Saturday, March 24, 2012

Weekend Post - Einstein seems to have been right all along

I don’t know whether to be pleased or disappointed. It looks like Einstein’s theories are still safe. His suggestion that the speed of light can never be exceeded seems still to be true.

Last year, amongst huge fanfare, some Italian scientists published results suggesting they had been able to break one of the fundamental laws of nature. They claimed that they had managed to force a beam of particles to travel faster than the speed of light. Admittedly only very slightly faster than light, but even a little bit would have been enough. Their beam of neutrinos had travelled all the way from the CERN laboratory in Geneva across the border into Italy, a trip of 730km, and they had arrived 60 billionths of a second earlier than light would have covered the same distance. If this was true, if something really could travel faster than light, faster than 300,000 kilometers per second, then our understanding of the universe would have been wrong. After the results were announced the international media was full of headlines asking “Was Einstein wrong?” The internet remains full of conspiracy theorists, alien abduction theorists and every single psychotic-with-a-website who thought this vindicated their bizarre theories. This was a great day for them.

However the scientific world was split. A small number of scientists took the results and went on long, fantastic imaginative journeys. If this is true then reverse time travel is possible, we can reach the stars and every science fiction book you’ve ever read could become true. Well, that’s what the newspapers, TV news shows and the internet said.

The better scientists were skeptical. That is, of course, how scientists are MEANT to be. Just because another scientist has suggested something, that doesn’t make it true. The skeptics said that if this was shown to be true then clearly it’s remarkable but, they said, let’s slow down for a moment. Let’s see if these results are true before we jump to any conclusions. The results had to be exposed to the most critical, skeptical and demanding of all of science: peer review.

To their credit the Italian scientists did just that. They published their results and gave the international scientific community the opportunity to tear them to pieces. That’s the nature of the scientific process. You have an idea, you test it, you publish your results and your colleagues do their best to find a flaw in what you’ve done. It’s not a competition, it’s just a rigorous way of testing ideas. Most importantly you give other scientists the opportunity to try and repeat your experiment.

Here’s an experiment I did at home to illustrate this. Three members of my family all measured the height of my youngest son. They all did it in different rooms but using exactly the same technique. He stood against a wall, we rested a book on his head, marked his height against the wall and then measured the distance to the floor. The results were all different. All three measurements were slightly different. He hadn’t grown in between the measurements, gravity hadn’t changed and we all used the same tape measure. This crude experiment demonstrated that there are always tiny variations in experiments, tiny flaws, tiny mistakes that lead to tiny differences in results.

I’m not saying that the Italian scientists were this incompetent in their measurements, I’m just pointing out that experiments have to be repeated many times to be certain they’re measuring things correctly.

That has now happened. A different group of scientists at exactly the same lab in Italy have repeated the experiment. Remember that last time the neutrinos were a mere 60 billionths of a second faster than light. That’s one forty-thousandth faster than expected. This time? They travelled at exactly the same speed as light.

Of course it’s perfectly possible that this repeat of the experiment is wrong and the first one was correct. That’s why they should probably do it again. However, it’s safe to assume for now that Einstein’s theories and propositions are still ok for now. They’ve worked perfectly well for almost a century and they’re no reason to kick them out yet.

A spokesman for the lab, Dr Sandro Centro, sounds like a proper scientist to me. He told the BBC:
"We are completely compatible with the speed of light that we learn at school … In fact I was a little sceptical since the beginning … Now we are 100% sure that the speed of light is the speed of neutrinos."
It looks like the alien, space travel and time travel fantasists will have to wait a little longer before their ideas come true. Perhaps a lot longer.

1 comment:

Rob Silver said...

I think the Italians were having a tiny financial crisis at the time which turned the world up-side-down. I'm surprised the results were only skewed by 60 billionths of a second as a result.