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  • 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, nooutsidethe 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, were 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

The beginning of everything.

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The Beginning of Everything -- The Big Bang

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    vulvul posted on 2015/09/29
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