Monday, July 13, 2009

Multiverse: Getting comfortable with a zillion of everything that is unique?

In "How to map the multiverse" (04 May 2009), Anil Ananthaswamy explains:
Greene's transformation is emblematic of a profound change among the majority of physicists. Until recently, many were reluctant to accept this idea of the "multiverse", or were even belligerent towards it. However, recent progress in both cosmology and string theory is bringing about a major shift in thinking. Gone is the grudging acceptance or outright loathing of the multiverse. Instead, physicists are starting to look at ways of working with it, and maybe even trying to prove its existence.

If such ventures succeed, our universe will go the way of Earth - from seeming to be the centre of everything to being exposed as just a backwater in a far vaster cosmos. And just as we are unable to deduce certain aspects of Earth from first principles - such as its radius or distance from the sun - we will have to accept that some things about our universe are a random accident, inexplicable except in the context of the multiverse.
However, if our universe is part of a multiverse then we can ascribe the value of the cosmological constant to an accident. The same goes for other aspects of our universe, such as the mass of the electron. The idea is simply that each universe's laws of physics and fundamental constants are randomly determined, and we just happen to live in one where these are suited for life. "If not for the multiverse, you would have these unsolved problems at every corner," says Linde.

Let's see. We don't need to prove fine tuning. It's just there. But there's no evidence for the multiverse; it is an attractive idea because it makes our current cosmological values and fine tuning appear random. I love this line: " ... starting to look at ways of working with it, and maybe even trying to prove its existence".

Question: How fit are people in this state of mind to evaluate what they are seeing?