So I’m in a vehicle fueled by plotdeviceium, and I’m going fast enough that time vs huge distances don’t matter. Also I packed a lunch so I won’t starve.
I am at the object furthest away from the Earth. I point the craft directly away from Earth and keep going.
What happens? Is there a point where I can go no further, that the Earth stops getting further away? Do I just keep going into void forever? What exactly is ‘the edge of the universe’?
There is no “edge of the universe”. As far as we can tell it is infinite and homogenous in all directions.
There is an edge of the OBSERVABLE universe. That’s the sphere centered on Earth that’s small enough for light to have traversed in the time since the Big Bang. But if you could magically teleport yourself out to the edge of the observable universe things would look pretty much the same as they do right here.
I’m pretty sure you’ll just keep right on going, from your perspective. But from an outside perspective, good question. It’s not like you’ll be hitting an imaginary wall or anything.
I’ve seen models of the universe that looked like a big ball, where someone travelling across it was always at the “center” of the ball, with it rolling around, like a big hamster ball with you, the traveller, perfectly suspended in the center. In this model, you’d get X distance from the earth, and it would then begin to “roll” up, down, or some other direction around the edge of the “ball” and no matter what, you couldn’t get any farther from it. It would just require you heading “back” in a different direction depending on where the “earth” spot on the ball rolled towards. In other words, there was a maximum distance between two points that you could achieve, based on how much the universe had expanded at that point in history, and you’d have to be going faster than light to actually have the above mentioned phenomenon happen…
maybe I’m doing a bad job explaining it, and I don’t have a cite, it was on TV…
Sounds pretty nifty though. I’m sure someone smarter than me will be along to correct all the rubbish I’ve just spewed.
I think there is a restaurant near there.
(Oh wait, that’s the “end”, not the “edge”, sorry, ignore that.)
There are different models.
Why?
Time is an illusion.
If this is true why don’t we see galaxies/quasars/etc suddenly appearing in the sky as their light reaches us?
You can’t reach the edge. There is no edge. Either the universe is infinite, or it is curved back on itself.
Either way, the observable universe is much smaller than either. The observable universe is the parts of the universe that, since the start of the big bang, could send a particle traveling at c that could interact with the earth and vice versa.
There are parts of the universe you can never interact with, even if you could travel at 99.999999% of c, because those parts are receding away from you faster than c.
Of course, if your space ship can travel faster than light, then all sorts of kooky things can happen.
We do. Or rather, when we look really really deeply into the sky, we see very early galaxies, from the very early universe. The light from those galaxies has taken almost the age of the universe to reach us. Anything farther than that would take more than the age of the universe to reach us, and so can’t reach us–light emitted from those galaxies is traveling toward the earth at the speed of light, but the space between earth and those galaxies is expanding faster than the speed of light, and so those photons can never reach earth.
Astronomers in those deep field galaxies who are looking back at earth wouldn’t be able to see our galaxy, because they’re seeing our region of space as it existed 13 billion years ago before our galaxy formed. And the galaxies we’re seeing in the deep field probably don’t exist anymore, we’re seeing them as they existed 13 billion years ago. Hubble Ultra-Deep Field - Wikipedia
If it’s curved back on itself, how would that look to an observer at it’s edge? If I’m moving away from earth at this point, watching the Distance From Earth meter going higher and higher, how does it behave when I reach the point where it starts to curve back on itself?
If we define the universe as “that which is”, then it follows that it must be infinite. Hence, there is no edge.
How does that follow? What if this universe is not all that there is? Why does this universe have to be infinite?
Remember there isn’t an edge, and if it curves back on itself the farthest away point is very likely farther away than we can see now.
Think of asking what happens if you travel on the earth in a “straight” line. Eventually you reach the antipode to your starting point, and from then on you’re moving closer. But when you’re at the antipode, you wouldn’t really know this unless you could see far enough in all directions to say “Hey that looks like home straight ahead.”
Just as there is no edge, there is no Distance From Earth Meter, but, if space is curved back on itself, if you kept going long enough you would come back to where you started from (although Earth probably would not be there any more).
We don’t know. There are different models because we’re guessing.
That said, even in the “curved back on itself” model, there is no edge as such. There may be some empty bits, where “populated universe” gives way to “whole lot of not much.” That’s an edge of something. But we don’t expect space itself to have a corner where it suddenly turns around. The whole spacetime fabric is, in this model, curved in dimensions we don’t perceive, or something.
Then again, in reality, who knows?
How does this work in 3D space? It’s easy to imagine on a 2D surface, but I don’t see how it could happen if you’re not following a continuous surface.
As I stated, if we define the universe as “that which is”, it follows that it is infinite, as it is everything. Nothing outside, as there is no inside or outside.
If you wish to redefine it, that is acceptable. It can be anything you want it to be.
If you’re not breaking the laws of physics, then it’s always going to look to you like you’re in the exact center of the observable universe.
If you are breaking the laws of physics, then there is literally no way to predict what you would see, because our ability to make those predictions is based wholly on the rules that emerge from the laws of physics. Once you invoke magic, then all logic and predictability goes out the window.