In a review of the Color Uncovered iPad app, Carl Zimmer highlights something I hadn’t heard before: Claude Monet could see in ultraviolet.
Late in his life, Claude Monet developed cataracts. As his lenses degraded, they blocked parts of the visible spectrum, and the colors he perceived grew muddy. Monet’s cataracts left him struggling to paint; he complained to friends that he felt as if he saw everything in a fog. After years of failed treatments, he agreed at age 82 to have the lens of his left eye completely removed. Light could now stream through the opening unimpeded. Monet could now see familiar colors again. And he could also see colors he had never seen before. Monet began to see — and to paint — in ultraviolet.
The Dyson sphere, also referred to as a Dyson shell, is the brainchild of the physicist and astronomer Freeman Dyson. In 1959 he put out a two page paper titled, “Search for Artificial Stellar Sources of Infrared Radiation” in which he described a way for an advanced civilization to utilize all of the energy radiated by their sun. This hypothetical megastructure, as envisaged by Dyson, would be the size of a planetary orbit and consist of a shell of solar collectors (or habitats) around the star. With this model, all (or at least a significant amount) of the energy would hit a receiving surface where it can be used. He speculated that such structures would be the logical consequence of the long-term survival and escalating energy needs of a technological civilization.
Needless to say, the amount of energy that could be extracted in this way is mind-boggling. According to Anders Sandberg, an expert on exploratory engineering, a Dyson sphere in our solar system with a radius of one AU would have a surface area of at least 2.72x1017 km2, which is around 600 million times the surface area of the Earth. The sun has an energy output of around 4x1026 W, of which most would be available to do useful work.
The downside: we’d have to part with Mercury to do it.
And yes, you read that right: we’re going to have to mine materials from Mercury. Actually, we’ll likely have to take the whole planet apart. The Dyson sphere will require a horrendous amount of material-so much so, in fact, that, should we want to completely envelope the sun, we are going to have to disassemble not just Mercury, but Venus, some of the outer planets, and any nearby asteroids as well.
At Forbes, Alex Knapp explains why Dvorsky’s scheme and timeline might not work.
I emailed Astronomer Phil Plait about this project, who told me in no uncertain terms that the project doesn’t make sense.
“Dismantling Mercury, just to start, will take 2 x 10^30 Joules, or an amount of energy 100 billion times the US annual energy consumption,” he said. “[Dvorsky] kinda glosses over that point. And how long until his solar collectors gather that much energy back, and we’re in the black?”
Now available in its entirety on YouTube, a 95-minute documentary on physicist Richard Feynman called No Ordinary Genius.
The excellent film on Andrew Wiles’ search for the solution to Fermat’s Last Theorem is available as well (watch the first two minutes and you’ll be hooked).
With their ability to move seamlessly through walls, rocks, lead shielding, and entire planets, neutrinos would seem like a great choice for a new method of wireless communication. Scientists at Fermilab have demonstrated sending messages via neutrino but the downside is that the slippery particles can also move seamlessly through detectors.
In the Fermilab experiment, the physicists fired a proton beam into a carbon target to produce a shower of particles called pions and kaons that quickly decay into neutrinos. For every pulse of 22.5 trillion protons, the physicists registered an average of 0.81 neutrino with the 170-ton MINERvA detector.
That translates into a data rate of 0.1 bits/second, or just slightly faster than America Online’s dialup service circa 1992. (Hey, hey, if you liked that one, perhaps you’ll also enjoy my impression of Dana Carvey doing George H.W. Bush.)
I’ve spent years studying all this, and it still sometimes gets to me: just how flipping BIG the Universe is! And this picture is still just a tiny piece of it: it’s 1.2 x 1.5 degrees in size, which means it’s only 0.004% of the sky! And it’s not even complete: more observations of this region are planned, allowing astronomers to see even deeper yet.
Here’s a full view of the image that looks sorta unimpressive:
The NY Times is reporting that a data bump “smells like the Higgs boson”. The odor is emanating not from CERN in Europe but from Fermilab near Chicago, where their Tevatron still flings some pretty fast particles.
“Based on the current Tevatron data and results compiled through December 2011 by other experiments, this is the strongest hint of the existence of a Higgs boson,” said the report, which will be presented on Wednesday by Wade Fisher of Michigan State University to a physics conference in La Thuile, Italy.
None of these results, either singly or collectively, are strong enough for scientists to claim victory. But the recent run of reports has encouraged them to think that the elusive particle, which is the key to mass and diversity in the universe, is within sight, perhaps as soon as this summer.
Update: The Tevatron is no longer flinging, having been shut down in 2011 due to budget cuts. Which makes the Higgs discovery a little bittersweet, to say the least. (thx, miles)
According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos’ flight and an electronic card in a computer. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed.
Neutrinos? More like Nintendo…they forgot to blow in the cartridge. (via @tcarmody)
The sound and picture are poor, but the entirety of Errol Morris’ A Brief History of Time is available on YouTube.
Featuring music from Philip Glass, the film is a documentary about Stephen Hawking and his ideas about the universe. Morris recently stated on Twitter:
Yes. I plan to re-release [A Brief History of Time]. (It was never properly color corrected and is one of my best films.)
The film is difficult, if not impossible, to find on DVD and isn’t available on Netflix, Amazon Instant Video, or iTunes. And as far as I can tell, the soundtrack was never released either.
If you drop a bunch of neodymium magnets down through a thick-walled copper pipe, an effect called eddy current braking will slow the magnets’ fall even though there’s no direct magnetic attraction between the copper and the magnets.
The teams are sworn to secrecy, but various physics blogs, and the canteens at Cern, are alive with talk of a possible sighting of the Higgs, and with a mass inline with what many physicists would expect.
Since the Higgs’ nickname is the God particle, does this count as the Second Coming? (@gavinpurcell)
4. You live in the past. About 80 milliseconds in the past, to be precise. Use one hand to touch your nose, and the other to touch one of your feet, at exactly the same time. You will experience them as simultaneous acts. But that’s mysterious - clearly it takes more time for the signal to travel up your nerves from your feet to your brain than from your nose. The reconciliation is simple: our conscious experience takes time to assemble, and your brain waits for all the relevant input before it experiences the “now.” Experiments have shown that the lag between things happening and us experiencing them is about 80 milliseconds.
5. Your memory isn’t as good as you think. When you remember an event in the past, your brain uses a very similar technique to imagining the future. The process is less like “replaying a video” than “putting on a play from a script.” If the script is wrong for whatever reason, you can have a false memory that is just as vivid as a true one. Eyewitness testimony, it turns out, is one of the least reliable forms of evidence allowed into courtrooms.
The distance between the metal bands holding the cylindrical structure together decreases from top to bottom because the pressure the water exerts increases with depth. The top band only needs to fight against the water at the very top of the tower but the bottom bands have to hold the entire volume from bursting out.
What the what? This video gives a little more explanation into the effect at work here (superconductivity + quantum trapping of the magnetic field in quantum flux tubes) and an awesome demonstration of a crude rail system. You can almost hear your tiny mind explode when the “train” goes upside-down.
Thousands of experiments have been undertaken to measure it ever more precisely, and no result has ever spotted a particle breaking the limit.
But Dr Ereditato and his colleagues have been carrying out an experiment for the last three years that seems to suggest neutrinos have done just that.
Neutrinos come in a number of types, and have recently been seen to switch spontaneously from one type to another.
The team prepares a beam of just one type, muon neutrinos, sending them from Cern to an underground laboratory at Gran Sasso in Italy to see how many show up as a different type, tau neutrinos.
In the course of doing the experiments, the researchers noticed that the particles showed up 60 billionths of a second sooner than light would over the same distance.
This is a tiny fractional change, but one that occurs consistently.
The team measured the travel times of neutrino bunches some 15,000 times, and have reached a level of statistical significance that in scientific circles would count as a formal discovery.
If true, saying this is a significant discovery is a doubly significant understatement.
“We are now entering a very exciting phase in the hunt for the Higgs boson,” Sharma said. “If the Higgs boson exists between 114-145 GeV, we should start seeing statistically significant excesses over estimated backgrounds, and if it does not then we hope to rule it out over the entire mass range. One way or the other we are poised for a major discovery, likely by the end of this year.”
The giants of physics (and Morgan Freeman, who can be a giant of anything he wants) explain quantum mechanics using relatively simple terms and autotune.
Put a spinning gyroscope into orbit around the Earth, with the spin axis pointed toward some distant star as a fixed reference point. Free from external forces, the gyroscope’s axis should continue pointing at the star—forever. But if space is twisted, the direction of the gyroscope’s axis should drift over time. By noting this change in direction relative to the star, the twists of space-time could be measured.
Gravity Probe B’s experiment was 47 years in the making, helped spawn 100 PhD theses, and required the invention of 13 brand-new technologies, including a “drag-free satellite.” The four gyroscopes in GP-B are “the most perfect spheres ever made by humans… If the gyroscopes weren’t so spherical, their spin axes would wobble even without the effects of relativity.”
NASA finished collecting the data in 2005; now they’ve crunched the numbers. And yes, Einstein was right. The gyroscopes wobble in just the way general relativity predicts.
The first and most famous empirical experiment testing Einstein’s theory was performed in 1919 by Arthur Eddington during a full solar eclipse. Photographs showed that the sun’s mass caused starlight to bend around it.
(Image by James Overduin, Pancho Eekels, and Bob Kahn via NASA.)
“Nobody knows what this is,” said Christopher Hill, a theorist at Fermilab who was not part of the team. “If it is real, it would be the most significant discovery in physics in half a century.”
We won’t have to wait too long to see if the bump is real…the LHC will reveal all soon.
For the vast majority of people, nuclear power is a black box technology. Radioactive stuff goes in. Electricity (and nuclear waste) comes out. Somewhere in there, we’re aware that explosions and meltdowns can happen. Ninety-nine percent of the time, that set of information is enough to get by on. But, then, an emergency like this happens and, suddenly, keeping up-to-date on the news feels like you’ve walked in on the middle of a movie. Nobody pauses to catch you up on all the stuff you missed.
As I write this, it’s still not clear how bad, or how big, the problems at the Fukushima Daiichi power plant will be. I don’t know enough to speculate on that. I’m not sure anyone does. But I can give you a clearer picture of what’s inside the black box. That way, whatever happens at Fukushima, you’ll understand why it’s happening, and what it means.
Even with the release of steam, the pressure and temperature inside Unit 1 continued to increase. The high temperatures inside the reactor caused the protective zirconium cladding on the uranium fuel rods to react with steam inside the reactor to form zirconium oxide and hydrogen. This hydrogen leaked into the building that surrounded the reactor and ignited, damaging the surrounding building but without damaging the reactor vessel itself. Because the reactor vessel has not been compromised, the release of radiation should be minimal. It appears that a very similar situation has occurred at Unit 3 and that hydrogen is again responsible for the explosion seen there.
Of immediate concern is the prospect of a so-called “meltdown” at one or more of the Japanese reactors. But part of the problem in understanding the potential dangers is continued indiscriminate use, by experts and the media, of this inherently frightening term without explanation or perspective. There are varying degrees of melting or meltdown of the nuclear fuel rods in a given reactor; but there are also multiple safety systems, or containment barriers, in a given plant’s design that are intended to keep radioactive materials from escaping into the general environment in the event of a partial or complete meltdown of the reactor core. Finally, there are the steps taken by a plant’s operators to try to bring the nuclear emergency under control before these containment barriers are breached.
In 2004, the astrophysicist Robin Canup, at the Southwest Research Institute in Texas, published some remarkable computer simulations of the Big Splat. To get a moon like ours to form — instead of one too rich in iron, or too small, or wrong in other respects — she had to choose the right initial conditions. She found it best to assume Theia is slightly more massive than Mars: between 10% and 15% of the Earth’s mass. It should also start out moving slowly towards the Earth, and strike the Earth at a glancing angle.
The result is a very bad day. Theia hits the Earth and shears off a large chunk, forming a trail of shattered, molten or vaporized rock that arcs off into space. Within an hour, half the Earth’s surface is red-hot, and the trail of debris stretches almost 4 Earth radii into space. After 3 to 5 hours, the iron core of Theia and most of the the debris comes crashing back down. The Earth’s entire crust and outer mantle melts. At this point, a quarter of Theia has actually vaporized!
After a day, the material that has not fallen back down has formed a ring of debris orbiting the Earth. But such a ring would not be stable: within a century, it would collect to form the Moon we know and love. Meanwhile, Theia’s iron core would sink down to the center of the Earth.
This equation’s initial purpose, he wrote, was to put meaningful prices on the terrestrial exoplanets that Kepler was bound to discover. But he soon found it could be used equally well to place any planet-even our own-in a context that was simultaneously cosmic and commercial. In essence, you feed Laughlin’s equation some key parameters — a planet’s mass, its estimated temperature, and the age, type, and apparent brightness of its star — and out pops a number that should, Laughlin says, equate to cold, hard cash.
At the time, the exoplanet Gliese 581 c was thought to be the most Earth-like world known beyond our solar system. The equation said it was worth a measly $160. Mars fared better, priced at $14,000. And Earth? Our planet’s value emerged as nearly 5 quadrillion dollars. That’s about 100 times Earth’s yearly GDP, and perhaps, Laughlin thought, not a bad ballpark estimate for the total economic value of our world and the technological civilization it supports.
“This year’s Breakthrough of the Year represents the first time that scientists have demonstrated quantum effects in the motion of a human-made object,” said Adrian Cho, a news writer for Science. “On a conceptual level that’s cool because it extends quantum mechanics into a whole new realm. On a practical level, it opens up a variety of possibilities ranging from new experiments that meld quantum control over light, electrical currents and motion to, perhaps someday, tests of the bounds of quantum mechanics and our sense of reality.”
Today, another group says they’ve found something else in the echo of the Big Bang. These guys start with a different model of the universe called eternal inflation. In this way of thinking, the universe we see is merely a bubble in a much larger cosmos. This cosmos is filled with other bubbles, all of which are other universes where the laws of physics may be dramatically different to ours.
The findings are currently difficult to reproduce, but with better data on the way, scientists are hoping to get to the bottom of the matter in the next few years.
By smashing together lead ions instead of protons, researchers at the Large Hadron Collider have produced a “mini-Big Bang”.
The collisions obtained were able to generate the highest temperatures and densities ever produced in an experiment. “This process took place in a safe, controlled environment, generating incredibly hot and dense sub-atomic fireballs with temperatures of over ten trillion degrees, a million times hotter than the centre of the Sun.
“At these temperatures even protons and neutrons, which make up the nuclei of atoms, melt resulting in a hot dense soup of quarks and gluons known as a quark-gluon plasma.” Quarks and gluons are sub-atomic particles — some of the building blocks of matter. In the state known as quark-gluon plasma, they are freed of their attraction to one another. This plasma is believed to have existed just after the Big Bang.
What they came up with is little more than an electromagnetic ring and a water pump. The ring, called a current probe, creates a magnetic field through which the pump shoots a steam of seawater (the salt is a key ingredient, as the tech relies on the magnetic induction properties of sodium chloride). By controlling the height and width of the, the operator can manipulate the frequency at which the antenna transmits and receives. An 80-foot-high stream can transmit and receive anywhere from 2 to 400 mHz, though much smaller streams can be used for varying other frequencies, ranging from HF through VHF to UHF.
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