Monday, 4 August 2008

Not so special

In a previous blog entry I bemoaned the tactic used by religious scientists of dragging up physical constants as if their values indicated fine-tuning and, ipso facto, The Good Lord. Given that we're rather ignorant about the consequences of different values for these parameters, it's always seemed rather presumptuous to me to state that the ones that we've got are particularly special.

Well, someone's now actually done some calculations to shed light on this conundrum. In a recent paper, a chap called Fred Adams has picked three fundamental constants (gravity, G; the fine-structure constant, α; a composite nuclear reaction rate parameter, C) and explored the consequences for star formation over ranges of values for them. When analysing the resulting model output, his criterion for success included things like star lifespan and energy output. Stars needed to stick around long enough, and produce enough energy, for things like us to do OK.

Not too surprisingly, he found that relatively large regions of parameter space were capable of producing star-like objects capable, to first order, of producing conditions favourable to life. He goes on to qualify this with reference to whether the resulting stars undergo sufficient nucleosynthesis to produce carbon, water, etc., in sufficient quantities, but that's for a future study. Interestingly, Ward spends some time in the paper considering the ability of stellar objects like black holes, neutron stars and exotic dark matter stars to produce conditions conducive to life. Although these aren't included in his headline analysis, he suggests that they could play a role and, in principle, this could further extend the region of viable parameter space.

Anyway, it looks like one of God's Gaps has just gotten a bit smaller. Surprise, surprise.

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