I have been thinking for a while about this. I would like to know the scientific side of things to make me understand why it is endless? It's crazy to think that it's endless! I mean the thought of not coming to a stop makes my mind go weird. Thanks guys.
-
It is possible that the universe is both not infinite and also endless.
In order to get the meaning of this possibility, you must walk up the dimensions (all spatial dimensions, not time). What we will be walking up are manifolds - mathematical concepts that locally (in a small section of it) have n dimensions, but when taken as a whole, they have n+1 dimensions.
The first step is to imagine a circle. Put a pen point somewhere on the circle, and then follow the circle with your pen. There is no end, right? The circle is endless. It is not infinite, though, it's just a little circle on a piece of paper. Endless, but not infinite.
Now, let's walk up to include another dimension. Imagine a surface of a sphere, a really really big sphere like as big as the whole Solar System. Imagine that you are walking or bicycling on this surface. It will look flat to you. Locally, it is essentially flat. You could walk for thousands of years and hardly get very far on it. Of course there is no end, you could walk forever on it and find no end. It is not infinite though, it's the size of the Solar System. Of course, since we are making an analogy of the universe, we should include the expansion of space in our analogy so imagine that this huge sphere is expanding all the time you're walking!
Now, let's walk up to include another dimension. Imagine a space that although slightly curved in a dimension that we can't see, locally it appears to have just 3 dimensions; 3-dimensional space. This is where it gets tricky for us 3-dimensional beings. You can travel forever in any direction you choose and never find an end. Even so, it is not infinite; at a particular time, it has a particular size. 13.7 billion years after starting to expand, it never reached infinity and never will. The whole observable part of the universe could be only a tiny tiny fraction of the whole universe.
In order to get the meaning of this possibility, you must walk up the dimensions (all spatial dimensions, not time). What we will be walking up are manifolds - mathematical concepts that locally (in a small section of it) have n dimensions, but when taken as a whole, they have n+1 dimensions.
The first step is to imagine a circle. Put a pen point somewhere on the circle, and then follow the circle with your pen. There is no end, right? The circle is endless. It is not infinite, though, it's just a little circle on a piece of paper. Endless, but not infinite.
Now, let's walk up to include another dimension. Imagine a surface of a sphere, a really really big sphere like as big as the whole Solar System. Imagine that you are walking or bicycling on this surface. It will look flat to you. Locally, it is essentially flat. You could walk for thousands of years and hardly get very far on it. Of course there is no end, you could walk forever on it and find no end. It is not infinite though, it's the size of the Solar System. Of course, since we are making an analogy of the universe, we should include the expansion of space in our analogy so imagine that this huge sphere is expanding all the time you're walking!
Now, let's walk up to include another dimension. Imagine a space that although slightly curved in a dimension that we can't see, locally it appears to have just 3 dimensions; 3-dimensional space. This is where it gets tricky for us 3-dimensional beings. You can travel forever in any direction you choose and never find an end. Even so, it is not infinite; at a particular time, it has a particular size. 13.7 billion years after starting to expand, it never reached infinity and never will. The whole observable part of the universe could be only a tiny tiny fraction of the whole universe.
12
keywords: universe,endless,the,How,is,How is the universe endless