The other third, the third pillar that I've already mentioned
is the cosmic microwave background radiation, which is, as I said,
perhaps the most important evidence we have that the universe must
have been hotter at one point, and must have been denser.
Because there's really no way to have this fossil radiation
existing all throughout the entire universe, no
matter which direction you point in, without having
a period, an earlier period when space
must've looked much different than it does today.
We go out and we look at space now, and it's pretty much empty.
Matter is, is very, very clumped, with, you know, large gaps or voids between
it, and that's just not the case if there was for the, if there.
That couldn't have been the case if you were to be
able to be be able to produce the cosmic microwave background.
So that's clear evidence that the universe must have
been much much hotter and much much denser earlier on.
Now we also talk about inflation, which is
this addition to the standard Big Bang model.
That early on a chunk of the universe, or not a
chunk, a tiny speck, actually went through a huge period of expansion.
A very rapid period of expansion.
And that little sliver of the universe
is what we called the observable universe today.
And there's actually some
evidence for inflation, it's not a huge amount
of evidence but there is some evidence for inflation.
And in particular it comes out of the fluctuations that must
have occurred during inflation, the quantum
mechanical ups and downs, jumps and
you know, regions of slightly over density or under density that
must have been imposed on the universe during that era of inflation.
And when we look today, when we go out and we look at the distribution
of galaxies in the universe today, or we
look at the cosmic microwave background and look
at the tiny fluctuations in temperature or density
we can tell the spectrum, the range of perturbations.
You know how much how large or how many
perturbations were there that were you know larger than
a few light years across and, how many that
were larger than ten light years across, et cetera.
And those actually compare
very well to the models of inflation.
So, there is actually some evidence that this
very early epoch of insane expansion, that went on
to inflate the bubble of this space time
that we call our universe actually occurred, as well.
So, we have three enormously solid pieces of evidence for the Big Bang and,
you know, some evidence for this addition to the Big Bang that we call inflation.
And if you want to come up with another model, if you're like the
Big Bang's crazy, then you need to address these three pieces of
evidence and if you cannot simultaneously account for the expansion, account for
the distribution of light elements and the cosmic microwave background, then your
model just isn't going to go head to head with the the Big Bang.
So, we really have excellent evidence for what
happened after the universe began, however it began.
You know, running the clock
forward from there, expansion, cosmic microwave background, et cetera.
So we have really a, a, a pretty coherent story that
is backed up by evidence, and that's the important thing to understand.
Okay?
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