Thinking About The Universe

Sometimes I think about the Universe. It’s hard for me to conceive of the Universe having a beginning, but it did. There was a time when our Universe and its trillions of galaxies did not exist. Then suddenly, seemingly from nowhere, it sprang into existence. That happened 13.8 billion years ago. We call that event the Big Bang.

We think of space as “empty space”. Of course, space contains galaxies and dust and radiation, but if you take all of that away, what’s left? Empty space. Except, space is something. Meaning, space is not nothing. It is definitely something.

When we point our telescopes at other galaxies, we can see that they are moving away from us. The farther a galaxy is from us, the faster it is traveling away from us. But this doesn’t mean there is something special about our place in the Universe. The fact is, this truth holds for every galaxy. If you could travel to any place in the Universe, you would see all the other parts of the Universe moving away from you.

You might think all these galaxies have some outward velocity, that they’re traveling though space like pieces of shrapnel traveling outward from a bomb, and it’s just a coincidence that each galaxy happens to have a speed and direction that results in its moving away from every other galaxy. But you would be wrong.

What is actually happening is this: the space between galaxies is expanding. Space itself is expanding. Galaxies are embedded in space, and as space expands it carries the galaxies away from each other. It’s like a loaf of raisin bread in the oven. As the loaf rises and expands, the raisins move away from each other. They’re not traveling through the loaf of bread. They’re staying put; it’s the loaf that is expanding and carrying the raisins farther apart.

If space were literally and truly nothing, how could it expand?

Our Universe, apart from the matter and energy it contains, is made of something we call spacetime. Space and time are the components of spacetime. That is why an object’s velocity through space affects the passage of time for that object. Space and time are woven together. If you tug on one you affect both.

The Big Bang created the Universe. But the Big Bang wasn’t something that happened somewhere in space. Before the Big Bang happened, space didn’t exist. The Big Bang created space. And it created Time. It created spacetime.

Suppose you had the power to remove everything from the Universe. You remove the stars, you remove the dust and gas, you remove light and x-rays and gamma-rays. You remove everything, until finally there is nothing left but a Universe of empty space. And finally, you remove the empty space. Now, what do you have?

You have the situation that existed before the Big Bang. I call it the Void. The Void can’t be pure nothingness, because if nothing at all existed – not matter, not space, not energy, not potential energy, not even some kind of mathematical framework to hang the laws of physics on – if nothing at all existed, then there would be nothing to cause the Big Bang.

If we had a time machine, we could travel back 13.8 billion years to a time when there was no Universe. We’d have to be in a very special time machine that could exist without occupying any space at all, because there was no space to occupy then. There would be no up or down or this way or that way, because those terms describe 3 dimensional space, of which there wasn’t any. Yet. But something happened. We don’t know how it happened, but we see the flotsam and jetsam it left behind. We see stars, galaxies, galaxy clusters, black holes, neutron stars, magnetars, blazars, quasars, and other wonders. We see trillions of galaxies. We see a Universe that might be infinite. In fact, there may very well be an infinite number of Universes, each sealed off from all the others, each a part of a vaster Multiverse.

Physicists have theories about how the Universe began and how it may end. In fact, with the recent discovery of the Higgs boson at CERN, physicists tell us the Universe is unstable and could collapse into an alternate reality at any time – a reality in which we won’t exist!

I try not to think too much about these things. They’re way above my “pay grade.” But for those who are interested, there are many videos on YouTube that discuss the Universe and how it might end. PBS Space Time is a good place to begin.