Ask Ethan #73: The Multiverse and you

Ethan Siegel
Jan 30, 2015 · 11 min read
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Image credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team.
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Image credit: ESA and the Planck Collaboration, modified by me for correctness.
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Image credit: wiseGEEK, © 2003–2014 Conjecture Corporation, viahttp://www.wisegeek.com/what-is-cosmology.htm#; original from Shutterstock / DesignUA.
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Image credit: Wikimedia Commons users Frédéric MICHEL and Azcolvin429, annotated by me.
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Image credit: Bock et al. (2006, astro-ph/0604101); modifications by me.
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Image credit: E. Siegel, of how spacetime expands when it’s dominated by Matter, Radiation or energy inherent to space itself.
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Images credit: E. Siegel. Inflation ends (top) when a ball rolls into the valley. But the inflationary field is a quantum one (middle), spreading out over time. While many regions of space (purple, red and cyan) will see inflation end, many more (green, blue) will see inflation continue, potentially for an eternity (bottom).
  1. This means that, as time goes on and more-and-more space gets created due to inflation, certain regions, probabilistically, are going to be more likely to see inflation come to an end, while others will be more likely to see inflation continue.
  2. The regions where inflation ends will give rise to a Big Bang and a Universe like ours, while the regions where it doesn’t will continue to inflate for longer.
  3. As time goes on, because of the dynamics of expansion, no two regions where inflation ends will ever interact or collide; the regions where inflation doesn’t end will expand between them, pushing them apart.
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Image credit: E. Siegel. Even though inflation may end in more than 50% of any of the regions at any given time (denoted by red X’s), enough regions continue to expand forever that inflation continues for an eternity, with no two Universes ever colliding.
  1. We don’t know if the regions where inflation ended are all the same, or whether they’re vastly different than our own. It’s conceivable that there are (unknown) physical dynamics that cause things like the fundamental constants — particle masses, strengths of forces, the amount of dark energy — to be exactly what they are for us in all regions where inflation ends. But it’s also possible that different regions where inflation ends, what we might consider different Universes, have arbitrarily different physics.
  2. And if the Universes are all the same as one another as far as physical laws go, and if the number of these Universes is truly infinite, and if the many-world interpretation of quantum mechanics is completely valid, does that mean that there are parallel Universes out there, where everything in it evolved exactly the same as our own Universe did, except one tiny quantum outcome was different?
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Image credit: Tim Warre of http://freeenglishlessonplans.com/2013/02/27/parallel-universe-3rd-conditional-conversation-practice/.
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Image credit: Wikimedia commons user Christian Schirm.
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Image credit: Jeff Miller, Ph.D. via Apologetics Press, from http://vnn.org/.
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Image credit: the “small” number 1000!, as computed at http://justinwhite.com/big-calc/1000.html.
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Image credit: deviantART user youvegottocarpediem, ©2012–2015 youvegottocarpediem, via http://youvegottocarpediem.deviantart.com/art/Some-infinities-are-bigger-than-other-infinities-334927832.
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Image credit: Mario Livio, via http://www.huffingtonpost.com/mario-livio/how-can-we-tell-if-a-multiverse-exists_b_2285406.html. Other Universes may exist, but they are not identical to our own.
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Image credit: Moonrunner Design, via http://news.nationalgeographic.com/news/2014/03/140318-multiverse-inflation-big-bang-science-space/.

Starts With A Bang!

The Universe is out there, waiting for you to discover it.

Ethan Siegel

Written by

The Universe is: Expanding, cooling, and dark. It starts with a bang! #Cosmology Science writer, astrophysicist, science communicator & NASA columnist.

Starts With A Bang!

The Universe is out there, waiting for you to discover it.

Ethan Siegel

Written by

The Universe is: Expanding, cooling, and dark. It starts with a bang! #Cosmology Science writer, astrophysicist, science communicator & NASA columnist.

Starts With A Bang!

The Universe is out there, waiting for you to discover it.

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