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arenton
2004-Aug-01, 10:54 AM
In a recent edition you made the following statement:
"Astronomers have tracked a fast moving binary pair of objects back to the original stellar nursery that they were ejected from 1.7 million years ago. "

This made me wonder if astronomers have located the BIRTHPLACE of the universe, i.e. the place in the cosmos where the big bang began.
I assume the big bang explosion would have proceeded outwards as a sphere. Have they tracked back the galaxies to the place where it all began - I believe that have estimated the time of the big bang -was it 13 billion years ???.
As a follow up to the above:
Are we able to see galaxies etc. on the other side of the big bang birthplace.
If we are able to see a galaxy equidistant from the big bang to us and travelling in the opposite direction, would it appear to be accelerating away at twice the speed - that is, twice the speed that we are moving away from big bang origins.
Thanks for your very informative emails.
Alan

antoniseb
2004-Aug-01, 12:46 PM
Originally posted by arenton@Aug 1 2004, 10:54 AM
Are we able to see galaxies etc. on the other side of the big bang birthplace.
Hi Alan, welcome to the forum.

The universe was formed in Schenectady NY by Thomas Edison. Any time you travel from Boston to Buffalo, or NYC to Montreal, you go past the center. :) OK, for the record, that first statement isn't true.

Generally, we can't identify a place of birth of the cosmos. For example, no matter which direction we look in, we see the cosmic microwave background radiation, which you can think of as light escaping from a cloudy wall that ceased to exist 380,000 years after the big bang. In all directions, this wall is about 13.7 billion lightyears away from us. So from some point of view you could say we are in the exact middle of a 27.4 billion lightyear diameter bubble.

A lot of people will point you to the analogy that galaxies are like spots printed on the surface of an inflating balloon, and that the center of the universe can only be found if you can think and see outside the dimensions of the surface of the balloon, which we normally cannot.

StarLab
2004-Aug-01, 06:41 PM
I disagree that the universe is 27.4 bilion light years acroos. That was the diameter the COBE measurement took for the universe 13.6 billion years ago! The universe has long since been expanding since then. Modern estimates for the true size of the universe range within the '00 billion light-years.

antoniseb
2004-Aug-01, 06:56 PM
Originally posted by StarLab@Aug 1 2004, 06:41 PM
I disagree that the universe is 27.4 bilion light years acroos.
I never said it was. You have misread one of my posts and then put false words in my mouth... AGAIN. What I said was:

So from some point of view you could say we are in the exact middle of a 27.4 billion lightyear diameter bubble.


I stand by this statement. If you look from here, this is what you see. The universe itself is probably vastly larger right now. Current theories say that initially the universe expanded much faster than the speed of light. What we see now is what we can see owing to the speed of light limitation.

StarLab
2004-Aug-01, 07:47 PM
In all directions, this wall is about 13.7 billion lightyears away from us. So from some point of view you could say we are in the exact middle of a 27.4 billion lightyear diameter bubble.

If you look from here, this is what you see. The universe itself is probably vastly larger right now. Current theories say that initially the universe expanded much faster than the speed of light.

Attack the ideas, not the person.
As opposed to the first two quotes, the third quote is actually rule # 3 of the Forum Rules. I think it should be understood that I am not attacking you yourself, Anton. Second of all, you are contradicting yourself in your effort to criticize me for what you thought was my criticism of you. I did not aim to criticize, and anyhow these two quotes of yours contradict each other. The first is too general. The second quote, first sentence says "this 27.4 billion light year universe is what you see." The second says that right now the universe is vastly larger. Both are present tense (here I'm getting into semantics) but both are opposites. In no way, in that other post, was I aiming to criticize you. Don't make me feel that I have to defend myself.

David S
2004-Aug-01, 08:02 PM
I assume the big bang explosion would have proceeded outwards as a sphere. Have they tracked back the galaxies to the place where it all began


Hello arenton. While this is a logical question to ask, it's unfortunatly based on a few assumptions (logical assumptions, certainly) that aren't true for the universe as a whole.

Correct me if I'm wrong, but this question comes from thinking of the universe in much the same way we think of the milky way galaxy. The center of the galaxy is over there, and we are over here, 30,000 light years from the center. Also, the edge of the galaxy is out that way, about 20,000 light years away. We know this cause when we look over in that direction we see a very high concentration of stares, but in the other direction there are relativly few stars. Also, off in that one direction we can see stars that are as far away as 80,000 lights years, whereas in this other direction we can only see stars as far away as 20,000 light years.

Unfortunatly our observations of the universe as a whole are not the same. When we look at distant glaxies we don't see a lot of galaxies in this one direction, and very few galaxies in the opposite direction. We see a relatively uniform number of galaxies 360 degrees around us, and all of them are moving away from us with the same speed (relative to distance) on all sides.

Also, we don't look in one direction and see objects 20 billion light years away, and then look in the other direction and can only see 5 billion light years away. In all directions, we can see about 13.6 billion light years away.

All this actually makes it look like we are, in fact, in the center of the universe with all galaxies rushing away from us. However, you would see the same thing regardless of what galaxy you where in. In otherwords, ALL points in the universe would appear to be the center of the universe.

There are some analgoies to try to explain this (a balloon, dough rising, ect) but the simplest analogy for me is: What point on the surface of the Earth is the center of the surface of the Earth? From any point on the surface of the earth you look around in all directions and see and equal amount of the earth (and I'm including oceans as the earth), so from any point on earth you might assume that that point was the center of the surface of the earth. But you would see the same thing from any other point as well.

StarLab
2004-Aug-02, 02:06 AM
One problem with that analogy...you have to determine which "center" of the earth you are talking about. There's a center of mass, a geographical center, a center of magnetism, and a center of gravity. I think the only one of these which would also apply to our universe is the center of gravity. This is because earth's center of gravity, being that it has a satellite, is near the surface. If there is such a similar situation for our universe, that idea would hold true for it too.

David S
2004-Aug-02, 03:03 AM
actually, I'm not talking about any of those types of centers. I was talking strictly about the surface of the earth. I'm saying if you standing on the surface of the earth (like most of us are doing right now), can you point to a spot on the surface and say "this is the center"? You can't, because there isn't any point on the SURFACE of the earth that all other surface points radiate out from.

Of course the planet earth as a whole has a center, but I was talking just about it's surface and nothing else. It's just an analogy to try to visualize why the universe has no center to it.

StarLab
2004-Aug-02, 03:09 PM
Well, it's the same as the balloon analogy. Can't make a difference between the two, except that we don't live on a balloon! :lol:

GOURDHEAD
2004-Aug-02, 04:55 PM
Tch! Tch! Tch! I see you folk haven't appreciated the brilliance of the shmoo field and its q-verse where the concept of a center and an edge abound in the depths of fantasy.

AndyHolland
2004-Aug-12, 08:51 PM
This topic looked allot like the Center of Universe discussion earlier.

Interestingly, the WMAP was launched to look for anisotropy and apparently has not found it. An interesting discussion if found at:

http://www.physics.ucdavis.edu/alumnewslet...n%20Meeting.htm (http://www.physics.ucdavis.edu/alumnewsletters/fall2003/Cosmic%20Inflation%20Meeting.htm)

and

http://map.gsfc.nasa.gov/m_mm/mr_limits.html

and

http://map.gsfc.nasa.gov/m_uni/uni_101bb2.html


andy

Tim Thompson
2004-Aug-13, 12:28 AM
Originally posted by StarLab@Aug 2 2004, 02:06 AM
... There's a center of mass, a geographical center, a center of magnetism, and a center of gravity. I think the only one of these which would also apply to our universe is the center of gravity. This is because earth's center of gravity, being that it has a satellite, is near the surface. ...
Oops. The "center of gravity" and "center of mass" for Earth are identical, and quite near to the geometric center. The "center of gravity" to which you refer is the center of gravity (or center of mass), for the Earth-moon system. Since the mass of the moon is ~ 1/81 of Earth's mass, the center of mass for the system will be at ~1/81 of the Earth-moon distance, from the center of Earth, which comes out to something like 1020 miles below the surface of Earth (radius ~3959 miles), along the Earth-moon line.

If one accepts the standard cosmology, then there is no center-of-anything for the universe, in 3-dimensions. Of course, if one does not accept standard cosmology, then, as they say, "anything is possible", depending on which cosmology one does accept.