The universe we see –stars, moons, planets, galaxies– is but a small, accidental tip of an infinite cosmic iceberg. During the epoch of inflation, thought to have been triggered by the phase transition that marked the end of the grand unification at approximately 10−36 seconds after the Big Bang, the accelerating expansion of space was far more dramatic than in today’s universe, expanding at an absolutely staggering rate, tearing space asunder. During this period no objects—even two elementary particles—remained close enough to one another for long enough to interact.
A Small Piece of Space Formed Our Universe
“Objects separated by the width of an atom at the beginning of inflation,” notes Dan Hooper, Senior Scientist and the Head of the Theoretical Astrophysics Group at the Fermi National Accelerator Laboratory, in At the Edge of Time, “were trillions of miles apart from one another by the time it was over—only a minuscule fraction of a second later. So utterly complete was this act of sequestration, that these regions became more than merely distant. Inflation left them in entirely different universes. A small piece of the space that emerged from inflation went on to form our universe, while other pieces were stretched into newly formed universes, populating a greater multiverse of disconnected worlds.”
Leads to a Multiverse
“It’s hard to build models of inflation that don’t lead to a multiverse,” observed MIT physicist Alan Guth who developed the idea, cosmic inflation and the nascent inflationary universe passed through a phase of exponential expansion soon after the Big Bang, driven by a positive vacuum energy density. “It’s not impossible, so I think there’s still certainly research that needs to be done. But most models of inflation do lead to a multiverse, and evidence for inflation will be pushing us in the direction of taking the idea of a multiverse seriously.”
What Exists Beyond the Edge?
Perhaps we will never know what exists beyond the “edge” of our spherical observable universe, but there’s a variation of the multiverse theory in which the multiple universes are not separate entities. Instead, they are isolated, non-interacting pockets of space within one continuous fabric of space-time—”like multiple ships at sea” says Neil deGrasse Tyson, “far enough away from one another so that their circular horizons do not intersect yet they all share the same body of water.”
There is every reason to suspect that in some fraction of these universes, matter and energy could take on forms that are the same or at least similar to those we find in our world—such as atoms and light with the same underlying laws of physics and many of the chemical species that we find in our Solar System.
Alien Worlds with Unknown Forces
Yet some regions within the multiverse are likely to be alien worlds with unknown forces and new forms of matter along with more—or fewer than three dimensions of space. Worlds may be utterly unlike anything we can imagine says Hopper.
Beyond, speculates Russian physicist Alexander Antonov, may exist a “hidden multiverse” of parallel universes from different dimensions, the edges of six of which are adjacent to our universe observable neither by electromagnetic nor by gravitational manifestations that are responsible for the phenomenon of dark matter and dark energy.
Perhaps, In another universe, another you is wondering if multiverse theory is true.
The Daily Galaxy with Avi Shporer, Research Scientist, MIT Kavli Institute for Astrophysics and Space Research via At the Edge of Time (Princeton University Press) and ArXiv.org . Avi was formerly a NASA Sagan Fellow at the Jet Propulsion Laboratory (JPL).
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