LHC and the Big Bang

LHC and the Big Bang

Having just returning to civilisation after watching the eclipse on the Faroe Islands I was suddenly reminded that the revamped LHC is about to be fired up. I tweeted the first LHC story that crossed my twitter feed, without even reading it. The article was ” Big Bang theory could be debunked by Large Hadron Collider“, by Sarah Knapton, the science editor at the Telegraph. I don’t know Sarah and don’t know anything about her science background. The headline was sensationalist, but when you work in journalism you soon learn that the headline writers are paid to cherry pick and then add a bit of hyperbole on top.

So, why I am blogging about this article and my tweet. Well, it is all because the reaction on twitter to this story was rather hostile. When I RTed a comment about Fred Hoyle being amused by the article, there were a couple more negative tweets. Some suggested that I should not be spreading such nonsense.

My opinion is that I don’t feel very strongly about this article, and I am surprised others are so outraged. This article is not going to win any prizes, but neither is it particularly terrible. As a positive, it might encourage a few non-physicists to become interested in the LHC restart. (N.B. That does not mean that I encourage exaggeration in order to generate interest in science.)

I did not respond on twitter as these issues are not simple and I did not want to get drawn into a long discussion limited to just a few words. Instead, I contacted someone who is actively researching this area and asked his opinion on the article. I have quoted him below, but he also made two additional comments. (1) The scientists in the article may have credited colleagues in the interview, but these credits might not have been included in the article. (2) He did not want be named as he was not impressed by the tone of the twitter discussion.

Anyway, here is the view of a researcher close to this topic:

You can read about rainbow gravity in Scientific American. As you can see, it is really an idea which might remove any singularity from the big bang, but of course everyone believes that some form of quantum gravity must intervene to prevent that in any case. Inflation is the conventional way of starting a big bang these days and that does not require a singularity either. Removing the singularity in no way debunks the big bang. You will also note that Smolin says in as many words that the authors have not really got to grips with the idea. (In fact, rainbow gravity has never been mentioned by theorists as a serious idea in my presence.)

When Dr Faizal says “we predict” he really means, “this was all predicted by smart people 15 years ago or more”. So all the stuff in the article below the picture is correct, but nothing to do with him. His new idea is to use rainbow gravity (speculative and not his idea) to make a prediction of the energy scale relevant to extra dimensions (also speculative). He then goes off into wilder shores of speculation by extrapolating to the early universe. In particular his quote “If we do detect mini black holes at this energy, then we will know that both gravity’s rainbow and extra dimensions are correct” is absolute rubbish.

As far as the LHC goes, none of this is novel. We started looking at mini-black-hole scenarios more than a decade ago when the ADD model brought extra space dimensions up to date and suggested that they could be observed via strong gravity effects. Observing a black hole at the LHC would prove that gravity is stronger at small scales, but nothing more than that. It could be that we just don’t understand gravity, or it could be that we are seeing extra space dimensions – you would need to make the measurements to try to find out. Even if we established the presence of extra dimensions, they would be relatively large ones (about the inverse TeV) and so nothing to do with string theory dimensions.

So I think you can conclude that the Big Bang theory is safe and well….