Universal expansion faster than c

Many people argue that the Universe cannot expand faster then c, and when the rate of expansion reaches c, the Universe will begin to contract or something like that. I just want to ask exactly why you say that.

Who?.....Me I didnt say that

It'll never reach the speed of light, just like it will never reach absolute zero...just physical limits.

Doesn't this physical limitation only affect things with Mass. When someone says that the Universe cannot expand faster than c , they are almost implying that the edge of the Universe is made up of a ' wall ' that has mass. I find this a very 'cartoon' approach to the Universe. It is like saying the Milky way is made up of Milk . I would think that Universal expansion has got to do with the expansion of the Fabric of the Universe or something like that.

Please correct me if my approach is faulty.

Originally posted by T_Jesus
It'll never reach the speed of light, just like it will never reach absolute zero...just physical limits.

We have a very bleak future, and from my understanding, without additional energy being put into the cycle, we will end up at absolute zero.

(just physical limits)

But of course this is billions of years in the future........

And isn't light already going at the speed of light?????
That would be the speed of expansion in all directions.

C is based on the speed light travels across space. But the universe, space itself, is expanding. The limitations of light speed do not apply. One may be able to measure the matter that is being dragged along as traveling very fast, but space itself can expand at any rate... space has no mass. The laws of relativity don't even apply anymore when you focus this close.

weather the alternate dimensions have anything to do with the c variable will cause the effect of gravitational distortion, as the new theory goes when crossing hyper vortex the laws and nature of our universe might shift dramatically, to say that some leakage of laws might persist in some unforseen sections in our universe is not entire plausible but not entirely impossible either.

Originally posted by siddharthsma
Many people argue that the Universe cannot expand faster then c, and when the rate of expansion reaches c, the Universe will begin to contract or something like that. I just want to ask exactly why you say that.

Sidd.,

Many people when considering the universe's expansion fail to consider that there is nothing against which to measure the rate. When we look at distant galaxies, we see that the farther away they are, the faster they are moving away from us. If we look far enough, we will eventually see galaxies moving away at a rate that is arbitrarily close to the speed of light (we cannot see any galaxies moving faster than this, the light from them won't reach us - this is not exactly true, some galaxies are receding faster than light but we can still see them, their light left before they achieved that speed.)

The point is, if anyone in those distant galaxies was looking at us, they would see us retreating from them at these high speeds. They would feel that they are motionless, that it is we that are moving away from them. Additionally, if they looked the other direction, they could see all these galaxies we cannot, being closer to these other galaxies means that the galaxies invisible to us are not moving away from them at such a high speed.

The idea here is that the rate of expansion of the universe need not approach lightspeed for it to result in most of the rest of the universe to appear to be moving away from us at lightspeed.

The "dots on a balloon" example explains why further galaxies appear to be receding faster.

In any case, the rate of expansion of the universe need not be limited by c. As was stated earlier, c applies to objects with mass. The massive objects contained in the universe are not being moved by the universe, the space between them is expanding.

Harte