I love this stuff.
Looks like the universe is getting bigger and more complicated all the time.
How to map the multiverseBRIAN GREENE spent a good part of the last decade extolling the virtues of string theory. He dreamed that one day it would provide physicists with a theory of everything that would describe our universe - ours and ours alone. His bestselling book The Elegant Universe eloquently captured the quest for this ultimate theory.
"But the fly in the ointment was that string theory allowed for, in principle, many universes," says Greene, who is a theoretical physicist at Columbia University in New York. In other words, string theory seems equally capable of describing universes very different from ours. Greene hoped that something in the theory would eventually rule out most of the possibilities and single out one of these universes as the real one: ours.
So far, it hasn't - though not for any lack of trying. As a result, string theorists are beginning to accept that their ambitions for the theory may have been misguided. Perhaps our universe is not the only one after all. Maybe string theory has been right all along.
Greene, certainly, has had a change of heart. "You walk along a number of pathways in physics far enough and you bang into the possibility that we are one universe of many," he says. "So what do you do? You smack yourself in the head and say, 'Ah, maybe the universe is trying to tell me something.' I have personally undergone a sort of transformation, where I am very warm to this possibility of there being many universes, and that we are in the one where we can survive."
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.
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Each form gives rise to a different vacuum of space-time, and hence a different universe - with its own vacuum energy, fundamental particles and laws of physics. The hope, nurtured by Greene and others, was that there was some kind of uniqueness principle that would pick out the particular form of space-time that produces our universe.
That hope has since receded dramatically. In 2004, Michael Douglas of the State University of New York in Stony Brook, and Leonard Susskind of Stanford University surveyed the developments in string theory to date and concluded that all these theoretical varieties of space-time should be taken seriously as physical realities - that is, they point to a multiverse. Susskind coined the term "the landscape of string theory" to describe the 10500 or more different universes. Nothing in string theory suggests that any one of these universes is preferred over others. Rather, it appears all are equally likely.
Complete article here. Well worth reading.
The article points out ways of testing the multiple universe theory so we may soon (in a decade or so) have confirmation of it, assuming it is true of course. That would provide one more nail in the coffins of antiquated religions. None of them predicted this.
Topic: How to map the multiverse