Posts Tagged ‘energy’
Physicists Say Speed-of-Light-Breaking Neutrinos Would’ve Lost Their Energy Along the Way
Another day, another wrinkle in the year's biggest physics story
And since that didn’t happen, those neutrinos . Case closed.
So let’s go a little deeper here. The physicists behind this assessment, Andrew Cohen and Sheldon Glashow of Boston University (Glashow has a Nobel under his belt, so these are no middling minds), ignore the debate over whether or not it’s possible for a fundamental particle to outpace the speed of light, and instead look directly at the OPERA neutrinos themselves.
In looking at the neutrino beams that landed at Italy’s Gran Sasso laboratory, Cohen and Glashow found that it was about the same as the beam emitted from CERN in Switzerland. That is, the neutrinos were of roughly the same high-energy flavor at their origin and at their destination.
But that’s not possible if these neutrinos surpassed the speed of light, they say. A neutrino achieving superluminal speeds would emit other lower energy particles--most likely an electron-positron pair-- along the way, and in doing so lose a good deal of its own energy. So the neutrino beam arriving at Gran Sasso should have been “significantly depleted” of high-energy neutrinos.
But this was not the case. Which means, they say, that in all likelihood these neutrinos never achieved superluminal speeds. The anomaly is an error in the data or measurement of the speed, or some other brand of misunderstanding or miscalculation.
Which makes a certain amount of sense, writes Steve Nerlich over at over the weekend. Neutrinos do move very fast, straight through the Earth (neutrinos don’t interact much with normal matter), relying on GPS time-stamping and other methods of man-made measurement that are very precise but certainly not infallible to determine time and distance traveled.
And it’s not like these neutrinos were clocked doubling the speed of light or something like that--the difference is 60 nanoseconds. That’s another way of saying that the neutrinos in question are thought to have traveled at 1.0025 times the speed of light. That’s certainly a small enough margin to be explained away by some kind of measurement error.
Still, the jury remains out on this one, and we certainly don’t want to dismiss a perfectly good game-changing science story just because it seems hard to reconcile with the status quo. After all, if OPERA’s result turns out to be confirmed it is going to completely reorient physics as we know them. More on this as it develops.
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Fermilab Stops Smashing Hadrons, Looks Into Smashing Muons
Hadrons are so last-decade anyhow
Here’s where the game stands. America dropped the ball when it dumped millions into the Superconducting Supercollider only to shutter the project back in the ‘90s. It was the next step in particle physics after Tevatron but it never was completed. CERN took up the mantle of high powered particle physics and now has the LHC, which stands as the largest physics lab in the known universe.
The LHC, like Tevatron, smashes hadrons (of which protons are a varietal). These are not fundamental particles, but are made up of smaller subatomic pieces, so when they collide the energy from the collision is split between the constituent quarks. If we could smash fundamental particles--those are particles that aren’t composed of other particles, but are already at the single-component level--more energy would go directly into the collision, and thus into spawning all kinds of exotic matter. Which is exactly what physicists want from a good collider.
And that’s why Fermilab’s physicists are thinking about muons these days. Now, here’s the cool trick--in order to smash muons, they’re going to have to bend time a little bit.
Muons are like electrons but heavier--about 200 times heavier actually--which is a good thing, considering we’re trying to manipulate and smash them together. But they’re also highly unstable, with a life spanning just a few microseconds. After that, they decay into a bunch of other less-useful stuff. A few microseconds isn’t very long, but there is a way to stretch it out long enough to be useful by playing with the rules of relativity.
It would work something like this: You get muons from high-energy particle collisions, which generally impart a good deal of energy to the particles they spawn. Which means the muon, from the moment it falls out of this particle collision, is moving very fast. If you can then grab it and give it a little accelerating up toward the speed of light, relativistic effects start to take over. As the muon approaches light speed, time slows down for the muon relative to the time frame of the surrounding accelerator. So those two microseconds stretch into a lifetime that’s long enough to be relevant to physicists--that is, long enough to smash two of them together.
It’s a complex trick but a feasible one, and such a collider isn’t very big--it would fit in Fermilab’s current footprint. And it would put Fermilab right back at the cutting edge of particle physics--not that it ever really left.
Hadrons. They’re so 2010. More details at .
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ILL Researchers Trap The Most Neutrons Ever Bottled, Setting a Science Record
When subatomic science gets wack, physicists get ILL
Neutrons may seem like the boring cousin to the more active and interesting protons and electrons that make up atoms, but neutrons hold some mysteries that could shed light on the Big Bang and the formation of the cosmos (life, the universe, everything, etc.). They can also mysteriously become other subatomic particles, like protons, electrons, and electron antineutrinos--a pretty neat trick of physics. But it’s precisely because they have no electric charge that they are notoriously difficult to manipulate.
And because they are difficult to trap and manipulate, they are also very difficult to study. Knowing how they pull off this transformation to other subatomic particles would tell physicists quite a bit about neutrons, their role in the Big Bang and the Standard Model, and how the universe came to be.
But experiments thus far have lacked the kind of precision necessary to make accurate assessments, chiefly because when measuring neutrons physicists are trying to hit a moving target. But no more. At the ILL--the single highest-intensity neutron source on the planet--researchers have corralled neutrons at a density of 55 particles per cubic centimeter, a full five times more than they were previously able to bottle up.
They did so by using superfluid helium-4 to chill the neutrons down to -450 degrees--roughly nine degrees above absolute zero. At that temperature everything slows down, bringing even elusive subatomic particles like neutrons under enough control to hit the 55-per-cubic-centimeter mark.
Still, that’s not enough to get the kind of statistical precision researchers need to do the kind of science the researchers want to carry out. To answer the really big questions about the universe, they need even higher densities and higher sample sizes. But with some fine tuning they might be able to reach 1,000 neutrons per cubic centimeter, the lead researcher told .
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Baffling CERN Results Show Neutrinos Moving Faster Than the Speed of Light
That's really fast
Just a refresher--not that you need it--but nothing travels faster than the speed of light. In physics-as-we-understand-them, it is the absolute and ultimate speed limit in our universe. We’ve tested and retested the speed of light, measured it in as many ways as we can think of, and much of modern physics is built upon the idea that nothing can exceed it.
So naturally this result is potentially huge. But, as noted above, it’s not yet time to tear down the whole of modern physics and start all over. Here’s what’s going on: CERN physicists are firing neutrinos--which don’t interact with normal matter and thus can pass straight through the earth--to a detector in Italy. The aim here was to test the frequency of oscillations (that’s when one flavor of neutrino to another flavor), so the Geneva team was sending a beam of muon neutrinos toward Gran Sasso, and the Gran Sasso team was recording how many ended up there as tau neutrinos.
But in doing so, they started to notice something odd. The neutrinos from CERN were showing up at Gran Sasso a few billionths of a second early--in other words, they appeared to be getting from Switzerland to Italy faster than light would travel the same distance.
This isn’t an isolated anomaly, but has been going on for years. The team has now measured some 15,000 batches of neutrinos coming across that distance, and they say they’ve reached a point where the statistical significance is such that, were they trying to prove anything else, it would count as as formal scientific discovery. But try as they might, they can’t explain what’s happening.
Nobody, least of all the researchers involved, is ready to call the Standard Model’s upper speed limit busted just yet. But they also can’t explain what’s happening, which is why they are opening up their data to scrutiny from the wider scientific community. So now we’ll have to wait and see if others in the physics world can replicate their results or come up with some kind of explanation as to why the neutrinos appear to be breaching a fundamental physical law.
Feel free to beat them to the punch by posting your own theories in the comments below.
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MIT’s Tiny Energy-Harvester Makes Electricity From Low-Frequency Vibrations
Wireless are used for all kinds of things, from monitoring factory machines and oil pipelines to keeping track of pollution. While the efficiency of their energy consumption has improved, the sensors' batteries still need to be changed occasionally. MIT's device, a microelectromechanical system (we prefer the term energy-harvester) makes electricity from the vibrations of foot traffic and other low-power energy sources from the environment, potentially removing the need for batteries completely.
The quarter-sized energy-harvester has improved on the designs of by taking inspiration from the bridges themselves. MIT's energy-harvester consists of a microchip with a bridge-like structure anchored at either end. On the bridge is a weight sitting on one layer of , which naturally gathers electric charge when faced with mechanical stress. Other devices use a cantilever beam instead of a bridge to pick up vibrations, which is much less efficient. MIT's design picks up a wider range of vibrations and produces 100 times more energy than any other harvester available.
The next step for the project is to get the device to pick up lower-frequency vibrations and generate at least 100 microwatts of power, a target that would be able to power a whole network of wireless sensors.
[MIT]
Google Releases its Energy Consumption Numbers, Revealing a 260 Million Watt Continuous Suck
How does that translate? Google also estimated that its total carbon emissions for 2010 were just below 1.5 million metric tons. Not all of Google’s electricity comes from carbon resources--a quarter comes from renewable fuels like wind, thanks to some deals the company has made with utilities--but that’s still some decent tonnage.
Still, Google argues that its consumption really isn’t so bad. Its data centers carry out billions of operations--a billion searches per day alone--and many of those save fuel. Google searches save trips to the library or the travel agent, for instance, offsetting the power consumed by its processing farms. And when you break it down it’s not so bad, considering the vast numbers of people using Google’s services. The company said an average user consumes just 180-watt hours per month, which roughly equates to running a 60-watt light bulb for three hours.
And how does that power usage break down? Google apparently didn’t detail every last watt, but it did say that search queries only burn 12.5 million of those 260 million watts. As for the other quarter billion, it’s probably a pretty even split between Gchat and Rebecca Black.
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IBM and 3M Team Up to Make a Semiconductor Adhesive That Will Enable Next-Gen Chips
In other words, it doesn’t sound easy. But a material like this is necessary if companies like IBM are going to move beyond stacking a few layers of silicon and get down to the business of stacking 100-chip towers that will power the devices of the future.
3-D semiconductors are basically multi-layered chips that can stack computing power, networking, and memory all into one neat system-on-a-chip. Right now companies like IBM can stack a handful of chips, but what they want are silicon towers. That means they need some kind of mortar that possesses these unique properties to hold everything together. That’s what 3M and IBM are striving for: some kind of adhesive that could coat entire silicon wafers, holding them tightly together while still dissipating heat away from heat-sensitive components like logic circuits.
And they want it by 2013--about the same time the first generation of smaller 3-D processors is expected to hit the market in mobile devices. If they get it right, they predict that they could leapfrog today’s existing processor technology, creating a silicon “brick” 1,000 times faster than today’s fastest microprocessors.