T Nation

Space, Infinite or Finite?


I just wanted to get others ideas as to space. I actually mean space itself. You can use hypotheticals to discuss as we really can't just go out and take measurements. Do you think you could travel in one direction and never stop? Would matter end and only empty space eventually occur? Would some phenomenon happen where you are essentially doubled back or simply not allowed to travel further away from the center of the universe?




Get ready for this....space is infinitely finite.



I've wondered this myself Vegita, like do you just hit a wall at some point, or do you pop out the other side like in pacman? I really have no idea since I don't know enough about the topic but I'm interested in what others have to say on the topic.


Care to expand on that? Pun Intended.



Back dropping acid again I see.

I dig it.


This question plagues my thoughts along with many others. I don't have any answers, only I can see many things being possibilities. Like say you could travel at like a billion times the speed of light, just for a good fast speed. You start heading out away from the center of the universe, and eventually you pass the last remnants of matter that are still expanding from the big bang. You will probably cross some sort of event horizon Just like there is an atmosphere around the earth, the solar system and probably each galaxy, there is likley some sort of barrier betweeen the physical universe and pure empty space. Now you being in a location outside of this psoes a real problem because it's no longer empty if you are there or traveling through it, but it would be interesting nonetheless. Would the laws of the universe apply if you are outside of it? What if you just keep going and going and going and there are still more galaxies, more space and more galaxies. Would you then start thinking, well maybe if I could travel at a trillion times the speed of light I could get somwehere. Who knows but I sure as hell would love to find out.



I don't understand how space COULD be finite. If you were to hit some sort of "wall", there'd have to be something on the other side. And falling off one side to get to the other doesn't make a whole let of sense, yet a lot of things don't...


Well think about this...does and explosion really ever end? It has its physical manifestation i.e. fire. Then it has the after shock, how long does the after shock last does it ever stop? They say that when France was detonating nuclear weapons under water, that it took exactly 6 hrs for the soundwaves/shockwaves to circumvent the globe. Certain animals were able to sense the waves.

So if the Universe is in theory the result of a monumental explosion, who is to say the explosion ever ends? How do you get to the fringe of an explosion?


There's really no discussion. Until there is some clue as to something different we have to assume space is infinite.

If you traveled faster than the speed of light (or what ever the fastest particle might be) and eventually breached the perimeter of our Universe and just kept on traveling you would still be moving through space. I'd like to believe there are other things out there besides our universe, but even if you do encounter something else you would again be moving through open space after passing it. No popping back out on the otherside. Just endless.


Well space and time are intertwined. The further away you move from earth (really should be the center of the universe) the further back in time you are going. After you get a certain distance away I forget the exact amount, galaxies become very sparse and are considered dead. Something like 420-440 billion light years away you reach a wall of radiation that science has yet to see beyond.

To a certain level the hugeness of the universe resembles the smallness of the atom. Once you get to a certain level of magnification (either zoomed in or out) they begin to look eerily alike.

This wall of radiation to me seems like that of cell wall. Maybe outside this wall are other cells or universes or maybe there is nothing. Sometimes I think about blackholes and how they are either massive destroyers of information (destroys everything that enters it) or transporters of information (wormhole). But, maybe the entire universe exists inside a blackhole with the wall of radiation being the event horizon. Now if the universe actual exists within a blackhole, the immense gravity alters space time so that anything falling in seems to fall infinitely from outside the blackhole. While within the blackhole it falls until it reaches the center, with the event horizon being the beginning of time.

Minds are now blown


It's probably impossible to get to the fringe of the Universe or at least so unlikely it may as well be impossible. Whether or not the "explosion" ever ends is one of the key questions about the universe. Will the expansion ever slow down, stop and then begin to contract or will it keep going on forever? No one knows for sure. If I remember right, the answer lies in the total mass of the universe. If it is high enough, it will collapse again, if it's not, it will expand for ever.

I hope it collapses because that leaves the chance of it happening all over again and life once again. If it doesn't, eventually all fire of life burns out and that's the end.

Side note. The current rate of expansion is accelerating


There are a few problems with this. Photons are the fastest particle, and indeed you cannot travel faster. I'm not sure what you mean by space existing outside of the universe either. That doesn't really make sense.

You could have an infinite universe, or a finite universe which in some sense loops back on itself (think of the way you can travel around the surface of a doughnut, or a Moebius strip).

It's the rate of expansion that's important.

I'm not sure where you get this idea from. You can only travel within the light cone, and unless you someone manage to travel faster than the speed of light, or you have a special type of universe (the Godel rotating universe model, for example) then you can't really travel back in time.

And the thing about black holes is that it's not that easy to talk about entropy and thermodynamics, so it's not strictly true to say they just destroy information.


On Edge,

It is impossible to travel faster that the speed of light, because of the amount of energy needed to more the mass. To move that faster than you need to have negative mass. I think that once something reaches the speed of light, that time stops, it basically teleports. This explains, at least in my mind, how light can be both a weightless energy and an actual particle.


Space is realistically two conceptions, with each being thrown around amongst the other it easily leads to confusion. There's the infinite space, which is yes, definitely infinite. Then there's space as we know it which is constantly expanding within the infinite space. Considering space is accelerating as it's expanding, you'd need to travel faster than light to get to the end of it. But due to implications of current understanding and technology, this is infeasible, so essentially you'd keep travelling for ever. At one point you'd end up in a part of space that doesn't even exist at this very moment! You'd keep travelling until the 'end of time'.

If by some miraculous technological achievement we could travel past the edge of the material universe and into empty space, then nobody knows what would happen. There are many theories and I currently believe that it would be the membrane of a dimension if you will. To ever get to this point you'd have to be able to warp space as to exceed the speed of light, so if you did the same thing here, you'd warp into another dimension. Our brains can't comprehend infinite nothingness, because how can nothing be. But perhaps this nothingness that lays outside of our finite universe is essentially time, never beginning and never ending? Perhaps this could yield time travel too. I definitely believe that time travel would be made possible anyhow if you could cross into other dimensions.


Light just moves at the speed of a massless particle. It just so happens that photons are massless.


I like to think you could run into yourself if you flew far enough in one direction, but you'd pass everything else first.
and I mean EVERYTHING that could EVER EXIST. Ants in top hats, giant naked women riding pterodactyls, a house where an exact duplicate of yourself lives in wedded bliss with the fat girl in the faded dirty dancing shirt from your high school, EVERYTHING.


By a bizarre coincidence, Casey Butt PHD is working on a formula that will predict the exact limits of the universe. Just tap in your current stats, and you can work out exactly how far you will get before burning up/ dying of asphxiation. The beauty of it is that if your genetics don't allow you to drift into infinity, then you can sit at home eating fast food and taking solace in the fact that you didn't waste your time. What's not to love? The e-book will be available via instant download for just $9.95 (cheaper than a spacecraft with light speed capacity).
/shameless plug


ucallthatbass..Consider my mind blown, though I understand fully what you are saying. Did you take a class on this shit or is this from Discovery or your own thoughts?


Treating the universe as being a black hole is quite easy.

As far as I know, information isn't leaving it.

I remember wondering about that "wall" back in 5thish grade... Damn it was a mental twister. (Of course, not knowing anything about space, didn't help)


The question is "what existed before what is now?"

Whatever was there before space would most likely occupy what is now beyond space. What is 'nothing'? When in time is 'before' the universe?

The main problem with our perception of universal realities is our subjectivity to time. Even our thoughts are linear and therefore we cannot truly look objectively at time and space together. We need an objective temporal model and the ability to perceive it without falling back to commonly understood (Past,Present,Future) concepts. For starters...