Here's an update on the effort to solve the Pioneer anomaly, the unexplained deviation in motion of deep space probes from what Newton and Einstein's theories predict.
As it sped through space, a specialist in radio-wave physics named John Anderson at NASA's Jet Propulsion Laboratory noticed an odd thing. The spacecraft was drifting off course. The discrepancy was less than a few hundred-millionths of an inch per second for every second of spaceflight, accumulating year after year across billions of miles. Then Pioneer 11, an identical probe escaping the solar system in the opposite direction, also started to veer off course at the same rate.
Ordinarily, such small deviations might be overlooked, but not by Dr. Anderson. He monitored the trajectories six years before calling attention to the matter. "I'm a little like an accountant," Dr. Anderson said. "We have Newton's theory and Einstein's theory, and when you apply them to something like this -- and it doesn't add up -- it bothers me."
The researchers, using data recovered from recently discovered Pioneer records and funded by sources outside of NASA, have figured out part of the problem but the rest remains a mystery.
I missed this earlier this week: physicist John Wheeler has died at the age of 96. A snippet from the NY Times obituary:
At the same time, he returned to the questions that had animated Einstein and Bohr, about the nature of reality as revealed by the strange laws of quantum mechanics. The cornerstone of that revolution was the uncertainty principle, propounded by Werner Heisenberg in 1927, which seemed to put fundamental limits on what could be known about nature, declaring, for example, that it was impossible, even in theory, to know both the velocity and the position of a subatomic particle. Knowing one destroyed the ability to measure the other. As a result, until observed, subatomic particles and events existed in a sort of cloud of possibility that Dr. Wheeler sometimes referred to as "a smoky dragon."
This kind of thinking frustrated Einstein, who once asked Dr. Wheeler if the Moon was still there when nobody looked at it.
Wheeler recognized that physics is about ideas and the language used to express those ideas, not just mathematics and experimentation. He coined and popularized several phrases during his long career, including black hole, wormhole, and quantum foam.
The airplane on a conveyor belt question was just recently settled and we're confronted with a related question: will a helicopter on a turntable take off? The image is short on details and likely a joke, but let's assume that the turntable will match the speed of the helicopter's rotor (and further that the rotor's speed is measured relative to the helicopter and the turntable's speed is relative to the ground, otherwise it doesn't make much sense). Will the helicopter take off? Does it matter which way the turntable is spinning relative to the rotor? (thx, daniel)
I did embarrassingly bad on this Elements of the Periodic Table quiz. I blanked after naming 17 elements in 2 minutes. Oh, and xylophone is not an element! My physics degree should be retroactively unawarded. (via mouser)
A solar furnace is a structure used to harness the rays of the sun in order to produce high temperatures. This is achieved by using a curved mirror (or an array of mirrors) acting as a parabolic reflector to concentrate light (Insolation) on to a focal point. The temperature at the focal point may reach up to 3,000 degrees Celsius, and this heat can be used to generate electricity, melt steel or make hydrogen fuel.
Whoa! Here's a great photo of a solar furnace in Uzbekistan and an even better photo of said furnace melting aluminum (close-up).
If you've got an old TV, you can use the Fresnel lens to make a solar furnace of your own. Caveats apply:
DANGER! This device is extremely dangerous. It should not be constructed or operated by anyone who does not observe proper safety precautions. It will instantly destroy flesh. It will melt metals, ceramics, and most any other material. Always wear welding goggles when operating this device! DO NOT leave this device unattended.
This DIY solar furnace is capable of melting brick (!!) and will "boil" a quarter in ~25 seconds.
Solar furnaces and the like have been around for centuries. In the 3rd century BC, Archimedes allegedly used a mirror to burn up the entire Roman fleet during the seige of Syracuse:
When Marcellus withdrew them [his ships] a bow-shot, the old man [Archimedes] constructed a kind of hexagonal mirror, and at an interval proportionate to the size of the mirror he set similar small mirrors with four edges, moved by links and by a form of hinge, and made it the centre of the sun's beams--its noon-tide beam, whether in summer or in mid-winter. Afterwards, when the beams were reflected in the mirror, a fearful kindling of fire was raised in the ships, and at the distance of a bow-shot he turned them into ashes. In this way did the old man prevail over Marcellus with his weapons.
This assertion was tested at MIT and on Mythbusters with mixed results. (via delicious ghost)
NY Times columnist and economist Paul Krugman wrote a paper when he was an assistant professor in 1978 called The Theory of Interstellar Trade. Here's the abstract:
This paper extends interplanetary trade theory to an interstellar setting. It is chiefly concerned with the following question: how should interest charges on goods in transit be computed when the goods travel at close to the speed of light? This is a problem because the time taken in transit will appear less to an observer travelling with the good than to a stationary observer. A solution is derived from economic theory, and two useless but true theorems are proved.
Why does the woman depicted in the Mona Lisa appear to be both smiling and not smiling at the same time? The smile part of the Mona Lisa's face was painted by Leonardo in low spatial frequencies. This means that when you look right at her mouth, there's no smile. But if you look at her eyes or elsewhere in the portrait, your peripheral vision picks up the smile. (via collision detection)
A series of four lectures on physics, specifically quantum electrodynamics, by Richard Feynman. Only Part 1 is available on Google Video and the rest are in streaming Real format (blech)...hopefully they too will make their way onto Google Video.
Update: Another lecture by Feynman, this one about Elementary Particles and the Laws of Physics.
Update: I got an email from the nice folks at Vega Science Trust asking me to change the wording of this entry with regard to encouraging people to put these copyrighted videos up on Google Video. Fair enough...what I really meant by that is I wish the videos were presented in a more useable manner than RealVideo format. If there's one thing that YouTube has shown us more than anything, it's that people find watching video in embedded Flash players really convenient.
Starting in about 40 minutes, I'll be liveblogging the Mythbusters episode where they take on the infamous airplane on a conveyor belt problem. Updates will be reverse chronological (newest at the top) so don't scroll down if you're DVRing the episode for later viewing or otherwise don't want anything spoiled.
Fair warning? Ok here we go.
10:32p I've turned comments on. Why not!!
10:04p
The plane took off so easily. The laws of physics are proven correct once again. But I'm not sure this is going to settle anything. I'm getting email as we speak that the test was unfair. Plane was too light. Tarp was pulled too slowly. Etc. But the thing is, it doesn't matter how large the plane is...given enough runway and a strong enough conveyor belt, it will still take off. Ditto for the speed of the treadmill...it doesn't matter how fast the treadmill is moving. It could be going 300 mph in the opposite direction and as long as the bearings in the plane's wheels don't melt, it's gonna take off. (For an explanation, try this one by my friend Mouser, who has a MIT Ph.D in Physics Sc.D. in Nuclear Science and Engineering.)
9:58p
Update: Due to popular demand, the above graphic is available on a t-shirt at CafePress. Prices start at $18 and they're available in men's and women's sizes.
9:58p
Heeeeeeeere we go.
9:56p
The pilot flying the ultralight is predicting that he won't be able to take off.
9:55p
Orville Wright died 60 years ago today.
9:50p
Cockroach mini-myth: cockroaches would survive a nuclear blast longer than humans but there were other kinds of bugs that fared better. Another commercial.
9:47p
Back to the shaving cream in the car prank. Now they're going to use A-B foam...they're trying to fill all the space in the car and perhaps explode it. Totally worked.
9:44p
Expedia commercial. Nice synergistic placement. Good work, Discovery Channel's ad sales team.
9:43p
Ok, to do the large-scale plane test, they're using a 2000 foot tarp and a 400 pound ultralight. Tarp is pulled in one direction and the plane tries to take off in the other direction. The wind is picking up and blowing the tarp runway all over the place. They're also having problems with punching holes in the tarp. They're going to try again after we hear some more about radioactive cockroaches. Aaaand, another commercial.
9:36p
Second mini-myth: if you freeze a can of shaving cream, cut it open, and then put the foam in a car, it will heat and expand to fill the car. One can did almost nothing. 50 cans didn't do too much either.
9:32p
Off to commercial again. Macbook Air ad. I don't understand all the whining about how expensive and underpowered it is. You can't get by with an 80 GB hard drive? Come on.
9:30p
Now a bit of explanation from the boys. (Things are moving faster now, which is welcome.) The thrust from the airplane acts upon the air so it doesn't matter too much what the runway is doing to the plane's wheels. And then back to the roach thing. They irradiated them (and some other bugs) and most of the roaches died. Still pending...
9:25p
Ok, they're dragging paper behind a Segway and trying to take off with the model airplane in the opposite direction. IT JUST TOOK OFF.
9:19p
Back to the roach thing. More recapping and a little bit more setup. I don't see how people can watch this show...it's sooooo slooooow. And now another commercial break. Hello picture-in-picture.
9:18p
As expected, the model airplane "flew" off the end of the exercise treadmill. It didn't have enough room to take off, but if it stayed straight, it probably would have.
9:14p
First recap...they took a solid minute to explain what they've already done. Ugh.
9:13p
Going into the first commercial, we've caught a glimpse of how they're going to test the main myth. They're going to drag a huge plastic sheet long the ground and have the plane sit on the plastic and being going the other way attempting to take off. A reasonable substitute for the treadmill.
9:08p
They're starting off small with a model airplane on an exercise treadmill. They're showing the two hosts learning how to fly the tiny airplane. One of them is riding around on a Segway. Oh, and they're also doing two other mini-myths during the episode. They just switched gears to the first mini-myth: can a cockroach survive a nuclear blast?
9:04p
And we're off. They're calling it "the moment we've all been waiting for". My guess: the plane will take off.
8:58p
I've only watched one other episode of Mythbusters before today. I found the show to be a little slow and very repetitive; 8 minutes of material stretched into 45 minutes of show. Unfortunately, this practice seems to be common among science programs on television.
8:40p
Watching Family Guy as a warmup. The one with the nudist family. Good stuff.
8:22p
Preemptive answer for the inevitable "Do you realize how boring/stupid/goofy it is to liveblog this?" Most definitely.
For real this time: Mythbusters will air their challenge of the airplane on a conveyor belt puzzle this Wednesday at 9pm ET. (thx, darin)
Absolute Zero looks like an interesting show on cold temperatures, airing on PBS in mid-January. For the Long Zoom fans out there, don't miss the Sense of Scale widget.
The closure, it draws near. Remember the epic thread about the plane and the conveyor belt from last year...the one that pitted pilot against physicist against random internet commenter? In an upcoming episode of Mythbusters, they're going to air the results of a test they conducted with an ultralight and a quarter-mile-long conveyor belt:
If a plane is traveling at takeoff speed on a conveyor belt, and that conveyor belt is matching the speed in reverse, can the plane take off? "We put the plane on a quarter-mile conveyor belt and tested it out," says Savage about the experiment using a pilot and his Ultralight plane. "I won't tell you what the outcome was, but the pilot and his entire flight club got it wrong."
Awesome. If the laws of physics hold, that plane should take off. (thx, matt)
Question of the day:
You are shrunk to the height of a nickel and your mass is proportionally reduced so as to maintain your original density. You are then thrown into an empty glass blender. The blades will start moving in 60 seconds. What do you do?
The obvious answer is "die", but I don't think that's they're after here. I have an idea...but what say you?
Why does your shower curtain do that thing where it blows into you while you're showering? David Schmidt did some fluid-flow modeling and found that the spray creates a vortex (basically a low pressure region) which sucks the curtain in. (via cyn-c)
Is the search for aliens such a good idea? If/when we find evidence of extraterrestrial intelligent life, will they welcome us as neighbors, treat us as vermin in their universe or something inbetween? "Jared Diamond, professor of evolutionary biology and Pulitzer Prize winner, says: 'Those astronomers now preparing again to beam radio signals out to hoped-for extraterrestrials are naive, even dangerous.'"
An illustration of how insanely effective water is at absorbing heat: you can hold a water balloon over a candle without popping it. The rest of Robert Krampf's videos are worth a look as well.
Temporal anomalies in time travel movies, an investigation of how time travel is represented in movies like Donnie Darko, 12 Monkeys, and Back to the Future. (via joshua)
Are there many small galaxies, like the one just discovered just outside our own, orbiting the larger visible galaxies?
Embiggen, the fauxcabulary word created for an episode of The Simpsons, has found its way into string theory. Here's the usage from a recently published paper on Gauge/gravity duality and meta-stable dynamical supersymmetry breaking:
Here's the original quote from The Simpsons episode, Lisa the Iconoclast:
A noble spirit embiggens the smallest man.
The uses are probably not related, but you never know.
The scale of the IceCube neutrino detector is amazing...a cubic kilometer telescope 1.5 miles deep into the ice caps of Antarctica. (via pruned, which has more thoughts on the architecture of particle physics)
Three trillion years from now, the universe will be observably static, the Milky Way alone, and scientists of the day likely won't be able to "infer that the beginning involved a Big Bang".
How to survive a black hole. If you're in a rocket ship about to fall into a black hole, you might live a bit longer if you turn on your engines. "But in general a person falling past the horizon won't have zero velocity to begin with. Then the situation is different -- in fact it's worse. So firing the rocket for a short time can push the astronaut back on to the best-case scenario: the trajectory followed by free fall from rest."
A pair of articles on the Large Hadron Collider at CERN: A Giant Takes On Physics' Biggest Questions and Crash Course. The LHC will hopefully provide the 1.21 gigawatts 7 trillion electron volts needed to uncover the Higgs boson, aka, The God Particle. "What we want is to reduce the world to objects that have no structure, that are points, that are as simple as we can imagine. And then build it up from there again."
While working on a particle accelerator, Anatoli Bugorski accidentally put his head into the proton stream. "The left half of Bugorski's face swelled up beyond recognition, and over the next several days started peeling off, showing the path that the proton beam (moving near the speed of light) had burned through parts of his face, his bone, and the brain tissue underneath." Some photos here. (via cyn-c)
Regarding the hypermiling business from last week, a question on Ask MetaFilter: Does a truck work extra to pull a drafting car?
A man outfitted his family minivan with high-precision cesium clocks to demonstrate to his kids that they gained 22 nanoseconds of vacation time on their mountain camping trip than they would have at a lower altitude.
Remembering a physics conference that took place in NYC 20 years ago about high-temperature superconductors. One session, the "Woodstock of Physics", lasted until 3:15 in the morning; "it was like the Texas chili cook-off or the Iowa State Fair apple pie bake-off." The conference was such a big deal at the time that physicists with conference badges were immediately ushered into a nightclub in Chelsea for free by the bouncers.
New Scientist recently compiled a list of strange substances (with accompanying video): ferrofluids, non-Newtonian liquids, superfluids, and materials that get thicker when stretched. (via bb)
Does free will exist? "The conscious brain was only playing catch-up to what the unconscious brain was already doing. The decision to act was an illusion, the monkey making up a story about what the tiger had already done."
"The Mpemba effect is the observation that, in some specific circumstances, hotter water freezes faster than colder water." I remember hearing about this on an old episode of Newton's Apple, but I think they never really got to the bottom of it on that show, which was highly disappointing to me at the time.
David Pogue and Boing Boing have been ensnared by the airplane-on-a-treadmill problem we debated here last February. The airplane still takes off. :)
Man tries to jump the mile-wide St. Lawrence River in a rocket-powered Lincoln Continental. I don't want to spoil the result for you, but the concepts of gravity, force, and aerodynamics are fairly well established and understood, so why did anyone involved ever think that this jump was even close to possible?
Jim Holt reports on a pair of books that argue that string theory is hurting theoretical physics. The article contains a good overview of the history and current status of the theory. For those looking to discover which book is better, Holt recommends Smolin's The Trouble with Physics.
Nobel Prize winning physicist Gerard 't Hooft on how to become a good theoretical physicist. He lists the subjects you need to learn (from languages to quantum field theory) and resources (both online and off) for learning them. A note on the 't in his name.
Satellites measuring the earth's gravity from orbit detected a change in gravity from the massive earthquake that caused the tsunami in the Indian Ocean. "The gravity at the earth's surface decreased by as much as about 0.0000015 percent, meaning that a 150-pound person would experience a weight loss of about one-25,000th of an ounce."
This image of the participants of a 1927 conference on quantum mechanics sets the record for the most brainpower in one photograph. Schrodinger, Pauli, Heisenberg, Dirac, Compton, Bohr, Einstein, Planck, Curie, de Broglie, and Lorenz, all in one place.
Update: A Great Day in Harlem depicts several of the world's top jazz musicians. More here. (thx, jim & greg)
On the heels of two books critical of string theory, a look at the string theory backlash.
Physicist Lawrence Krauss sums up his thoughts from a small conference he organized on the topic of gravity. "There appears to be energy of empty space that isn't zero! This flies in the face of all conventional wisdom in theoretical particle physics. It is the most profound shift in thinking, perhaps the most profound puzzle, in the latter half of the 20th century."
Vincent van Gogh painted turbulence quite accurately. Mexican scientists "have found that the Dutch artist's works have a pattern of light and dark that closely follows the deep mathematical structure of turbulent flow".
Italian scientists have created glass made out of carbon dioxide. At high pressure, instead of forming a crystal (dry ice), the CO2 forms a clear, hard, vitreous material. More info. (Little known fact: I did research on glass in college, rubidium and cesium borosilicates mostly. Here's a few citations on Google Scholar.)
@ the movies
I know I'm going to get mail about my five-star rating for this movie, but it cannot be helped. One summer when I was a kid, a friend and I watched Bill and Ted's Excellent Adventure -- no joke -- every single day for a span of 2 months. I still know every line by heart, the timing, inflection, everything. If there were a Broadway production of this movie, I could slide effortlessly into the role of either Bill S. Preston, Esq. or Ted Theodore Logan, no rehearsal needed.
In my high school physics class my senior year, we had to do a report on something we hadn't learned about in class -- which, I discovered when I got to college, was a lot -- and I did mine on time travel. I went to our small school library and read articles in Discover and Scientific American magazines about Stephen Hawking, Kip Thorne, quantum mechanics, causality, and wormholes. To illustrate the bit about wormholes, I brought in my well-worn VHS tape of Bill and Ted's (a dub of a long-ago video rental) and showed a short clip of the phone booth travelling through space and time via wormhole. I got a B+ on my presentation. The teacher told me it was excellent but marked me down because it was "over the heads" of everyone in the class...which I thought was completely unfair. How on earth is Bill and Ted's Excellent Adventure over anyone's head?
This is the most wonderfully nerdy thing I've ever read about politics and blogging. "So in fact, Reynolds has managed to fit five units of wrongness into only four declarative statements! This is the hackular equivalent of crossing the Chandrasekhar Limit, at which point your blog cannot help but collapse in on itself." (via cyn-c)
Maybe the universe is a trillion years old and has experienced several big bangs and big collapses over the years. "People have inferred that time began then, but there really wasn't any reason for that inference. What we are proposing is very radical. It's saying there was time before the big bang."
Science blog Cocktail Party Physics has a list of "physics cocktails" in the sidebar (scroll down a bit). The Black Hole is "so called because after one of these, you have already passed the event horizon of inebriation." Boy, am I a huge sucker for physics puns.
A moving mass has been shown to generate a gravitomagnetic field (just like a moving electrical charge creates a magnetic field) and "the measured field is a surprising one hundred million trillion times larger than Einstein's General Relativity predicts". (via rw)
Now that I've closed the comments on the question of the airplane and the conveyor belt, I'm still getting emails calling me an idiot for thinking that the plane will take off. Having believed that after first hearing the question and formulating several reasons reinforcing my belief, I can sympathize with that POV, but that doesn't change the fact that I was initially wrong and that if you believe the plane won't take off, you're wrong too[1].
The only thing is, I'm not sure how to prove it to you if you don't understand the problem and the physics involved. I guess I could urge you to read the question and answer again carefully. I could tell you that not only does the conveyor belt not keep the plane stationary with respect to the ground but it *can't* keep that plane stationary with respect to the ground[2] and once you know that, of course it'll take off. My pal Mouser has a Ph.d in Physics from MIT and he says the plane will take off:
The airplane would take off normally, with the wheels spinning twice as fast as normal and a *slight* reduction in acceleration due to added friction.
Is that enough to convince you?
[1] This situation reminds me of Richard Dawkins' and Jerry Coyne's assertion that "one side can be wrong".
[2] The motion of the conveyor belt does nothing[3] to affect the movement of the plane when the plane is in motion...it doesn't matter if it's moving forward, backward, at 2 MPH, or at 400 MPH. If the plane were on castors that could spin freely from side to side as well as front to back, that treadmill could be spinning 100 MPH to the left and the plane would take off.
[3] Well, almost nothing. The friction of the turning wheels will slow things down a bit, but not enough to not make the plane take off. After all, the main function of the wheels of a plane is to provide a near-frictionless interface with the ground (or whatever the plane happens to be taking off from).
How do you find extra-solar planets? "I think the techniques employed by planet-hunters are pretty cool so the following is a brief primer on how the techniques work and the pros and cons of each."
This question posed to Cecil at The Straight Dope has occupied most of my day today:
Here's the original problem essentially as it was posed to us: "A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?"
I'll give you a few moments to think about that before discussing the answer...
...
...
...
Cecil says that the obvious answer -- that the plane does not take off because it remains stationary relative to the ground and the air -- is wrong. The plane, he says, can take off:
But of course cars and planes don't work the same way. A car's wheels are its means of propulsion--they push the road backwards (relatively speaking), and the car moves forward. In contrast, a plane's wheels aren't motorized; their purpose is to reduce friction during takeoff (and add it, by braking, when landing). What gets a plane moving are its propellers or jet turbines, which shove the air backward and thereby impel the plane forward. What the wheels, conveyor belt, etc, are up to is largely irrelevant. Let me repeat: Once the pilot fires up the engines, the plane moves forward at pretty much the usual speed relative to the ground--and more importantly the air--regardless of how fast the conveyor belt is moving backward. This generates lift on the wings, and the plane takes off. All the conveyor belt does is, as you correctly conclude, make the plane's wheels spin madly.
After reading the question this morning and discussing it with Meg for, oh, about 3 hours on and off, I was convinced that Cecil was wrong. There's no way that plane could take off. The conveyor belt keeps pace with the speed of the plane, which means the plane remains stationary from the POV of an observer on the ground, and therefore cannot lift off.
Then I read Cecil's answer again this evening and I've changed my mind; I'm fairly certain he's right. For a sufficiently long conveyor belt, that plane is taking off. It doesn't matter what the conveyor belt is doing because the airplane's energy is acting on the air, not the belt. I had better luck simplifying the problem like so: imagine instead of a plane, you've got a rocket with wheels sitting on that belt. When that rocket fires, it's eventually going to rocket off the end of that belt...which means that it doesn't remain stationary to the ground and if it had wings, it would fly.
What do you think? Can that plane take off?
See also Feynman's submerged sprinkler problem (answer) and an old argument of Newton and Huygens: can you swim faster through water or syrup?
Update: Well, that got out of control in a hurry...almost 300 comments in about 16 hours. I had to delete a bunch of trolling comments and it's not productive to keep going, so I closed it. Thanks for the, er, discussion and remember, the plane takes off. :)
Free 1200-page physics textbook, available online or for download. I have no idea if it's any good or not. Is anyone using this in their high school or college classroom?
A relativistic examination of gravity in the galaxy may indicate that the invention of dark matter may not be necessary to solve the not-enough-matter problem. "The motions of stars in galaxies is realized in general relativity's equations without the need to invoke massive halos of exotic 'dark matter' that nobody can explain by current physics."
Update: mjt has doubts about the paper referenced here and notes that there's other evidence for dark matter that is not questioned by the above study.
Scientists want to build an array of submillimeter telescopes across the whole earth to peer "inside" the massive black hole at the center of the galaxy.
Update: Many people wrote in to correct me in saying that "submillimeter" referred to the size of the telescopes...it of course referred to the EM wavelength. Me brain not working right.
Brian Greene on Einstein's most famous equation, E =mc^2. When he finally gets around to it in the middle of the article, Greene's got a pretty good layman's explanation of what the formula actually means.
A rare interview with Stephen Hawking about his remix of A Brief History of Time. The interview's a bit weird...the interviewer doesn't seem to know a whole lot about science.
A couple of guys calculated the average color of the universe to be turquiose. Then it turned out they had made an error and the actual color of the universe is beige.
Odd story of one astronomer possibly "stealing" another astronomer's discovery of a large trans-Neptunian object. The original discoverer alleges that the usurper looked at a couple of Web sites that detailed the discovery and where the discover's telescopes were pointed...the astronomy equivalent of stealing signs.
A sequel to Stephen Hawking's A Brief History of Time: A Briefer History of Time. "More Accessible. More Concise."
The existence and behavior of dark matter is puzzling indeed, but some UK astrophysicists speculate that adding three more spacial dimensions to the universe explains the gravitational behavior of dark matter. If they exist, these extra dimensions would be about a nanometer across. A baby step toward string theory?
Physicist Stephen Hawking has been reduced to blinking to control his helper computer.
Adriana: "I thought you might be interested in a post I wrote a while back about a former editor of Elle who communicated for the last year of his life via blinks".
PBS has put up a companion web site to the Nova program on Einstein airing in October. Features include audio clips of several physicists describing e=mc^2 to non-physicists.
When bent, why does dry spaghetti break into three or more pieces instead of two? This was one of the simple problems Richard Feynman amused himself with but never solved. Someone's come up with the answer: when the first breakage occurs, it causes a local increase in the curvature of the two pieces, resulting in more breakage. (thx dj)
Modelling nuclear decay in atoms may tell us something about dating and relationships. One of the findings: people who date often are beneficial to the dating ecosystem "because they break up weak couples, forcing their victims to find better relationships".
Los Alamos From Below: Reminiscences 1943-1945, by Richard Feynman. Today marks the 60th anniversary of the first atomic bomb test which bomb Feynman helped build.
In celebration of its 125th anniversary, Science magazine has a list of the 125 biggest questions facing science over the next 25 years. "How did cooperative behavior evolve?"; "Do deeper principles underlie quantum uncertainty and nonlocality?"; "What is the universe made of?"
It's not every day that a new form of matter is created. Physicists at MIT have created something called a superfluid, "a gas of atoms that shows high-temperature superfluidity".
Researching quantum honeybees. Can bees detect quantum fields and use them to find food?
"There is no physics theory that explains the nature of, or even the existence of, football matches, teapots, or jumbo-jet aircraft.". "Consequently physics per se cannot causally determine the outcome of human creativity; rather it creates the 'possibility space' to allow human intelligence to function autonomously."
How to turn a block of Antarctic ice into a giant neutrino detector. "To turn the ice into a telescope, all you have to do is drill an array of 80 holes half a meter across by 2.5km deep using a very powerfull jet of hot water. Then lower a string of 60 optical detectors into each hole before they refreeze, conect them up to some powerful computer analysers and you are good to go."
Astronomers may have detected the formation of a black hole. "A faint visible-light flash moments after a high-energy gamma-ray burst likely heralds the merger of two dense neutron stars to create a relatively low-mass black hole."
The Oh-My-God particle is a proton with the energy of a slow-pitched baseball. And it's moving so fast that after travelling for a year, it would only be a few nanometers behind a photon travelling at the speed of light.
"Fads, fashions and dramatic shifts in public opinion all appear to follow a physical law: one of the laws of magnetism". "Michard and Bouchaud checked this prediction against their model and found that the trends in birth rates and cellphone usage in European nations conformed quite accurately to this pattern. The same was true of the rate at which clapping died away in concerts."
A near perfect Einstein Ring found. Close galaxies can act as a lens for farther galaxies, focusing the distant light with an "Einstein Ring".
Some bacteria in Africa beat Fermi to the first stable nuclear reactor on Earth by almost 2 billion years. The bacteria enriched the uranium into a critical mass and the flow of water through the reactor kept the reaction going for millions of years.
This seems familiar:
It made Feynman think wistfully about the days before the future of science had begun to feel like his mission -- the days before physicists changed the universe and became the most potent political force within American science, before institutions with fast-expanding budgets began chasing nuclear physicists like Hollywood stars. He remembered when physics was a game, when he could look at the graceful narrowing curve in three dimensions that water makes as it streams from a tap, and he could take the time to understand why.
Rhodes' followup to The Making of the Atomic Bomb (for which he won a Pulitzer), while not as tight a narrative as its predecessor, was more interesting to me because I was less familiar with the story. In particular, the Soviet espionage effort during WWII was fascinating.
