damage, but climate change will disproportionately affect poor countries, poor people (even in rich countries), women, and people of color. The rich need to do something about it so that the poor will not suffer. The problem is, the world's wealthy have a long history of not being incentivized to help anyone but themselves. I hope this will turn out differently...or, as sometimes happens, the desires of the wealthy and the needs of the poor dovetail into action of joint benefit.
The scientists who conducted a study at the Delft University of Technology in the Netherlands say they have proved that quantum entanglement is a real effect.
The Delft researchers were able to entangle two electrons separated by a distance of 1.3 kilometers, slightly less than a mile, and then share information between them. Physicists use the term "entanglement" to refer to pairs of particles that are generated in such a way that they cannot be described independently. The scientists placed two diamonds on opposite sides of the Delft University campus, 1.3 kilometers apart.
Each diamond contained a tiny trap for single electrons, which have a magnetic property called a "spin." Pulses of microwave and laser energy are then used to entangle and measure the "spin" of the electrons.
The distance -- with detectors set on opposite sides of the campus -- ensured that information could not be exchanged by conventional means within the time it takes to do the measurement.
The study, published in Nature, has yet to be verified, but still, exciting!
A recent paper found that the time it takes for an animal to move the length of its own body is largely independent of mass. This appears to hold from tiny bacteria on up to whales -- that's more than 20 orders of magnitude of mass. The paper's argument as to why this happens relies on scaling laws. Alex Klotz explains.
A well-known example is the Square-Cube Law, dating back to Galileo and described quite well in the Haldane essay, On Being the Right Size. The Square-Cube Law essentially states that if something, be it a chair or a person or whatever, were made twice as tall, twice as wide, and twice as deep, its volume and mass would increase by a factor of eight, but its ability to support that mass, its cross sectional area, would only increase by a factor of four. This means as things get bigger, their own weight becomes more significant compared to their strength (ants can carry 50 times their own weight, squirrels can run up trees, and humans can do pullups).
Another example is terminal velocity: the drag force depends on the cross-sectional area, which (assuming a spherical cow) goes as the square of radius (or the two-thirds power of mass), while the weight depends on the volume, proportional to the cube of radius or the first power of mass. As Haldane graphically puts it
"You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom, it gets a slight shock and walks away, provided that the ground is fairly soft. A rat is killed, a man is broken, a horse splashes."
Scaling laws also come into play in determining the limits of the size of animals: The Biology of B-Movie Monsters.
When the Incredible Shrinking Man stops shrinking, he is about an inch tall, down by a factor of about 70 in linear dimensions. Thus, the surface area of his body, through which he loses heat, has decreased by a factor of 70 x 70 or about 5,000 times, but the mass of his body, which generates the heat, has decreased by 70 x 70 x 70 or 350,000 times. He's clearly going to have a hard time maintaining his body temperature (even though his clothes are now conveniently shrinking with him) unless his metabolic rate increases drastically.
Luckily, his lung area has only decreased by 5,000-fold, so he can get the relatively larger supply of oxygen he needs, but he's going to have to supply his body with much more fuel; like a shrew, he'll probably have to eat his own weight daily just to stay alive. He'll also have to give up sleeping and eat 24 hours a day or risk starving before he wakes up in the morning (unless he can learn the trick used by hummingbirds of lowering their body temperatures while they sleep).
Hopes&Fears asked a group of scientists and researchers if reality is actually real or if it's all an illusion or hallucination.
How do we know this is real life? The short answer is: we don't. We can never prove that we're not all hallucinating, or simply living in a computer simulation. But that doesn't mean that we believe that we are.
There are two aspects to the question. The first is, "How do we know that the stuff we see around us is the real stuff of which the universe is made?" That's the worry about the holographic principle, for example -- maybe the three-dimensional space we seem to live in is actually a projection of some underlying two-dimensional reality.
Astronomers are interested in the goings-on around a star in our galaxy called KIC 8462852. There appears to be a lot of debris around it, which is a bit unusual and might have any number of causes, including that an extraterrestrial intelligence built all sorts of things around the star.
Jason Wright, an astronomer from Penn State University, is set to publish an alternative interpretation of the light pattern. SETI researchers have long suggested that we might be able to detect distant extraterrestrial civilizations, by looking for enormous technological artifacts orbiting other stars. Wright and his co-authors say the unusual star's light pattern is consistent with a "swarm of megastructures," perhaps stellar-light collectors, technology designed to catch energy from the star.
"When [Boyajian] showed me the data, I was fascinated by how crazy it looked," Wright told me. "Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build."
Boyajian is now working with Wright and Andrew Siemion, the Director of the SETI Research Center at the University of California, Berkeley. The three of them are writing up a proposal. They want to point a massive radio dish at the unusual star, to see if it emits radio waves at frequencies associated with technological activity.
Phil Plait has more context on this weirdo star and how the alien angle is pretty far-fetched but also worth checking out.
I noted the other day that since the early 1980s, the world has lost about half of its coral reefs. According to a recent study, there's more to worry about in the sea: the ocean contains half the fish it did 45 years ago.
Professor McIntyre and his contemporaries believed that overfishing was inherently self-correcting. People might catch too much, but then they would stop fishing, letting the stock recover. They did not reckon on improvements in technology such as a monofilament line, factory trawlers, or fish finders that make it possible to catch so many fish so quickly that it can take decades for a stock to recover (if it ever does). Nor did he or his contemporaries understand food webs and ecological connections; reducing stocks of some species has more of an impact than others.
Update: Here's a PDF copy of the actual report by the WWF. (via @RachelAronson)
It's getting more difficult for new painkilling drugs to be approved because the rate of effectiveness vs. placebos in drug tests is falling. But oddly, the drop is only being seen in the US.
Based on patients' ratings of their pain, the effect of trialled drugs in relieving symptoms stayed the same over the 23-year period -- but placebo responses rose. In 1996, patients in clinical trials reported that drugs relieved their pain by 27% more than did a placebo. But by 2013, that gap had slipped to just 9%. The phenomenon is driven by 35 US trials; among trials in Europe, Asia and elsewhere, there was no significant change in placebo responses. The analysis is in press in the journal Pain.
A persistent underwater heatwave is causing corals worldwide to bleach, and scientists believe up to 5% of the world's coral will die permanently.
Hoegh-Guldberg said he had personally observed the first signs of bleaching on Australia's Great Barrier Reef in the past fortnight, months before the warm season begins. He said the warming pattern indicated bleaching this summer would likely affect 50% of the reef, leaving 5-10% of corals dead. Eakin said seeing bleaching on the reef at this time of year was "disturbing".
Also, no matter how many times I read this, it never gets less scary:
Since the early 1980s the world has lost roughly half of its coral reefs.
The oceans are slowly boiling and we're the frogs who aren't noticing. (via @EricHolthaus)
When the Curiosity rover landed on the surface of Mars, it took high-resolution photos all the way down. Luke Fitch took those photos and stitched them together into a first-person HD video of the rover's landing.
Update: I was wondering if someone had done a stabilized version of this video and lo:
That is the question that physicist Lawrence Krauss answers in his book, A Universe from Nothing. The book's trailer provides a little more context.
Everything we see is just a 1% bit of cosmic pollution in a Universe dominated by dark matter and dark energy. You could get rid of all the things in the night sky -- the stars, the galaxies, the planets, everything -- and the Universe would be largely the same.
And my favorite line from the trailer:
Forget Jesus, the stars died so you could be born.
(via open culture)
From the landmark science series Cosmos, Carl Sagan narrates the evolution of humans from the first cells billions of years ago.
NASA's press conference doesn't start for a few minutes yet, but the NY Times has the scoop: NASA has found "definitive signs" of liquid water on the surface of Mars. Like, right now on Mars, not millions of years ago.
In a paper published in the journal Nature Geoscience, Dr. McEwen and other scientists identified waterlogged molecules -- salts of a type known as perchlorates - in readings from orbit.
"That's a direct detection of water in the form of hydration of salts," Dr. McEwen said. "There pretty much has to have been liquid water recently present to produce the hydrated salt."
By "recently," Dr. McEwen said he meant "days, something of that order."
This is fantastic timing for the release of The Martian movie, which comes out this weekend.
Update: And here's the official press release from NASA.
"Our quest on Mars has been to 'follow the water,' in our search for life in the universe, and now we have convincing science that validates what we've long suspected," said John Grunsfeld, astronaut and associate administrator of NASA's Science Mission Directorate in Washington. "This is a significant development, as it appears to confirm that water -- albeit briny -- is flowing today on the surface of Mars."
These downhill flows, known as recurring slope lineae (RSL), often have been described as possibly related to liquid water. The new findings of hydrated salts on the slopes point to what that relationship may be to these dark features. The hydrated salts would lower the freezing point of a liquid brine, just as salt on roads here on Earth causes ice and snow to melt more rapidly. Scientists say it's likely a shallow subsurface flow, with enough water wicking to the surface to explain the darkening.
Artist and programmer Jeff Thompson has compiled 15,000 hand-drawn maps of the Sun made by astronomers into a single video, creating a mesmerizing and delightfully makeshift stop-motion animation of the Sun's activity over the last 43 years. Astronomers have been drawing these "solar synoptic maps" since 1956 in order to keep track of the Sun's "weather"...sunspots, flares, and the like. (via slate)
Scientists have discovered that an insect has evolved something like a gearbox to coordinate its leg movements while jumping. That's right, nature invented mechanical gears before man got around to it.
The gears in the Issus hind-leg bear remarkable engineering resemblance to those found on every bicycle and inside every car gear-box.
Each gear tooth has a rounded corner at the point it connects to the gear strip; a feature identical to man-made gears such as bike gears -- essentially a shock-absorbing mechanism to stop teeth from shearing off.
The gear teeth on the opposing hind-legs lock together like those in a car gear-box, ensuring almost complete synchronicity in leg movement -- the legs always move within 30 'microseconds' of each other, with one microsecond equal to a millionth of a second.
This is critical for the powerful jumps that are this insect's primary mode of transport, as even minuscule discrepancies in synchronisation between the velocities of its legs at the point of propulsion would result in "yaw rotation" -- causing the Issus to spin hopelessly out of control.
"This precise synchronisation would be impossible to achieve through a nervous system, as neural impulses would take far too long for the extraordinarily tight coordination required," said lead author Professor Malcolm Burrows, from Cambridge's Department of Zoology.
Edward Snowden has come up with a solution to the Fermi Paradox that I hadn't heard of before. Maybe we haven't discovered intelligent life elsewhere in the Universe, says Snowden, because their communications encryption is indistinguishable from cosmic background radiation.
"If you look at encrypted communication, if they are properly encrypted, there is no real way to tell that they are encrypted," Snowden said. "You can't distinguish a properly encrypted communication from random behaviour."
Therefore, Snowden continued, as human and alien societies get more sophisticated and move from "open communications" to encrypted communication, the signals being broadcast will quickly stop looking like recognisable signals.
"So if you have an an alien civilization trying to listen for other civilizations," he said, "or our civilization trying to listen for aliens, there's only one small period in the development of their society when all their communication will be sent via the most primitive and most unprotected means."
After that, Snowden said, alien messages would be so encrypted that it would render them unrecognisable, "indistinguishable to us from cosmic microwave background radiation". In that case, humanity would not even realise it had received such communications.
Snowden shared his hypothesis with Neil deGrasse Tyson on Tyson's podcast, StarTalk.
The backlit photos of Pluto just posted by NASA are breathtaking. Look at this:
Just 15 minutes after its closest approach to Pluto on July 14, 2015, NASA's New Horizons spacecraft looked back toward the sun and captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto's horizon. The smooth expanse of the informally named Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 11,000 feet (3,500 meters) high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. The backlighting highlights more than a dozen layers of haze in Pluto's tenuous but distended atmosphere. The image was taken from a distance of 11,000 miles (18,000 kilometers) to Pluto; the scene is 230 miles (380 kilometers) across.
As they say, best viewed large. Some of those features don't look like mountains at all, but like reptile scales or huge shards of ice pushed up into the sky. Fantastic.
Last month I shared a video showing the thousands of nuclear weapons that humans have detonated on Earth. I hadn't really thought about it too much apart from the two dropped in Japan in WWII, but those weapons created some permanent physical changes in the landscape of the Earth. For instance, dozens of circular scars are visible at this testing range in Nevada near Area 51.
Also located in the same area is the Sedan Crater, the largest man-made crater in the United States. The crater is 320 feet deep, 1280 feet across, listed on the National Register of Historic Places, and was made by a thermonuclear device with a 104 kiloton yield detonated in 1962.
Now, I haven't read a whole lot about nuclear tests, but this one seems particularly idiotic. The purpose of the Sedan shot was not to test a new kind of weapon or to determine the effects of the bomb, but to move earth. Yeah, no big deal, we're just gonna use a fusion bomb like a big stick of dynamite. Sedan was part of Operation Plowshare, an effort to use nuclear devices for peaceful purposes like mining and moving earth. From Wikipedia:
Proposed uses for nuclear explosives under Project Plowshare included widening the Panama Canal, constructing a new sea-level waterway through Nicaragua nicknamed the Pan-Atomic Canal, cutting paths through mountainous areas for highways, and connecting inland river systems. Other proposals involved blasting underground caverns for water, natural gas, and petroleum storage. Serious consideration was also given to using these explosives for various mining operations. One proposal suggested using nuclear blasts to connect underground aquifers in Arizona. Another plan involved surface blasting on the western slope of California's Sacramento Valley for a water transport project.
The Pan-Atomic Canal! This quaint US government video has more on Sedan:
In my post the other day, I said that the Soviets didn't care about their citizenry when testing nuclear devices. Apparently the US didn't either: the Sedan shot -- the purpose of which, as a reminder, was to move a bunch of dirt -- resulted in a significant amount of nuclear fallout, about 7% of the total radioactive fallout generated by all the nuclear tests in Nevada. Fallout from the test reached as far as West Virginia and was particularly high in counties in Iowa and Illinois. Buy hey, they moved 12 million tons of soil! (via @kyledenlinger)
In retrospect, it was an unlikely set of conditions that came together to produce the Space Age. Not just the postwar blend of prosperity and paranoia, but a series of scientific breakthroughs, both pure and applied, that happened in such close succession that we nearly had a surplus, one that had to be invested in something.
We had to know our world well enough to be able to escape it, but not so well that we couldn't ignore the price we were paying. And now that window may be closing.
Here are two stories that have me in an elegiac mood. "This Used To Be the Future" is a photoessay by Rachel Sussman that looks at NASA's Ames Research Center in Silicon Valley. Most stories about Ames focus on the cutting edge stuff, the public/private partnerships; Sussman focuses on the old stuff, the military leftovers, the junk.
Next is a piece in Scientific American on plutonium-238. NASA uses the slow-burning plutonium to power its long-range probes and interplanetary craft.
Over the past half-century, NASA has used a total of 140 kilograms of Pu-238 to push the frontiers of exploration. Coupled to one of the agency's "thermoelectric" generators that convert heat into electricity, four kilograms of the stuff can power a spacecraft for decades. Pu-238 was used in Apollo-era science experiments on the Moon, in the Galileo mission to Jupiter and in the Pioneer and Voyager space probes now exiting our solar system. Hefty hunks of Pu-238 power the Mars Curiosity rover, the Cassini orbiter at Saturn and the New Horizons spacecraft now roaming beyond Pluto. In the future, Pu-238 could power robotic probes to burrow beneath the ice of ocean-bearing moons, planes to fly in the alien atmospheres of other worlds, ships to sail the liquid ethane seas of Saturn's moon Titan and much, much more.
Those future missions can only occur if there's enough plutonium to go around. Practically all of NASA's Pu-238 stockpile was made as a byproduct of building nuclear weapons during the Cold War. As the Cold War wound down, so too did the Department of Energy's Pu-238 production; it made its last batch in 1988, shutting off NASA's supply save for occasional deliveries of small, lower-quality batches from Russia that ceased in 2010. At present, only about 35 kilograms of Pu-238 are left for the space agency, and radioactive decay has rendered all but 17 kilograms too weak to be readily used in NASA's thermoelectric generators. NASA and DOE officials estimate there is only enough for four more generators, one of which is already committed to NASA's upcoming Mars 2020 rover.
The plutonium shortfall makes it impossible for NASA to plan future missions that would require it, but in the absence of specific mission needs, nobody wants to make any more. Solar-powered craft could eventually fill in the gap, but the technology's not there yet.
So the stars get further and further away.
Jonathan Hickman is currently writing Secret Wars for Marvel, but the roots of that story go back to his earlier run on Fantastic Four. There's a great scene where Reed Richards, Mister Fantastic, resigns from the Singularity Conference (think TED/O'Reilly/Davos on steroids), a group of scientists he founded, as they argue for increasingly limited approaches to exploration.
The other scientists are basically correct. It is irresponsible to fund manned space missions in a global recession. Our global population may be impossible to sustain on our planet going forward. But Mister Fantastic, being a superhero, rejects the premise. "The future of man is not one billion of us fighting over limited resources on a soon-to-be-dead planet, but one trillion human beings spanning an entire galaxy," he says. "The future of man is not here. It is out there. Because it's our new horizon. Because it's what's next."
It's a corny, Sorkin-esque speech.... but I love it. It thrills me. And it makes me afraid.
I would like to think that that time isn't over yet, that there is a way to reconcile what we know now with what we were willing to risk for the sake of knowledge then -- that if not in outer space, then in medicine or genetics or some other field. But part of me wonders if the time for us to come together to do big things -- that space age, that Marvel Age, that time of the Fantastic Four -- is over. And all that's left is how we manage our decline.
There's a new (extinct) hominin on the block (in a cave system in Africa): Homo naledi.
Basically, Homo naledi had humanlike hands, legs, and feet, but tiny little australopithecine skulls, i.e., brains.
And, there are a lot of them, fossil-wise: "Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa."
But we don't yet know exactly how long ago they lived: maybe two million years ago, when the Homo genus emerged, or as late as a hundred thousand years ago, when it contracted to, well, us. In an accompanying article, Chris Stringer gets a little testy about it.
Frustratingly, the rich and informative H. naledi material remains undated. Given that this hominin material could conceivably even date within the last 100,000 years, I am puzzled by the apparent lack of attempts to estimate its age. This could have been achieved directly via radiocarbon dating (even if only to test whether the material lies beyond the effective range of that method) or indirectly based on ancient DNA samples. For example, after ancient DNA was successfully recovered from the Sima de los Huesos fossils, it was used to date them to about 400,000 years old (Meyer et al., 2014). Moreover, tests on even small fragments of bone and tooth enamel could have narrowed down the possible age range and at least ruled out either a very ancient or very young age (Grün, 2006).
As Dan Cohen points out, this discovery is also unusual in that it didn't make its splash at Science or Nature, but eLife, a free, open-access journal. Study leader Lee Berger tells Buzzfeed the article was rejected by Nature because the authors couldn't meet the mag's demands to squeeze the whole thing into 2500 words. Well, whatever the reason for going open-access, we of the science-following-but-not-institutional-password-having-audience approve.
Update: Ed Yong has a terrific account of the discovery, with a ripping narrative about the caving team's expedition and an intelligent analysis of the new species and its implications. Well worth reading.
Rain-Bros by Daniel Savage is a fun visualization of the different wavelengths of light in the visible spectrum, from the loping walk of red to blue's energetic bounce.
Oliver Sacks was a champion of one of humankind's most admirable qualities: Curiosity. The neurologist and writer died on Monday. He wrote beautifully about his impending death in a piece published a couple weeks ago:
And now, weak, short of breath, my once-firm muscles melted away by cancer, I find my thoughts, increasingly, not on the supernatural or spiritual, but on what is meant by living a good and worthwhile life...
Longform has a collection of links to some of Sacks' most popular essays.
Riffing on a question Richard Feynman once posed to himself, Tom Chivers asked 12 scientists:
If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words?
I liked the pragmatic answer by Lewis Dartnell, author of The Knowledge: How to Rebuild Civilization in the Aftermath of a Cataclysm
While Feynman's sentence is all good and true, it isn't particularly useful in an immediate pragmatic sense. I wrote a book recently which was intended as a guidebook for rebooting civilisation after an apocalypse, looking at the key technologies and central scientific principles that underpin our lives - the behind-the-scenes fundamentals that we all just take for granted today - and what enabled society to progress through the centuries of history. I argue how the greatest invention of history is the scientific method itself - the knowledge-generation machinery that we have been using for over 350 years now to come to understand how the world works. So if you could preserve only one single sentence, I would push for: 'The natural world is not governed by whimsical gods, but is essentially mechanical and can therefore be understood and then predicted by people, using careful observation, experimentation, and measurement, and importantly by testing your explanations to try to refute them.' It's this reiterative process of refinement that sets science apart from any other system for explaining how the world works.
There are other tips that could help with immediate survival. Diarrhoeal disease kills millions of people every year - all preventable by simple means. One method recommended by the World Health Organisation in developing nations for low-tech treatment of drinking water is called SODIS, or solar disinfection. All you need to do is pour your suspect water into a plastic bottle and leave it in the sun. Ultraviolet rays in sunlight pass straight through and kill any germs. So you can come back to your bottle a day or two later and know that the water you put to your lips isn't going to kill you.
Up until very recently, humans were thought to be the only animals who made and used stone tools, an era in human development that began roughly 3.3 million years ago. But according to this piece at the BBC, some chimpanzees and monkeys in various places around the globe have been using primitive stone tools for hundreds or even thousands of years.
Boesch and his colleagues had previously studied modern chimpanzee stone tool culture in the region. This research revealed that the chimpanzees have an idiosyncratic way of choosing and using their tools.
For instance, chimpanzees will often deliberately opt for particularly large and heavy stone hammers, between 1kg and 9kg, while humans prefer to use stones that weigh 1kg or less. Many of the 4300-year-old stone tools weighed more than 1kg, suggesting they were used by chimpanzees.
Chimpanzees also use their stone tools to crack open certain types of nuts that humans don't eat. Starch residues on some of the ancient tools came from these nuts.
Together, these findings led to an obvious conclusion: chimpanzees have been using stone tools in the rainforests of Ivory Coast for at least 4300 years.
Bjorn Jonsson used the photos taken by NASA's New Horizons spacecraft to make an animation of the probe's flyby of Pluto.
The time covered is 09:35 to 13:35 (closest approach occurred near 11:50). Pluto's atmosphere is included and should be fairly realistic from about 10 seconds into the animation and to the end. Earlier it is largely just guesswork that can be improved in the future once all data has been downlinked from the spacecraft. Light from Pluto's satellite Charon illuminates Pluto's night side but is exaggerated here, in reality it would be only barely visible or not visible at all.
Fantastic...and Pluto's moons flying about in the background is the cherry on the top. (via @BadAstronomer)
In A Children's Picture-book Introduction to Quantum Field Theory, Brian Skinner explains quantum field theory -- "the deepest and most intimidating set of ideas in graduate-level theoretical physics" -- as if you and I are five-year-old children.
The first step in creating a picture of a field is deciding how to imagine what the field is made of. Keep in mind, of course, that the following picture is mostly just an artistic device. The real fundamental fields of nature aren't really made of physical things (as far as we can tell); physical things are made of them. But, as is common in science, the analogy is surprisingly instructive.
So let's imagine, to start with, a ball at the end of a spring.
How massive are they? The Sun is 1 solar mass and as wide as 109 Earths. Sagittarius A, the black hole at the center of the Milky Way, weighs 4.3 million solar masses and is as wide as Mercury is far from the Sun. The black hole at the center of the Phoenix Cluster is one of the largest known black holes in the Universe; it's 73 billion miles across, which is 19 times larger than our entire solar system (from the Sun to Pluto). As for how much it weighs, check this out:
I also like that if you made the Earth into a black hole, it would be the size of a peanut. (thx, reidar)
Emily Lakdawalla provides an update on all of the exploration that's going on in our solar system this month. Here's a quick map view of the 20+ spacecraft exploring our solar system beyond Earth:
Mars remains the most active spot beyond Earth in the solar system. This week, Mars Reconnaissance Orbiter reaches its 10th anniversary of service in space, but it's far from the oldest spacecraft in orbit at Mars; Mars Express and Mars Odyssey are still at work up there. Mars Orbiter Mission has ventured into an extended mission and is still returning photos, though apparently none of the full-disk images in a variety of phases that I had hoped for from its 4-Megapixel color camera. Even Mars' newest resident, MAVEN, is three-quarters of the way through its one-year primary science mission, which began on November 16, 2014. MAVEN's mission will undoubtedly be extended long beyond that, as it will be needed to support surface missions if and when Odyssey and Mars Reconnaissance Orbiter eventually fail.
Both Opportunity and Curiosity have been very active lately. Opportunity has finally reached Marathon Valley, a site identified from orbit to have signs of clay chemistry. The team is excited about the science prospects even though the rover's memory problems persist.
Artist Sam Van Aken is using grafting to create trees that bear 40 different kinds of fruit. National Geographic recently featured Van Aken's Tree of 40 Fruit project:
The grafting process involves slicing a bit of a branch with a bud from a tree of one of the varieties and inserting it into a slit in a branch on the "working tree," then wrapping the wound with tape until it heals and the bud starts to grow into a new branch. Over several years he adds slices of branches from other varieties to the working tree. In the spring the "Tree of 40 Fruit" has blossoms in many hues of pink and purple, and in the summer it begins to bear the fruits in sequence -- Van Aken says it's both a work of art and a time line of the varieties' blossoming and fruiting. He's created more than a dozen of the trees that have been planted at sites such as museums around the U.S., which he sees as a way to spread diversity on a small scale.
No hunger. No pollution. No disease. Wired's Amy Maxmen welcomes you to the age of copy and paste DNA editing and the end of life as we know it.
Genome editing started with just a few big labs putting in lots of effort, trying something 1,000 times for one or two successes. Now it's something that someone with a BS and a couple thousand dollars' worth of equipment can do. What was impractical is now almost everyday. That's a big deal.
[I recently listened to Radiolab's show on Crispr. Recommended. -jkottke]
A company called Oxitec has genetically modified mosquito eggs so that the mosquitos born from them pass along a gene to their offspring that prohibits the mosquitos from reaching sexual maturity and mating. They release the mosquitos into the wild, they mate with the local population of mosquitos, and those born from those matings will die before mating themselves. Voila! Pest control.
Oxitec has conducted trials with its modified mosquito in dengue-ridden regions of Panama, Brazil, Malaysia, and the Cayman Islands. The results show population suppression rates above 90 percent-far greater than the typical 30 percent achieved with insecticides.
The company is currently planning a trial in Florida using this technique to curb an influx of mosquito-borne illness.
This morning, the New Horizons probe zinged safely1 past Pluto. Before it did, it transmitted the best photo we've seen of Pluto so far...the last one we'll get before we get the really good stuff. Look at this:
The probe's "I'm OK!" message will reach Earth around 9pm ET tonight and we'll start seeing photos from the flyby Wednesday afternoon...there's a NASA press conference scheduled for 3pm ET on July 15. So exciting!
Update: The photo above is also the best full-disk image of Pluto that we will get...the rest will be close-ups and such. So that's the official Pluto portrait from now on, folks.
CERN's LHC (Large Hadron Collider) has discovered a new subatomic particle, the pentaquark.
"The pentaquark is not just any new particle," said LHCb spokesperson Guy Wilkinson. "It represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before in over fifty years of experimental searches. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we're all made, is constituted."
Here's the paper, with more than 680 authors. Between New Horizons zipping past Pluto earlier today (look at this pic!) and this, what a day for science.
Psychologists Dacher Keltner and Paul Ekman served as scientific consultants during the production of Pixar's Inside Out. Keltner studies the origins of human emotion and Ekman pioneered research of microexpressions. In this NY Times piece, they discuss the science behind the movie.
Those quibbles aside, however, the movie's portrayal of sadness successfully dramatizes two central insights from the science of emotion.
First, emotions organize -- rather than disrupt -- rational thinking. Traditionally, in the history of Western thought, the prevailing view has been that emotions are enemies of rationality and disruptive of cooperative social relations.
Second, emotions organize -- rather than disrupt -- our social lives. Studies have found, for example, that emotions structure (not just color) such disparate social interactions as attachment between parents and children, sibling conflicts, flirtations between young courters and negotiations between rivals.
I've thought about Inside Out every day since I saw it. Pixar clearly did their homework on the emotional stuff and it paid off.
As the New Horizons probe nears Pluto, I've been reading a bit more about how it's going to work and what sort of photos we're going to get. Emily Lakdawalla has a comprehensive post about what to expect when you're expecting a flyby of Pluto. The post contains an image of approximations of the photos New Horizon will take, using Voyager images of Jovian and Saturnian moons as stand-ins. The highest resolution photo of Pluto will be 0.4 km/pixel...it'll have this approximate level of detail:
Which is pretty amazing and exciting considering that before the mission started this was our best view of Pluto:
NASA's Eyes app lets you see a simulation of the probe as it approaches Pluto, but if you don't want to download anything, you can watch this video of the flyby instead:
I had no idea the probe spun around so much as it grabs photos & scans and then beams them back to Earth. And the flyby is so fast! New Horizons is currently moving at 32,500 mph relative to the Sun...it's travelling just over 9 miles every second. (via @Tim_Meyer_ & @badastronomer)
Pluto is so far away that we haven't even been able to get a good look at it, not even with the crazy-powerful Hubble telescope. But with NASA's New Horizons mission closing in on our solar system' ninth planet,1 we are getting a better and better view of Pluto every day.1Here's the latest, from just a few hours ago:
New Horizons will reach its closest approach to Pluto in just under 6 days, on July 14. The probe will pass within 7,800 miles of the surface...I can't wait to find out what that day's photos look like.
Update: You don't even need to wait until tomorrow for that better image...here's one that NASA released just a short while ago. Tune in tomorrow for an even better view.
Unlike the Earth, Mars and the Moon don't have strong directional magnetic fields, which means traditional compasses don't work. So how did the Apollo rovers and current Mars rovers navigate their way around? By using manually set directional gyroscope and wheel odometers.
While current un-crewed rovers don't have to return to the comfort of a lunar module, some aspects of the Apollo systems live on in their design. Four U.S. Martian rovers have used wheel odometers that account for slippage to calculate distance traveled. They've also employed gyroscopes (in the form of an inertial measurement units) to determine heading and pitch/roll information.
One of the fun things about reading The Martian is you get to learn a little bit about this sort of thing. Here's a passage about navigation on Mars where astronaut Mark Watney is trying to get to a landmark several days' drive away.
Navigation is tricky.
The Hab's nav beacon only reaches 40 kilometers, so it's useless to me out here. I knew that'd be an issue when I was planning this little road trip, so I came up with a brilliant plan that didn't work.
The computer has detailed maps, so I figured I could navigate by landmarks. I was wrong. Turns out you can't navigate by landmarks if you can't find any god damned landmarks.
Our landing site is at the delta of a long-gone river . NASA chose it because if there are any microscopic fossils to be had, it's a good place to look. Also, the water would have dragged rock and soil samples from thousands of kilometers away. With some digging, we could get a broad geological history.
That's great for science, but it means the Hab's in a featureless wasteland.
I considered making a compass. The rover has plenty of electricity, and the med kit has a needle. Only one problem: Mars doesn't have a magnetic field.
So I navigate by Phobos. It whips around Mars so fast it actually rises and sets twice a day, running west to east. It isn't the most accurate system, but it works.
I wonder why the rovers in the story weren't outfitted with directional gyroscopes and wheel odometers? (See also the operations manual for the lunar rovers.) (via @JaredCrookston)
Here's something that I knew as a kid but had forgotten about: if you get a bike going on its own at sufficient speed, it will essentially ride itself. MinutePhysics investigates why that happens.
Interesting that the bike seems to do much of the work of staying upright when it seems like the rider is the thing that makes it work. (via devour)
While reading this otherwise excellent article written by US soccer player Christie Rampone, I discovered a type of diet I'd never heard of before, the blood type diet (italics mine).
Age and parenting make me think about longevity. I definitely believe one big reason for my longevity has to do with the dietary and fitness changes I made after being diagnosed with auto-immune conditions after giving birth to my youngest daughter Reece in 2011. For example, I've gone gluten-free and have started to eat to my blood-type. Also, a friend introduced me to a natural ingredient called EpiCor to help strengthen my immune system. I have taken EpiCor daily for the past three years and it has become a beneficial part of my daily routine of rest, recovery, working out, eating healthy, and being in airports and hotels more than my own house.
From Wikipedia, an overview of the diet:
The underlying theory of blood type diets is that people with different blood types digest lectins differently, and that if people eat food that is not compatible with their blood type, they will experience many health problems. On the other hand, if a person eats food that is compatible, they will be healthier.
That theory is, in turn, based on an assumption that each blood type represents a different evolutionary heritage. "Based on the 'Blood-Type' diet theory, group O is considered the ancestral blood group in humans so their optimal diet should resemble the high animal protein diets typical of the hunter-gatherer era. In contrast, those with group A should thrive on a vegetarian diet as this blood group was believed to have evolved when humans settled down into agrarian societies. Following the same rationale, individuals with blood group B are considered to benefit from consumption of dairy products because this blood group was believed to originate in nomadic tribes. Finally, individuals with an AB blood group are believed to benefit from a diet that is intermediate to those proposed for group A and group B."
As you might have already guessed, there is no evidence that eating your blood type is beneficial nor do the claims of differing lectin digestion have scientific merit. Homeopathic nonsense.
Tasha Sturm, a lab technician at Cabrillo College, had her 8-year-old son put his handprint on a prepared petri dish and then incubated it for several days. This was the result:
If you'll excuse me, I have to go wash my hands about 4,000 times. Bacteria is cooooool though:
Because of climate change and other activities caused by humans (invasive species, habitat loss), hybridization of species is resulting in things like super-sized coyotes, pizzly bears (grizzly/polar bear hybrids), and other animals that may not be ideally suited to survive.
Some scientists and conservationists see the coywolf as a nightmare of the Anthropocene -- a poster child of mongrelization as plants and animals reshuffle in response to habitat loss, climate change and invasive species. Golden-winged warblers increasingly cross with blue-winged warblers in the U.S. Northeast and eastern Canada. Southern flying squirrels hybridize with northern flying squirrels as the southern species presses northward in Ontario. Polar bears mate with grizzlies in the Canadian Arctic along the Beaufort Sea to produce "pizzly bears."
All of this interbreeding upsets the conventional notion of species as discrete, inviolable entities. Moreover, some scientists and conservationists warn that hybridization will degrade biodiversity as unusual species are lost to genetic homogenization.
Partly scientists fear hybrids will be less fit than organisms that have evolved in place over eons. And often that is true, but the problem solves itself over time as hybrids lose out in the competitive race for survival.
University of Minnesota student Daniel Crawford and geography professor Scott St. George have collaborated on a piece of music called Planetary Bands, Warming World. Composed for a string quartet, the piece uses climate change data to determine the musical notes -- the pitch of each note is tuned to the average annual temperature, which means as the piece goes on, the musical notes get higher and higher.
Researchers using the Keck Observatory have discovered a new kind of galaxy that are large but filled with relatively few stars.
"If the Milky Way is a sea of stars, then these newly discovered galaxies are like wisps of clouds", said van Dokkum. "We are beginning to form some ideas about how they were born and it's remarkable they have survived at all. They are found in a dense, violent region of space filled with dark matter and galaxies whizzing around, so we think they must be cloaked in their own invisible dark matter 'shields' that are protecting them from this intergalactic assault."
The night sky in such galaxies would look a lot like our skies do in large cities:
"If there are any aliens living on a planet in an ultra-diffuse galaxy, they would have no band of light across the sky, like our own Milky Way, to tell them they were living in a galaxy. The night sky would be much emptier of stars," said team member Aaron Romanowsky, of San Jose State University.
If you hold a lit match an inch or two over the smoking wick of a recently extinguished candle, the candle will light again. If you record that happening with a high speed camera and then slow it way down, it gives you some clues to how that happens:
Hint: wax is a candle's fuel and smoke is wax vapor... (via digg)
Here's a video of a titanium bar being anodized...it cycles through several different colors before settling on a pinkish hue.
Ok neat, but why does it do that? Anodizing is an adjustment of the oxide levels on the surface of the titanium. The colors are caused by the interference of the light traveling through the oxide and reflecting off the shiny metal surface underneath...different thicknesses produce different colors.1 As the voltage is applied to the metal, more and more oxide builds up, producing the color cycling even shown. Pretty cool!
From juice cleanses to vaccines to gluten to exercise to, uh, vagina steaming, celebrities like Jenny McCarthy and Gwyneth Paltrow are often found making claims that have little or no scientific evidence behind them. Timothy Caulfield recently wrote a book exploring the world of celebrity pseudoscience called Is Gwyneth Paltrow Wrong About Everything?
But while much has been written about the cause of our obsession with the rich and famous, Caulfield argues that not enough has been done to debunk celebrity messages and promises about health, diet, beauty, or the secret to happiness. From the obvious dangers, to body image of super-thin models and actors, or Gwyneth Paltrow's enthusiastic endorsement of a gluten free-diet for almost everyone, or Jenny McCarthy's ill-informed claims of the risks associated with vaccines, celebrity opinions have the power to dominate our conversations and outlooks on our lives and ourselves.
Julia Belluz of Vox interviewed Caulfield about the book.
JB: So is Gwyneth actually wrong about everything?
TC: It's incredible how much she is wrong about. Even when she is right about stuff -- like telling people to eat more fruits and vegetables -- there is always a bit of a tinge of wrongness. She'll say, "It has to be organic," for example. She is still distracting us with these untrue details, as opposed to just pushing the honest truth.
See also Your detoxing juice cleanse is bullshit.
Do you think you could ride a bicycle that steers backwards...aka it turns left when you turn right and vice versa? It sounds easy but years of normal bike riding experience makes it almost impossible. Destin Sandlin of Smarter Everyday taught himself how to ride the backwards-steering bike; it took months. Then he tried riding a normal bicycle again...
Loved this video...great stuff. (via ★interesting)
After years of the Flintstones lying to me, I'd just gotten used to the idea of the Brontosaurus not actually being a dinosaur. But a recent study of the classifications given to various species and genera within the diplodocid group of dinosaurs has determined that the Brontosaurus and the Apatosaurus are different enough to be two separate species.
Very broadly, their tree confirmed established ideas about the evolutionary relationships among diplodocids. But the scientists also concluded that Apatosaurus and Brontosaurus were different enough to belong in their own genera. Many of the anatomical differences between the two dinosaurs are obscure, Tschopp says, but Apatosaurus's stouter neck is an obvious one. "Even though both are very robust and massive animals, Apatosaurus is even more so," he adds.
Tschopp and his team thought very carefully about their decision to reinstate Brontosaurus, and they expect some pushback. "We knew it would be a major finding because Brontosaurus is such a popular name," he says. "I'm pretty sure there will be a scientific discussion around this. I hope there will be. That's how science works."
Huzzah! Now reinstate Pluto to full planetary status and we'll be all set. See also The Kindly Brontosaurus. (via @coudal)
In 1983, the BBC aired a six-part series called Fun to Imagine with a simple premise: put physicist Richard Feynman in front of a camera and have him explain everyday things. In this clip from one of the episodes, Feynman explains in very simple terms what fire is:
So good. Watch the whole thing...it seems like you get the gist about 2 minutes in, but that's only half the story. See also Feynman explaining rubber bands, how trains go around curves, and how magnets work.
James Krupa teaches a mandatory biology class at the University of Kentucky and some students have a difficult time because Krupa refuses to shy away from evolution.
Rarely do I have a Kentucky student who learned about human evolution in high school biology. Those who did usually attended high schools in large urban centers like Louisville or Lexington. Given how easily it can provoke parents, the teaching of human evolution is a rarity in high school, so much so in Kentucky that it startled me when I first arrived.
The story of our evolutionary history captivates many of my students, while infuriating some. During one lecture, a student stood up in the back row and shouted the length of the auditorium that Darwin denounced evolution on his deathbed -- a myth intentionally spread by creationists. The student then made it known that everything I was teaching was a lie and stomped out of the auditorium, slamming the door behind him. A few years later during the same lecture, another student also shouted out from the back row that I was lying. She said that no transitional fossil forms had ever been found -- despite my having shared images of many transitional forms during the semester. Many of her fellow students were shocked by her combativeness, particularly when she stormed out, also slamming the door behind her. Most semesters, a significant number of students abruptly leave as soon as they realize the topic is human evolution.
I personally don't understand the compatibility of evolutionary biology and Christianity Krupa emphasizes in his class, but I guess it helps to meet people halfway?
This article on the science of free diving is fascinating. Boyle's Law predicted that the human body couldn't survive depths past 100 feet -- after which, the lungs would rupture -- but millions of years of evolution has equipped the human body with all sorts of tricks to survive at depths of over 900 feet.
Lundgren, among others, demonstrated how these phenomena might counteract Boyle's law. He recruited volunteer firemen from a fire brigade in the Swedish city of Malmo, submerged them up to the neck in water, and used a heart catheter to measure the increase in blood circulation in the chest. Lundgren discovered the body was able to counteract the increased outside water pressure by reinforcing vessels in the walls of the lungs with more blood, in much the same way we increase tire pressure by adding more volume of oxygen to the inside of a tire.
Boyle's Law had not been overturned. Scientists simply hadn't taken into account the effect this counterforce could exert to allow survival underwater. "A lot of blood, much more than was usually thought, can be transferred from the blood circulation out in the tissues into the blood vessels of the lung," Lundgren said, placing that amount at about half a gallon. The extra, densely packed blood can act as a bulwark, exerting a counterforce against the increased pressure pushing inward by the water.
A group of astronomy enthusiasts rented a plane and flew through the shadow cast by the recent eclipse of the Sun. One passenger took the following video. Look at that shadow creeping across the cloud cover! So cool.
P.S. Still super excited for the 2017 eclipse! (via slate)
Ok, Pluto fans. They evicted Pluto from our solar system's planetary pantheon, but a NASA mission launched in 2006 is nearing the dwarf planet with its cameras. We'll soon have photos of Pluto that are much more high resolution than we currently have, which means scientists will need names for all the new geographic features. The Our Pluto site has been set up to help suggest and vote on names for these features. Naming themes include historic explorers, travelers to the underworld, and scientists and engineers. Go vote! (via slate)
Apparently, this is what it looks like when a lion is getting a CAT scan.
(via Amanda Macias)
This video, shot at 36,000 frames per second, shows a balloon popping underwater. I am not quite sure what I expected, but it wasn't this.
For instance, the air bubbles do not immediately rise to the surface...it takes them about 20-25 ms to get in the mood. Compare with a slow motion video of popping a water balloon in air:
Again, watch how it takes for gravity to kick in. It's like Wile E. Coyote after having run off a cliff, hanging in midair holding a sign that says "EEP!" (via @BadAstronomer)
Two teams of NASA scientists have discovered evidence that hydrothermal vents on the Saturnian moon of Enceladus show signs of "active hot-water chemistry". Why is that exciting? Because similar chemistry occurs deep in the Earth's oceans *and* can support life. Phil Plait explains.
We see these vents in the ocean bottom on Earth, too. The water there is very hot, heated by tectonic processes inside Earth's crust. It brings up minerals and nutrients, and life thrives there. A lot of the processes are the same as what's imagined is happening on Enceladus; minerals are dissolved in hot water that spews up into the cold ocean, precipitating out. A lot of it is sulfur based, but amazingly life exists there anyway. The environment is highly toxic to humans-huge pressure, boiling water near the vents, freezing a bit farther away, and loaded with icky chemicals-but as a scientist once said, "Life finds a way."
Between the evidence of past flowing water on Mars, Titan's hydrocarbon lakes, Europa's underground ocean, and Enceladus, it seems increasingly probable we'll find life somewhere else in the solar system. That's a pretty exciting prospect! (via @ericholthaus)
Update: It was also announced today that the Hubble has detected signs of a salty underground ocean on Jupiter's moon Ganymede.
New observations of the moon using Hubble support this. Ganymede has a weak magnetic field, and, like on Earth, this generates an aurora-the glow created when high-speed subatomic particles slam into the extremely thin atmosphere. This glow is brightest in ultraviolet, and so astronomers used the Space Telescope Imaging Spectrograph (my old camera!) on Hubble to observe Ganymede. STIS is quite sensitive to UV and detected the aurora.
Now this part is a bit tricky: Jupiter has a powerful magnetic field as well, which interacts with Ganymede's. As they do, the aurora changes position over time, moving up and down in latitude. However, the observations show that the aurorae do not change nearly as much as expected if Ganymede were solid. The best way to explain this is if the moon has a salty ocean under its surface. The ocean would have its own magnetic field and would resist the influence of Jupiter's magnetic field, which in turn keeps the aurora steadier.
Turns out there's water all over the place in the solar system. How about that?
Astronomers have been able to view the same supernova in a distant part of the Universe several times due to the gravitational lensing effect of a cluster of galaxies in-between here and there. From Dennis Overbye in the NY Times:
Supernovas are among the most violent and rare events in the universe, occurring perhaps once per century in a typical galaxy. They outshine entire galaxies, spewing elemental particles like oxygen and gold out into space to form the foundations of new worlds, and leaving behind crushed remnants called neutron stars or black holes.
Because of the galaxy cluster standing between this star and the Hubble, "basically, we got to see the supernova four times," Dr. Kelly said. And the explosion is expected to appear again in another part of the sky in the next 10 years. Timing the delays between its appearances, he explained, will allow astronomers to refine measurements of how fast the universe is expanding and to map the mysterious dark matter that supplies the bulk of the mass and gravitational oomph of the universe.
Scientists expect the supernova to reappear in the next few years. Gravitational lensing was predicted by Einstein's general theory of relativity and as Overbye writes, "the heavens continue to light candles for Albert Einstein."
For Scientific American, Jen Christiansen tracks down where the iconic image on the cover of Joy Division's Unknown Pleasures came from. Designer Peter Saville found the image, a stacked graph of successive radio signals from pulsar CP 1919, in a 1977 astronomy encyclopedia but it actually originated in a 1970 Ph.D. thesis.
By now I had also combed through early discovery articles in scientific journals and every book anthology on pulsars I could get my hands on to learn more about early pulsar visualizations. The more I learned, the more this descriptor in the 1971 Ostriker caption began to feel significant; "computer-generated illustration." The charts from Bell at Mullard were output in real time, using analogue plotting tools. A transition in technology from analogue to digital seemed to have been taking place between the discovery of pulsars in 1967 to the work being conducting at Arecibo in 1968 through the early 1970's. A cohort of doctoral students from Cornell University seemed to be embracing that shift, working on the cutting edge of digital analysis and pulsar data output. One PhD thesis title from that group in particular caught my attention, "Radio Observations of the Pulse Profiles and Dispersion Measures of Twelve Pulsars," by Harold D. Craft, Jr. (September 1970).
When a star gets old and fat, it explodes in a supernova, leaving a neutron star in its wake. Neutron stars are heavily magnetized and incredibly dense, approximately two times the mass of the Sun packed into an area the size of the borough of Queens. That's right around the density of an atomic nucleus, which isn't surprising given that neutron stars are mostly composed of neutrons. A teaspoon of neutron star would weigh billions of tons.
A pulsar is a neutron star that quickly rotates. As the star spins, electromagnetic beams are shot out of the magnetic poles, which sweep around in space like a lighthouse light. Pulsars can spin anywhere from once every few seconds to 700 times/second, with the surface speed approaching 1/4 of the speed of light. These successive waves of electromagnetic pulses, arriving every 1.34 seconds, are what's depicted in the stacked graph. Metaphorical meanings of its placement on the cover of a Joy Division record are left as an exercise to the reader.
The results of a major new trial, published in the New England Journal of Medicine, indicate that for children who are at risk of developing a peanut allergy, eating peanuts greatly reduces the chance of an allergy. This is pretty huge news.
All the babies were between 4 and 11 months old when they were enrolled, and all had either an egg allergy, severe eczema, or both-putting them at high risk of a peanut allergy down the road. Indeed, 98 of them were already heading in that direction: They tested positive for mild peanut sensitivity in a skin-prick test. This meant that these babies were already churning out antibodies to the peanut protein. Eating peanuts in the future could set off an allergic reaction.
The team divided the babies into two groups. Half were to avoid eating peanut products until they were 5 years old. The other half received at least 6 grams of peanut protein a week, spread across at least three meals, until they were 5 years old. Bamba was the preferred offering, though picky eaters who rejected it got smooth peanut butter.
Around the 5th birthdays of the trial subjects came the big test. The children consumed a larger peanut portion than they were used to in one sitting, and the results were clear-cut. Among 530 children who had had a negative skin-prick test when they were babies, 14% who avoided peanuts were allergic to them, compared with 2% of those who'd been eating them. In the even higher risk group, the children who were sensitized, 35% of the peanut-avoiders were allergic versus just over 10% of the peanut eaters.
Even if further studies confirm these results, will American parents start feeding their infants peanuts? I don't know...there are lots of similarities to vaccines in play here.
Update: Somewhat related: children in developed countries might be growing up too clean, making them more likely to develop allergies.
The findings are the latest to support the "hygiene hypothesis," a still-evolving proposition that's been gaining momentum in recent years. The hypothesis basically suggests that people in developed countries are growing up way too clean because of a variety of trends, including the use of hand sanitizers and detergents, and spending too little time around animals.
As a result, children don't tend to be exposed to as many bacteria and other microorganisms, and maybe that deprives their immune system of the chance to be trained to recognize microbial friend from foe.
That may make the immune system more likely to misfire and overreact in a way that leads to allergies, eczema and asthma, Hesselmar says.
Host Hank Green of the SciShow looks at the anti-vaccination movement from a scientific perspective: why are US parents growing less likely to vaccinate their children?
In psychology, the search for these explanations is called "Explanatory Attribution" and different people have different "explanatory styles". Some people are more prone to blame themselves, while others search for an external event to blame. But one thing is clear: we are very bad at not blaming anything. It's not surprising that parents of children with autism, especially parents who notice a sudden loss of previous development, will search for a possible cause. And when the most significant recent event in the health of the child was a vaccination, as can be said for many moments in the life of a young American, we might identify that as a potential cause and deem that link worthy of further examination.
Now this, is completely logical. The problem is that over a dozen peer-reviewed papers have found no correlation between autism and the MMR vaccine, or any other vaccine for that matter. And yet, when you Google vaccines and autism, a fair number of the results claim that there is a link between the two, and that that link is being covered up either by the government or by big corporations. A parent, already experiencing frustration with the medical community's inability to tell them why this thing has happened to their child, will, on the internet, find a vibrant community of similarly frustrated people who share their values and experiences. These communities are full of anecdotes that draw connections between vaccines and autism. And so, unsurprisingly, some people become convinced that they have found the reason for their child's disability.
Once their mind has been made up, confirmation bias sets in. Confirmation bias is simply our tendency to more readily, and with less scrutiny, accept information, anecdotes, and world views that confirm our existing beliefs. And, again, it is a completely normal thing that every person does. Indeed, trying to convince someone that a previously held belief is incorrect has been proven to actually increase their affinity for that idea. And so a community is born, and the safety of vaccines is called into question. And once the procedure for getting a vaccine goes from the doctor telling you that it is now time for a vaccine -- and 99% of parents agreeing because that person went through medical school -- to it being a question to ponder, vaccination rates will go down.
The Spaceprob.es site tracks the active probes in operation in and around our solar system, from Voyager I (19.56 billion km from Earth) to the Artemis probes (358,000 km away). (via @BadAstronomer)
Update: Spaceprob.es now has a shop with posters, pillows, t-shirts, and stickers.
A recent paper by three climate scientists concludes there's a high risk of an unprecedented drought in the Southwest and Midwest United States later this century, even if we manage to get our carbon emissions under control. The scientists say it'll be drier in the Western US than at any point in the past 1000 years.
In the Southwest and Central Plains of Western North America, climate change is expected to increase drought severity in the coming decades. These regions nevertheless experienced extended Medieval-era droughts that were more persistent than any historical event, providing crucial targets in the paleoclimate record for benchmarking the severity of future drought risks. We use an empirical drought reconstruction and three soil moisture metrics from 17 state-of-the-art general circulation models to show that these models project significantly drier conditions in the later half of the 21st century compared to the 20th century and earlier paleoclimatic intervals. This desiccation is consistent across most of the models and moisture balance variables, indicating a coherent and robust drying response to warming despite the diversity of models and metrics analyzed. Notably, future drought risk will likely exceed even the driest centuries of the Medieval Climate Anomaly (1100-1300 CE) in both moderate (RCP 4.5) and high (RCP 8.5) future emissions scenarios, leading to unprecedented drought conditions during the last millennium.
Eric Holthaus has the layperson's explanation of the study and its implications.
Smerdon's study is the first to examine the future risk of "megadrought" in the southwest and central United States in the context of historical episodes of drought in the same regions. Smerdon's study suggests that the coming years are likely to see droughts worse than the epic dry periods that are thought to have caused profound changes to human settlement in the region over the last millennium.
"They're 'mega' because they are droughts that lasted in these regions for multiple decades," said Smerdon in an interview with Slate. "We haven't seen anything like this since at least the 1400s." In comparison, the current California drought is four years old, though drought has been present in most of the last 15 years somewhere in the West.
Update: This NASA video provides a quick overview of this study and what it means for our climate.
From the Physics arXiv Blog, a list of paradoxes in modern cosmological physics, i.e. areas where theory and observation disagree, sometimes by a whopping 120 orders of magnitude.
Perhaps the most dramatic, and potentially most important, of these paradoxes comes from the idea that the universe is expanding, one of the great successes of modern cosmology. It is based on a number of different observations.
The first is that other galaxies are all moving away from us. The evidence for this is that light from these galaxies is red-shifted. And the greater the distance, the bigger this red-shift.
Astrophysicists interpret this as evidence that more distant galaxies are travelling away from us more quickly. Indeed, the most recent evidence is that the expansion is accelerating.
What's curious about this expansion is that space, and the vacuum associated with it, must somehow be created in this process. And yet how this can occur is not at all clear. "The creation of space is a new cosmological phenomenon, which has not been tested yet in physical laboratory," says Baryshev.
What's more, there is an energy associated with any given volume of the universe. If that volume increases, the inescapable conclusion is that this energy must increase as well. And yet physicists generally think that energy creation is forbidden.
Baryshev quotes the British cosmologist, Ted Harrison, on this topic: "The conclusion, whether we like it or not, is obvious: energy in the universe is not conserved," says Harrison.
This is a problem that cosmologists are well aware of. And yet ask them about it and they shuffle their feet and stare at the ground. Clearly, any theorist who can solve this paradox will have a bright future in cosmology.
Luckily, these paradoxes are an opportunity to do some great science.
Nothing is faster than the speed of light. But compared to the unimaginable size of the Universe, light is actually extremely slow. This video is 45 minutes long and during that time, a photon emitted from the Sun1 will only travel through a portion of our solar system.
In our terrestrial view of things, the speed of light seems incredibly fast. But as soon as you view it against the vast distances of the universe, it's unfortunately very slow. This animation illustrates, in realtime, the journey of a photon of light emitted from the sun and traveling across a portion of the solar system.
It takes light more than 43 minutes to travel to Jupiter and even to travel the diameter of the Sun takes 4.6 seconds. (thx, andy)
Administrators at Palm Desert High School in California have banned 66 students who never got measles vaccinations.
"I think some parents see it as a personal choice, like homeschooling. But when you choose not to vaccinate, you're putting other children at risk." From WaPo: Why this baby's mom is so angry at the anti-vaxxers.
"I respect people's choices about what to do with their kids, but if someone's kid gets sick and gets my kid sick, too, that's a problem." A Marin County father has demanded that his district keep unvaccinated kids out of school.
Vox: How an Amish missionary caused 2014's massive measles outbreak.
Bonus tweet: "If my kid can't bring peanut butter to school, yours shouldn't be able to bring preventable diseases."
Using ice-penetrating radar and ice cores, NASA has been able to map the layers in the Greenland ice sheet.
This new map allows scientists to determine the age of large swaths of Greenland's ice, extending ice core data for a better picture of the ice sheet's history. "This new, huge data volume records how the ice sheet evolved and how it's flowing today," said Joe MacGregor, a glaciologist at The University of Texas at Austin's Institute for Geophysics and the study's lead author.
Greenland's ice sheet is the second largest mass of ice on Earth, containing enough water to raise ocean levels by about 20 feet. The ice sheet has been losing mass over the past two decades and warming temperatures will mean more losses for Greenland. Scientists are studying ice from different climate periods in the past to better understand how the ice sheet might respond in the future.
One way of studying this distant past is with ice cores. These cylinders of ice drilled from the ice sheet hold evidence of past snow accumulation and temperature and contain impurities like dust and volcanic ash that were carried by snow that accumulated and compacted over hundreds of thousands of years. These layers are visible in ice cores and can be detected with ice-penetrating radar.
Ice-penetrating radar works by sending radar signals into the ice and recording the strength and return time of reflected signals. From those signals, scientists can detect the ice surface, sub-ice bedrock and layers within the ice.
New techniques used in this study allowed scientists to efficiently pick out these layers in radar data. Prior studies had mapped internal layers, but not at the scale made possible by these newer, faster methods. Another major factor in this study was the amount of Greenland IceBridge has measured.
It's amazing that the detectors and data analysis are sensitive enough to pick out different layers in the ice just from radar. (via @ptak)
From the Russian Space Agency, a video of what the sky would look like if the Sun were replaced by some other stars. It starts off with the binary star system of Alpha Centuri, but watch until the end for Polaris, which has a radius 46 times that of the Sun.
See also the view from Earth of different planets replacing the Moon and imagining Earth with Saturn's rings.
A map published by Bernard Porter in 1939 depicting physics as a landmass through which several rivers corresponding to the main branches (light, sound, heat, etc.) run and converge into one.
This simulator evolves increasingly effective walking creatures through genetic algorithms. After each round, the winners are sent through to the next round and copied by the rest of the competitors, with mutations introduced. At first, the pace of improvement is swift -- two orders of magnitude within 100 generations -- but slows pretty dramatically after that. (via @nickrichter)
Scientists have discovered the first promising new antibiotic in 25 years. And even better, says Ed Yong, is that the antibiotic in question is "resistant to resistance".
A team of scientists led by Kim Lewis from Northeastern University have identified a new antibiotic called teixobactin, which kills some kinds of bacteria by preventing them from building their outer coats. They used it to successfully treat antibiotic-resistant infections in mice. And more importantly, when they tried to deliberately evolve strains of bacteria that resist the drug, they failed. Teixobactin appears resistant to resistance.
Bacteria will eventually develop ways of beating teixobactin -- remember Orgel -- but the team are optimistic that it will take decades rather than years for this to happen. That buys us time.
...and also that the process by which teixobactin was discovered is the real breakthrough:
Teixobactin isn't even the most promising part of its own story. That honour falls on the iChip-the tool that the team used to discover the compound. Teixobactin is a fish; the iChip is the rod. Having the rod guarantees that we'll get more fish-and we desperately need more.
Buzzfeed's Carolyn Kylstra asked some scientists and medical professionals about juice cleanses and while they are (mostly) harmless, they definitely don't do any of the magical things you think they do, like flush the toxins out of your body or reset your system.
"I don't know why someone would do a juice cleanse," Dr. John Buse, M.D., Ph.D., chief of the division of endocrinology at the University of North Carolina at Chapel Hill, told BuzzFeed Life. "There's very little evidence that it does anything good for you."
And it definitely won't "rid your body of toxins." That really is what your liver (and your kidneys and intestines) is for. "I don't like the marketing around juice cleanses," Eric Ravussin, Ph.D., associate executive director for clinical science at Pennington Biomedical Research Center, told BuzzFeed Life. "That it's going to detox and mobilize all these toxins and all that -- this is pure marketing."
Update: From the NY Times in 2009, Flush Those Toxins! Eh, Not So Fast. The last paragraph makes me angry:
Still, many people swear by these programs. Denise Whitney, 37, a registered nurse and mother of three in Traverse City, Mich., did the Master Cleanse over a seven-day period, plus six days of pre and post cleanse, which included consuming copious amounts of organic juice, fruit and vegetables. "With all the fast food, preservatives, chemicals in our food, it seems impossible that our bodies are not loaded with toxins," Ms. Whitney said, adding that she plans to repeat it in the next few months. "I had more energy during this cleanse than I can ever remember having."
Can we get this nurse unregistered, please? FFS. But at The Guardian, Oliver Burkeman cautions against over-debunking.
We live in the Age of Debunking: no sooner has somebody made a false or hyperbolic claim online (resulting in clicks) than someone else announces, with an air of triumph, that they've debunked it (resulting in clicks). I plead guilty. And often enough, debunking is a noble pursuit: the idea that we only use 10% of our brains, to pick one example, is flat wrong, and people who believe it ought to be corrected. No convincing evidence of a Benghazi conspiracy has ever been unearthed. Marie Antoinette almost certainly didn't say "let them eat cake".
But the internet's enthusiasm for a vigorous debunking now frequently spills over into what you might call the pseudo-debunk. Sometimes, this involves cynically claiming you're debunking when you're really just disagreeing -- thereby implying that your opinion is more than mere opinion; it's "the facts".
Update: Tara Fuller of Greatist writes I've Tried Almost Every Cleanse. Here's Why I'll Never Do One Again:
2. Eating fruit is much healthier than drinking it.
While juice cleanses may seem like an easy way to load up on vitamins and minerals, they're often full of added sugars and devoid of the good stuff (like fiber and antioxidants). Juicing fruits does tend to preserve some vitamins, but why guzzle several hundred calories worth of fruit when you can eat one serving and actually feel full? Plus, all that juice can actually lead to type 2 diabetes-whereas eating fruit reduces the risk!
(via @fakejoshstein & @neversent & @alainabrowne)
The Hubble Space Telescope was launched 25 years ago, and to start the celebration, NASA has released a pair of images that actually did make this space nerd's jaw drop. The first is an update of a classic: a much sharper photo of the so-called Pillars of Creation:
Although NASA's Hubble Space Telescope has taken many breathtaking images of the universe, one snapshot stands out from the rest: the iconic view of the so-called "Pillars of Creation." The jaw-dropping photo, taken in 1995, revealed never-before-seen details of three giant columns of cold gas bathed in the scorching ultraviolet light from a cluster of young, massive stars in a small region of the Eagle Nebula, or M16.
The second image isn't so immediately amazing but is my favorite of the two. It's a photo of half of the Andromeda galaxy, the big galaxy closest to our own in distance but also in rough size and shape. Here's a very very scaled-down version of it:
The largest NASA Hubble Space Telescope image ever assembled, this sweeping view of a portion of the Andromeda galaxy (M31) is the sharpest large composite image ever taken of our galactic neighbor. Though the galaxy is over 2 million light-years away, the Hubble telescope is powerful enough to resolve individual stars in a 61,000-light-year-long section of the galaxy's pancake-shaped disk. It's like photographing a beach and resolving individual grains of sand. And, there are lots of stars in this sweeping view -- over 100 million, with some of them in thousands of star clusters seen embedded in the disk.
The original image is 1500 megapixels (1.5 gigapixels!), which is so big that you'd need 600 HD televisions to display the whole thing. But if you take the biggest reasonable size available for download (100 megapixels) and zoom in on it, you get this:
That looks like JPEG compression noise, right? Nope, each one of those dots is a star...some of the 100 million individual stars that can be seen in the full image.
That's right, Keanu. Whoa. For an even closer look, check out this annotated close-up released by NASA:
If you're curious and feel like crashing your browser and/or Photoshop a bunch of times (I did not), the full-res Andromeda images are available here. And Phil Plait writes much more joyfully and knowledgeably about these images than I do...go take a look at his Pillars of Creation and Andromeda posts.
Update: Rob Griffiths took 50+ photos from the Hubble web site and made them into Retina iMac-sized wallpapers. (via @djacobs)
From astrophysicist Robert Simpson, a tour of the Universe from humans to the largest structure of the Universe. The piece is full of interesting little bits like:
The average female is 1.62 metres [tall] -- that's 5.4 light-nanoseconds.
If the Earth was a beach ball then all life on Earth exists within just 1mm around the surface.
Out by Pluto, the Sun itself is has dimmed to look like an other stars.
If the Sun was a blood cell then the Milky Way is the size of Europe.
See also Steven Strogatz on the Sagan Planet Walk in Ithaca, NY.
As you stroll from one to another, you can't help noticing that the first four planets are really close together. It takes a few seconds, a few tens of steps, to walk from the Sun to Mercury and then on to Venus, Earth and Mars. By contrast, Jupiter is a full two-minute walk down the block, just past Moosewood Restaurant, waiting for someone to stop by and admire it. The remaining planets are even lonelier, each marooned in its own part of town. The whole walk, from the Sun to Pluto, is about three-quarters of a mile long and takes about 15 minutes.
My favorite detail: they added a new station to the Sagan Walk, the star nearest to our solar system. It's in Hawaii.
As a young graduate student, Brian Greene caught the very beginning of the superstring revolution in physics. 30 years later, Greene provides an accessible overview of string theory's current status.
While spectacularly successful at predicting the behavior of atoms and subatomic particles, the quantum laws looked askance at Einstein's formulation of gravity. This set the stage for more than a half-century of despair as physicists valiantly struggled, but repeatedly failed, to meld general relativity and quantum mechanics, the laws of the large and small, into a single all-encompassing description.
Such was the case until December 1984, when John Schwarz, of the California Institute of Technology, and Michael Green, then at Queen Mary College, published a once-in-a-generation paper showing that string theory could overcome the mathematical antagonism between general relativity and quantum mechanics, clearing a path that seemed destined to reach the unified theory.
The idea underlying string unification is as simple as it is seductive. Since the early 20th century, nature's fundamental constituents have been modeled as indivisible particles-the most familiar being electrons, quarks and neutrinos-that can be pictured as infinitesimal dots devoid of internal machinery. String theory challenges this by proposing that at the heart of every particle is a tiny, vibrating string-like filament. And, according to the theory, the differences between one particle and another -- their masses, electric charges and, more esoterically, their spin and nuclear properties -- all arise from differences in how their internal strings vibrate.
A major study conducted by the Harvard School of Public Health has found a significant link between autism and the exposure of the mother to high levels of air pollution during the third trimester of pregnancy.
Researchers focused on 1,767 children born from 1990 to 2002, including 245 diagnosed with autism. The design of the study and the results rule out many confounding measures that can create a bias, Weisskopf said. The researchers took into account socioeconomic factors that can influence exposure to pollution or play a role in whether a child is diagnosed with autism.
The fact that pollution caused problems only during pregnancy strengthened the findings, since it's unlikely other factors would have changed markedly before or after those nine months, he said in a telephone interview.
The ultimate cause of autism remains a mystery in most cases, said Charis Eng, chairwoman of the Lerner Research Institute's Genomic Medicine Institute at the Cleveland Clinic in Ohio. While the Harvard study isn't definitive and the findings could be coincidental, it's not likely given the large size and the precise results, she said in a telephone interview.
"The truth is there has to be gene and environmental interactions," said Eng, who wasn't involved in the study. "I suspect the fetus already had the weak autism spectrum disorder genes, and then the genes and the environment interacted."
It would be a huge help (and I am not in any way being facetious about this) if Jenny McCarthy and all the other celebrity "vaccines cause autism" folks threw their weight behind cleaning up pollution the way they attacked vaccination. Redeem yourselves. (via @john_overholt)
There's no blue pigment present in the wings of the morpho butterfly. So where does that shimmering brilliant blue color come from? It's an instance of structural color, where the physical structure of the surface scatters or refracts only certain wavelengths of light...in this case, blue.
Eye color is another example of structural color in action. Eyes contain brown pigments but not blue. Blue, green, and hazel eyes are caused by Rayleigh scattering, the same phenomenon responsible for blue skies and red sunsets. Blue eyes and blue skies arise from the same optical process...that's almost poetic. (thx, jared)
According to a recent paper, as little as 12 seconds of video is enough to identify a particular shooter's personal "motion signature".
Here's a way to shake off anonymity - literally. Footage from wearable cameras contains a "motion signature" unique to you. The discovery could identify police wearing body cameras, but also let authorities single out protesters uploading footage, say.
Physics World, the magazine of the Institute of Physics, has named their 2014 Breakthrough of the Year and nine runners-up. The top spot goes to the ESA's Rosetta mission for landing on a comet.
By landing the Philae probe on a distant comet, the Rosetta team has begun a new chapter in our understanding of how the solar system formed and evolved -- and ultimately how life was able to emerge on Earth. As well as looking forward to the fascinating science that will be forthcoming from Rosetta scientists, we also acknowledge the technological tour de force of chasing a comet for 10 years and then placing an advanced laboratory on its surface.
The other nine achievements, which you can click through to read about, are:
Quasar shines a bright light on cosmic web
Neutrinos spotted from Sun's main nuclear reaction
Laser fusion passes milestone
Electrons' magnetic interactions isolated at long last
Disorder sharpens optical-fibre images
Data stored in magnetic holograms
Lasers ignite 'supernovae' in the lab
Quantum data are compressed for the first time
Physicists sound-out acoustic tractor beam
From Quora, an answer to the question "If we pour water on the sun with a bucket as big as the sun, will the sun be extinguished?"
The probable answer is "no." The Sun involves a special type of fire that is able to "burn" water, and so it will just get hotter, and six times brighter.
Water is 89% oxygen BY MASS. And the Sun's overall density is 1.4 times that of water. So if you have a volume of water the VOLUME of the Sun, it will have 1/1.4 = 0.71 times the mass of the Sun, and this mass will be .71*.89 = 63% of a solar mass of oxygen and 8% of a solar mass of hydrogen. The Sun itself is 0.74 solar masses of hydrogen and 0.24 solar masses of helium.
So you end up with a 1.7 solar mass star with composition 48% hydrogen, 37% oxygen, and 14% helium (with 1% heavier elements).
Now, will such a star burn? Yes, but not with the type of proton-proton fusion the Sun uses. A star 1.7 times the mass of the Sun will heat up and burn almost entirely by the CNO fusion cycle, after making some carbon and nitrogen to go along with all the oxygen you've started with. So with CNO fusion and that mass you get a type F0 star with about 1.3 times the radius and 6 times the luminosity of the present Sun, and a temperature somewhat hotter than the Sun (7200 K vs. the Sun's 5800 K). It will be bluish-white, with more UV. That, along with that 6 times heat input, will cause the Earth's biosphere to be fried, and oceans to probably boil.
Well, we probably shouldn't do that then. (via gizmodo)
Whilst roving about Mars, Curiosity has slowly but surely racked up evidence for a past Mars that was warm, wet, and possibly habitable.
John P. Grotzinger of Caltech, the project scientist for the mission, reported at a news conference on Monday that the rover's yearlong trek to Mount Sharp provided strong new evidence that Gale Crater had large lakes, rivers and deltas, on and off, for millions to tens of millions of years. The geology shows that even when the surface water dried up, plenty of water would have remained underground, he said.
Moreover, the team concluded, numerous deltalike and lakelike formations detected by orbiting satellites are almost certainly the dried remains of substantial ancient lakes and deltas. None of this proves that life existed on the planet, but the case for an early Mars that was ripe and ready for life has grown stronger.
"As a science team, Mars is looking very attractive to us as a habitable planet," Dr. Grotzinger said in an interview. "Not just sections of Gale Crater and not just a handful of locations, but at different times around the globe."
See also the interactive 28 Months on Mars.
Update: And right on cue, Curiosity has recorded a two-month-long methane burst on Mars. One explanation for the methane is that it's a waste product of living organisms.
The presence of methane is significant because the gas cannot exist for long. Calculations indicate that sunlight and chemical reactions in the Martian atmosphere would break up the molecules within a few hundred years, so any methane there now must have been created recently.
It could have been created by a geological process known as serpentinization, which requires both heat and liquid water. Or it could be a product of life in the form of microbes known as methanogens, which release methane as a waste product.
Even if the explanation for the methane turns out to be geological, the hydrothermal systems would still be prime locations to search for signs of life.
Update: And now Curiosity has found "biologically useful nitrogen" on Mars.
There is no evidence to suggest that the fixed nitrogen molecules found by the team were created by life. The surface of Mars is inhospitable for known forms of life. Instead, the team thinks the nitrates are ancient, and likely came from non-biological processes like meteorite impacts and lightning in Mars' distant past.
Features resembling dry riverbeds and the discovery of minerals that form only in the presence of liquid water suggest that Mars was more hospitable in the remote past. The Curiosity team has found evidence that other ingredients needed for life, such as liquid water and organic matter, were present on Mars at the Curiosity site in Gale Crater billions of years ago.
"Finding a biochemically accessible form of nitrogen is more support for the ancient Martian environment at Gale Crater being habitable," said Jennifer Stern of NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Update: The analysis of a year of weather and soil data collected by Curiosity indicates that a small amount of liquid water could exist below the surface of Mars.
Martian weather and soil conditions that NASA's Curiosity rover has measured, together with a type of salt found in Martian soil, could put liquid brine in the soil at night.
Perchlorate identified in Martian soil by the Curiosity mission, and previously by NASA's Phoenix Mars Lander mission, has properties of absorbing water vapor from the atmosphere and lowering the freezing temperature of water. This has been proposed for years as a mechanism for possible existence of transient liquid brines at higher latitudes on modern Mars, despite the Red Planet's cold and dry conditions.
New calculations were based on more than a full Mars year of temperature and humidity measurements by Curiosity. They indicate that conditions at the rover's near-equatorial location were favorable for small quantities of brine to form during some nights throughout the year, drying out again after sunrise. Conditions should be even more favorable at higher latitudes, where colder temperatures and more water vapor can result in higher relative humidity more often.
The Guardian and other media outlets have translated this news into Nasa's Curiosity rover finds water below surface of Mars even though NASA's release clearly states "we have not detected brines". Come on, guys.
A shell found in the 1890s was recently found to have what scientists are calling the world's oldest "abstract marking", a 500,000-year-old etching made by Homo erectus, an extinct ancestor of modern humans.
Close inspection under the microscope suggested that the engraving was intentional. The weathering patterns of the grooves, each of which is about 1 centimetre long, show signs of significant ageing, and there are no gaps between turns, indicating that the maker paid attention to detail. He or she probably made the engraving on a fresh shell, and the newly made etching would have resembled white lines on a dark canvas, Joordens' team notes. Sand grains still embedded in the shell were dated to around 500,000 years ago.
It turns out if you break some kinds of slow-growing corals into tiny pieces, these microfragments grow much much faster than usual, even 25-50 times faster.
"Part of the coral had grown over the back side and had attached to the bottom of the aquarium," he said. When he grabbed it, "it broke off and left two or three polyps behind. I thought I just killed those. But oh, well, I moved the puck over."
A week later he happened to glance at the abandoned polyps -- the individual hydra-shaped, genetically identical organisms that make up a coral colony -- on the bottom of the aquarium. "I noticed that those one to three polyps were now five to seven polyps," he said. "They not only had lived -- they had grown and had doubled in size."
It was, he said, "my eureka mistake." He cut a few more polyps from the original colony and placed them on other pucks. "And they grew like crazy. The coral seems to want to repair itself quickly and grow back over its lost ground before something else takes its territory."
Both this and the article about the quickly regenerating corals I posted last month seem to hinge on a realization scientists have had recently about coral: what matters most is the surface area, not the volume. You look at a massive brain coral and you think the whole thing is the organism, but most of it is just a base for the thin layer of stuff coating it that actually matters.
A new analysis of the genomes of two extinct human species (Neanderthals and Denisovans) shows more clearly that they interbred with our species of human, contributing 2-4% of our modern genomes in some cases.
"What it begins to suggest is that we're looking at a Lord of the Rings-type world -- that there were many hominid populations," says Mark Thomas, an evolutionary geneticist at University College London who was at the meeting but was not involved in the work.
But, more interestingly, the analysis also detected the Denisovans also bred with an as-yet-unknown species of humans.
The Denisovan genome indicates that the population got around: Reich said at the meeting that as well as interbreeding with the ancestors of Oceanians, they also bred with Neanderthals and the ancestors of modern humans in China and other parts of East Asia. Most surprisingly, Reich said, the genomes indicate that Denisovans interbred with yet another extinct population of archaic humans that lived in Asia more than 30,000 years ago -- one that is neither human nor Neanderthal.
Is this the first time a new human species has been discovered through DNA evidence alone?
Google Research built an interactive periodic table of the elements where you can see the relative amounts of the elements as found in the human body, in the sea, and, most interestingly, by the number of mentions in books.
If you've ever wondered why the periodic table is shaped the way it is, click on "electrons" under "Shape" and pay attention to the number of electrons in the outer shells in each column of elements. Amazingly, when Dmitri Mendeleev and German chemist Julius Meyer published the first periodic tables in 1869/1870, the elements were organized only by atomic weights and chemical properties; they didn't know what an electron was and certainly weren't aware of quantum shells of electrons. (via @djacobs)
Photographer Ernie Button photographs the dried remains of single malt scotch whiskies, which end up looking like desolate landscapes on distant worlds.
Curious as to how these patterns were formed by some kinds of whiskey but not others, Button reached out to an engineering professor at Princeton.
Dr. Stone's group found that the key difference in whisky is that unlike coffee, it consists of two liquids -- water and ethyl alcohol. The alcohol evaporates more quickly, and as the fraction of water increases, the surface tension of the droplet changes, an effect first noticed in the 19th century by an Italian scientist, Carlo Marangoni. That, in turn, generates complex flows that contribute to the patterns Mr. Button photographed.
"Here, they actually looked at what happens when you change the fluids that are drying," said Dr. Yunker, who is soon heading to the Georgia Institute of Technology as a physics professor, "and they found some very neat effects." (That would be neat in the usual sense of "cool and intriguing" and not as in "I'll have my whisky neat.")
Now this is an ambitious Kickstarter project: Lunar Mission One wants to send an unmanned probe to an unexplored area of the Moon, land on the surface, drill a hole at least 20 meters in depth to analyze geological composition of the Moon, and then drop a time capsule in the hole that will last 1 billion years. That's. Insane.
We're going to use pioneering technology to drill down to a depth of at least 20m -- 10 times deeper than has ever been drilled before -- and potentially as deep as 100m. By doing this, we will access lunar rock dating back up to 4.5 billion years to discover the geological composition of the Moon, the ancient relationship it shares with our planet and the effects of asteroid bombardment. Ultimately, the project will improve scientific understanding of the early solar system, the formation of our planet and the Moon, and the conditions that initiated life on Earth.
The Rosetta mission has opened the way for a new era of pioneering space exploration and demonstrates the public appetite to engage with the secrets of the solar system. We want this to be a truly international mission that everyone everywhere can get involved in, so we are using Kickstarter to finance the next phase of development. This is your chance to be part of Lunar Mission One and to reserve your place in space. Your pledge will reserve you a digital memory box that will be buried in the moon during the mission as part of a 21st Century time capsule.
This is a great way to think about how big the planets of our solar system are: in terms of fruits.
(via boing boing)
A European Space Agency landing craft the size of a washing machine is scheduled to land on a comet tomorrow, November 12, 2014. How cool is that?
Never before has a space mission put a lander on a comet. But the European Space Agency (ESA) plans to change that. Its Rosetta craft has been orbiting comet 67P/Churyumov-Gerasimenko since August and is set to release the washing-machine-sized lander, Philae, on 12 November. This would set in motion a nail-biting seven-hour fall designed to deliver Philae to a landing site called Agilkia on the comet's surface. Philae is programmed to beam data and images back to Earth to help scientists to understand comets, including whether these conglomerations of ice, rock and dust supplied our planet with water and other building blocks of life when they smashed into it billions of years ago.
You can watch the landing live (or here too)...touch down on the comet's surface is scheduled for 11:03 AM EST. Here's a full rundown of the events on landing day. Good luck, Philae!
Update: Randall Munroe of XKCD is live drawing the landing.
Kip Thorne is a theoretical physicist who did some of the first serious work on the possibility of travel through wormholes. Several years ago, he resigned as the Feynman Professor of Theoretical Physics from Caltech in part to make movies. To that end, Thorne acted as Christopher Nolan's science advisor for Interstellar. As a companion to the movie, Thorne wrote a book called The Science of Interstellar.
Yet in The Science of Interstellar, Kip Thorne, the physicist who assisted Nolan on the scientific aspects of Interstellar, shows us that the movie's jaw-dropping events and stunning, never-before-attempted visuals are grounded in real science. Thorne shares his experiences working as the science adviser on the film and then moves on to the science itself. In chapters on wormholes, black holes, interstellar travel, and much more, Thorne's scientific insights -- many of them triggered during the actual scripting and shooting of Interstellar -- describe the physical laws that govern our universe and the truly astounding phenomena that those laws make possible.
Wired has a piece on how Thorne and Nolan worked together on the film. Phil Plait was unimpressed with some of the science in the movie, although he retracted some of his criticism. If you're confused by the science or plot, Slate has a FAQ.
Update: Well, well, the internet's resident Science Movie Curmudgeon Neil deGrasse Tyson actually liked the depiction of science in Interstellar. In particular: "Of the leading characters (all of whom are scientists or engineers) half are women. Just an FYI." (via @thoughtbrain)
Update: What's wrong with "What's Wrong with the Science of Movies About Science?" pieces? Plenty says Matt Singer.
But a movie is not its marketing; regardless of what 'Interstellar''s marketing said, the film itself makes no such assertions about its scientific accuracy. It doesn't open with a disclaimer informing viewers that it's based on true science; in fact, it doesn't open with any sort of disclaimer at all. Nolan never tells us exactly where or when 'Interstellar' is set. It seems like the movie takes place on our Earth in the relatively near future, but that's just a guess. Maybe 'Interstellar' is set a million years after our current civilization ended. Or maybe it's set in an alternate dimension, where the rules of physics as Phil Plait knows them don't strictly apply.
Or maybe 'Interstellar' really is set on our Earth 50 years in the future, and it doesn't matter anyway because 'Interstellar' is a work of fiction. It's particularly strange to see people holding 'Interstellar' up to a high standard of scientific accuracy because the movie is pretty clearly a work of stylized, speculative sci-fi right from the start.
This is a time lapse of the surface of the Sun, constructed of more than 17,000 images taken by the Solar Dynamics Observatory from Oct 14 to Oct 30, 2014. The bright area that starts on the far right is sunspot AR 12192, the largest observed sunspot since 1990.
The sunspot is about 80,000 miles across (as wide as 10 Earths) and it's visible from Earth with the naked eye. Best viewed as large as possible...I bet this looks amazing on the new retina iMac. (via @pageman)
A children's book about space featuring information graphics illustrated by the completely awesome Jennifer Daniel!?
The third in a visually stunning series of information graphics that shows just how interesting and humorous scientific information can be. Complex facts about space are reinterpreted as stylish infographics that astonish, amuse, and inform.
INSTANT PURCHASE. February 2015 cannot come fast enough.
In 2013, a group of researchers published a paper called Collective Motion of Moshers at Heavy Metal Concerts. The paper's abstract reads:
Human collective behavior can vary from calm to panicked depending on social context. Using videos publicly available online, we study the highly energized collective motion of attendees at heavy metal concerts. We find these extreme social gatherings generate similarly extreme behaviors: a disordered gas-like state called a mosh pit and an ordered vortex-like state called a circle pit. Both phenomena are reproduced in flocking simulations demonstrating that human collective behavior is consistent with the predictions of simplified models.
The authors built an interactive mosh pit simulation based on their simplified models. You can try it out right here:
If you believe in gravity, then you know that if you remove air resistance, a bowling ball and a feather will fall at the same rate. But seeing it actually happen, in the world's largest vacuum chamber (122 feet high, 100 feet in diameter), is still a bit shocking.
In the late 1500s, Galileo was the first to show that the acceleration due to the Earth's gravity was independent of mass with his experiment at the Leaning Tower of Pisa, but that pesky air resistance caused some problems. At the end of the Apollo 15 mission, astronaut David Scott dropped a hammer and a feather in the vacuum on the surface of the Moon:
In a rare bit of good news about climate change, it appears that some types of coral have the ability to recover more quickly from trauma caused by rising ocean temperatures (archive).
At Palau in the western Pacific, a survey completed just three years after the 1998 bleaching event showed more coral had recovered on reefs within protected bays and on deep slopes.
Scientists suggest this is because heat and light serve as a double-whammy to coral health and corals that hang out in shady zones will escape the scorching combination, upping the chances that remnants will survive.
Seven years after the bleaching event, some reefs had regained nearly 40 per cent of their corals, with two species of plate-like acroporid coral, A. digitifera and A. hyacinthus, particularly prevalent. "We sampled plating coral colonies there a few years ago and found them to be pool-table size," says Stephen Palumbi, Director of Stanford University's Hopkins Marine Station, in Pacific Grove, California, US.
Today's Google Doodle honors Jonas Salk on what would have been his 100th birthday. Salk developed the first successful polio vaccine in 1955 and was hailed as a hero for it.
On April 12, 1955, Dr. Thomas Francis, Jr., of the University of Michigan, the monitor of the test results, "declared the vaccine to be safe and effective." The announcement was made at the University of Michigan, exactly 10 years to the day after the death of President Roosevelt. Five hundred people, including 150 press, radio, and television reporters, filled the room; 16 television and newsreel cameras stood on a long platform at the back; and 54,000 physicians, sitting in movie theaters across the country, watched the broadcast on closed-circuit television. Eli Lilly and Company paid $250,000 to broadcast the event. Americans turned on their radios to hear the details, department stores set up loudspeakers, and judges suspended trials so that everyone in the courtroom could hear. Europeans listened on the Voice of America. Paul Offit writes about the event:
"The presentation was numbing, but the results were clear: the vaccine worked. Inside the auditorium Americans tearfully and joyfully embraced the results. By the time Thomas Francis stepped down from the podium, church bells were ringing across the country, factories were observing moments of silence, synagogues and churches were holding prayer meetings, and parents and teachers were weeping. One shopkeeper painted a sign on his window: Thank you, Dr. Salk. 'It was as if a war had ended', one observer recalled."
Because of Salk's vaccine and subsequent vaccines, the US has been polio-free since 1979.
Lockheed Martin is in the process of developing a compact fusion reactor they say could revolutionize the world's energy industry.
Dubbed the compact fusion reactor (CFR), the device is conceptually safer, cleaner and more powerful than much larger, current nuclear systems that rely on fission, the process of splitting atoms to release energy. Crucially, by being "compact," Lockheed believes its scalable concept will also be small and practical enough for applications ranging from interplanetary spacecraft and commercial ships to city power stations. It may even revive the concept of large, nuclear-powered aircraft that virtually never require refueling-ideas of which were largely abandoned more than 50 years ago because of the dangers and complexities involved with nuclear fission reactors.
The key difference in Lockheed's approach seems to be the configuration of the magnetic field containing the reaction:
The CFR will avoid these issues by tackling plasma confinement in a radically different way. Instead of constraining the plasma within tubular rings, a series of superconducting coils will generate a new magnetic-field geometry in which the plasma is held within the broader confines of the entire reaction chamber. Superconducting magnets within the coils will generate a magnetic field around the outer border of the chamber. "So for us, instead of a bike tire expanding into air, we have something more like a tube that expands into an ever-stronger wall," McGuire says. The system is therefore regulated by a self-tuning feedback mechanism, whereby the farther out the plasma goes, the stronger the magnetic field pushes back to contain it. The CFR is expected to have a beta limit ratio of one. "We should be able to go to 100% or beyond," he adds.
Charles Seife, who wrote a book about the history of fusion, is skeptical of Lockheed's claims.
This week, Lockheed Martin supposedly managed to achieve a "breakthrough" in nuclear fusion that has gotten a lot of media attention. As Charles Seife points out, it did so "without having built a prototype device that, you know, fuses things on an appreciable scale. It's a stunning assertion, even by fusion-research standards. But a quick look at the defense contractor's ambitious plan-a working reactor in five years-already shows the dream fraying around the edges. A year and a half ago, the company promised that fusion was four years away, meaning that the schedule is already slipping. Negative one years of progress in 20 months is, sadly, business as usual for fusion. At this rate, it'll take Lockheed Martin at least a decade before the natural endpoint: desperately spinning victory out of an underwhelming result generated by a machine whose performance comes nowhere near predictions-and which brings us no closer to actually generating energy from a fusion reaction."
This is fun...Aatish Bhatia maps out the forces and motions involved in doing an ollie on a skateboard.
It's a neat piece of science art, and it also tells us something interesting. The arrows show us that the force on the skateboard is constantly changing, both in magnitude as well as in direction. Now the force of gravity obviously isn't changing, so the reason that these force arrows are shrinking and growing and tumbling around is that the skater is changing how their feet pushes and pulls against the board. By applying a variable force that changes both in strength and direction, they're steering the board.
Gorgeous videos of chemical reactions (precipitation, bubbling, crystallization, etc.). I think the metal displacement reaction video is my favorite:
The sound made by the Krakatoa volcanic eruption in 1883 was so loud it ruptured eardrums of people 40 miles away, travelled around the world four times, and was clearly heard 3,000 miles away.
Think, for a moment, just how crazy this is. If you're in Boston and someone tells you that they heard a sound coming from New York City, you're probably going to give them a funny look. But Boston is a mere 200 miles from New York. What we're talking about here is like being in Boston and clearly hearing a noise coming from Dublin, Ireland. Travelling at the speed of sound (766 miles or 1,233 kilometers per hour), it takes a noise about 4 hours to cover that distance. This is the most distant sound that has ever been heard in recorded history.
A much much smaller eruption occurred recently in Papua New Guinea. From the video, you can get a tiny sense of the sonic damage unleashed by Krakatoa:
Holy smoking Toledos indeed. On Reddit, a user details how loud a Saturn V rocket is and what the effects would be at different distances. At very close range, the sound from the Saturn V measures an incredible 220 db, loud enough to melt concrete just from the sound.
At 500 meters, 155 db you would experience painful, violent shaking in your entire body, you would feel compressed, as though deep underwater. Your vision would blur, breathing would be very difficult, your eardrums are obviously a lost cause, even with advanced active noise cancelling protection you could experience permanent damage. This is the sort of sound level aircraft mechanics sometimes experience for short periods of time. Almost twice as "loud" as putting your ear up to the exhaust of a formula 1 car. The air temperature would drop significantly, perhaps 10-25 degrees F, becoming suddenly cold because of the air being so violently stretched and moved.
Even at three miles away, the sound is loud enough to cause permanent hearing damage. But that's nothing compared to the Krakatoa sound. The Saturn V sound is ~170 db at 100 meters away while the Krakatoa explosion was that loud 100 miles away! What happens at 170 db?
...you would be unable to breathe or likely see at all from the sound pressure, glass would shatter, fog would be generated as the water in the air dropped out of suspension in the pressure waves, your house at this distance would have a roughly 50% chance of being torn apart from sound pressure alone. Military stun grenades reach this volume for a split second... if they are placed up to your face. Survival chance from sound alone, minimal, you would certainly experience permanent deafness but probably also organ damage.
The word "loud" is inadequate to describe how loud that is. (thx, david)
Every year, evolutionary biologist and professor David Barash gives his students The Talk about how evolution and religion do and do not get along.
It's irresponsible to teach biology without evolution, and yet many students worry about reconciling their beliefs with evolutionary science. Just as many Americans don't grasp the fact that evolution is not merely a "theory," but the underpinning of all biological science, a substantial minority of my students are troubled to discover that their beliefs conflict with the course material.
Until recently, I had pretty much ignored such discomfort, assuming that it was their problem, not mine. Teaching biology without evolution would be like teaching chemistry without molecules, or physics without mass and energy. But instead of students' growing more comfortable with the tension between evolution and religion over time, the opposite seems to have happened. Thus, The Talk.
This is the sort of thing Barash talks about:
The more we know of evolution, the more unavoidable is the conclusion that living things, including human beings, are produced by a natural, totally amoral process, with no indication of a benevolent, controlling creator.
Eleanor Lutz has a degree in molecular biology, works as a designer, and loves to combine the two interests by making these wonderful information graphics on her site, Tabletop Whale. Her most recent post is an animated graphic showing how several animals (birds, bats, insects) move their wings while flying.
I love love love Lutz's animated chart of North American butterflies. So playful!
There are only four posts on the site so far, but she's done other stuff as well; this woodcut map for instance. Prints are available...I'm getting one of the butterflies for sure.
Give me even the simplest gravity simulator and I will play with it for many many minutes. Or hours. Or days. (Send help!)
This looks like a time lapse, but it's not. It's just a straight-up gorgeous video of the aurora borealis filmed in Yellowknife, Northwest Territories, Canada.
It is real time motion! NOT time-lapse. Brighter the Aurora, faster the movement.
(via the kid should see this)
Erik Vance on why real working archaeologists don't care for Indiana Jones.
"Oh God," he groans, "Don't even go there. Indiana Jones is not an archeologist."
It's not surprising that academics -- hell bent on taking the fun out of everything -- would hate our beloved and iconic movie version of them. But Canuto is no killjoy. His ironic tone and acerbic wit seem honed by long boring days in the sun. So I bite. I quickly learn that there's a good reason why most every archeologist on Earth hates Indy. And that they might have a point. Because Jones isn't an archeologist at all.
"That first scene, where he's in the temple and he's replacing that statue with a bag of sand -- that's what looters do," Canuto says, grinning. "[The temple builders] are using these amazing mechanisms of engineering and all he wants to do is steal the stupid gold statue."
Makes you wonder if Jones was one of the Raiders referred to in the title of the first movie. (via @riondotnu)
As part of a course he was teaching, a biologist sent away for a genetic testing kit from 23andMe for himself and his parents. When he went looking for other relatives on the service (which is now an automatic opt-out feature), he discovered he had a half-brother his dad had not told his family about.
At first, I was thinking this is the coolest genetics story, my own personal genetics story. I wasn't particularly upset about it initially, until the rest of the family found out. Their reaction was different. Years of repressed memories and emotions uncorked and resulted in tumultuous times that have torn my nuclear family apart. My parents divorced. No one is talking to my dad. We're not anywhere close to being healed yet and I don't know how long it will take to put the pieces back together.
After this discovery was made, I went back to 23andMe and talked to them. I said, "I'm not sure all your customers realize that when they participate in your family finder program, what they're participating in what are essentially really advanced paternity tests." People find out that their parents aren't who they think they are. They have nearly a million people in the database. If there happens to be anyone in there you're related to, they'll find your match. This is a solid science.
I know a family in which one of the children is adopted and they haven't told her. Which is crazy...she's gonna find out eventually (through something like 23andMe or because of some medical emergency or test) and go totally berzerk.
There's a new king of the dinosaurs: Dreadnoughtus schrani. A skeleton of the species was unearthed in Argentina in 2005 and the results of the recently released analysis show this Dreadnoughtus was 85 feet long, weighed around 65 tons, and had a powerful "weaponized tail". The kicker? It was not yet an adult and still growing when it died.
While other giants from Patagonia are known from a handful of bones, almost half of the Dreadnoughtus skeleton has been recovered. What's more, the fossilised bones are in such good condition -- even revealing where muscles attached -- that the skeleton could provide unprecedented insights into the biology, movement and evolution of the group of huge plant-eating dinosaurs it belonged to, called the titanosaurian sauropods.
By comparison, an Apatosaurus (née Brontosaurus) is ~75 feet long and weighed 22 tons while a Boeing 737-900 weights around 50 tons. Here's some more background on the Dreadnoughtus and a video showing some of the fossils:
Hmm, this is interesting. Recent studies suggest that food allergies may be caused by the absense of certain intestinal bacteria...in part due to increased use of antibiotics in very young children.
Food allergies have increased about 50% in children since 1997. There are various theories explaining why. One is that the 21st century lifestyle, which includes a diet very different from our ancestors', lots of antibiotic use, and even a rise in cesarean section deliveries, has profoundly changed the makeup of microbes in the gut of many people in developed countries. For example, the average child in the United States has taken three courses of antibiotics by the time he or she is 2 years old, says Martin Blaser, an infectious disease specialist and microbiologist at New York University in New York City. (See here for more on the reach of microbiome research these days.)
Cathryn Nagler, an immunologist at the University of Chicago in Illinois, has spent years probing links between the immune system, intestinal bacteria, and the onset of allergies. Back in 2004, she and her colleagues reported that wiping out gut bacteria in mice led to food allergies. Since then, Nagler has continued trying to understand which bacteria offer allergy protection and how they accomplish that.
Spanning from comets in the south to the termination shock zone in the northern part of the country, The Sweden Solar System is a scale model of the solar system that spans the entire country of Sweden, the largest such model in the world.
The Sun is represented by the Ericsson Globe in Stockholm, the largest hemispherical building in the world. The inner planets can also be found in Stockholm but the outer planets are situated northward in other cities along the Baltic Sea.
Today's brain-melter: Every Insanely Mystifying Paradox in Physics. It's all there, from the Greisen-Zatsepin-Kuzmin limit to quantum immortality to, of course, the tachyonic antitelephone.
A tachyonic antitelephone is a hypothetical device in theoretical physics that could be used to send signals into one's own past. Albert Einstein in 1907 presented a thought experiment of how faster-than-light signals can lead to a paradox of causality, which was described by Einstein and Arnold Sommerfeld in 1910 as a means "to telegraph into the past".
If you emerge with your brain intact, at the very least, you'll have lost a couple of hours to the list.
Oh man, this is great. A Spacecraft For All is an interactive video about the ISEE-3 Reboot Project, in which a group of scientists working out of an old McDonald's crowdfunded an effort to communicate with a nearly forgotten satellite launched by NASA in 1978 to observe the Sun and chase a comet. After the intro, click on "See the Journey"...it's well worth your time if you're at all interested in space or science.
For instance, did you know there exists several points between the Earth and the Sun at which a satellite can orbit around, enabling spacecraft to stay more or less in the same spot for observation purposes? So cool!