However, if the theorists are right, before it ever finds the Higgs, the LHC will see the first outline of something far bigger: the grand, overarching theory known as supersymmetry. SUSY, as it is endearingly called, is a daring theory that doubles the number of particles needed to explain the world. And it could be just what particle physicists need to set them on the path to fresh enlightenment.
If you haven't been keeping up with particle physics for the past few years (as I haven't), this will bring you up to speed a bit.
The natural nuclear reactor formed when a uranium-rich mineral deposit became inundated with groundwater that acted as a neutron moderator, and a nuclear chain reaction took place. The heat generated from the nuclear fission caused the groundwater to boil away, which slowed or stopped the reaction. After cooling of the mineral deposit, short-lived fission product poisons decayed, the water returned and the reaction started again. These fission reactions were sustained for hundreds of thousands of years, until a chain reaction could no longer be supported. Fission of uranium normally produces five known isotopes of the fission-product gas xenon; all five have been found trapped in the remnants of the natural reactor, in varying concentrations. The concentrations of xenon isotopes, found trapped in mineral formations 2 billion years later, make it possible to calculate the specific time intervals of reactor operation: approximately 2 hours and 30 minutes
Nice try Fermi, but Mother Nature got there first.
Due to a mistranslation, Soviet reports on Enrico Fermi claimed that his work was performed in a converted "pumpkin field" instead of a "squash court", squash being an offshoot of hard racquets.
When the first self-sustained nuclear chain reaction was achieved, a coded phone call was made by one of the physicists, Arthur Compton, to James Conant, chairman of the National Defense Research Committee. The conversation was in impromptu code:
Compton: The Italian navigator has landed in the New World. Conant: How were the natives? Compton: Very friendly.
Pumpkin field, tube alloy, the Italian navigator, the Manhattan Project...the building of the atomic bomb had no shortage of fanciful language.
Update: BLDGBLOG did a post on fossil reactors recently, which is probably where I got the link above in the first place.
Are the problems that have plagued the Large Hadron Collider and previous high-energy efforts (SSC, I'm looking at you here) a result of the Higgs boson travelling back from the future to meddle in its own discovery? A pair of scientists think it's a possibility.
"It must be our prediction that all Higgs producing machines shall have bad luck," Dr. Nielsen said in an e-mail message. In an unpublished essay, Dr. Nielson said of the theory, "Well, one could even almost say that we have a model for God." It is their guess, he went on, "that He rather hates Higgs particles, and attempts to avoid them."
This malign influence from the future, they argue, could explain why the United States Superconducting Supercollider, also designed to find the Higgs, was canceled in 1993 after billions of dollars had already been spent, an event so unlikely that Dr. Nielsen calls it an "anti-miracle."
Nothing like a little science on the Moon, I always say.
Astronaut David Scott in 1971, from the Apollo 15 Lunar Surface Journal. Scott was part of the Apollo 15 crew, and applied Galileo's findings about gravity and mass by testing a falcon feather and a hammer. The film, shown in countless high school physics classes, is the nerdy, oft-neglected cousin of Neil Armstrong's space paces.
I don't put people on pedestals very much, especially not physicists. Feynman [who won a 1965 Nobel for his work in particle physics] was pretty good, although not as good as he thought he was. He was too self-absorbed and spent a huge amount of energy generating anecdotes about himself. Fermi [who developed the first nuclear reactor] was good, but again with limitations-every now and then he was wrong. I didn't know anybody without some limitations in my field of theoretical physics.
I read one such anecdote involving Gell-Mann in a book some years ago:
Richard Feynman, Gell-Mann's chief competitor for the title of the World's Smartest Man but a stranger to pretension, once encountered Gell-Mann in the hall outside their offices at Caltech and asked him where he had been on a recent trip; "Moon-TRAY-ALGH!" Gell-Mann responded in a French accent so thick that he sounded as if he were strangling. Feynman -- who, like Gell-Mann, was born in New York City -- had no idea what he was talking about. "Don't you think," he asked Gell-Mann, when at length he had ascertained that Gell-Mann was saying "Montreal," "that the purpose of language is communication?"
Assuming you're not in a big lecture hall and the professor shuts the door at the start of class, how long does it take for you and your classmates to deplete the oxygen enough to feel it?
Here's a taste of the reasoning behind the answer:
So one person needs about 2lb of oxygen a day, or .9 kg. But how many liters is that? Oxygen has a molar mass of 16 grams, so oxygen gas, or O2, has a mass of 32 grams per mole. One mole of gas at standard pressure and temperature takes up 22.4 liters.
I don't know if they brought this up on physicsbuzz yet, but lack of oxygen isn't really uncomfortable (though it can kill you). Increase in CO2 is what triggers the apparent need to breath. I am pretty sure the minimum partial pressure of O2 is around 0.16 bar. Actually, that is the min recommended, I don't know if that is the pass-out limit.
On July 17, 1969, The New York Times issued a correction related to an editorial the paper published in 1920 that dismissed the idea of rocket travel in the vacuum of space. The editorial read, in part:
That Professor Goddard, with his 'chair' in Clark College and the countenancing of the Smithsonian Institution, does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react -- to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high school.
The correction stated:
Further investigation and experimentation have confirmed the findings of Issac Newton in the 17th Century and it is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error.
The Times regrets the error! Wish I'd written that next to a few muffed physics exam questions. Here's a pretty good explanation of why rockets work in vacuums. (via @davidfg)
Law of Gravitation - An Example of Physical Law
The Relation of Mathematics and Physics
The Great Conservation Principles
Symmetry in Physical Law
The Distinction of Past and Future
Probability and Uncertainty - The Quantum Mechanical View of Nature
Seeking New Laws
If I ever write a book, it might have something to do with the two minds that govern creative expertise: the instinctual unconscious mind (the realm of relaxed concentration) and the thinking mind (the realm of deliberate practice). The tension between these two minds is both the key to and fatal flaw of human creativity. From the world of sports1, here's Rockies pitcher and college physics major Jeff Francis describing the interplay of the minds on the mound:
Even though I do understand the forces and everything, there's a separation when I'm pitching. If I throw a good pitch, I know what I did to do it, but there has to be a separation between knowing what I did and knowing why what I did helped the ball do what it did, if that makes any sense at all. If I thought about it on the mound, I'd be really mechanical and trying to be too perfect instead of doing what comes naturally.
But you don't need to be a physics major to wrestle with the consequences of the conflict between the two minds. After an injury and subsequent surgery, Francis' instinctual mind works to protect his body from further injury:
Francis repeatedly pulled the ball back in preparation to throw. But as he flashed his arm forward, his hand would, mind unaware, bring the ball back toward his ear rather than at full extension. It was his body essentially shortening the axis of his arm to decrease the force on his shoulder, protecting him from pain. And Francis could not stop it.
After his 10th pitch and first muffled groan of pain, he stopped.
"It's hurting you?" Murayama said.
"Yeah," Francis said.
"I can tell. You're getting out ahead of your arm. Slow down, stay back a little more."
"Does it look like I'm scared to throw a little?"
"Are you scared?"
"Not consciously."
To fully recover and regain his former effective pitching motion, Francis will utilize his thinking mind to retrain his unconscious mind through deliberate practice to ignore the injury potential. (thx, adriana)
[1] Most of the examples I've cited over the years deal with sports, mostly because professional athletes are among the most trained, scrutinized, studied, and optimized creative workers in the world. For a lot of other professions and endeavors, the data and scrutiny just isn't as evident. ↩
When they are passing in front of their stars, their atmospheres are backlit in a way that can make spectroscopic analysis of the different chemicals in their atmospheres comparatively easy: the wavelengths of light absorbed by the various chemicals will show up, in a tiny way, in the spectrum of the starlight. And this is what makes it possible to imagine looking at them for signs of life.
What scientists would look for are planets with unstable atmospheres, which James Lovelock said was an indication of life.
After the extragalactic planet post this morning, Sam Arbesman sent me a link to systemic, a blog dedicated to the search for extrasolar planets written by Greg Laughlin, one of the scientists involved in the effort. Here are two relevant posts. In Forward, Laughlin says we're very close to finding a nearby Earth-like planet:
Detailed Monte-Carlo simulations indicate that there's a 98% probability that TESS will locate a potentially habitable transiting terrestrial planet orbiting a red dwarf lying closer than 50 parsecs. When this planet is found, JWST (which will launch near the end of TESS's two year mission) can take its spectrum and obtain resolved measurements of molecular absorption in the atmosphere.
In Too cheap to meter, Laughlin presents a formula for the land value of such a discovery that depends on how far away the planet is, the age of the star it orbits, and the star's visual magnitude.
Applying the formula to an exact Earth-analog orbiting Alpha Cen B, the value is boosted to 6.4 billion dollars, which seems to be the right order of magnitude. And applying the formula to Earth (using the Sun's apparent visual magnitude) one arrives at a figure close to 5 quadrillion dollars, which is roughly the economic value of Earth (~100x the Earth's current yearly GDP)...
The idea is to use gravitational microlensing, in which a distant source star is briefly magnified by the gravity of an object passing in front of it. This technique has already found several planets in our galaxy, out to distances of thousands of light years. Extending the method from thousands to millions of light years won't be easy, says Philippe Jetzer of the University of Zurich in Switzerland, but it should be possible.
The levitation trick works because giant magnetic fields slightly distort the orbits of electrons in the frog's atoms. The resulting electric current generates a magnetic field in the opposite direction to that of the magnet. A field of 16 teslas created an attractive force strong enough to make the frog float until it made its escape.
After two to three weeks, the team found a small number of "triple tracks" in the plastic -- three 8-micrometre-wide pits radiating from a point (see diagram, top right). The team says such a pattern occurs when a high-energy neutron strikes a carbon atom inside the plastic and shatters it into three charged alpha particles that rip through the plastic leaving tracks.
It'll be interesting to see if this can be replicated and the source of the neutrons verified.
The reality in question -- admittedly rather a small part of the universe -- was the polarisation of pairs of photons, the particles of which light is made. The state of one of these photons was inextricably linked with that of the other through a process known as quantum entanglement. The polarised photons were able to take the place of the particle and the antiparticle in Dr Hardy's thought experiment because they obey the same quantum-mechanical rules. Dr Yokota (and also Drs Lundeen and Steinberg) managed to observe them without looking, as it were, by not gathering enough information from any one interaction to draw a conclusion, and then pooling these partial results so that the total became meaningful.
That's a relief, although the head of one of the group called their results "preposterous", so perhaps we're still not really here.
You may remember reading the New Yorker article on Garrett Lisi, a surfer, physicist, and snowboarder who came out of nowhere in 2007 to present a plausible Theory of Everything, "a unifying idea that aims to incorporate all the universe's forces in a single mathematical framework". I do but I missed this visualization of Lisi's theory posted by New Scientist in late 2007. You may want to break out the bong for this one. (thx, matt)
Let me point to the Adjacent Possible of the biosphere. Once there were lung fish, swim bladders were in the Adjacent Possible of the biosphere. Before there were multicelled organisms, the swim bladder was not in the Adjacent Possible of the biosphere. Something wonderful is happening right in front of us: When the swim bladder arose it was of selective advantage in its context. It changed what was Actual in the biosphere, which in turn created a new Adjacent Possible of the biosphere. The biosphere self consistently co-constructs itself into its every changing, unstatable Adjacent Possible.
If the becoming of the swim bladder is partially lawless, it certainly is not entailed by the fundamental laws of physics, so cannot be deduced from physics. Then its existence in the non-ergodic universe requires an explanation that cannot be had by that missing entailment. The universe is open.
We determined that, generally speaking, the gravity in each Mario game, as game hardware has increased, is getting closer to the true value of gravity on earth of 9.8 m/s^2. However, gravity, even on the newest consoles, is still extreme.
In Super Mario 2, Mario experiences a g-force of 11 each time he falls from a ledge, a force that would cause mere humans to black out. In Madden 2006, the game's fastest cornerbacks can run the 40 in 2.6 seconds. (via waxy)
It's true that after 300 years, nuclear waste is still about 100 times more radioactive than the original uranium that was removed from the earth. But even this isn't as scary as it sounds. If the waste is stored underground in such a way that there's only a 10 percent chance that 10 percent of it will leak -- which should be more than doable -- the risk will be no worse than if we had never mined the uranium in the first place.
Muller asserts that safe nuclear power is a solved technical problem and that the use of it is a political issue.
It looks like black holes can grow to be as massive as 50 billion suns. How massive is that? It's approximately 99 duodecillion kilograms....which is a 99 followed by 39 zeros. (Put another way, if you had 99 duodecillion dollars, you could buy as many PlayStation 3s as you wanted. Blows your mind, right?)
On the basis of their measurements, the team concluded that if the photons had communicated, they must have done so at least 100,000 times faster than the speed of light -- something nearly all physicists thought would be impossible. In other words, these photons cannot know about each other through any sort of normal exchange of information.
The Higgs Boson: 95%. The Higgs is the only particle in the Standard Model of Particle Physics which hasn't yet been detected, so it's certainly a prime target for the LHC (if the Tevatron doesn't sneak in and find it first). And it's a boson, which improves CERN's chances. There is almost a guarantee that the Higgs exists, or at least some sort of Higgs-like particle that plays that role; there is an electroweak symmetry, and it is broken by something, and that something should be associated with particle-like excitations. But there's not really a guarantee that the LHC will find it. It should find it, at least in the simplest models; but the simplest models aren't always right. If the LHC doesn't find the Higgs in five years, it will place very strong constraints on model building, but I doubt that it will be too hard to come up with models that are still consistent.
The list also functions as a nice overview of what's happening at the edges of our physics understanding. (via 3qd)
Quantum mechanics is the girl you meet at the poetry reading. Everyone thinks she's really interesting and people you don't know are obsessed about her. You go out. It turns out that she's pretty complicated and has some issues. Later, after you've broken up, you wonder if her aura of mystery is actually just confusion.
Would like to see the list for men as well. (via snarkmarket)
Physicists of the 20th Century on Banknotes (5 MB PDF), including Marie & Pierre Curie on a short-lived 500 franc note, Niels Bohr on a Danish 500 kroner note, and Nikola Tesla on several notes from Yugoslavia and Serbia. The author of the article is Steve Feller, physics professor at Coe College and my college advisor. Feller has a keen interest in numismatics and recently published a book about the money used in WWII camps.
The element gallium is in very short supply and the world may well run out of it in just a few years. Indium is threatened too, says Armin Reller, a materials chemist at Germany's University of Augsburg. He estimates that our planet's stock of indium will last no more than another decade. All the hafnium will be gone by 2017 also, and another twenty years will see the extinction of zinc. Even copper is an endangered item, since worldwide demand for it is likely to exceed available supplies by the end of the present century.
Many of the elements listed above are used in the construction of computer equipment and flat-panel TVs.
The "Pillars of Creation" may be the most iconic Hubble photograph ever taken. "Located in the Eagle Nebula, the pillars are clouds of molecular hydrogen, light years in length, where new stars are being born," says Aguilar. "However, recent discoveries indicate these pillars were destroyed by a massive nearby super nova some 6,000 years ago. This is a ghost image of a past cosmic disaster that we won't see here on Earth for another thousand years or so-and a perfect example of the fact that everything we see in the universe is history."
Is the universe fractal-like, even on large scales? A group of Italian and Russian scientists argue that it displays a fractal pattern on a scale of 100 million light years. Other scientists aren't so sure.
Many cosmologists find fault with their analysis, largely because a fractal matter distribution out to such huge scales undermines the standard model of cosmology. According to the accepted story of cosmic evolution, there simply hasn't been enough time since the big bang nearly 14 billion years ago for gravity to build up such large structures.
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.
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.
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 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.
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: 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.
9:50p
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.
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.
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)
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?
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.'"
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)
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.
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.
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".
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?
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.
[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."
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...
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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.
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?
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.
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.
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".
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)
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."
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.
