Was Einstein wrong? Probably not.

XKCD's take on public understanding of science

Ok, this is where my profile picture becomes relevant(-ish)

You may have read in the news today that Einstein was wrong. This is due to people drawing conclusions without enough information (it’s not the first time either, see physicists try to destroy Earth with black hole, Higgs boson found, and other such news stories). Luckily though, not everyone out there has jumped on the bandwagon.

The result published by CERN today (the paper in question is here) was from an experiment involving a very very (very) small particle called a neutrino which barely interacts matter making it tough to detect. They’re extremely interesting to physicists and neutrino physics has greatly expanded over the last decade.

The experiment was designed to measure the speed of neutrinos (these things matter to physicists) and involved firing a beam of them from CERN in Geneva to the OPERA detector in Italy.

The surprising thing was that the neutrinos appeared to be travelling faster than light (ftl) going against Einstein’s theory of relativity, which explains everything bigger than an atoms movement (to an extent) by having the speed of light as a sort of physical speed limit (it turns out space and time bend when you get faster!). Some have used this neutrino result to say Einstein was wrong. This is bad science.

The first thing to note is that more often than not, an astounding result like this is due to a systematic error, i.e. something in the experiment that causes an inaccurate result, though by this stage most errors have been ruled out.

Secondly, if the result is accurate and repeatable it doesn’t necessarily mean Einstein was wrong. For starters, Einstein’s relativity has worked for nearly a century, and since it’s inclusion into physics it has explained many many physical phenomena very well. It might just be that neutrinos have slightly different rules!

With respect to the former case, all the previous data on neutrino speeds suggests an erroneous result, in this post the data from an observation of light and neutrinos arriving from a supernova is compared with what the data would have been if the neutrinos were travelling ftl.

The results were that they couldn’t have been travelling at the speeds detected at OPERA. Errors are of great importance in experimental physics as they are very easy to make and very hard to find. When I did my first undergraduate lab it was explained that working out the error on an experiment often takes longer than the experiment itself, so this is a distinct possibility. You can find a more in depth piece about the errors here.

If the latter case is true however, what we will have is a new neutrino physics, or maybe some alterations to the Higgs model which is not quite an entirely new physics but still very exciting. Due to the nature of physics, this will change a lot of modern physics. The main impact though is on causality (via relativity), Surib Sarkar at Oxford University had this to say about it’s impact on causality:

“The constancy of the speed of light essentially underpins our understanding of space and time and causality, which is the fact that cause comes before effect.”

The upshot of this is we can no longer eliminate paradoxes that exist without relativity. Which would cause more problems.

All in all, it’s likely that there is some explanation for the result that doesn’t change our physics, but if there isn’t, physicists are going to have a lot of work to do!

But in the spirit of scientific scepticism, I could be wrong and so too could Einstein. But it’s unlikely..