dJJ said:

morningsong said:

Silly.

Comoving distance is the distance between two points measured along a path defined at the present cosmological time. For objects moving with the Hubble flow, it is deemed to remain constant in time. The comoving distance from an observer to a distant object (e.g. galaxy) can be computed by the following formula:

The math is such a completely different language I don't think there's a layman term that can be translated into.

I have a fetish for intelligent people...

I couldn't solve this equation if you had a gun to my head. Maybe a longtime ago if I'd of applied myself this would be like cutting through soft butter, but I didn't so I can't.

We went to the McDonald Observatory in Fort Davis, Texas this weekend. Wow!

I looked through several telescopes, although not the biggest one (the roads were too icy to get up there). At one, I was looking at a galaxy cluster and I asked the operator how many stars was I looking at through this telescope.

He said, "At least a trillion".

A trillion stars! And that was just one small part of the universe!

Mind blowing.

RodeoSchro said:

We went to the McDonald Observatory in Fort Davis, Texas this weekend. Wow!

I looked through several telescopes, although not the biggest one (the roads were too icy to get up there). At one, I was looking at a galaxy cluster and I asked the operator how many stars was I looking at through this telescope.

He said, "At least a trillion".

A trillion stars! And that was just one small part of the universe!

Mind blowing.

The REAL mind-blowing question is...where you eating a McRib while making said observation?

Wait. If two objects moving at the speed of the light are moving in opposite directions the cumulative speed of their separation is still only the speed of light and not twice the speed of light. At least, that's what I remember to be true, or was told was true. Now I'm wanting to know if traveling faster than the speed of light is possible. How could it be, then?

this faster than light expanding of the universe can be explained

by velocity;

by dividing the comoving distance by the present cosmological time,

the resulting velocities of distant objects can be faster than the

speed of light.

the faster than light expansion of the universe is not in conflict with

the theory of relativity.

[Edited 1/7/13 19:20pm]

Fauxie said:

Wait. If two objects moving at the speed of the light are moving in opposite directions the cumulative speed of their separation is still only the speed of light and not twice the speed of light. At least, that's what I remember to be true, or was told was true. Now I'm wanting to know if traveling faster than the speed of light is possible. How could it be, then?

Space isn't actually travelling through space.

It's expanding faster than the speed of light because it's not travelling from point A to poing B. Rather, point A and point B are moving further apart on the fabric of space--the same fabric that light travels on. Think of light as an ant moving on the surface of a baloon. Nothing can run faster than the ant, but the baloon is expanding faster than the aunt runs.

I'm making no fucking sense am I?

imago said:

Fauxie said:

Wait. If two objects moving at the speed of the light are moving in opposite directions the cumulative speed of their separation is still only the speed of light and not twice the speed of light. At least, that's what I remember to be true, or was told was true. Now I'm wanting to know if traveling faster than the speed of light is possible. How could it be, then?

Space isn't actually travelling through space.

It's expanding faster than the speed of light because it's not travelling from point A to poing B. Rather, point A and point B are moving further apart on the fabric of space--the same fabric that light travels on. Think of light as an ant moving on the surface of a baloon. Nothing can run faster than the ant, but the baloon is expanding faster than the aunt runs.

I'm making no fucking sense am I?

i think that has to be the case.

imago said:

Fauxie said:

Wait. If two objects moving at the speed of the light are moving in opposite directions the cumulative speed of their separation is still only the speed of light and not twice the speed of light. At least, that's what I remember to be true, or was told was true. Now I'm wanting to know if traveling faster than the speed of light is possible. How could it be, then?

Space isn't actually travelling through space.

It's expanding faster than the speed of light because it's not travelling from point A to poing B. Rather, point A and point B are moving further apart on the fabric of space--the same fabric that light travels on. Think of light as an ant moving on the surface of a baloon. Nothing can run faster than the ant, but the baloon is expanding faster than the aunt runs.

I'm making no fucking sense am I?

no, you are making sense

indeed the distant objects do not physically move away from each other,

rather the fabric of spacetime between them expands.

this also explains the inflationary period during the Big Bang when

the universe expanded from a size a hundred billion times smaller than

a proton to approximately one hundred million light years in diameter

in a fraction of a second.

[Edited 1/8/13 11:47am]