Tripping over the light fantastic

Note from the Cosm overlord: Rather annoyingly, I was on holiday when this story first broke – but I figured that (unlike the neutrinos) I would employ the 'better late than never' philosophy...

On September 23, researchers at CERN (home of the Large Hadron Collider) made an announcement that shook the foundations of modern science: the speed limit of light – that most unbreakable of unbreakable things – seemed to have been broken.

Despite the researchers urging caution, ‘Einstein was wrong’ headlines bounced around the media faster than shotgun pellets fired into a safe.

The basis of the announcement was that neutrinos (see box below) seemed to have covered a distance of 730km faster than the speed of light would allow.

The majority of physicists maintain that the results will prove to be flawed. But if the findings are proven to be accurate... is there an explanation that doesn’t involve thowing Einstein’s baby out with the bath water?

First though, a quick look at neutrinos...

Now a peek at light speed...

Next, let's have a look at the experiment...

The experiment that 'broke' the rules

[Graphic: The experiment that broke the rules. Click image to relativisticate]

Ok, now on to what the results could mean (if they prove to be accurate)...

 

The neutrinos just skipped through another dimension

String theory (see box) allows for the existence of dimensions beyond the three (not counting the extra dimension of time) that we recognise as the world around us. One suggestion is that, instead of travelling the full 730km at record speed, the neutrinos took a ‘short cut’ through one of these extra dimensions – allowing them to arrive earlier than expected.

A variation of this involves something called a membrane universe. This suggests that our three dimensional universe sits within a higher dimensional membrane. It could be that the speed of light is limited within the membrane but can be exceeded outside of the membrane. Neutrinos created in violent collisions could be thrown out of our universe within the membrane – by ‘jumping’ out of our dimension, the neutrinos can travel faster.

One analogy is to think of two waves travelling across the surface of a swimming pool. The water in the waves is limited to how fast it can travel across the pool, but if the waves collide, some of that water is thrown out of the pool – allowing it to travel faster

 

The neutrinos did travel faster than light... but so what if they did?

One misconception about the ‘speed limit’ imposed by special relativity is that it is just that: a speed limit.

What Einstein actually says is that nothing can cross the light-speed barrier. This works fine for particles that have to be accelerated up to speed, but not all particles need to be accelerated. Light, for example is ‘born’ already travelling at light speed.

It could be that these neutrinos were ‘born’ already travelling faster than light speed – as long as they don’t cross the limit threshold (by accelerating or decelerating), they won’t have broken any laws

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via cosmonline.co.uk