Friday, June 29, 2012

Consensus and/or reality

Physics is certainly an experimental science where everybody can prove or disprove hypotheses...... but!

But as experiments become more and more expensive and difficult the possibility to test a theory is restricted to a small number of collaborations.
This is certainly true in particle physics where some hypothesis can be tested only by some very specific experiments.

Therefore is true that part of the "truth" behind a theory is built upon consensus among the physics community. This is certainly good, and means, for example, that one cannot come up with a stupid idea and pretend to be founded for inconclusive experiments. This also means that theories cannot be disproved by one single crucial experiment (yes naive Popper fans I'm talking to you).

But consensus leads also to some interesting features.
Here is a plot (obtained with this nice website) about the percentage of arXiv.org papers talking about neutrinos (blue), Majorana neutrinos (green) and superluminal neutrinos (red) in the category "phenomenology of high energy physics".


Do you notice any interesting bump?  


 Well, the bump is already fading out as the experimental evidence for too-fast neutrinos has disappeared... but it is interesting in itself: for six months the theoretical physics community has believed this phenomenon to be "true" and reasoned about it. Note that I do not find this bad at all, it has stimulated a discussion and forced people to re-think a lot of long-standing certainties (and confirmed them, by the way). 
But this is a way to demonstrate how physics (science?) develops...

And now to whet your appetite (before the independence day) another plot (always for the same category) but this time showing at which energy "something" is believed to be about to happen/happening.



Fortunately the consensus reasoning works only looking backward to understand what is believed to be true starting from experiments and not to foresee the result of an experiment starting from what people believe! But...

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