Is it possible we live in a multiverse?
Our universe is unimaginably big.
The diameter of the known universe is 45 million light years.
It might expand beyond that to infinity or it might not!!
Is our Universe just one of many in an infinite, ever-expanding multiverse?
Well you heard that right!
The multiverse.
One of the most baffling questions in Astronomy and astrophysics is are we really a part of
infinite universes?
We all have this concept of the multiverse being used in movies, comics, fiction and
at a lot of other places.
The concept of uniqueness has been in humanity since the last few centuries.
But this has been discarded by recent scientific endeavours.
Ever since Copernicus came and discarded our special status in the solar system and that
we are not at the centre, scientists have been building upon his idea.
Now we know that we live on an ordinary planet in an insignificant part of an ordinary galaxy.
But what about the Universe?
Is there only one universe or multiple ones?
Our understanding of the universe is limited for now, because the Big Bang happened 13.8
billion years ago and the speed of light is constant.
Even though the universe might be infinite the Observable universe is finite.
Our Universe may be just one minuscule region of a much larger multiverse, within which
many Universes, perhaps even an infinite number, are contained.
Quantum mechanics also points towards the existence of possible parallel universes.
In this video let's talk about how science tells us about the existence of the multiverse.
Uniqueness is one of those ideas that is unquestionable where we easily identify things as unique
and then it's unique forever.
There are very low chances of something being identical to it.
Just like your fingerprints are unique!!
But in a very recent picture of the cosmos, which says nothing is unique, the very notion
of uniqueness is being challenged.
It says that there might be duplicates of everything not only of objects but of me,
you and everyone else.
And if it’s right, why haven’t we seen them?
Where are they?
There was a time when the idea of a multiverse seemed impossible.
But in recent years scientists have observed some compelling evidence of another universes,
some being born all the time.
Some of them might look identical to ours, having the same star and even the same planet
except for the slightest details.
These universes might also have our duplicates, very identical to us except for the slightest
details.
For example, in any other universe it might be possible that we would be dying or being
born.
We could be getting married, not us(to be precise), but our identical selves.
We can even be the president of the United States!!
There could be a number of possibilities.
But how is it possible?
Doesn’t this idea seem absurd?
Let us take a look at why this idea is compelling not only to us but also to the scientists.
First let’s talk about where this idea of multiverse came from?
Well, we all know about the Big Bang theory which tells us about the massive explosion
that led to the formation of our universe.
Around 13.7 billion years ago, everything we know of was an infinitesimal singularity.
Then that singularity burst into action inflating faster than the speed of light in all directions.
But the Big Bang misses one thing, it doesn’t tell us anything about the BANG!
What caused the BANG?
And how it BANGED?
What caused everything to move outwards into an ever expanding universe.
Our universe has been expanding since the Big Bang, which means that everything is moving
away from each other because the space between them is expanding.
This was observed by scientist Edwin Hubble who gave the Hubble law.
In 1979, Alan Guth and his fellow mate were studying the particles in the early universe.
Alan Guth later observed in the mathematics of the early universe that under the violent
and harsh environments or the early universe the Gravity can be repulsive!
This repulsive gravity would drive apart everything around it and repel it, causing a massive
expansion.
This force was so powerful that it could take a molecule and blow it up-to the size of a
Galaxy in less than a billionth of a billionth of a blink of the eye.
This idea gave birth to the theory of inflation.
And as inflation ends in a particular place, a new bubble universe forms.
Those bubble universes can't contact each other because they continue to expand indefinitely.
If we were to set off for the edge of our bubble, where it might butt up against the
next bubble universe over, we'd never reach it because the edge is zipping away from us
faster than the speed of light, and faster than we could ever travel.
The theory of the multiverse gained unexpected support from two major areas of modern science
that may be the key to understanding many important phenomenons in our universe and
beyond.
One of these fields was string theory and the other one was the breathtaking discovery
made by scientists made on a larger scale.
A discovery that is crazy if we are a part of only one universe but makes sense if we
are a part of the multiverse.
Astronomers in the starting of the 20th century believed that the universe might be shrinking
or might be slowing down.
Just as you throw a ball up in the air and it comes back to you after some time, Astronomers
believed that the universe was expanding and thought it would slow down in the same way
because of the gravitational pull of the stars and galaxies.
But when detailed observations were made and specially by Edwin Hubble astronomers observed
that the universe was not slowing down, instead it was accelerating outwards.
These observations were baffling.
Everything was moving away from each other at an increasing speed.
Scientists believed there had to be an invisible force behind this.
Astronomers called it Dark Energy, discovered by mainly three scientists Adam Riess, Saul
Perlmutter and Australian astronomer Brian Schmidt who won the Nobel prize in 2011 for
their discovery.
It is the most important discovery in the history of science.
Dark energy is one of the most important discoveries in astronomy.
But there was another aspect of this strange force, its strength.
Scientists believed that at quantum level, the amount of energy that would be generated
would be enormous.
But when the astronomers measured the amount of dark energy present in our universe, it
was 0.138×10-120, which seems an infinitesimal amount.
Later they found out that this tiny amount of dark energy which is present in our universe
would have been slightly more, it would have ripped apart all the matter and nothing would
exist.
So how can this amount of dark energy be so perfect for our universe?
The multiverse gives us an answer.
The amount of dark energy differs in every universe.
In some it might be so less that the matter would collapse in on itself and hence nothing
could exist.
In some, dark energy is so large that matter could never get a chance to form and hence
nothing would exist there.
And this was a baffling realization for scientists.
But there was another piece of this puzzle missing.
How can we be so sure about this diversification of universes so that every value for dark
energy including the curious value found in our universe, can be found somewhere?
The answer lies with the STRING THEORY.
In simple words, String theory proposes that at subatomic levels small particles called
quarks that make up protons, are also made of something smaller, tiny vibrating loops
of energy or STRINGS!
Just like a string of violin produces a different kind of notes, depending on how they vibrate.
Strings can also create different particles based on how they vibrate.
This theory is also believed to lay the foundation for one fundamental equation for our universe.
But let’s leave this aspect for another video.
The theory also proposes Extra dimensions of space.
We are familiar with the three dimensions of space- length, breadth and height.
Let’s suppose we look at a wire which is hanging at a distance from us.
If we observe it looks like a line, one dimensional.
But what about an ant that’s on the wire, it would see an extra-dimension.
And if we could shrink down billions of times than those ants, we will find extra dimensions
curled up into a loop everywhere in space.
The shape of those dimensions determine how these strings will vibrate and these vibrations
of space define different original properties of particles.
These extra dimensions also have different shapes which define their properties.
When scientists tried to find out these different shapes they were blown away by million contestant
shapes of these dimensions each as unique as the other one.
This was heartbreaking for them.
What good is the theory that has millions of millions of solutions, finding anything
is impossible in there?
But some string theorists thought to look at the problem differently, a way that would
lead to the multiverse.
The enormous diversification of contestant shapes says string theory fits perfectly for
cosmology and multiverse.
All these different shapes might correspond to a different unique universe, some of which
might be identical to ours.
Each solution represented a different possible universe.
String theory was describing a multiverse!
A very distinct multiverse.
Some researchers base their ideas of parallel universes on quantum mechanics.
Quantum mechanics says that an electron can be in a superposition if all possible locations.
There is no such thing as the position of an electron.
In quantum mechanics, multiple states for existence of tiny particles are all possible
simultaneously-- a “wave function” encapsulates all those possibilities.
But when we actually look, we only observe one of the possibilities.
As soon as we take a look at the wavefunction to observe it, the wave function collapses
into a single reality.
Schrodinger's cat analogy is based upon this idea only.
The many-world interpretation by Everett proposes that instead that every time one state, or
outcome, is observed, there is another "world" in which a different quantum outcome becomes
reality.
This is a branching arrangement, in which instant by instant, our perceived universe
branches into near-infinite alternatives.
According to Many Worlds, the universe continually splits into new branches, to produce multiple
versions of ourselves.These alternate universes are completely separate from each other and
do not intersect.
So there may be unaccountable versions of you living a life that's slightly or wildly
different than yours.
Sean Carroll, a widely renowned quantum physicist, writes in his book, Something Deeply Hidden,
that the many worlds interpretation is the most courageous take on the quandary of quantum
mechanics.
He thinks that so far, the many worlds is the simplest possible explanation of quantum
mechanics.
At the end of the day scientists can see many different theories pointing to a single theory:
The theory of multiverse.
Different lines of research were focusing on one idea and ‘The Theory of Multiverse’
seemed convincing.
All the various alternate universes out there have a different amount of dark energy naturally,
and the unique shapes of these extra dimensions and different possibilities of a wavefunction.
In the future we might see other advances in this research, but as of the scientific
advances now, we can never observe beyond our observable universe as the space between
these galaxies and the space itself is expanding.
So what do you think about these different theories pointing towards the existence of
the multiverse?
Can it be really possible that there might be another you in a parallel universe or identical
to ours?
Let us know your thoughts and questions in the comment section below.
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