…it would be a ‘border’ between nothing and nothing?
In: Planetary Science
based on all the discussion and different answer in this thread I think the real ELI5 answer is “we don’t know”.
So my understanding is as follows
1 Space is effectively a vacuum but there is small amounts of matter and energy flying around
2 The universe is everything so there is no “edge” in the same way that say a dinner plate has an edge
3 If you wanted to call something an edge you would say that matter or energy that has no other matter/energy father than it in a direct line away from the center of the universe is where the ‘edge’ is. But that edge is constantly expanding outward.
as far as it goes it could be bending on itself and things that are behind bend is multiverse
>If Space is a vacuum with nothing in it,
This is a misunderstanding of what space is. To be fair even the physicists don’t know what space is so it’s understandable.
But, space is a thing. It’s mostly vacuum as you mentioned but there is still a lot going on in there.
It can be bent by gravity for one thing. If it was nothing, there would be nothing to bend. So space is something that can be bent.
Space is made up of forces too. Weak, Strong, the electromechanical, and gravitational forces. Again nobody is sure exactly what those are but they make up space.
And there is a lot of other stuff going on when you get below the traditional things you can see and touch and feel.
So, space is something, the edge of the universe might be where that something isn’t there anymore. But again, nobody knows.
This was one of the first arguments made by the ancient Greeks for why the universe must be infinite. If you reached the edge and stuck your hand through it, what would you reach?
There are a few solutions, one being that you call whatever is outside a hyper-universe (this would be like the idea that we are living in a 3d bubble that exists within a higher dimensional soup). Another is that, like the Earth, the universe is round so that if you go far enough in any direction you eventually end up where you started. If this were true the actual size of the universe would have to be billions of times larger than we currently know since it looks flat to us.
When scientists today talk about the edge of the universe they mean the edge of the visible universe. This is because looking far away is like looking backwards in time. Eventually we hit a place where everything is universally hit and universally crammed together so that you can’t see past it. We call this point the big bang. So we are certain that, way over there, the universe is much like it is here, we just won’t be able to see what is happening over there right now until billions of years in the future.
There’s snakes in space?!
Everything’s in space Morty!
Imagine you live your entire life on a planet and everything you know is on the surface. You can walk in any direction for as long as you want, and you will still be on the surface. But in order to leave, you need to go upwards. In a sense, the whole planet surface is the edge. Everything you know is on the edge the entire time. It’s kind of the same thing with the Universe and it’s edge. The “edge” isn’t some place we can “go to” in a spaceship, its everywhere, but its another dimension that we can’t perceive. In order to go beyond the edge we need travel into that dimension.
The universe has “nothing in it”, but isn’t nothing. It’s a blank piece of paper.
The edge of the universe is the edge of that sheet. Something on the sheet cannot go out of it. It’s the end of “potential locations”, if you will.
Altough I don’t believe there is an edge of the universe (but the universe being infinite isn’t that much more believable, actually), that’s how I’d describe it.
The “big bang” is a misnomer.
Everything, everywhere came into existence at once. It didn’t start in a pinpoint, and expand like a globe.
Infinite pinpoints are expanding. It’s easier to imagine that the universe is already infinite in size, you could travel forever and never reach an edge. And yet, that infinite space is expanding, even further.
I wouldn’t worry about it much. That “border” (if it’s even what it really is) is expanding faster than the speed of light in vacuum, so in principle if Einstein’s postulate is true, then we have absolutely no way of observing it. By the time any light even shines from that “edge” it’s already far from the “actual edge”.
So, just table that thought. We need massive breakthroughs in fundamental physics to even ask this question “what’s on the edge?”.
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