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How to understand looking into the past light?

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posted on Sep, 29 2005 @ 08:52 AM
I always get a head ache when trying to figure out how I can be looking at light over 13 billion years old when looking into a telescope. How can an object 13 billion years old light just now be reaching earth?

If their was a big bang..then what ever eventually formed the earth(milky way) had to be right next to everthing else that exisited at the big bang. At that moment the light between two objects should have been nearly real time.

Ok I move 13 billion years into the future and peer out into deep space all the while the light from the first objects should have been with us.... here is were I cannot wrap my mind around this subject.

Since the beggining the matter formed at the big bang has spread away from each other at the speed of light?

If our planet existed right after the big bang then we would be sitting right next to any other galaxies formed at that time... why would it take 13 billion years for that light to reach us unless we were moving away from the object at the or faster than the speed of light? It seems like the light would have always been here to view?

How could we just now be seeing a baby universe that formed 13 billion years ago while it was sitting right next to the milky way galaxy (when it to was a baby after the big bang) while it was forming 13 billion years ago. It seems like everything that was emitting light 13 billion years ago while sitting next to this galaxy would be visible all the while and not just now be reaching us... I know some light has passed us be 13 billion light years away from us and to be seeing light for the first time does not seem possible unless we were allready that far apart at the begining..All galaxies light began with the big bang should have been viewable since the begining?

I know. I do not even think I am asking this question correctly as I cannot seem to grasp it. Can someone clear it up?

posted on Sep, 29 2005 @ 09:38 AM
Ok I'm having a tough time interperting your post mostly because I am just waking up but I will give it a go.

THe earth was not formed during the big bang, and neither did the milky way. Hell the universe was dark for billions of years after the big bang. What the big bang was was the release of matter and energy into the universe. THe only actually matter there was after the big bang was Hydrogen atoms because they are the simplest of all atoms. It took billions of years of expansion for that hydrogen to even colace into stars. Then billions of year upon that for galaxies to form. So anything emiting light would already have quite a large leg up.

Also even if there were objects emiting light at the moment the universe was created in the big bang and they were right next to each other the light would be in "real" time but they would be moving apart from each other so the delay of time it takes the light to go would increase. We would not still see that light for it would be far gone by now.

And now I don't know where to continue...

posted on Sep, 29 2005 @ 09:47 AM
When you look at the sun, you're actually looking at 8 minutes ago. it takes 8 minutes for light from the sun to reach us. Light is endless, so it will keep travelling through the universe. Just because we don't see it doesn't mean it's not there. It takes time for it to get anywhere though.

Ok, let's use sound as an example. There's a man 1/4th mile away from you. He pulls our a rifle and shoots it straight up in the air. You see him do this, but you don't HEAR the rifle report until at least several seconds later, if not longer. The farther away you are the longer it takes the sound to reach you.

Light is the same way. The farther you are from it the longer it takes to reach you. Just instead of seconds, it takes years, because of the distance involved.

posted on Sep, 29 2005 @ 10:55 AM
Also, you have to take into account the fact that as EMR (electromagnetic radiation, light, etc) travels across vast --billions of light years-- distances of space, the frequencies within the visible spectrum tend to be absorbed (and scattered) by hydrogen that permeates the universe.

So even if something has been shining since the big bang, we may not necessarily be able to *see* any of its light (see the big baby galaxy thread for more on this).

[edit on 29-9-2005 by blackholebrain]

[edit on 29-9-2005 by blackholebrain]

posted on Sep, 29 2005 @ 02:00 PM
Imagine I'm ten feet away from you. Imagine you throw a rock at me at 25 miles an hour, but before you do I run away at 20 miles per hour. You'll eventually hit me, but not right away.

That's what's happening here. Light, which travels at 3x10^8 meters a second, leaves a star. As it's travelling, that star is moving away from us, we're moving away from the star. Space itself is expanding. What may have been 1 billion light years away when it left could easily be five times as far away by the time it gets there.

And, just think, that light that's 13 billion years old, imagine how old the light source is now. You won't be seeing the light it emits for over 13 billion more years.

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