How Many Universes Are There?

By Antonia Čirjak on June 1 2020 in Science

If we take mother Earth as a central point, the universe we live in expands around us for around 93 billion light-years in diameter.
If we take mother Earth as a central point, the universe we live in expands around us for around 93 billion light-years in diameter.
  • A false-vacuum is, technically, unstable, which makes it possible to act as a generator for the creation of new universes.
  • When we discuss the size of our universe, we are only able to talk about the observable space, which does not mean that there is nothing beyond that point.
  • Our universe was created through the Big Bang, approximately 13.8 billion years ago.

If we take mother Earth as a central point, the universe we live in expands around us for around 93 billion light-years in diameter. However, this is only the observable universe, and when we discuss the size of our universe, we are referring to what we can see, and not what is beyond. What lies beyond the points we can see with the current generation of telescopes, and is there another universe we might detect one day?

There Is More Than ‘’Everything’’

The universe that surrounds us is our home. It contains everything we know about, and it gives us a chance to talk and discuss existence itself. The enormous and incomprehensible size, the idea of time, dark matter, and all of the physics laws that define the behavior of space objects - everything is here. The term itself suggests how ‘’everything’’ that can be perceived (or even things we can not see, like dark matter or dark energy) is in this one universe. It can be hard to discuss things we do not see, but it is expected that numerous theories try to tackle the idea that our universe is not the only one. If we change the prefix ‘’uni-’’ to ‘’multi-’’ we are enabled to create hypotheses that can deconstruct reality as we know it. 

The multiverse is a theoretical frame that suggests how there are more universes than ours. This idea makes the term ‘’universe’’ feel insufficient and, basically - small. In popular culture, but also in various scientific approaches to space exploration, these are often referred to as either parallel or alternate universes, or simply ‘’other’’ universes. 

Eternal Chaotic Inflation

A theory that goes under an extremely cool name - eternal chaotic inflation is trying to tackle the idea how there are more universes that exist somewhere (or even ‘’some-time’’, if we are brave enough to embrace the notion of time travel, wormholes or just the plausible suggestion how not all universes have to follow the same physical rule that explain how time and space are interconnected). This theory was postulated by a physicist called Alan Guth, who expanded (pun intended) on the idea of cosmic inflation. 

The multiverse is a theoretical frame that suggests how there are more universes than ours.
The multiverse is a theoretical frame that suggests how there are more universes than ours.

There are still many issues and unanswered questions about the nature of our universe. One of the most common ones is asking: why was this universe so dense and hot in the beginning? To discuss time or space before the Big Bang is indeed a difficult task. But, from the time when all of this exploded, it is possible that multiple universes came to life.

The ''Vacuum'' Concept

One concept linked to the aforementioned theory is the idea of a vacuum. Quantum theory explains how vacuum is a space that has minimum amounts of energy.

However, the vacuum does not have the lowest possible amounts of energy, which means that it can act as a, for lack of a better term, generator of other universes. An unstable vacuum, as it is viewed by eternal chaotic inflation, has the potential to release huge amounts of energy. 

This means that, if the so-called false-vacuum space does not decay - it expands exponentially. From this point of view, our universe is still expanding, and the system itself is not stable but ‘’metastable’’. Because of this, we can think about how pocket universes come to life. The false vacuum creates a gravitational field that is repulsive by nature, which drives the exponential expansion of space. This would mean that the creation of multiple universes is a process that never stops, as the speed of expansion always exceeds the speed of decay.

How many universes are there - nobody knows for sure. However, how big is this pocket is also theorized in eternal chaotic inflation theory. It is possible that the place we live in is, hear this, 100 billion trillion times bigger than the space we can currently observe. Now, the idea that there is only one universe seems ridiculous.

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