In the beginning, there was energy. We think.
Everything in the universe was in a very small space. About the size of this dot. We aren’t 100% sure why, but we’re very confident this is true.
That means there was a lot of pressure at this one point. But around this point there was nothing but plenty of space to expand into. So it did.
This was called The Big Bang
The universe expanded very rapidly.
We estimate the universe expanded many lightyears across in less than a second.
While nothing within the universe can travel faster than the speed of light, nothing is stopping the universe itself from expanding into nothingness at lightyears per second.
1 second after The Big Bang, the vast universe would have felt hot, dense, & smooth.
No light could travel without immediately bumping into something.
Imagine it like this…
As the universe expands, the temperature goes down and pressure is released.
As pressure is released, gravity begins to start pulling things back together again–making the universe less smooth and more clumpy.
This is cosmic background radiation. It’s the farthest thing away from us that we can see, both in distance and in time.