Today I think I had a revelation. I spent a lot of my youth being fascinated with Space and everything about it. I’m still a big sci-fi fan now, but nowadays it’s purely for entertainment purposes rather than learning.
But a quote that was posted on Twitter today got me thinking again:
“Once you can accept the universe as matter expanding into nothing that is something, wearing stripes with plaid comes easy” – Albert Einstein
As a kid I used to accept that before the universe, there was nothing, and that the universe is expanding into more nothingness. But because of that I kept thinking “well, what does ‘nothing’ look like? Our universe isn’t infinite, nothing is infinite so it has to stop somewhere, what happens when we get to the edge of our universe?”.
What I didn’t realise until today is that I had answered my own question. Nothing is infinite. The nothingness that the universe is expanding into, is infinite. In my head I was bundling Space and the universe as one thing, which is false. Space is just a vacuum – the name we humans gave this vacuum – and is the same vacuum that the edge of our universe is expanding into. The vacuum that the universe is expanding into is infinite, because it’s nothing.
Imagining nothingness like that seems really hard, but it’s not. If we had an object and sucked all of the atmosphere out of it, what would be left inside? Nothing. Nothing apart from any objects which weren’t sucked out. Imagine those objects (which would be floating if it wasn’t for our planet’s gravity) are parts of our universe, and the vacuum around them is Space. The only real difference here is that we’ve had to use an object to create a vacuum, because of the atmosphere already on our planet.
The key point here is to stop thinking of Space and the universe as one thing, as though the universe ‘contains’ space. It doesn’t, Space ‘contains’ the universe. (Or more precisely, the universe exists in Space). Space would be there even if the universe didn’t exist.
At least that’s what I think. Where’s my stripy shirt?