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Greetings everyone. So now we have the players and the stage;
let's tell the story.
So in the beginning, right,
here's how we - what science tells us about the first moments of the universe.
So the beginning is what we call the Planck Era,
because it is the era when space and
time and matter were all under such extreme states that,
without a theory of quantum gravity,
we really can't get very far.
And we don't have a theory of quantum gravity.
So it means that this is really the Planck Era, what we call the Planck Era,
which is basically 10 to the minus 43 of a second after the Big Bang.
Okay. So that is 0 point 43 zeroes and a 1, okay.
That's how early it is in the history of the universe.
And the temperature of the universe,
remember the further we go back in time that the temperature of
the universe increases because everything is being squeezed together,
was 10 to the 32 degrees, okay.
So this is the Planck Era.
And we really don't understand much about this time.
But according to Hubble's Law and general relativity, which are classical,
you know, sort of results from classical physics,
if we were to just move everything back in time,
we should get to a period when all space-time matter,
energy and dimension are - they're all,
space-time matter and energy are squeezed into a single point,
or at least a point of infinite density,
infinite temperature and infinite stretching,
right; the curvature of space,
the curvature should have been infinite.
Now, this is just not realistic,
it can't possibly - this can't possibly happen.
Until like black holes,
what we need is really a theory of quantum gravity to tell us what
happens when we get to these super-small scales and super-high energies.
And since we don't have that,
you know, it's all sort of conjecture.
So all we can say is that the universe was in some kind of
quantum gravitational state and there were quantum fields everywhere.
And the only thing that we can say also,
or the one thing that we can expect is that we know that quantum,
anything that is associated with quantum mechanics has fluctuations in it.
There are natural random fluctuations associated with quantum fields,
so we can expect random quantum fluctuations
to be part of the early history of the universe.
Okay. So the next step in the history of the universe,
after we get out of the Planck Era,
the universe - you know, the Big Bang has been initiated.
The universe is expanding;
it is cooling as it expands.
It is becoming less dense as it expands.
And at some point, the universe hits - goes through an era of what we call inflation.
So this begins at around 10 to the minus 35th of a
second and a temperature of 10 to the 28th degrees.
And the idea is that what we get is that we take some little tiny fraction of space-time,
post Big Bang space time.
And what occurs there is there must be a quantum field that is
kicked up into a higher state;
it's in an excited state.
And we call this the false vacuum because it's filling all of space.
And in that one little tiny bit of space-time,
when that quantum field drops back down,
it releases an enormous amount of energy,
which takes the little tiny piece
of space-time that we're talking about and it inflates it.
It suddenly pushes it apart;
it takes it - and the universe is already expanding.
But now this little part of the universe expands on steroids.
And so what you get is a small bit of the universe that expands by
a factor of 10 to the 60 in about 10 to the minus 34th of a second.
So that little bit of space-time,
that little fraction of it,
ends up expanding and to become everything that we live in,
that becomes the known universe.
So what inflation does is this.
So we have Big Bang cosmology and now,
we've added something to it called inflationary Big Bang cosmology,
is that the universe we live in,
the universe that we experience as the observable universe,
is actually a small bit of the total space-time that has undergone inflation.
Of course, the rest of the universe is still out there in the,
you know - expanding and full of the false vacuum.
So, you know, we're not going to ask about the rest of the universe.
But our part of the universe, the part we can see, has undergone inflation.
Okay. So we have the Planck Era and the Inflationary Era. And now, let's move on.
Adam FrankProfessor
