Thread: universe border, reality or fiction ?

considering that the universe is continuisly expanding and that one day it will stop expanding and retract or continue expanding (depending on your beleifs) do you think we can say that the universe as a border ? because if the universe is a humongus space filled whit matter on the outside there can only be anti matter or other matter so can we say that there IS a universe border ?

i look foward to this debate

The universe is probably "unbounded". In the sense that there's isn't an "edge" to the universe. The expansion of the universe means that the distance between any two points increases with time. It doesn't mean that if you travel far enough you'll reach a point where there's no matter. The big bang wasn't an explosion of matter, it was an explosion of space. Which is understandably difficult to understand.

your right but admitting that we can travel faster then the universe expansion (wich is most probably impossible for human knowledge and physical capacity) if we woudl reach universe ''border'' and go threw it, if we can woudnt that create a space warp or do you think we woudl simply cease to exist ? or even just float in a total emptyness ?

Think of it like this: at the big bang, all points in space were infinitely close together. Then the distance between points increased in an "explosion". All points in space were the "center" of this explosion.

The universe is either positively curved, meaning that it's finite and if you go far enough you'll end up back where you are (like travelling on the surface of the Earth). Or it has zero curvature or negative curvature, and it's really infinite. But in both cases there isn't an "edge" to the universe. No matter how far you go, or how fast you get there, it will always look like you're at the center of the universe, with all sorts of galaxies and stuff around you. There's no edge.

Well, unless you mean the "surface of last scattering" (ie: cosmic background radiation). This is a "wall" at the edge of the visible universe, from when ~15 billion years ago the universe cooled enough not to be opaque to light anymore. But this isn't an actual "edge". If you were to magically transport yourself to the surface of last scattering, it would look pretty much like it does here at Earth. And if you looked in the direction of Earth you'd see what looked like an "edge" where the Earth is. This is you looking at what the universe looked like a few thousand years after its birth at the place the Earth is now.

I know this really stretches the mind. It's a lot to take in all at once.

the universe in matter terms has an end, the point at which no matter of any form is, is the end of the universe


Because 'Space' is a false vacuum we can also assume space has an end as well, a boundry of sorts, what would happen we we to cross this boundry I cannot say, I doubt the human conciousness is capable of such thought (it boggles the mind! )it's possible you would cease to exist, maybe god lives there, perhaps you would exit one end of the universe and enter the other side. In my opinion however by crossing the boundary you would be taking a part of the universe with you (youself) thus extending the boundry and making it as though you never had crossed



As einstien said Time and Space are relative, therefore connected (hence you hear things like 'the space time continueum!') as a result measuring the unvierse or 'space' can probably only be done in terms of time, the universe is aproxamately 29 billion years across in every direction, (assuming the BBT sent space in equal speeds the universe would have a radius of 14.4 billion years)
therefore you would need to 'travel faster than time' for anywhere between 14.4billion years and 0 seconds (it's unknown how close to the centre of the universe we are, we could infact be right on the edge of the universe)




I personally Like the idea of the 'Void' from Doctor Who, that the edge of the universe is outside of time itself

Originally Posted by Booms

the universe in matter terms has an end, the point at which no matter of any form is, is the end of the universe


Because 'Space' is a false vacuum we can also assume space has an end as well, a boundry of sorts, what would happen we we to cross this boundry I cannot say, I doubt the human conciousness is capable of such thought (it boggles the mind! )it's possible you would cease to exist, maybe god lives there, perhaps you would exit one end of the universe and enter the other side. In my opinion however by crossing the boundary you would be taking a part of the universe with you (youself) thus extending the boundry and making it as though you never had crossed



As einstien said Time and Space are relative, therefore connected (hence you hear things like 'the space time continueum!') as a result measuring the unvierse or 'space' can probably only be done in terms of time, the universe is aproxamately 29 billion years across in every direction, (assuming the BBT sent space in equal speeds the universe would have a radius of 14.4 billion years)
therefore you would need to 'travel faster than time' for anywhere between 14.4billion years and 0 seconds (it's unknown how close to the centre of the universe we are, we could infact be right on the edge of the universe)




I personally Like the idea of the 'Void' from Doctor Who, that the edge of the universe is outside of time itself

Read my post above yours. There isn't an edge. No matter where in the universe you magically poof to, you'll see basically stuff that looks like the night sky around Earth. And all points in the universe are the "center".

Originally Posted by Numsgil

Think of it like this: at the big bang, all points in space were infinitely close together. Then the distance between points increased in an "explosion". All points in space were the "center" of this explosion.

The universe is either positively curved, meaning that it's finite and if you go far enough you'll end up back where you are (like travelling on the surface of the Earth). Or it has zero curvature or negative curvature, and it's really infinite. But in both cases there isn't an "edge" to the universe. No matter how far you go, or how fast you get there, it will always look like you're at the center of the universe, with all sorts of galaxies and stuff around you. There's no edge.

Well, unless you mean the "surface of last scattering" (ie: cosmic background radiation). This is a "wall" at the edge of the visible universe, from when ~15 billion years ago the universe cooled enough not to be opaque to light anymore. But this isn't an actual "edge". If you were to magically transport yourself to the surface of last scattering, it would look pretty much like it does here at Earth. And if you looked in the direction of Earth you'd see what looked like an "edge" where the Earth is. This is you looking at what the universe looked like a few thousand years after its birth at the place the Earth is now.

I know this really stretches the mind. It's a lot to take in all at once.

yea i understand what u mean and that makes a lot of sens and yea its a lot to take at a time but i do get what u mean

thank you for your awnser !

Originally Posted by oblivion825

considering that the universe is continuisly expanding and that one day it will stop expanding and retract or continue expanding (depending on your beleifs) do you think we can say that the universe as a border ? because if the universe is a humongus space filled whit matter on the outside there can only be anti matter or other matter so can we say that there IS a universe border ?

i look forward to this debate

I dont know If I have read what most here would call a lot on this topic but my opinion and I need to emphasize opinion and this could also be wrong, because of any number of things but please feel free to correct me improving my knowledge is why I joined this forum

So my view, I firstly think that if the universe encompasses everything and that includes say dark matter or light waves(radiation) etc then there is a boundary between the universe in the so called strict definition and well nothingness.(I know this is highly debatable)

So the question becomes what if we could travel at the speed of light well technically time stands still(I think again correct me if I am wrong), so what if we travel faster than light this seems to be the only way we would be able to reach the light and radiation that is already ahead of us(again a debatable issue because the definition of space encompasses time itself making it difficult to comprehend traveling faster than time, I dont know what happens but again my view comes down to relative velocities and I am not a strong believer in the theory that traveling beyond lightspeed has any real effect it just means the light around u travels slower I dont think things grind to a complete stop and yeah there are assumptions in the light travel theory because its still based on the faster u go the slower u PERCEIVE everyone else to be traveling)

So now we can travel faster than the speed of light safely

With this the case getting to the so called edge will just take a very long time, but we will get there at some point before the light thats expanding outwards that has the 13 bill years + head start

So we get to the edge and then what we go lets say ahead of the expanding light by 20 lightminutes, and then we stop and decide to take a look around in my opinion there would be nothing no stars no galaxys no solar systems no back ground radiation, because that stuff is all shooting outwards at the speed of light 20 minutes behind us

So now we wait 20 minutes, and with the universe expanding towards us we would in 20 minutes be back in the universe

Now lets think about what that first sight of the universe would look like

it would be the big bang because the big bang is where the universe began and in that way we have sort of moved back in time, in the view that we PERCEIVING the beginning of the universe. even though we haven't traveled in time or done anything extraordinary except travel really really fast.

time is linked to the creation of space but going beyond the speed of light bends that rule a bit.

again just my opinion and with the rather limiting knowledge I have its certainly my answer and if anything here is completely wrong feel free to let me know

If u have a doubt read the signiture

Your logic seems sound, except for the faster than speed of light part and assuming that the big bang was after all some kind of explosion in infinity.

The problems are that relativity, which has never been shown to be false, require the speed of light to be the maximum. All tests of relativity that has been done have shown that mass (or rather inertia) does in fact increase with speed exactly as predicted by relativity. That means that your inertia would approach infinity the closer you came to C, as well as the amount of energy needed to accelerate you further. You would never reach C, not to mention exceed it.

As for infinite space: If space is in fact infinite, it would mean that the big bang happened at our location. There is simply no reason to think that to be the case. If the big bang happened here, then I would think that we would see a different distribution of galaxies than what we see now. As far as we can tell, the universe is homogeneous on a large scale, meaning it is the same everywhere we look, which does not fit with an infinite universe that well. This part also has some of my personal opinions, so they might still be corrected by others.

Originally Posted by KALSTER

Your logic seems sound, except for the faster than speed of light part and assuming that the big bang was after all some kind of explosion in infinity.

The problems are that relativity, which has never been shown to be false, require the speed of light to be the maximum. All tests of relativity that has been done have shown that mass (or rather inertia) does in fact increase with speed exactly as predicted by relativity. That means that your inertia would approach infinity the closer you came to C, as well as the amount of energy needed to accelerate you further. You would never reach C, not to mention exceed it.

As for infinite space: If space is in fact infinite, it would mean that the big bang happened at our location. There is simply no reason to think that to be the case. If the big bang happened here, then I would think that we would see a different distribution of galaxies than what we see now. As far as we can tell, the universe is homogeneous on a large scale, meaning it is the same everywhere we look, which does not fit with an infinite universe that well. This part also has some of my personal opinions, so they might still be corrected by others.

thanks for the fast response, the reason I used the faster than light speed was really just to visually show that mentally at least it is possible. I could of just said start 20 minutes outside the universe but some people find the traveling bit easier to imagine

I guess I dont know enough about the theory of relativity I knew there would be something wrong

Instantly found and corrected thanks, and as for the other assumption about the big bang being a explosion of everything including time

that i am not so sure about but I am keen to read more thanks for plugging the holes