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Another day, another wrinkle in the year's biggest physics story

And since that didn’t happen, those neutrinos couldn’t have traveled faster than light. 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 Universe Today 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.

[SciAm]

The main problem with MAVs has to do with the way they respond (or don’t respond) to dynamic environments--things like shifting or gusting winds, moving bodies, and other variables that have to be accounted for in realtime. MAVs are tiny, so there’s not a lot of space for computing assets or sensor payloads, and that leads to a sort of intractable problem: how can engineers make these things smaller and more capable while also adding increased situational awareness and better in-flight processing?

When facing a tough problem like this a little biomimicry never hurts, and that’s exactly where the Pentagon is looking with its recent contracts. If two research stipends recently handed down are any indication, the micro-drones of the future may have tiny hair-like sensors all over their bodies and big, compound eyes.

The cilia-like hairs will serve to keep the drones’ hovering and flight stable by sensing changes in air flow at the tiniest levels. That means the drone could sense a wind gust coming shortly before it arrives, allowing it to compensate for the change in circumstance. It would also aid in maintaining overall stability during flight, as the MAVs central processor would possess a constant awareness of--and the ability to manipulate--the boundary flow layer of air surrounding the drone as it hovers and flies.

The bug-like compound eyes would similarly help MAVs navigate in cluttered spaces by increasing the amount of visual data available to the drones’ processors. An on-board minicomputer would process images in realtime, using those visual cues to automatically avoid obstacles and navigate cleanly and efficiently.

[Danger Room]

[AFP]

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 Ars.

[Ars Technica]

A new shrimp farming technology devised by researchers in Texas is churning out record-setting levels of shrimp. Called super-intensive stacked raceways, its a system of indoor aquaculture that generates far more shrimp per cubic meter of water than open pond farming or any other aquaculture technique. And it could be deployed just about anywhere.

The shrimp grow in huge enclosed tubs called raceways, stacked four high in a column. As the shrimp develop and grow under computer-controlled conditions (the water is carefully circulated but not completely renewed, keeping environmental costs and water usage in check), they are moved downward from one raceway to the next--baby shrimp go in the top and progress downward to the bottom raceway, from which they are eventually harvested.

That innovation--the ability to raise very large, protein-rich shrimp (they’re called U15, but you probably know them as “jumbo”) in very little water--means the kilo-per-cubic-meter numbers are through-the-roof: 25 kilograms of shrimp from just one cubic meter of water. For some perspective, that’s equivalent to 1 million pounds of shrimp per acre of water. U.S. shrimp farms top out at about 20,000 pounds per acre of water. The best shrimp farms in tropical climates, working year round, yield something like 60,000 pounds per acre in a good year.

So we’re talking about a vast improvement to our shrimp stores. But the impact isn’t just an abundance of jumbo shrimp to batter up and fry. For one, it provides countries like the U.S. with a means to produce fresh shrimp (we import the vast majority of ours, and it’s usually frozen and thawed a few times before it gets to us). And shrimp exporters like China are on the verge of becoming shrimp importers due to socioeconomic trends and population growth, and that would make shrimp quite expensive. With stacked raceways, we could have our own domestic supply of shrimp, circumventing the need for a series of violent “shrimp wars.”

But further, this method could provide a simple-to-produce means of protein in places where food in general and protein in particular are growing scarce. Plus: jumbo shrimp you guys! These will go great on an hors d'oeuvre table next to those popper-optimized jalapenos we’ve been cultivating.

The footage comes via an event at Southmead Hospital in the U.K. aimed at raising awareness of men’s cancers. To show just how effective Da Vinci can be in the operating room, urology fellow Ramesh Thurairaja grabbed the sticks and delicately showed a grape just what Da Vinci is capable of.

There are more than 1,000 Da Vinci robots worldwide, and this particular robot has performed 450 prostate cancer removals alone. No man wants to think of his grapes anywhere near the forceful hands of a massive multi-armed machine, but this demo shows just how magnificently precise and steady-handed our robot surgeons can be.

[WIRED UK]

This is useful because atom interferometers are super sensitive, more so than the inertial sensors used widely on modern aircraft. Those inertial sensors have been known to fail with potentially disastrous results, but more frequently they cause slight errors to creep into navigation systems that must later be corrected. With no moving parts and a high degree of accuracy, atom interferometers could mitigate these problems, recording inertial effects 300 times weaker than the normal fluctuations in the acceleration in a standard aircraft.

But the vibrations in an aircraft have previously made deployment of atom interferometers in planes unfeasible. That’s where Remi Geiger at the Laboratoire Charles Fabry in Paris comes in. He and his colleagues have created a system that compensates for the effects of vibrations via mechanical accelerometers that record the movements of the aircraft itself.

Using that vibration data, their system recalculates the interferometer’s data to compensate for any vibration that might be skewing its final result. By stripping out the vibration noise, they end up with a clean, high-resolution atom interferometer result. The system could go a long way toward delivering better acceleration data to the cockpits of large jets. Geiger and company have already tested their system successfully on an Airbus A300.

But an atom interferometer that can operate free of laboratory constraints isn’t limited to jetliner applications. The researchers hope their method will lead to more precise measurements of geodesy and of gravity itself, enabling some fundamental experiments that have been previously very difficult to conduct and challenging some existing principles of physics with more and better data. More at arXiv.

[Technology]