Monday, 26 September 2011

Those neutrinos travelling faster than light

Amplify’d from
An Italian experiment has unveiled evidence that fundamental particles known as neutrinos can travel faster than light. Other researchers are cautious about the result, but if it stands further scrutiny, the finding would overturn the most fundamental rule of modern physics—that nothing travels faster than 299,792,458 meters per second. [...]
The idea that nothing can travel faster than light in a vacuum is the cornerstone of Albert Einstein's special theory of relativity, which itself forms the foundation of modern physics.


Doug Clow said...

The point about what counts as 'things travelling faster than the speed of light' is well made.

An even more accessible example is sweeping a laser across the moon - like sweeping the spot of a laser pointer across a distant wall, only a bit larger scale. You don't have to move the laser that fast to have the 'spot' zip across the moon's surface faster than the speed of light. From memory, if you have a laser about a metre long, you only need to have the end moving at about 1 m/s (2mph) to do this. Of course, there isn't actually a 'thing' on the moon that is moving - it's just a succession of photons hitting the surface at different times.

But I'm pretty sure neutrinos count as a thing. They are, as you say, particles, and even have non-zero (but very very small) mass.

My money is on this experiment - and the earlier (not statistically significant but interesting) result from Fermilab - pointing up an interesting (for some values of interesting) new source of systematic error in such experiments. I reckon there's an outside chance they're pointing the way to something really really interesting about the nature of neutrinos beyond the Standard Model. And almost no chance that they're violating Special Relativity.

David Chapman said...

Yes, thanks, the laser on the moon is indeed a very nice example.