Kind: captions
Language: en
One of the most incredible and
surprising physics discoveries of the
century was just made by a team of
scientists based at the South Pole
operating a telescope called BICEP 2.
They found a celestial fingerprint that
not only explains the explosive
beginning of time, but also reveals
gravity's microscopic secrets. To
understand what this fingerprint is,
imagine turning back the cosmic clock to
just after the big bang when the
universe was crowded into a hot, dense
ball over a billion times smaller than
an atom's nucleus. For decades,
physicists have wondered what laws of
nature would dominate here. The tiny
size of the universe meant the sthing
ethereal world of quantum particles
should be at play, but the immense mass
meant the spacebending world of gravity
should also be at work. So physicists
merged these worlds and came up with a
strange idea. They proposed that gravity
is actually made of quantum particles
which they called gravitons. Anywhere
there's gravity, there would be
gravitons. On earth, in solar systems,
and most importantly in the minuscule
infant universe where quantum
fluctuations of gravitons sprung up,
bending pockets of this tiny spaceime.
But if gravitons are everywhere, why
can't we see them? Unfortunately, a
single graviton is too measly to detect.
So, we had no evidence of them. But
scientists made another assumption about
the moment after the big bang. They
proposed that in this tiny cramped ball,
instead of a gravitational attraction
between matter, there would have been a
fierce gravitational repulsion which
would have caused everything to explode
outward in a momentary event called
inflation. During inflation, the once
tiny graviton fluctuations also inflated
into large gravitational waves. In the
following infant years of the universe,
photon particles of light and charged
particles were so crowded in space that
they were constantly colliding.
Meanwhile, the gravitational waves
stretched and contracted parts of space,
causing cold spots and hot spots to
form. Where these spots met, photons
ricocheting off charged particles became
aligned and together all these photons
produced distinct patterns in the cosmic
glow. Around 380,000 years after the big
bang, the universe became so large and
the particles were so spread out that
the collisions stopped and the final
patterns of light streamed out through
space where we can see them today. The
swirls in these twisting patterns of
light are called Bodes and they are the
fingerprint that the scientists found.
They're the first direct evidence for
the inflation or explosion that birthed
our universe and the strongest evidence
we've ever had that gravity is in fact
made of tiny particles called gravitons.
[Music]