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SOMSOC
2004-May-28, 04:56 PM
Hi All

According to a topic on the BBC the universe is 156 billion miles wide!! thats amazing far bigger then we ever thought.

The link is below.

http://news.bbc.co.uk/1/hi/sci/tech/3753115.stm

Littlemews
2004-May-29, 03:27 AM
It's just a prediction ;) and I believe that wasn't the right number after all...

SOMSOC
2004-May-29, 03:35 AM
Oh ok thanks for the input always good to hear another persons view.

Kind Regards

pmf71
2004-May-29, 06:53 PM
156 billion lightyears or not, i always wondered how it was possible that the universe, in it's earliest infancy, managed to expand faster than the speed of light. according to EVERY scientist travelling faster than light is not possible, however most of them say the universe expanded lightyears within a few minutes, or something like that.
makes it even more peculiar that the universe is 156 billion lightyears across. assuming the universe is about 13.6 billion years old, and started as a singularity,that would mean the universe has been expanding at an average of approx. 5.7 times the speed of light.... boggles me. Anyone got an explanation?

GOURDHEAD
2004-May-30, 03:43 AM
Anyone got an explanation?

There are more ideas entered here (http://www.universetoday.com/forum/index.php?showtopic=3327)

A lot depends on the variability of the cosmological coeeficient of expansion and the duration and velocity of inflation during the inflation era.

fortyseven
2004-May-30, 05:08 AM
Maybe c was faster back then

Pandora
2004-May-30, 12:55 PM
[FONT=Impact][COLOR=green] Here is the explanation from the Space.com article referenced earlier.

"The problem is that funny things happen in general relativity which appear to violate special relativity (nothing traveling faster than the speed of light and all that).

"Let's go back to Hubble's observation that distant galaxies appear to be moving away from us, and the more distant the galaxy, the faster it appears to move away. The constant of proportionality in that relationship is known as Hubble's constant.

"One seemingly paradoxical consequence of Hubble's observation is that galaxies sufficiently far away will be receding from us at a velocity faster than the speed of light. This distance is called the Hubble radius, and is commonly referred to as the horizon in analogy with a black hole horizon.

"In terms of special relativity, Hubble's law appears to be a paradox. But in general relativity we interpret the apparent recession as being due to space expanding (the old raisins in a rising fruit loaf analogy). The galaxies themselves are not moving through space (at least not very much), but the space itself is growing so they appear to be moving apart. There is nothing in special or general relativity to prevent this apparent velocity from exceeding the speed of light. No faster-than-light signals can be sent via this mechanism, and it does not lead to any paradoxes.

"Indeed, the WMAP data [on cosmic microwave background radiation] contain strong evidence that the very early universe underwent a period of accelerated expansion in which the distance been two points increased so quickly that light could not outrace the expansion so there was a true horizon -- in precise analogy with a black hole horizon. Indeed, the fluctuations we see in the CMB are thought to be generated by a process that is closely analogous to Hawking radiation from black holes.

"Even more amazing is the picture that emerges when you combine the WMAP data with [supernova] observations, which imply that the universe has started inflating again. If this is true, we have started to move away from the distant galaxies at a rate that is increasing, and in the future we will not be able to see as many galaxies as they will appear to be moving away from us faster than the speed of light (due to the expansion of space), so their light will not be able to reach us." :huh:

StarLab
2004-May-30, 07:13 PM
I don't get it. I just don't get it. No one here seems to be thinking of a way around the redshift theory - that the farther away something is, the faster it's receding from us. Now, people keep saying the following clause: "the most distant galaxies that recede faster than C."
Has anyone thought of a way around this idea? Has anyone come up with an exception? Because I think that if closer galaxies are moving away slowly, and farther ones move away faster, then at some point galaxies are moving away at the speed of light.
But, what if the point where redshift=c is so far away from us (in space and, therefore, in time of course) is so far off that galaxies don't even exist that far away! I think this would solve a lot of problems! ;) :P :) B) :rolleyes:
Now, about that "Ekpyrotic Universe" idea (I hope I spelled it right): when the two univeses collided, the point at which this collision took place was the bigbang. As the universes began to overlap, spacetime as we know it was created. But, because the universe was so hot, as the two universes interlocked spacetime was growing within the new universe rapidly. As the two universes began to gridlock and cool, the spread of spacetime itself slowed, and at this point spacetime is spreading at a constant rate. Spacetime will stop expanding in the future when the two universes have reached a total gridlock, perfectly overlapping one another.

Deep_Eye
2004-May-31, 04:15 PM
I have a way to explain why the further-away galaxies that Hubble viewed MIGHT be appearing to be moving away faster than the speed of light. Ok, say the galaxies are moving away from us at half the speed of light (or 0.5c). Now, the article said that space is expanding and so raidiation that left the early universe 13.7 billion years ago actually traveled a distance of 78 billion light years due to the fact that not only are galaxies moving away form each other, but the 'space' is also expanding. So, with the galaxies that Hubble viewed-the only appear to be moving faster than light becasue that is the net force of movement. Say space is expanding (at that point) 5 times faster than light. And, since it is only space expanding faster than light-no "laws of physics" are being broken. Now, since the galaxies are in that space are also expanding, you add their speed of movement together and get 5.5c (5 and a half times faster than light). Thoughts?

StarLab
2004-May-31, 04:28 PM
Now, since the galaxies are in that space are also expanding, you add their speed of movement together and get 5.5c (5 and a half times faster than light). Thoughts?
Wait. I don't get that last bit of math there...what does 5.5c mean? Also, if you wanted to combine the expansion rate of galaxies with spacetime, wouldn't you subtract one from the other, as opposed to addition?


And, since it is only space expanding faster than light-no "laws of physics" are being broken.
I like your thinking here. You are treating spacetime and light as if they are two different dimensions. I have a feeling, especially in the Ekpyrotic universe model, that you are correct. Spacetime, the four-dimensional dimension we live in, can exist with either v=c, v<c, or v>c. It exists, at least in my view, as v>c (faster than light), and I have the strangest feeling that spacetime is carried via neutrinos. Light, of course, travels at v=c.

Deep_Eye
2004-May-31, 08:35 PM
Okay, say the galaxies are moving away at .5c (half the speed of light). Also say that space-time is expanding in the same direction at 5c (5 times the speed of light). Since it is space-time (and this is only my theory), I think it can expand faster than light because it is only the empty space between galaxies. So, while the galaxies are moving out, space-time is also stretching out in the same direction. This would make (using my numbers) the net force 5.5c (5 and a half times faster than light). The galaxies are not moving away from us at 5.5c, it only looks that way because space time is also expanding. And no-you wouldn&#39;t subtract because they are moving in the same direction as each other. Thanks for the compliment :)

StarLab
2004-May-31, 09:54 PM
Spacetime, the four-dimensional dimension we live in, can exist with either v=c, v<c, or v>c. It exists, at least in my view, as v>c (faster than light), and I have the strangest feeling that spacetime is carried via neutrinos.
Of course, this does not mean that we perceive things this way. We live in a universe with overlapping dimensions, and though neutrinos can go faster than light, they go so fast that they seem to collide with matter very sparsely. Because we do not witness too many things happen at greater than c, we assume that we live in a v<c universe.

Deep_Eye
2004-Jun-01, 12:54 PM
I thought we believed that because thats what the laws of physics say...

StarLab
2004-Jun-01, 07:25 PM
The laws of physics and relativity are different only in that things may look one one way but be something completely different.

Deep_Eye
2004-Jun-01, 07:28 PM
The laws of physics and relativity are different only in that things may look one one way but be something completely different.

Uh? Could you explain that please?

StarLab
2004-Jun-01, 08:52 PM
Like, for example, a car coming towards me at the same speed I&#39;m going towards it would look like, from my perspective, the car that is coming towards me is actually moving faster. That&#39;s relativity. Relativity states that to an outside observer, the two cars are moving at the same speed. That&#39;s a law of physics (assuming my car and the idiot&#39;s car are ligh particles in a vacuum).
Then, of course, the cars collide, and I die unless one of us swerves out of the way.

Deep_Eye
2004-Jun-01, 10:27 PM
English :) Got it. I knew what relative meant. I just couldn&#39;t make sense of your sentence that I quoted in my previous post.

Technito20
2004-Jun-07, 04:18 AM
I&#39;m thinking maybe our Galaxy is that big. But the Universe, or I should say the whole physical Cosmos is Never ending. I mean there isn&#39;t just a giant brick wall at the end.

StarLab
2004-Jun-07, 05:15 PM
I think our universe is finite, but that an energy field that exists outside our universe is infinite.

rahuldandekar
2004-Jun-08, 06:10 AM
Maybe the universe is finite but we would never discover this, because it has no boundary.
Anyway, if we imagine a four dimensional universe like a sphere, does the &#39;time&#39; dimension flow from north to south? i.e. are we advancing to the south pole every moment? If we are, is there already a south pole or is new spacetime bieng made as time goes on?

StarLab
2004-Jun-08, 05:04 PM
Maybe the universe is finite but we would never discover this, because it has no boundary.
Everthing finite has a boundary...even the solar wind is at some point overpowered by interstellar wind. ;)

If we are, is there already a south pole or is new spacetime bieng made as time goes on?
That&#39;s my theory, in any case...the spacetime is still expanding as the boundaries of the universe expand...