Someone Smart help me out

reply to post by Mianeye


Because what you (are) observing is what is around you, when you look back, you see what is behind you. When we look into the dark spaces between light in the sky and see an image of a galaxy 14 billion light years distant, we see WMAP, the afterglow of the Big Bang, where ever it is, the source isn't important, just how far away it is, (how long ago it happened) and we see nothing further away so we call it the beginning of space and time.

Look at the simplistic video I posted earlier, light speed is constant, if you and Einstein are traveling light speed side by side you see each other like you are standing still, because you are side by side. It gets more complicated if you are approaching each other or receding from each other but light speed is constant, (outside of gravitational lensing) but lets just leave that theory out of it for now.

reply to post by Illustronic




Thanks, i think i get it

Originally posted by Mianeye
reply to post by Fiberx

 

I understand what you are saying, but that is from a fixed point, two person's standing still, and traveltime from point A (emiter) and point B (wiever).

What i was thinking was.

If everything starts from the same point ( Big bang) and travel away together (Mass and light) how can it be the past we are seeing, when the light around us is traveling with us at the same speed or faster?

Or maybe im just to stupid to understand it

edit on 27-3-2011 by Mianeye because: (no reason given)

The idea that things in the universe are moving away from the "Big Bang" is a misunderstanding of the concept. Time dilation caused by relative velocity is physically caused, according to Special Relativity, by the contraction of length of a reference frame, which preserves the speed of light as measured by two or more reference frames. For instance, a car at rest may be 3 metres long, but, if it's moving at half the speed of light (0.5c), the car appears 86.6% as long, or 2.6 metres. The apparent decrease in length increases the apparent time (time dilation), which, when distance over time is taken into account, allows light to always be measured as travelling at a constant speed.

This is in contrast to the expansion of the universe, which what's called a metric expansion. When the Big Bang occurred, it was not an explosion, as such - rather, it was a creation of space-time, which immediately went through a period of rapid expansion, called the Inflationary Epoch. During this epoch, space-time, itself, was stretched. Notice, the matter within the universe was not flung out away from a single point, like is suggested by picturing the Big Bang as an explosion. The expansion of the universe created matter, which expanded right along with the rest of the universe, like raisins rising with the dough when raisin bread is made. The raisins don't have any actual velocity, they just expand with the dough. Likewise, the matter that fills the universe isn't moving out in all directions - the universe is expanding, and the distance between the objects is increasing.

Because of this, velocity-based time dilation doesn't apply to the expansion of the universe. In that case, the only things that really matters is how far away things are (given the finite speed of light) and how much distance has increased in the time the light has been travelling (which is the source of redshift).

reply to post by Mianeye


Well, to be accurate as to WHEN you are seeing one does take into account the expansion of the universe.

When we look at out a galaxy 35 million light years away, the light we see did leave it about 35 million years ago, as the speed of light is a constant. However, the galaxy is no longer where it appears to be. We cannot see beyond this limit.

We know we are looking at the past condition of the universe, but we do not know what the current condition is.

To answer the speculation about expansion relative to light speed.. The universe expands A) seperately from the light emitted within and B) in all directions, at every point.

The closest we can easily to come to seeing this occur is the old balloon trick.

Draw a few dots on various points on the surface of an empty balloon, then slowly blow it up and observe that each point moves away from all of the others. This is the first introduction to the concept of Einsteinian Relativity as it describes the expansion of the universe. The realization that the universe expanded combined with the obvious fact that the matter and energy we observe is not being torn assunder in the process is what gave rise to the intimately linked but distinctly seperate concept of the "Fabric" of "space/time".

This fabric is what expands, somewhat like a balloon..

After you have blown up your balloon, go ahead and gently press your finger into it's stretchy surface.. Welcome to Einstein's Concept of Gravity!

reply to post by Fiberx


The old ballon expanding universe analogy prompts the laymen to look for a dark area singularity left, while CLPrime tried to explain the misnomer of singularity not being a single infinitely small point in space. I'm not sure I made any sense there, singularity started space and time as we know it, it's not a description of a point in space everything is expanding from. We just can't see anything beyond that point in time, and we have an image of shortly after it, WMAP. So that is our time and space frame of reference. It's working fairly well so far.