Disturbing the Universe

David L Clements, science and science fiction


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Fine tuning or not?

The issue of the suitability of the universe to life, and the fine tuning of physical laws that this seems to require, is a long running one in cosmology. It’s led to the Anthropic Principle, something often misunderstood and misinterpreted, many worlds interpretations of quantum mechanics and, probably inevitably, to theology.

But does the existence of life really require physical laws to be fine tuned?

A new paper preprint on the arXiv suggests this might not be so. The authors looked to see what the consequences would be of a stronger strong nuclear force. The conventional argument goes that protons would bind strongly to other protons early in the universe, so you end up with most of the universe being helium and you get no chemistry.

However, it turns out that in this new universe neutrons still bind more strongly to protons than protons. The new two-proton nuclei would thus decay into something like deuterium and you still get something like hydrogen chemistry.

There are a lot more steps from hydrogenic chemistry to life, but this analysis shows that some of the conventional ‘fine tuning’ arguments might not be as solid as they appear. Quite where that leaves the many worlds anthropic or theological arguments remains to be seen.

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