I once thought I read that we can now look into a telescope and and almost look back on how the universe began because of time etc. how is this done? Surely the beginning of the universe was a long time ago.....was I dreaming?
2007-10-30 10:11:30 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
The idea is this: the farther away we see something, the longer ago in time are we seeing it.
So, if you look at a star that is 1 light year away, we are seeing what that star was doing 1 year ago. For star 1000 light years away, we're seeing what the star was doing 1000 years ago.
By examining very very distant objects, astronomers can get an idea of what was happening long long ago...
Make sense?
2007-10-30 10:23:06 · answer #1 · answered by hcbiochem 7 · 0⤊ 0⤋
The universe started off at very high temperature/pressure/energy/density (at that level, the words all means the same thing).
After approximately 400,000 years, the universe had cooled enough (3000 K = 5000 F) that hydrogen atoms could be formed (hotter than that, electrons are knocked off their orbits around the protons).
Free electrons and photons (particles of light) interfere a lot with each other. Matter and radiation are said to be 'coupled'.
When the electrons took orbits around the protons, they were no longer free. They stopped interfering with the photons: the universe suddenly became transparent. All the light that existed at the time is visible now as microwave radiation (because of cosmological redshift).
http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation
It is also known as 'decoupling' radiation, because that is when matter and radiation stopped being coupled.
It is impossible to see 'prior' to that event, simply because the universe was not transparent before that time.
2007-10-30 10:29:59 · answer #2 · answered by Raymond 7 · 1⤊ 0⤋
No one can see that far into space and time. Yes, it's true that by looking through a telescope at a star located - for example - 8000 light years away from us, you're actually looking at it the way it was 8000 years ago ( because it takes the light 8000 years to reach your eyes).
But the beginning of the Universe is impossible to be seen mainly because the matter is too dense to see through.
2007-10-30 10:17:30 · answer #3 · answered by 343 3 · 0⤊ 1⤋
No you weren't dreaming, Edwin Hubble made careful measurements using his telescope and discovered that the entire universe is expanding as we move forward in time, therefore as we move back in time the entire universe will contract into a single point. When this point began expanding is the begining of the universe, this is known as the big bang theory.
2007-10-30 10:16:05 · answer #4 · answered by aaron.brake 3 · 0⤊ 0⤋
well . . . I kinda get what you're saying. . . the reason would be because light takes time to travel. . . if something took (for example) 200 thousand light years to travel, and it was destroyed 199 thousand years ago. . . we could still see what existed for another year. . . our time. We see the light of things that have already happened.. . when they have such a great distance to travel to reach us.
2007-10-30 10:17:14 · answer #5 · answered by Iceman 3 · 0⤊ 0⤋
It begins when there was a hot ball which is called Big Bang...
2007-10-30 13:06:41 · answer #6 · answered by Kristian C 2 · 0⤊ 0⤋