One Big Bang or Billions? Discussing the Philosophy of Cosmology

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“Our big bang could be just one island of space-time in a vast cosmic archipelago,” observed Martin Rees, Astronomer Royal and 2011 Templeton Prize laureate, in a public talk earlier this month titled “Our Universe and Others.” He was speaking at Cosmology and the Constants of Nature, a conference at the University of Cambridge designed to introduce philosophers of physics to fundamental problems in cosmology and associated areas of high-energy physics. The conference was part of a larger collaborative project, “Establishing the Philosophy of Cosmology,” funded by a grant from the John Templeton Foundation.

Rees highlighted the possibility that we are part of a vast cosmic archipelago because of two fundamental questions for 21st century physics: Are there many, perhaps billions of, “big bangs” rather than just one? And if there are many, are they all governed by the same physics? Another issue is the far, far distant future. Will the universe collapse in on itself again, or is it ever-expanding so that eventually even our current near-galactic neighbors will disappear over an event horizon?

Other speakers included 2006 Templeton Prize laureate John Barrow, John Ellis of King’s College London, and John Webb of the University of New South Wales, Sydney. The discussions included observational programs that test the constancy of traditional fundamental constants, and how self-consistent theories of varying constants might be formulated.