The beginning of everything. The Big Bang. The idea that the universe was suddenly
born and is not infinite. Up to the middle of the 20th century,
most scientists thought of the universe as infinite and ageless. Until Einstein’s theory of relativity gave
us a better understanding of gravity, and Edwin Hubble discovered that galaxies
are moving apart from one another in a way that fits previous predictions. In 1964, by accident, cosmic background
radiation was discovered, a relic of the early universe, which, together with other observational
evidence, made the Big Bang the accepted theory in science. Since then, improved technology like the
Hubble telescope has given us a pretty good picture of the
Big Bang and the structure of the cosmos. Recent observations even seem to suggest
that the expansion of the universe is accelerating. But how did this Big Bang work? How can something come from nothing? Let’s explore what we know. We can ignore the beginning part
for now. First of all, the Big Bang was not
an explosion. It was all space stretching
everywhere all at once. The universe started
very, very, very small and quickly expanded to the
size of a football. The universe didn’t expand into anything,
space was just expanding into itself. The universe cannot expand into anything
because the universe has no borders; there is, by definition, no “outside”
the universe. The universe is all there is. In this hot, dense environment, energy
manifested itself in particles that existed only for the
tiniest glimpses of time. >From gluons, pairs of quarks were created,
which destroyed one another, perhaps after giving off more gluons. These found other short-lived quarks
to interact with, forming new quark pairs and
gluons again. Matter and energy were not just
theoretically equivalent, it was so hot they were practically
the same stuff. Somewhere around this time, matter
won over antimatter. Today, we’re left with almost all
matter and nearly no antimatter at all. Somehow, one billion and one matter
particles were formed for every one billion particles of
antimatter. Instead of one massive ultimate force
in the universe, there were now several refined versions
of it acting under different rules. By now the universe has stretched to a
billion kilometers in diameter, which leads to a decrease in temperature. The cycle of quarks being born and
converted back to energy suddenly stops. >From now on, we work with what we have. Quarks begin forming new particles,
hadrons, like protons and neutrons. There are many, many combinations of
quarks that can form all sorts of hadrons, but only very few are reasonably stable
for any length of time. Please take a moment to appreciate that
by now, only one second has passed since the beginning of everything. The universe, which has grown to one
hundred billion kilometers, is now cold enough to allow most of the
neutrons to decay into protons and form the first atom, hydrogen. Imagine the universe at this point as an
extremely hot soup, ten billion degrees Celsius, filled with
countless particles and energy. Over the next few minutes, things cooled
and settled down very fast. Atoms formed out of hadrons and electrons, making for a stable and electrically
neutral environment. Some call this period the Dark Age,
because there were no stars and the hydrogen gas didn’t allow visible
light to move around. But what’s the meaning of visible light,
anyway, when there’s nothing alive yet that could have eyes? When the hydrogen gas clumped together
after millions of years and gravity put it under great pressure, stars
and galaxies began to form. Their radiation dissolved the stable
hydrogen gas into a plasma that still permeates the universe today
and allows visible light to pass. Finally, there was light! Okay, but what about the part
we didn’t talk about? What happened right at the beginning? This part can be defined as the Big Bang. We don’t know at all what happened here. At this point, our tools break down. Natural laws stop making sense,
time itself becomes wibbly-wobbly. To understand what happened here,
we need a theory that unifies Einstein’s relativity and quantum
mechanics, something countless scientists are working on right now. But this leaves us with lots of
unanswered questions. Were there universes before our own? Is this the first and only universe? What started the Big Bang, or did it
just occur naturally, based on laws we don’t understand yet? We don’t know, and maybe we never will. But what we do know is that the universe
as we know it started here and gave birth to particles, galaxies,
stars, the Earth, and you. Since were ourselves are made of
dead stars, we are not separate from the universe; we are part of it. You could even say that we are the
universe’s way of experiencing itself. So, let’s keep on experiencing it, until
there are no more questions to ask. Subtitles by the Amara.org community
Jesus christ u just took this to another level