kottke.org posts about science
While driving a couple weeks ago, I happened to catch a meteor shooting across the sky:
Saw one of the coolest things ever tonight: a meteor burning up in the lower atmosphere. Super bright, exploded at the end like a firework.
It turned out that “one of the coolest things ever” wasn’t hyperbole. You see, earlier that day over the UK, a meteor streaked across the sky for about 50 seconds:
And then the one I saw happened about two-and-a-half hours later. Spurred by this unlikely coincidence, mathematician Esko Lyytinen of the colorfully named Finnish Fireball Working Group of the Ursa Astronomical Association did some calculations and determined that the two events were actually the same meteor.
He believes a large body grazed the upper atmosphere, dipping to an altitude of 33 miles (53 km) over Ireland before escaping back to space. Because it arrived moving at only about 8 miles (13 km) per second, barely above Earth’s escape velocity, it lingered for more than a minute as it crossed the sky. (This explains why some witnesses mistook it for reentering spacecraft debris.)
Lyytinen says the brief atmospheric passage took its toll. As the meteoroid broke apart, its velocity dropped to just 5.7 miles (9.2 km) per second, too slow to make an escape back to space. Instead, it became a temporary satellite of Earth, looping completely around the globe before reentering the atmosphere — this time for good. “It looks now that the fireball witnessed 155 minutes later in U.S. and Canada, may have been one fragment of the British fireball, most probably the biggest one,” Lyytinen explains.
These earth-grazers are not common but they do happen from time to time. But a visible Earth grazing meteor that enters the atmosphere twice? Unprecedented. So cool! (thx, alex)
Hey, if Randall keeps writing them, I’m gonna keep posting links to them…today’s XKCD What If is “If every person on Earth aimed a laser pointer at the Moon at the same time, would it change color?”
Unfortunately, the laser energy flow would turn the atmosphere to plasma, instantly igniting the Earth’s surface and killing us all.
Earlier this month, the Curiosity rover photographed a dry stream bed on the surface of Mars.
That’s the Mars river bed on the left and an Earth river bed on the right. Note the flat smooth rocks in the Mars pic. Pretty cool.
Plant grafting is something I always sort of knew existed, but never really thought it worked well enough to create fruit salad trees. A plant with multiple different kinds of herbs would be amazing.
In Australia, James and Kerry West grow and sell four types of fruit salad trees, each of which bears several different kinds of fruit. Stone fruit salad trees grow peaches, plums, nectarines, apricots and peachcots. Citrus salad trees offer a winter and summer orange, mandarins, lemons, limes, grapefruits, tangelos and pomelos. Multi-apple trees boast between two and four different kinds of apples and multi-nashi trees produce between two and four different kinds of Asian pears.
(thanks, Jessie)
Gorilla Glass is the thin strong glass used for the screens of most smartphones. It was invented in the 1960s by Corning but was shelved in the early 1970s due to a lack of demand. The iPhone brought it out of retirement in a big way.
Chemical strengthening, the method of fortifying glass developed in the ’60s, creates a compressive layer too, through something called ion exchange. Aluminosilicate compositions like Gorilla Glass contain silicon dioxide, aluminum, magnesium, and sodium. When the glass is dipped in a hot bath of molten potassium salt, it heats up and expands. Both sodium and potassium are in the same column on the periodic table of elements, which means they behave similarly. The heat from the bath increases the migration of the sodium ions out of the glass, and the similar potassium ions easily float in and take their place. But because potassium ions are larger than sodium, they get packed into the space more tightly. (Imagine taking a garage full of Fiat 500s and replacing most of them with Chevy Suburbans.) As the glass cools, they get squeezed together in this now-cramped space, and a layer of compressive stress on the surface of the glass is formed. (Corning ensures an even ion exchange by regulating factors like heat and time.) Compared with thermally strengthened glass, the “stuffing” or “crowding” effect in chemically strengthened glass results in higher surface compression (making it up to four times as strong), and it can be done to glass of any thickness or shape.
I did glass research in college so I’m a sucker for this sort of thing. (via @joeljohnson)
XKCD’s What If? science feature continues to delight. This week’s question is “What if a rainstorm dropped all of its water in a single giant drop?”
The drop is now falling at 90 meters per second (200 mph). The roaring wind whips up the surface of the water into spray. The leading edge of the droplet turns to foam as air is forced into the liquid. If it kept falling for long enough, these forces would gradually disperse the entire droplet into rain.
Before that can happen, about 20 seconds after formation, the edge of the droplet hits the ground. The water is now moving at over 200 m/s (450 mph). Right under the point of impact, the air is unable to rush out of the way fast enough, and the compression heats it so quickly that the grass would catch fire if it had time.
Fortunately for the grass, this heat lasts only a few milliseconds because it’s doused by the arrival of a lot of cold water. Unfortunately for the grass, the cold water is moving at over half the speed of sound.
It turns out that yo-yos work pretty well in space. Astronaut Don Pettit demontrates from the International Space Station.
(via explore)
Researchers in Germany have found evidence of room temperature superconductivity in graphite powder that has been soaking in water and then dried. Not surprisingly, the results come with a few caveats:
First, this is not a conventional bulk material. The claim from Germany is that the superconductivity occurs at the interface between grains of graphite after they have dried out.
So that’s a surface effect which involves only a tiny fraction of the total mass of carbon in the powder—just 0.0001 per cent of the mass, according to Esquinazi and co.
What’s more the effect is clearly fragile. Esquinazi and co say the superconductivity disappears if the treated powder is pressed into pellets.
So whatever allows the superconductivity to occur at the grain interfaces is destroyed when the grains are pressed together.
I’m pretty sure this is the technology used by the aliens who designed The Machine in Contact.
Writing for Slate, Daniel Engber takes a closer look at the magic cooling glove and finds some (but not a lot of) evidence that the thing actually works as advertised.
The study, which aggregates results from a decade’s worth of experiments, found that “palm cooling” helped people do 144 percent more pull-ups than they did before, on average. A closer look reveals that the effect might not be so beefy as it looks, however. That figure comes from testing just a handful of people in the lab-even after 10 years of research-and it has some honking error bars (+/-83 percent). To put it in perspective: Before the palm-cooled training, their scores ranged from 70 to 153 pull-ups in each session; after training, they ranged from 70 to 616.
Nanocrystalline cellulose is made from wood pulp, is light, strong, and even conducts electricity.
So why all the fuss? Well, not only is NCC transparent but it is made from a tightly packed array of needle-like crystals which have a strength-to-weight ratio that is eight times better than stainless steel. Even better, it’s incredibly cheap.
“It is the natural, renewable version of a carbon nanotube at a fraction of the price,” says Jeff Youngblood of Purdue University’s NanoForestry Institute in West Lafayette, Indiana.
In partnership with sciencedebate.org, Scientific American asked both major party candidates to answer questions about the important scientific questions of the day. Here are the results.
I am not a scientist myself, but my best assessment of the data is that the world is getting warmer, that human activity contributes to that warming, and that policymakers should therefore consider the risk of negative consequences. However, there remains a lack of scientific consensus on the issue — on the extent of the warming, the extent of the human contribution, and the severity of the risk — and I believe we must support continued debate and investigation within the scientific community.
Leveraging the high number of specialized heat-transfer veins in the palm of the human hand, researchers at Stanford have developed a thermal exchange glove that is able to cool a person’s core temperature in a matter of minutes. Turns out this is helpful for athletes.
The glove’s effects on athletic performance didn’t become apparent until the researchers began using the glove to cool a member of the lab — the confessed “gym rat” and frequent coauthor Vinh Cao — between sets of pull-ups. The glove seemed to nearly erase his muscle fatigue; after multiple rounds, cooling allowed him to do just as many pull-ups as he did the first time around. So the researchers started cooling him after every other set of pull-ups.
“Then in the next six weeks he went from doing 180 pull-ups total to over 620,” said Heller. “That was a rate of physical performance improvement that was just unprecedented.”
The researchers applied the cooling method to other types of exercise — bench press, running, cycling. In every case, rates of gain in recovery were dramatic, without any evidence of the body being damaged by overwork - hence the “better than steroids” claim.
The cooling resets a temperature-sensitive enzyme that muscles need to generate energy, “essentially resetting the muscle’s state of fatigue”. I expect this will be either everywhere in pro sports in a couple of years or banned. (via @jsnell)
The crazy (and possibly high) folks at Backyard Brains hooked an iPod up to a squid in such a way that when the music played, it was converted into electrical impulses that triggered color changes on the squid’s skin, thereby creating the world’s first cephalo-iPod. Here’s a video of the squid’s skin pulsing along to Insane in the Membrane by Cypress Hill:
During experiments on the giant axons of the Longfin Inshore Squid (loligo pealei) at the Marine Biological Laboratory in Woods Hole, MA; we were fascinated by the fast color-changing nature of the squid’s skin. Squids (like many other cephalopods) can quickly control pigmented cells called chromatophores to reflect light. The Longfin Inshore has 3 different chromatophore colors: Brown, Red, and Yellow. Each chromatophore has tiny muscles along the circumference of the cell that can contract to reveal the pigment underneath.
(via colossal)
Opening on September 15 at Edward Tufte’s gallery in Chelsea is All Possible Photons, an exhibit of sculptures by Tufte of Richard Feynman’s subatomic particle diagrams.
Made from stainless steel and air, the artworks grow out of Richard Feynman’s famous diagrams describing Nature’s subatomic behavior. Feynman diagrams depict the space-time patterns of particles and waves of quantum electrodynamics. These mathematically derived and empirically verified visualizations represent the space-time paths taken by all subatomic particles in the universe.
The resulting conceptual and cognitive art is both beautiful and true. Along with their art, the stainless steel elements of All Possible Photons actually represent something: the precise activities of Nature at her highest resolution.
Using just the camera on your iPhone, the Cardiio app can accurately measure your heart rate. Here’s how it works:
Every time your heart beats, more blood is pumped into your face. This slight increase in blood volume causes more light to be absorbed, and hence less light is reflected from your face. Using sophisticated software, your iPhone’s front camera can track these tiny changes in reflected light that are not visible to the human eye and calculate your heart beat!
This video shows this process in action (with a short explanatory intro of the mathematical technique):
That is flat-out amazing. (via @delfuego)
Where have I seen this before, a massive long-lasting Arctic storm that looks a lot like a hurricane? Oh right, The Day After Tomorrow.
The storm had an unusually low central pressure area. Paul A. Newman, chief scientist for Atmospheric Sciences at NASA’s Goddard Space Flight Center in Greenbelt, Md., estimates that there have only been about eight storms of similar strength during the month of August in the last 34 years of satellite records. “It’s an uncommon event, especially because it’s occurring in the summer. Polar lows are more usual in the winter,” Newman said.
Arctic storms such as this one can have a large impact on the sea ice, causing it to melt rapidly through many mechanisms, such as tearing off large swaths of ice and pushing them to warmer sites, churning the ice and making it slushier, or lifting warmer waters from the depths of the Arctic Ocean.
I love The Day After Tomorrow. I know it’s a cheeseball disaster movie (which is pretty much why I love it) but it’s also looking more than a little prescient. Well, as prescient as a cheeseball disaster movie can be anyway. In the Washington Post the other day, prominent climatologist James Hansen wrote that human-driven climate change is responsible for an increase in extreme weather.
My projections about increasing global temperature have been proved true. But I failed to fully explore how quickly that average rise would drive an increase in extreme weather.
In a new analysis of the past six decades of global temperatures, which will be published Monday, my colleagues and I have revealed a stunning increase in the frequency of extremely hot summers, with deeply troubling ramifications for not only our future but also for our present.
This is not a climate model or a prediction but actual observations of weather events and temperatures that have happened. Our analysis shows that it is no longer enough to say that global warming will increase the likelihood of extreme weather and to repeat the caveat that no individual weather event can be directly linked to climate change. To the contrary, our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.
In many ways, the phrase “global warming” is grossly misleading. “Oh,” we think, “it’s gonna be a couple degrees warmer in NYC in 20 years than it is now.” But the Earth’s climate is a chaotic non-linear system, which means that a sudden shift of a degree or two — and when you’re talking about something as big as the Earth, a degree over several decades is sudden — pushes things out of balance here and there in unpredictable ways. So it’s not just that it’s getting hotter, it’s that you’ve got droughts in places where you didn’t have them before, severe floods in other places, unusually hot summers, and even places that are cooler than normal, all of which disrupts the animal and plant life that won’t be able to acclimate to the new reality fast enough.
But pretty Arctic cyclone though, right?
The main imaging cameras on the Mars Curiosity rover have only 2-megapixel sensors with 8 GB of flash memory — compare that to a maxed-out iPhone 4S with an 8-megapixel sensor and 64 GB of flash memory (not to mention 30-fps 1080p video). Planning timeframes and communications bandwidth contributed to the chosen camera size.
‘There’s a popular belief that projects like this are going to be very advanced but there are things that mitigate against that. These designs were proposed in 2004, and you don’t get to propose one specification and then go off and develop something else. 2MP with 8GB of flash [memory] didn’t sound too bad in 2004. But it doesn’t compare well to what you get in an iPhone today.’
The cameras were also supposed to be outfitted with zoom lenses but that part of the project was scrapped.
In this slow-motion video, you can see how cats rotate themselves in the air while conserving angular momentum.
This is an interesting companion to yesterday’s owl rotation video. (via @stevenstrogatz)
On Twitter right now, Neil deGrasse Tyson is imagining how various Olympic events would work on Mars.
Women’s Beach Volleyball on Mars: No protective ozone layer there. Solar UV would irradiate all exposed legs, buns, & tummies
Gymnastics: On Mars, with only 38% of Earth’s gravity, the Vault & other spring-assisted leaps would resemble circus cannons.
(via @jaycer17)
The rest of you can have your Olympics, but the early August event I’m most looking forward to is the arrival on Mars of the Curiosity rover. But NASA has had some problems in the past delivering payloads to Mars, so this is going to be somewhat of a nail-biter. If you haven’t seen it, Curiosity’s Seven Minutes of Terror is well worth watching to see the logistical challenge of getting the rover down to the surface.
Curiosity will hopefully land on the surface on Aug 6 at about 1:30 am ET.
Three people are HIV-free due to bone marrow transplants and that’s providing scientists with hope for a possible AIDS cure.
AIDS patients are susceptible to cancers, but they usually stop taking HIV drugs before receiving cancer treatment. “That allows the virus to come back and it infects their donor cells,” Kuritzkes said.
About 34 million people are infected with HIV, the virus that causes AIDS, globally; 25 million have died from it. While there’s no vaccine, cocktails of powerful antiviral drugs called antiretroviral therapy (ART) can keep the virus suppressed and keep patients healthy. No matter how long patients take ART, however, they are never cured. The virus lurks in the body and comes back if the drugs are stopped. Scientists want to flush out these so-called reservoirs and find a way to kill the virus for good.
Brown, and now these two other men, offer some real hope.
Dr. Timothy Henrich and colleagues at Brigham and Women’s Hospital launched a search about a year ago for HIV patients with leukemia or lymphoma who had received bone marrow stem cell transplants. Bone marrow is the body’s source of immune system cells that HIV infects and it’s a likely place to look for HIV’s reservoirs.
“If you took an HIV patient getting treated for various cancers, you can check the effect on the viral reservoirs of various cancer treatments,” Kuritzkes, who works with Henrich, said. They found the two patients by asking colleagues at Dana-Farber Cancer Institute in Boston which, like Brigham and Women’s, is associated with Harvard Medical School.
Both men had endured multiple rounds of treatment for lymphoma, both had stem cell treatments and both had stayed on their HIV drugs throughout. “They went through the transplants on therapy,” Kuritzkes said.
It turns out that was key.
“We found that immediately before the transplant and after the transplant, HIV DNA was in the cells. As the patients’ cells were replaced by the donor cells, the HIV DNA disappeared,” Kuritzkes said. The donor cells, it appears, killed off and replaced the infected cells. And the HIV drugs protected the donor cells while they did it.
The two men have been HIV-free for two years and three-and-a-half years, respectively. Another man who benefited from a bone marrow transplant from a donor whose immune cells resist HIV infection has been free of HIV for five years. (via @gavinpurcell)
Ignoring the prequels (of course), how much power does Yoda put out when he’s using the Force? It’s perhaps less than you’d realize.
Yoda’s greatest display of raw power in the original trilogy came when he lifted Luke’s X-Wing from the swamp. As far as physically moving objects around goes, this was easily the biggest expenditure of energy through the Force we saw from anyone in the trilogy.
The energy it takes to lift an object to height h is equal to the object’s mass times the force of gravity times the height it’s lifted. The X-Wing scene lets us use this to put a lower limit on Yoda’s peak power output.
First we need to know how heavy the ship was. The X-Wing’s mass has never been canonically established, but its length has-16 meters. An F-22 is 19 meters long and weighs 19,700 lbs, so scaling down from this gives an estimate for the X-Wing of about 12,000 lbs (5 metric tons).
The Apollo 11 Lunar Module landed on the surface of the Moon 43 years ago today. For the 40th anniversary of the landing in 2009, I put together a page where you can watch the original CBS News coverage of Walter Cronkite reporting on the Moon landing and the first Moon walk, synced to the present-day time. I’ve updated the page to work again this year: just open this page in your browser and the coverage will start playing at the proper time. Here’s the schedule:
Moon landing broacast start: 4:10:30 pm EDT on July 20
Moon landing shown: 4:17:40 pm EDT
Moon landing broadcast end: 4:20:15 pm EDT
{break}
Moon walk broadcast start: 10:51:27 pm EDT
First step on Moon: 10:56:15 pm EDT
Nixon speaks to the Eagle crew: approx 11:51:30 pm EDT
Moon walk broadcast end: 12:00:30 pm EDT on July 21
Here’s a post I wrote when I launched the project.
If you’ve never seen this coverage, I urge you to watch at least the landing segment (~10 min.) and the first 10-20 minutes of the Moon walk. I hope that with the old time TV display and poor YouTube quality, you get a small sense of how someone 40 years ago might have experienced it. I’ve watched the whole thing a couple of times while putting this together and I’m struck by two things: 1) how it’s almost more amazing that hundreds of millions of people watched the first Moon walk *live* on TV than it is that they got to the Moon in the first place, and 2) that pretty much the sole purpose of the Apollo 11 Moon walk was to photograph it and broadcast it live back to Earth.
Thanks to Dave Schumaker for the reminder.
A team in Boston is working on a method for injecting oxygen straight into a person’s bloodstream, which is faster than the more traditional method (you know, breathing).
Researchers led by Harvard Medical School’s John N. Kheir engineered tiny, gas-filled microparticles, which were about three micrometers in size and invisible to the naked eye. They used a device called a sonicator, which uses high-intensity sound waves, to produce a foamy liquid solution with microparticles that consist of a single layer of lipids that trap a tiny pocket of oxygen gas. They then injected the resulting mixture directly into the bloodstream of rabbits that were severely oxygen-deprived.
Within seconds, infusions of the microparticles restored the blood oxygen saturation of these mammals to near-normal levels. When the rabbits’ windpipes were completely blocked, the solution kept them alive for 15 minutes without a single breath and reduced the likelihood of cardiac arrest and organ injury.
More here and here.
XKCD is answering “hypothetical questions with physics” once a week and the first installment is just flat-out delightful: What would happen if you tried to hit a baseball pitched at 90% the speed of light?
The ideas of aerodynamics don’t apply here. Normally, air would flow around anything moving through it. But the air molecules in front of this ball don’t have time to be jostled out of the way. The ball smacks into them hard that the atoms in the air molecules actually fuse with the atoms in the ball’s surface. Each collision releases a burst of gamma rays and scattered particles.
These gamma rays and debris expand outward in a bubble centered on the pitcher’s mound. They start to tear apart the molecules in the air, ripping the electrons from the nuclei and turning the air in the stadium into an expanding bubble of incandescent plasma. The wall of this bubble approaches the batter at about the speed of light-only slightly ahead of the ball itself.
All science writing should (and probably could!) be this entertaining. (via @delfuego)
From a collection of his papers recently acquired by The Library of Congress, a 1954 reading list from physicist Carl Sagan. Huxley, Plato, Shakespeare, and the Bible are all on there among many others. If I understand mathematics properly, and I think I do, using the associative property, if you read all these books, you will become as smart and cool as Carl Sagan was. Or is it the transitive property?
Frazil ice is a Slushee-like mixture of ice and supercooled water that behaves a lot like lava or flowing cement. Here’s a short video about frazil ice in Yosemite…it starts off a bit slow but gets good around 1:30.
Motherboard journeyed out onto the streets of Williamsburg to see if the hipster on the street knew what the Higgs boson was. And he/she did not.
If you’re in that same boat, take a few minutes to learn about what the Higgs is. (via @alexismadrigal)
Or, to put it in the cautious words of science, researchers have observed a “particle consistent with long-sought Higgs boson”.
“We observe in our data clear signs of a new particle, at the level of 5 sigma, in the mass region around 126 GeV. The outstanding performance of the LHC and ATLAS and the huge efforts of many people have brought us to this exciting stage,” said ATLAS experiment spokesperson Fabiola Gianotti, “but a little more time is needed to prepare these results for publication.”
“The results are preliminary but the 5 sigma signal at around 125 GeV we’re seeing is dramatic. This is indeed a new particle. We know it must be a boson and it’s the heaviest boson ever found,” said CMS experiment spokesperson Joe Incandela. “The implications are very significant and it is precisely for this reason that we must be extremely diligent in all of our studies and cross-checks.”
How sure are they that they’ve found the Higgs? Brian Cox notes on Twitter:
5 sigma is the usual particle physics threshold for discovery. It roughly means that you’re 99.9999% sure
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