Another use of Entropy in Cosmology


Last week came word of a different way of looking at Gravity – seeing it in terms of entropic flow in a holographic universe gives us the ability to simply connect quantum phenomenon and gravitational theory. (Something that’s been a sort of Holy Grail in physics for decades.)

Now a team of physicists here in the United States is making a simple argument from entropic principles that answers the questions raised by the Anthropic principle; the idea that our Universe seems “tuned” to give rise to carbon based life.

From the Physics ArXive blog:

“Today, they outline their idea and it makes a fascinating read. By thinking about the way entropy increases, Bousso and Harnik derive the properties of an average Universe in which the complexity has risen to a level where observers would have evolved to witness it.

They make six predictions about such a Universe. They say ‘typical observers find themselves in a flat universe, at the onset of vacuum domination, surrounded by a recently produced bath of relativistic quanta.These quanta are neither very dilute nor condensed, and thus appear as a roughly thermal background.’

Sound familiar? It so happens that we live in a (seemingly) flat universe, not so long after it has become largely a vacuum and we’re bathed in photons that form a thermal background. That’s the cosmic infrared background that is emitted by galactic dust heated by starlight (this is different from the cosmic microwave background which has a different origin).

That’s a remarkably accurate set of predictions from a very general principle. The question, of course, is how far can you run with a theory like this.”

Read the full article here.

I’ve just finished Antony Flew’s book “There IS a God”. Much of his argument hinges on the taking the Anthropic principle seriously. He finds it leading him to a relatively strong form of deism. I’m wondering, if this paper survives challenges and review, what effect the paper’s point that the Anthropic Principle is derivable from first principles will have on his argument.

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Episcopal bishop, dad, astronomer, erstwhile dancer...