Friday, September 23, 2011

Neutrinos break cosmic speed law

The UK Telegraph reports:
Antonio Ereditato, spokesman for the international group of researchers, said that measurements taken over three years showed neutrinos pumped from CERN near Geneva to Gran Sasso in Italy had arrived 60 nanoseconds quicker than light would have done. ...

If confirmed, the discovery would undermine Albert Einstein's 1905 theory of special relativity, which says that the speed of light is a "cosmic constant" and that nothing in the universe can travel faster.

That assertion, which has withstood over a century of testing, is one of the key elements of the so-called Standard Model of physics, which attempts to describe the way the universe and everything in it works.
AP also says:
GENEVA (AP) — A startling find at one of the world's foremost laboratories that a subatomic particle seemed to move faster than the speed of light has scientists around the world rethinking Albert Einstein and one of the foundations of physics. ...

Plunkett said he is keeping an open mind on whether Einstein's theories need an update, but he added: "It's dangerous to lay odds against Einstein. Einstein has been tested repeatedly over and over again."

Going faster than light is something that is just not supposed to happen according to Einstein's 1905 special theory of relativity — the one made famous by the equation E equals mc2. The speed of light — 186,282 miles per second (299,792 kilometers per second) — has long been considered a cosmic speed limit.

"We'd be thrilled if it's right because we love something that shakes the foundation of what we believe," said famed Columbia University physicist Brian Greene. "That's what we live for."
This is very unlikely to be confirmed. Physicist Brian Cox says that this would be the most profound discovery of the last 100 years.

Einstein's 1905 relativity paper said:
We will raise this conjecture (the purport of which will hereafter be called the “Principle of Relativity”) to the status of a postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body.
He did not explicitly say that nothing could go faster than light. It could be inferred from the way that light is used to define time, or the way that mass increases with velocity. So going faster than light is like going backwards in time or exceeding infinite mass. But you could also infer that from previous results, as Poincare used light to define time in 1898 and 1900, and Lorentz showed that mass increases with velocity in 1899.

Neutrinos were not even suspected until the 1930s, and thought to be massless until the 1990s.

Poincare was the first to explicitly say that relativity requires a cosmic speed limit, as he said in his 1904 St. Louis lecture:
From all these results, if they were confirmed, would arise an entirely new mechanics, which would be, above all, characterized by this fact, that no velocity could surpass that of light, (1 Because bodies would oppose an increasing inertia to the causes which would tend to accelerate their motion; and this inertia would become infinite when one approached the velocity of light.) any more than any temperature can fall below absolute zero.

No more for an observer, carried along himself in a translation he does not suspect, could any apparent velocity surpass that of light; and this would be then a contradiction, if we did not recall that this observer would not use the same clocks as a fixed observer, but, indeed, clocks marking 'local time.'
Poincare was also the first to apply these laws of relativity to all physics. Einstein just applied them to electromagnetism in 1905.

There is already an xkcd comic about the neutrinos, and about how news stories about new physics sometimes "end up in pointless arguments about Galileo." Yes, those pointless arguments nearly always are triggered by someone claiming to support science by giving some completely bogus Galileo argument.

While I think that it is very unlikely that neutrinos can go faster than light, it is not impossible. Neutrinos are very hard to detect, and this is a very slight effect. They were thought to travel at the speed of light until about 10 years ago, and now it is thought that they are slower. It is possible that the maximum speed of communication is actually somewhat faster than the speed of light, and light is slowed down by the aether just as it is slowed by glass. And maybe neutrinos are not slowed down by the aether. That would disrupt a lot of known physics, but I do not think that it would cause any time-travel paradoxes. There are actually a bunch of reasons for thinking that neutrinos might violate special relativity.

No comments:

Post a Comment