10.
Quasi-Steady State
In the beginning, there were two theories.
The Big Bang stated that the Universe began
with the singularity - a point at which everything
was infinitely concentrated and time didn’t
yet exist.
Opposing it, the Steady State model said that
the Universe never began because it has always
been here.
Over time and with new evidence, the Big Bang
emerged victorious because radiation that
was found in the 1950s was discovered to be
a relic of a massive expansion, which pointed
to a universe that had a beginning.
But some people just couldn’t let go of
the disproved Steady State model and in 1993
it was updated.
It became the Quasi-Steady State model instead.
This said that as the Universe expands little
pockets of matter are spontaneously created
throughout 
the universe, called ‘little bangs’.
However, it still fails to deal with the radiation
that was discovered.
9.
Eternal Inflation
For a split second after the birth of the
Universe, it expanded at an incredibly intense
rate.
This intense inflationary energy was then
converted into matter and radiation.
After this, the growth, or ‘inflation’,
of the universe slowed substantially.
At least that’s according to the Big Bang.
However, proponents of the Eternal Inflation
theory, like physicist Alan Guth, claim that
the intense period of expansion didn’t need
to stop all at once.
He theorized that our universe was just one
small pocket of a much, much larger universe.
The much larger universe is expanding incredibly
quickly, while our universe is a small bubble
within it that slowed down.
The implication of this theory is that there
are many other slowly expanding bubble universes
emerging in the greater universe.
8.
Mirrored Universe
In 2014 Julian Barbour at the University of
Oxford modeled a system of particles under
gravity.
When the particles expanded outwards, he found
that they did so in two different directions
of time.
Barbour likened his particle model to a replica
of our universe, coming to the conclusion
that the expansion of the Big Bang should
have created two universes moving in two different
time directions.
Essentially, on the ‘other side’ of our
Big Bang is a mirror universe, moving in the
opposite direction in time.
Unfortunately for time travel fans though,
the theory states that if you were in the
mirror universe, you would still feel as if
time was going forwards.
7.
Colliding in Higher Dimensions
Princeton String Theorist Paul Steinhardt
has come up with his own idea that explains
the Big Bang.
In String Theory there are more spatial dimensions
than we can see day to day in our 3 dimensional
world.
Steinhardt argues that our 3D universe can
be imagined as an object moving through a
higher dimension that is invisible to us - and
there could be other 3D universes doing the
same thing.
So, if two 3D universes were to collide and
stick together in this higher dimension, they
would create something that looked like the
Big Bang within the 3D universes themselves.
The energy of the higher dimensional collision
becomes the searing temperature that we see
at the beginning of our universe.
6.
Gravity’s Rainbow
The Rainbow Gravity theory states that light
experiences gravity to a different degree,
based on its wavelength, and therefore its
color.
In this system, for example, red light would
feel gravity more strongly than blue light
due to its longer wavelength.
The effect is usually very weak, but extreme
objects like supermassive black holes should
be able to demonstrate it.
As you approach the beginning of the Universe,
Rainbow Gravity becomes more important, due
to its more extreme state.
When this has been modeled, scientists find
that the Big Bang’s singularity can disappear
and in fact there are instances in which the
Big Bang doesn’t even occur, with time stretching
back forever.
This suggests that the universe has always
existed.
5.
The Slow Freeze
In the standard model, the Big Bang is super
hot and expands quickly, but Christof Wetterich
claims that the universe was actually cold
and evolving slowly.
He thinks that the past just appears hotter
to us, rather than actually being hotter.
To get to this picture, he asserts that gravity
weakens with time, while particles get heavier.
Today this would make the early universe look
hotter than it in fact was.
In this theory, the universe has always existed
in a state of deep freeze, before it began
to thaw around the time of the Big Bang.
Unfortunately, Wetterich’s idea is impossible
to prove, as we’re unable to measure whether
all particles in the universe are getting
heavier, as there is nothing to use as a benchmark
that wouldn’t change itself.
Scientists have been critical of his model,
saying it’s like arguing a ruler is getting
shorter, rather than the line it’s measuring
getting longer.
4.
Digital Simulation
Imagine that humans don’t go extinct and
instead advance to a super civilization with
unimaginably impressive computing power.
We then decide to run a simulation of the
universe to better understand it.
In fact, we create many, many simulations
varying the initial conditions slightly in
each one.
Nick Bostrom argued in 2003 that in such a
scenario we are almost certain to be in a
simulated universe.
This is because simulated universes outnumber
the one real universe by such a staggering
amount that the probability that we are living
in the unadulterated ‘Universe Classic’
is as good as zero.
In this theory, which has gained many supporters
including Elon Musk, the universe may have
started with a Big Bang, but that Big Bang
was started with the tapping of an Enter key.
3.
Quantum Graviton Fluid
After making a few tweaks to Einstein’s
theory of General Relativity using quantum
mechanics, scientists have suggested that
the Big Bang might not be correct.
These quantum adjustments essentially remove
the Big Bang’s singularity - the point where
the universe was infinitely dense and hot.
It doesn’t just remove the singularity,
however, it also seems to remove the Big Bang
itself.
This model has suggested that the universe
is infinitely old and full of quantum fluid.
This fluid is literally everywhere and is
made up of tiny particles called gravitons
that mediate gravity.
We just haven’t detected them yet.
According to this theory, dark energy arises
naturally out of the quantum adjustments.
However, there is still a lot of work to prove
that this model is an accurate description
of reality.
2.
Dimensional Ripping
There are a pair of superstring theorists
who believe that the universe has 9 dimensions
of space and 1 dimension of time, and they
think they have found an alternative explanation
to the Big Bang.
By using a supercomputer to simulate a 9 dimensional
universe, Sang-Woo Kim and Jun Nishimura have
discovered that, after a given time, a fluctuation
will occur and 3 dimensions will break off
and rapidly unwrap.
Those 3 dimensions are the ones we know and
love, and this dimensional disentanglement
is supposedly the creation of our universe.
After these 3 dimensions broke off in the
model, the physicists saw a similar Big Bang
and rapid inflation characteristic of our
own universe.
What happened to the other 6 dimensions?
Apparently, they are so small as to be unnoticeable.
Pretty convenient...
1.
Cyclic Universes
Roger Penrose is a giant of the physics world
and recently he proposed his own earth shattering
cosmological theory.
Titled ‘Conformal Cyclic Cosmology’, it
neatly expressed a very attractive theory
that you yourself may have thought of: the
universe repeats in a cycle with each new
big bang.
Penrose says that the state of the end of
our universe, which stretches off into infinity,
is in many ways mathematically identical to
the singularity at the Big Bang.
He says that this mathematical resemblance
is not just a concept, but also a reality.
So, at the end of each universe, another one
begins.
What’s more is that Penrose thinks he can
detect the echo of a collision of supermassive
black holes from the most recent previous
universe.
So he may actually be proven correct.
