Blog on the Run: Reloaded

Sunday, November 6, 2011 11:06 am

More on those faster-than-light neutrinos …

… from Tom Levinson at Balloon Juice (but also cross-posted at Scientific American if you want to avoid Reality-Based cooties). Short version: Light interacts with charged particles and thus slows down, while neutrinos don’t. Thus, it is possible for some neutrinos to go faster than some light, but we’re a long way from proving that things actually can go faster than light generally:

That’s the problem for any challenge to a fundamental pillar of knowledge:  if the new observation is correct, it must be understood in a way that accommodates all the prior work consistent with the older view that is under scrutiny.  As physics popularizers always note:  Einstein’s account of gravity — the General Theory of Relativity — delivers results that collapse into those of Newton’s earlier theory through the range of scales for which Newtonian physics works just fine.  If it didn’t, then that would be a signal that there was something wrong with the newer theory.

It’s a nice, plain-English discussion of the issue, with several links to other, equally good related discussions. He goes on to point out how this aspect of scientific research has important implications for the climate-change-denial crowd. I’m sure they won’t want to hear about it, but still.



Tuesday, October 4, 2011 8:10 pm

Not so bizarre after all

Filed under: Cool! — Lex @ 8:10 pm
Tags: , ,

So, the recent report that scientists had found particles traveling faster than the speed of light? The one that was going to blow up Einstein’s theory of relativity?

Maybe not so much, actually.

Oh, it’s not that the neutrinos in question weren’t traveling slightly faster than 186,200 miles per second. They might have been. It’s just that that might not actually be the top speed of light, depending on what light is going through.

In a Q&A with the Chronicle of Higher Education, Marvin L. Marshak, a professor of physics at the University of Minnesota-Twin Cities, breaks it down:

Q. Could Einstein and his immensely famous ratio, E=mc2, really be wrong?

A. I’ve convinced myself that this could actually be real. If it’s real, I don’t think it overthrows relativity completely. It could be basically telling us that the constant that Einstein proposed—namely, the speed of light—is not actually the right constant. In other words, when light goes through material, it slows down, and so it could be that what we think is a vacuum is not actually empty. And that’s not that shocking, because for the last 10 years or so we’ve been talking about dark energy. We’ve been talking even longer than 10 years about the Higgs field. So the possibility is that a vacuum is not empty, and therefore, just like light going through glass, light is slowed down relative to neutrinos, which don’t have electromagnetic interactions, and therefore could possibly go a little faster.

Q. But there’s still some ultimate speed limit at which matter converts into energy?

A. Right. There’s still some point. And in any event, for us here, the exciting thing is that we have the only other experiment that could really check this result, and that’s the neutrino beam that goes from Fermilab to northern Minnesota. This is an existing experiment that actually published a result four years ago on this topic, but not with sufficient accuracy to detect the effect at the level that the people at CERN are claiming exists. So now our plan is to improve our timing and go back and look at this with a different setup.

Q. So what does this mean for Einstein and relativity?

A. I don’t want to minimize the impact on physics of this, but personally, I think it could fit into Einstein’s basic framework with some relatively small modifications. What the implications of those modifications are, that would be still significant.

So: significant, but not quite “What if everything you thought you knew was wrong?” significant.


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