How many Universes are there?

One of the fundamental ideas that the confluence of Quantum Theory and Modern Cosmology has posed is that there is not one, but many many Universes. String Theory is based fundamentally on the idea that matter/energy exists in not just one Universe but in multiple ones simultaneously – it uses that property to explain the observed matter/energy spectrum of elementary particles.

Of course once you stop thinking about a Universe and instead of a Multiverse, you start wondering if there’s a limit, an upper bound to the number of Universes.

A pair of researchers at Stanford have worked out a methodology for approximating the total.

“Their answer goes like this. The Big Bang was essentially a quantum process which generated quantum fluctuations in the state of the early universe. The universe then underwent a period of rapid growth called inflation during which these perturbations were ‘frozen’, creating different initial classical conditions in different parts of the cosmos. Since each of these regions would have a different set of laws of low energy physics, they can be thought of as different universes.

What Linde and Vanchurin have done is estimate how many different universes could have appeared as a result of this effect. Their answer is that this number must be proportional to the effect that caused the perturbations in the first place, a process called slow roll inflation, and in particular to the number ‘e-foldings’ of slow roll inflation.

Of course, the actual number depends critically on how you define the difference between universes.”

Read the full article here. (More coverage here.)

And their answer? Actually the answer has two parts. First is the number of Universes that we can observe. (Which is limited because of the criteria they use for “discernible” and the limitations of the human brain and human lifetime.)


Which is bigger than a Googol but smaller than a Googolplex.

How many Universe in principle, discernible or not?

A “humongous” number. (10^10^10^7) Which is way big.

And now you know.

Author: Nick Knisely

Episcopal bishop, dad, astronomer, erstwhile dancer...

11 thoughts on “How many Universes are there?”

  1. Somewhere in the Confessions, Augustine suggests the world is like a sponge floating in the middle of the Ocean that is God. As i recall, he dismisses this as idle speculation. Still, I wonder. Presumably, God is bigger and older than all universes. Perhaps one wat to try to undersatnd this is to imagine God as an eternal Sea of Champagne in which bubbles of universes are constantly being created and eventually bursting or coming to whatever end universes come to. It’s an image of an effevescent God which captures something of the celebration I believe to be at the heart of it all. But, that might be just as idle, and idolatrous even, as imaging the world as a sponge in the middle of the ocean.

  2. So there may indeed be at least one parallel universe in which I am a starting pitcher for the Cubs and they win the World Series consistently?

  3. @Dan – I’m sure there are many. I mean, each Universe represents only a small perturbation from the reality of our own. Since your winning career as a pitcher is so close to reality, it must exist across a whole brane of universes.

  4. I don’t know, Dan. As one Cubs fan to another, I’m not sure even 10^10^10^7 universes are enough to overcome the Cubs propensity of blowing it.

  5. I remember talking to Rowan Greer, my advisor, about that sermon when I was working on it. He listened patiently and, when I was quite through, asked “Are you planning on bringing your own congregation?”

  6. I think that this article while very interesting, is pure speculation. While I think that it is important to keep an open mind we should take articles such as this with a grain of salt. The entire concept of Multiverses at this point relies on Quantum Theory which relies on probability for the basis of its arguments. I think people are beginning to tire of hearing about the possibility of this and the possibility of that. After awhile according to QM everything that anyone can concieve of is possible. This is NOT the way the Universe works in the observable macroscopic world. That is why I suggest an alternative to Quantum Mechanics. Someone has got to to do it else we will be stuck in this fundametally flawed paradigm indefinitely. Einstein was right about the shortcomings of Quantum Mechanics and so therefore String Theory is also the incorrect approach. As an alternative to Quantum Theory
    there is a new theory that describes and explains the mysteries of physical reality.
    While not disrespecting the value of Quantum Mechanics as a tool to explain the role of quanta in our universe. This theory states that there is also a classical explanation for the paradoxes such as EPR and the Wave-Particle Duality. The Theory
    is called the Theory of Super Relativity and is located at:
    This theory is a philosophical attempt to reconnect the physical universe to realism and deterministic concepts. It explains the mysterious.

  7. So does sin infect only this universe, or all of them, since all are part of God’s Creation? Was the Incarnation, life, death, Resurrection, and Ascension of Jesus effective only for this universe? Or did it act in all of them? Perhaps they all intersected at that point, or points….

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