Cosmological constant not optimal after all

Paul Raven @ 19-01-2011

Interesting news from that weird and wonderful intellectual space where physics and theology trade slow, dignified blows; new research into the effects of varying the cosmological constant swings out like a haymaker from the atheist corner and knocks at least one God-of-the-gaps out of the ring [via SlashDot].

… although positive, the cosmological constant is tiny, some 122 orders of magnitude smaller than Planck’s constant, which itself is a small number.

So Page and others have examined the effects of changing this constant. It’s straightforward to show that if the the constant were any larger, matter would not form into galaxies and stars meaning that life could not form, at least not in the form we know it,.

So what value of the cosmological constant best encourages galaxy and star formation, and therefore the evolution of life? Page says that a slightly negative value of the constant would maximise this process. And since life is some small fraction of the amount of matter in galaxies, then this is the value that an omnipotent being would choose.

In fact, he says that any positive value of the constant would tend to decrease the fraction of matter that forms into galaxies, reducing the amount available for life.

Therefore the measured value of the cosmological constant, which is positive, is evidence against the idea that the constants have been fine-tuned for life.

I guess the obvious theist retort would be that God’s ineffable decision to use a sub-optimal value for the constant is a test of our faith… hi-ho, anthropic principle!