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Do We Live In A Closed Universe?
Per Krauss, there is only one type of universe where its “total energy is precisely zero.” This is a closed universe. In this theory, a closed universe can “appear spontaneously with impunity, carrying no net energy.”
As Krauss notes, this assumes that Richard Feynman’s sum-of-all-paths method applies to quantum gravity. This area of theoretical physics research attempts to unite quantum mechanics and general relativity into a single theory. However, it is very much a work-in-progress. To date, there is no single piece of clear empirical evidence to support or deny its claims. Currently, quantum gravity remains merely a possibility.
If the big bang began with a closed universe, it would have had a very short lifetime. “A closed expanding universe filled with matter,” Krauss writes, “will in general expand to a maximum size and then recollapse just as quickly.” This tiny closed universe would last perhaps about 10-44 seconds.
Inflation to the Rescue
According to inflation theory, just a miniscule moment after the big bang, the universe expanded exponentially.
What if inflation occurred during the oh-so-brief period when our baby closed universe was still alive? Our closed universe would expand by a stupendous factor — more than ten-thousand trillion trillion times — in a fraction of a second. The curvature of our nascent closed universe would then, as Krauss put it, “be driven to an absurdly small value.”
What does this mean? Imagine we are ants at the center of a football field here on Earth. The football field appears flat to us because it is such a small portion of the entire curved surface of the Earth. Similarly — as a result of the gargantuan expansion of the closed universe due to inflation — it now appears flat.
A long-lasting flat universe — just what the CMB and other observations indicate!
Thus, an initially closed universe made flat by inflation is a possible scenario for our universe — a universe created from nothing. By nothing, Krauss means “the absence of space and time”. And, according to quantum gravity theory, this nothingness is unstable — it can and must produce universes.
God and Parallel Universes
Because a universe can be created from nothing in theory, Krauss argues that a pre-existent God is unnecessary.
Krauss then invokes eternal inflation theory. It predicts the creation of multiple universes, each with its own random laws of physics. This, Krauss contends, even precludes Einstein’s God — the creator of a single set of physical laws which govern the cosmos.
Krauss’s attempts to explain away the need for God are clever, to say the least. However, as he himself admits, they do not prove God does not exist. His metaphysical musings leave many questions.
For one thing, even if there are multiple universes where the laws of physics are different, each set of laws are presumably logical. We would expect that they would each follow a specific set of mathematical formulas.
This begs the question: why does each universe in the so-called multiverse (if there really is one) obey certain laws of physics — laws which, although different, all operate within a logical framework. Who or what created this inherent logic?
I welcome all comments, pro and con.
Krauss, L. M. A Universe from Nothing, Why There is Something Rather than Nothing. (2012). New York: Free Press.
Greene, B. The Fabric of the Cosmos, Space, Time, and the Texture of Reality. (2005). New York: Vintage Books.
University of Tennessee, Knoxville. The Geometry of the Universe. Accessed March 12, 2012.
NASA. Cosmology: The Study of the Universe. Accessed March 12, 2012.
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