# Thread: does the universe have an escape velocity?

1. the universe is curved right? do you think if you travel with enough energy, say .9999^googol c, you would stop going along with the curve of the universe and leave it to whatever's beyond?

2.

3. There is no beyond. If a beyond existed, it would not be "beyond", but a part of the universe. Unless you are thinking of multiple universes idea? In that case, still no dice :wink: .

4. Originally Posted by KALSTER
There is no beyond. If a beyond existed, it would not be "beyond", but a part of the universe. Unless you are thinking of multiple universes idea? In that case, still no dice :wink: .
well theres different ways of looking at the word universe, i mean our local universe that we can interact with and shares our laws of physics.

mabye you'd end up in some kind of 4d multiverse?

5. if you leave the universe you will be travaling at the speed of light the human body would not be able to withtand the pressure neather would eny material used to build this futuristic ship but if you were able to make a ubership that sheilded you from death you may end up in a differend demention or quite possably dissapear lol.

6. isn't the universe flat?

7. Originally Posted by numb3rs
if you leave the universe you will be travaling at the speed of light the human body would not be able to withtand the pressure neather would eny material used to build this futuristic ship but if you were able to make a ubership that sheilded you from death you may end up in a differend demention or quite possably dissapear lol.
well if you accelerated slowly enough.... its a hypothetical anyways
but weird things do happen at high speeds, mabye with future particle accelerators this could be tested

8. Originally Posted by medlakeguy
.9999^googol
This is a really small number. 0.9999^25000 is already less than 0.1, and so 0.9999^(10^100) is about 10^(-4*10^96). I think I sit still faster than that times the speed of light.

9. Wouldn't it be funny if at one end of the universe you appeared on the other?

10. That's possible in two different ways. The universe may have positive curvature, in which case just by the nature of its geometry it'd have finite volume (like the surface of a sphere having finite area). Or it may be glued together in a weird way so that if you go far enough in any direction, you "appear on the opposite side" (like the surface of a donut).

11. Originally Posted by serpicojr
Originally Posted by medlakeguy
.9999^googol
This is a really small number. 0.9999^25000 is already less than 0.1, and so 0.9999^(10^100) is about 10^(-4*10^96). I think I sit still faster than that times the speed of light.
the closer you get to the speed of light the more energy your traveling with, going .9c takes considerably less energy than travling .999c, thats why i said that.

if the universe did have an escape velocity it would likely be dependent on the kinetic energy, not the speed of the object. seeing as how you cant go any faster than light

12. I'm just saying that 0.9999^googol doesn't mean what you think it does. It means 0.9999 times itself googol times, and this is a tiny number. The number you're trying to talk about is (I believe):

(10^googol-1)/(10^googol)

which is a decimal point followed by googol 9's. And, yes, this times c is very fast.

13. Originally Posted by serpicojr
I'm just saying that 0.9999^googol doesn't mean what you think it does. It means 0.9999 times itself googol times, and this is a tiny number. The number you're trying to talk about is (I believe):

(10^googol-1)/(10^googol)

which is a decimal point followed by googol 9's. And, yes, this times c is very fast.
haha well lets not get too technical, you see what i was trying to say right?

14. if you left the universe would you not becume a universe in your entirety? just a realy small one. if you were able to make something go faster then the speed of light to surpass the universe in its expantion you will have to have a like enormus power. :|

Wouldn't it be funny if at one end of the universe you appeared on the other?
its possable that the universe is round and would be quite funny as well we finnaly find smething to traval faster then light and we end up right back at earth lol.

15. Originally Posted by medlakeguy
haha well lets not get too technical, you see what i was trying to say right?
Well, yes, but I still think it's something worth pointing out. It's one thing to use loose language to talk about math and science (e.g., "near-light speed"), but it's another to loosely use a technical term to mean something it doesn't.

16. Originally Posted by serpicojr
Originally Posted by medlakeguy
haha well lets not get too technical, you see what i was trying to say right?
Well, yes, but I still think it's something worth pointing out. It's one thing to use loose language to talk about math and science (e.g., "near-light speed"), but it's another to loosely use a technical term to mean something it doesn't.
i gotcha, thanks
god knows how many times id do the same thing on other threads, or with one of my professors

17. Originally Posted by medlakeguy
the universe is curved right? do you think if you travel with enough energy, say .9999^googol c, you would stop going along with the curve of the universe and leave it to whatever's beyond?
If light cannot escape becuse it has to follow the curvature of space, than there is no escape velocity to speak of.

However, as humans in a space ship, we would not have to follow the curvature, but instead, move in a straight line. So when we get to the edge of the BB and come to it in a straight line, we 'crash'.
We hit the 'nothing' wall!. Ha ha.
Well, come to think of it, that ain't funny.
We are prisoners of the BB.

Cosmo

18. "Following the curvature of space" and "moving in a straight line" are the same thing.

19. Originally Posted by Cosmo
Originally Posted by medlakeguy
the universe is curved right? do you think if you travel with enough energy, say .9999^googol c, you would stop going along with the curve of the universe and leave it to whatever's beyond?
If light cannot escape becuse it has to follow the curvature of space, than there is no escape velocity to speak of.

However, as humans in a space ship, we would not have to follow the curvature, but instead, move in a straight line. So when we get to the edge of the BB and come to it in a straight line, we 'crash'.
We hit the 'nothing' wall!. Ha ha.
Well, come to think of it, that ain't funny.
We are prisoners of the BB.

Cosmo
maybe light, being massless doesn't possess enough kinetic energy to escape the universe?

there is no wall at the end of the universe,
if space is closed then you could travel in a straight line and end up right back where you started

if there is a 4d multiverse then in a very real sense we are already at the edge of the universe... weird eh?

Originally Posted by serpicojr
"Following the curvature of space" and "moving in a straight line" are the same thing.
it appears that way but your really still following a curved line

20. Actaully light has mass and takes up space.

21. Originally Posted by SuperNatendo
Actaully light has mass and takes up space.
it has volume and takes up space but photons are massless

22. Originally Posted by medlakeguy
it appears that way but your really still following a curved line
No. When you're dealing with nontrivial curvature in geometry, straight lines are defined as "(locally) distance minimizing paths". And following the curvature of space is precisely moving along distance minimizing paths.

23. Originally Posted by serpicojr
Originally Posted by medlakeguy
it appears that way but your really still following a curved line
No. When you're dealing with nontrivial curvature in geometry, straight lines are defined as "(locally) distance minimizing paths". And following the curvature of space is precisely moving along distance minimizing paths.
i think from the perspective of the person in the curved space that's right, and mathematically and physically curved space can be described as flat, while your in it, but to an outside observer you'd still be traveling along a curve.

24. Originally Posted by medlakeguy
i think from the perspective of the person in the curved space that's right, and mathematically and physically curved space can be described as flat, while your in it, but to an outside observer you'd still be traveling along a curve.
Okay, I think I see where the confusion is arising. You can always immerse curved space in Euclidean (flat) space, and to someone living in that Euclidean space, the straight lines of the curved space do look curved. But this isn't because the lines are actually curved--this is just due to the distortion of looking at curved space in flat space.

Now I think this is what you're picturing when you talk about an outside observer seeing straight lines in curved space as being curved. But this only makes sense in the abstract setting I propose above. In physical reality, this doesn't make sense, unless you believe that the universe is a manifold immersed in a larger dimensional Euclidean space into which you can step and see the universe for its curved self.

What I'm saying, then, is there is no distinguished, outside vantage point from which you can view the universe. You're stuck in it. And the perspective you have as an observer in and of the universe is the only one that matters. A straight line, a distance minimizing path, a path following the curvature of space--these are all the same thing. And you cannot go anywhere and see these things as being anything else than straight lines.

25. In physical reality, this doesn't make sense, unless you believe that the universe is a manifold immersed in a larger dimensional Euclidean space into which you can step and see the universe for its curved self.
this whole threads kinda been about if that were true... but even if it weren't, wouldn't you agree a traveling through wormhole (assuming they exist) would be a straighter line than just traveling along the curve of space?

26. it would be fairly improbable to use worm holes to traval through space like that if they did exist they probubly would dissapear the secent eny matter tryed to go through it thus makeing it impossable to travle

27. Originally Posted by medlakeguy
this whole threads kinda been about if that were true... but even if it weren't, wouldn't you agree a traveling through wormhole (assuming they exist) would be a straighter line than just traveling along the curve of space?
Okay, so let's suppose the universe is contained in some higher dimensional thing, and let's suppose we want to get out of the universe and into this thing. If we're going to try to do this by going real fast in a straight line, the only way this is possible is if the universe has a (topological) boundary in this thing and if some point on said boundary is a finite distance from somewhere (anywhere) in the universe. Then you can literally bump into the wall at the edge of the universe (assuming you can get there).

In the boundaryless or infinite distance boundary scenario is correct, then no amount of going straight or going fast is going to get you away from the curve of the universe. Any direction you can think of to go corresponds to a straight line, and going straight necessarily means moving along this straight line. If this line doesn't hit a boundary at some finite distance, you're stuck speeding around the universe.

A wormhole doesn't affect the definition of a straight line. A straight line is defined by locally being the shortest path between two points--i.e., if I take two points that are close enough together that space looks pretty close to flat space, then I define the line as such. You can, thanks to wormholes or other topological phenomena, end up with many straight lines connecting two distant points, and one of them may be the shortest, but that doesn't mean that the longer ones aren't lines.

28. i think i can help shine a lil light on this thread

29. Originally Posted by numb3rs
i think i can help shine a lil light on this thread
That image is wrong because if you are standing at the edge of the BB, the outside view should be black (no light escaping) rather than as shown.

The worm hole between the professor and the man should be white because the light is escaping there. Ha ha.

Cosmo

ok everyone lets think about this if you wonted to traval faster then the speed of light if you experianced this for like 10minuts wouldent 1000 years have past? why would you not age eny? is it possable in that 10min you get old and die?if not why not? its very confuzeing to me

31. Originally Posted by serpicojr
In the boundaryless or infinite distance boundary scenario is correct, then no amount of going straight or going fast is going to get you away from the curve of the universe. Any direction you can think of to go corresponds to a straight line, and going straight necessarily means moving along this straight line. If this line doesn't hit a boundary at some finite distance, you're stuck speeding around the universe.
thats what i was saying, maybe your speed alone would let you break free of a closed universe instead of just going in circles, just like if you fired a cannonball fast enough on earth you could expect it to leave the planet or go into orbit

(yes, i know how many things are wrong with that analogy... you get my point)

32. To All

I do not believe in the curvature of space and space as the medium for light to travel.

Light uses the EM Fields as its medium to travel through. No charged particles, no medium for light to travel through. But space is still there.

The light approaching us can have either a curved radiation line or a straight line.
This radiation line would depend on the movement of the radiating source (Star or Galaxy).
If it is moving 'laterally' to our line of sight, the radiation line would have curvature. But it the object is moving toward us or away from us, the path of the radiation would be straight.

This would effect the redshift of the objects slightly and 'ever' so slightly when the object is moving laterally.

Cosmo.

 Bookmarks
##### Bookmarks
 Posting Permissions
 You may not post new threads You may not post replies You may not post attachments You may not edit your posts   BB code is On Smilies are On [IMG] code is On [VIDEO] code is On HTML code is Off Trackbacks are Off Pingbacks are Off Refbacks are On Terms of Use Agreement