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picaohm t1_j1gokwp wrote

Reply to comment by Shadowkiller00 in Did you know it will still take 46 billion years to cross the universe at the speed of light? 65 mph = 4.8 * 10^17 years! by NotAndroid545

What is the universe expanding into? Or is there nothing there which in turn would actually be something?

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Shadowkiller00 t1_j1grlc9 wrote

We can't see the "edge" of the universe. So we have no idea. We don't even know if there is an edge.

Pretend the universe is a balloon. While it's deflated, using a marker, draw two dots on the balloon an inch apart. Now blow the balloon up. As you blow, the balloon is expanding. The two dots will get further and further apart. And yet they haven't actually moved.

Is there really an edge to the balloon? It's hard to say. In a way, the balloon is a two dimensional surface with no clear edge. But only when you look at it in 3 dimensions can you say there is an inside, an outside, and the balloon itself.

Well if the universe is a 3 dimensional balloon, there might not be an edge on 3D space, but if you were to look at the universe in 4D, there might be an inside, an outside, and the universe itself.

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tiregroove t1_j1grzc8 wrote

And how do you even know when you reach the end of the universe? Is there an electrified fence or something? Or a bubble membrane you'd bounce off?

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splittingheirs t1_j1gz3h0 wrote

Space and Time itself are intrinsic properties of our universe. That is: they do not exist outside of it, they are a part of it, entirely. The universe doesn't expand into anything, it simply creates more space between things.

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