The edge of space

[amt7565]

Wait!

I was reading that some parts of the galaxies were receding faster than 'c'. So this means the universe is expanding faster than 'c'?

 

Apparently the speed limit of light does not apply to these.

[Little Bang]

Tormod, your saying for the answer to #2 that the rate of expansion of the Universe has an effect on the speed of light, surely I misunderstood you?

[infamous]

Wait!

I was reading that some parts of the galaxies were receding faster than 'c'. So this means the universe is expanding faster than 'c'?

 

Apparently the speed limit of light does not apply to these.

 

Try this link, http://www.physics.hku.hk/~tboyce/sf/topics/lightfreeze/0701haubox1.html

 

They discuss the apparent reason for this phenomenon.

[karlfreak]

___Not only is the Universe folding in on itself, not only is it flattened, it all sits on the back of a turtle. ;)

well done i agree with u

[infamous]

___Not only is the Universe folding in on itself, not only is it flattened, it all sits on the back of a turtle. ;)

 

A veryyyyyyyyyyyyyyyyyyyyyyyyyyyyyy larrrrrrrrrrrrrrrrrrrrrrrrge

Turtle.

[karlfreak]

The results of our study contribute to the mountain evidence that suggests that prospects for ancient DNA studies from the tropics are less promising than those from higher latitudes, but when the results are potentially of such compelling interest, it’s always worth a try

 

and how does this help the scientific community let alone the average jo-blo

it could just be the fact that i am a very simple country aussie but hey if i saw that published any where i would normally see it i would think who cares is this what there spending there funds onprhaps the should try to find a cure for aid or some thing

[karlfreak]

well no about the size of a snapper turtle at most

 

any way in realation is there a barier

i was wondering if it would be the oppisete to absolute zero where every thing is moveing that fast they are causing explotions and creatin new galixes and stuff but i guess that would only work if the univers was continuing to exoand out form the origanal startin point

[coldcreation]

What reference point are we using to say the universe is expanding at C?

 

Good point little bang. We are using the only reference point we have; our own. An observer from a galaxy at the horizon sees us moving at the speed of c.

 

Galaxies are not realy moving much. It is supposed to be the space between them that is growing, expanding (I disagree), where space is continually created. The big bang little bang is a continuous creation theory: of space.

 

So, question: why is there an edge of space?

[Tormod]

Tormod, your saying for the answer to #2 that the rate of expansion of the Universe has an effect on the speed of light, surely I misunderstood you?

 

The rate of expansion of the *observable* universe is at the speed of light. Since it expands at the speed of light (by necessity, since we see only so far as the light has travelled since the Big Bang), the rate of expansion = c. We could twist it around and say c = rate of expansion of the observalbe universe (at the moment). I didn't say that the rate of expansion has an effect on c.

[Tormod]

...but i guess that would only work if the univers was continuing to exoand out form the origanal startin point

 

This has been discussed in another thread - there is no "universal center" because the entire universe grew out of the Big Bang. So technically speaking every point in the universe can be said to be the center. The same reasoning tells us that there is no physical edge to the universe.

[coldcreation]

The rate of expansion of the *observable* universe is at the speed of light. Since it expands at the speed of light (by necessity, since we see only so far as the light has travelled since the Big Bang), the rate of expansion = c. We could twist it around and say c = rate of expansion of the observalbe universe (at the moment). I didn't say that the rate of expansion has an effect on c.

 

Important: The rate of expansion is estimated between 50 and 70 km s -1 Mpc -1(I think). That falls far short of light speed. Only at the horizon is that relative velocity attained. It is not a true velocity.

 

Your other mail Tormod is correct, there is no real edge of space (but not for the reason you give)...

 

Something has only just begun

[Tormod]

Important: The rate of expansion is estimated between 50 and 70 km s -1 Mpc -1(I think). That falls far short of light speed.

 

The rate of expansion of the diameter of the observable universe is the speed of light, by definition. This is NOT the same as cosmic expansion. I was pointing out a flaw in Infamous' question.

[Tormod]

In fact, the diameter would of course grow at *twice* the speed of light. ;)

[coldcreation]

The rate of expansion of the diameter of the observable universe is the speed of light, by definition. This is NOT the same as cosmic expansion. I was pointing out a flaw in Infamous' question.

 

Diameter implies an edge from where one can begin measuring, otherwise the idea of diameter has no meaning. Your concept of the universe has an edge of space. It is a boundary or singularity at the horizon. Even if it is only a relative one the problems created are insurmountable: mass moving at speed of c, infinite curvature, infinite time dilation, i.e., time appears to stop.

 

Is there a way out of this quandry?

[Tormod]

Diameter implies an edge from where one can begin measuring, otherwise the idea of diameter has no meaning. Your concept of the universe has an edge of space. It is a boundary or singularity at the horizon. Even if it is only a relative one the problems created are insurmountable: mass moving at speed of c, infinite curvature, infinite time dilation, i.e., time appears to stop.

 

Is there a way out of this quandry?

 

I missed this, sorry for bumping up an old thread.

 

Diameter does indeed suggest a center. There is no quandry however as I was talking about the observable universe. We are at the bang smack middle of it.

[blazer2000x]

What if the universe isn't flat, and dosn't have any edge? What if it's just a big jumbled bunch of strands or something and we alternate between strands all the time without knowing it? As far as I know, no one has ever reached the edge, or seen the edge, and no one ever will. So we really know nothing about its shape or size or expansion patterns. Maybe it's all already there, and sort of comes into perspective as light from the big-bang finally reaches it. If that were true, then it would eventually come to an end, but we would most likely never reach it then anyway as it would have gone to far... But what I don't understand is how everyone seems to have an image of what it looks like in there heads, when they don't even understand exactly how or why it works? It all seems like one giant guess to me. ;)

[EWright]

Wow! Some ideas are way off base here. The speed of light has NOTHING to do with the rate at which space is or can expand. In fact, physics allows for space to expand at a rate faster than the speed of light. Space is not limited to a speed of less than c by modern physics. It is light that is limited to c, not the expansion rate of the universe that is limited by a produce of itself.

 

As for those having trouble imagining a universe in three dimensions that wraps back on itself. Think of the old video game "Astroids" and what happened when you left one side of the screen... you popped back up on the other side of the screen. Now just imagine this in a cubical form (easier to imagine than spherical). But it is harder to be sure where your corresponding point of return would be in 3D as opposed to 2D.

 

However, here is a question to ponder. If you leave one point and return to the same point after traveling in a straight line however many gazillion light years later after traveling through space that wraps back on itself; would you not have a reading on your odometer that told you exactly what the diameter of the universe must then be?