About 14 billion years ago the
universe came into existence with the Big Bang. Early in process the
universe was too hot for matter to form and the was a fairly uniform
“glow”. As the universe expanded it cooled. You can think of
compressed gas in a can being released, like spray paint or cooking
spray, as the gas expands it cools off. After a while things cooled
down so that matter could start forming.
But that “glow” is still around.
It too has cooled off, to just a few degrees, but it comes from
everywhere as its discovery was some of the first, best, evidence for
the Big Bang. That “glow” is called the cosmic microwave
background radiation (CMB). But if the “glow” was uniform then
how dis we end up with matter clumping into stuff. Well NASA put up a
couple observatories and showed that the CMB actually had some
variation in it.
The Big Bang is well accepted as what
happened. But there are always details to work out. Back in the 70s
it was noticed that there were problems with the Big Bang. Some of
the things that were predicted, weren't found. So an addition to the
Big Bang theory was made. That was of “inflation”. Not the other
kind of inflation that was big in the 70s, but a theory that shortly
after the Big Bang, (and I do mean shortly 10-32 seconds
after, and that's small) the universe had a short period where it
expanded quickly (faster than the speed of light).
While inflation did help explain some
things, science grows by confirming predictions. And one of the
predictions that were made about inflation was that gravitational
waves would have caused a certain type of polarization of the CMB.
These predictions were made years ago (back in the 80s).
Well, just recently BICEP2, a special
telescope built down near the South Pole, released a report where the
polarization was confirmed. This has provided good evidence for the
hypothesis that this period of inflation occurred shortly after the
Big Bang happened.
And that's the way science is supposed
to work. People come up with a hypothesis and from that hypothesis
they make predictions. Things that can be measured. At least in
theory. Sometimes you have to wait a while before technology catches
up so the devices can be built that can measure the effect that was
predicted. But then you or other scientists make the measurements and
determine if the predictions were true or not.
And if the predictions were found to
be true, then the hypothesis gets some confirming evidence. And once
enough evidence is found that the not believing that the hypothesis
is true is silly, the hypothesis graduates up to a scientific theory.
Which unlike the vernacular is a pretty prestigious class of
scientific ideas. (In science, saying “It's just a theory” is a
good way to get you laughed at. You're not using the word the way
scientists do.)
So right now, we might still be
wondering about the wacky idea of cosmic inflation. But for now the
scientists that hypothesized it have some evidence to back them up. I
think I can hear them saying “Bazinga” right now.
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