Where in the world is earth?, page 1
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ATS Members have flagged this thread 2 times
Topic started on 31-3-2008 @ 10:27 PM by ben91069
I had posted a quick comment here about where the earth's relationship is to the recent GRB (gamma ray burst) labeled 080319B.

Briefly, it stated that it was the largest release of energy ever observed in the entire universe with the naked eye, and it occurred half way across the universe.

Considering the big bang probably is a sphere, I asked whether that meant the earth is in the center of this sphere and we are observing the light from the GRB at the edge of the big bang, or if the earth is at the edge of the big bang and this GRB is in the center of the universe. No one answered this question to my satisfaction so I emailed the primary investigator on the Swift mission team at NASA and got a response, much to my surprise.

Here is what Mr. Neil Gehrels said about the earth in relation to GRB 080319 in his email response. You decide if it says where we are inside the big bang:


Dear Mr. XXXXXXXXX,

The universe is isotropic with every point equivalent. So Earth is not
at the center. You can picture the universe as being the surface of a
ball and Earth is a point on it, the same as any other point. Since the
universe is expanding, envision the ball being inflated as time goes
on. The GRB happened when the ball was smaller and its light has been
traveling to us as the ball inflated. The light travel time was about 7
billion years and the light travel time to the other side of the ball
emitted when it first started inflating is 13.6 billion years. That is
an approximate analogy.

Sincerely,
Neil Gehrels


I'm still kind of scratching my head. I know that the big bang is expanding, and this occured at the half way point in time and space, but where does that leave us??


reply posted on 1-4-2008 @ 11:32 AM by TheRedneck
reply to post by ben91069


The balloon analogy is 2D, while we live in a universe that is (at least) 3D.

There is no center. If you take a balloon that is perfectly spherical, is there a left or right side? Up or down? No, unless you arbitrarily define a point as such. So every point can be considered as a 'center'. The same thing happens with a big bang universe. Everything is in the 'center'. The only way a center like you are thinking could exist is with an arbitrary definition of one point as 'This is our center'.

Now you should be seeing why I suggested sunglasses.

TheRedneck


reply posted on 1-4-2008 @ 11:41 AM by ben91069
Originally posted by TheRedneck
reply to
post by ben91069


The same thing happens with a big bang universe. Everything is in the 'center'. The only way a center like you are thinking could exist is with an arbitrary definition of one point as 'This is our center'.

Now you should be seeing why I suggested sunglasses.

TheRedneck


You know that makes no sense to me at all, and I have no way to grasp it. I cannot conceive an explosion without a center. That just makes no sense and I don't even see how science can accept it as fact.


reply posted on 1-4-2008 @ 12:19 PM by Hal9000
I agree that this is difficult to understand. From reading the e-mail reply it sounds like he is saying we are on the edge of one side of the universe, and the GRB occurred on the other? Considering that the age of the universe is 13.8 billion years, and the GRB happened 7 billion years ago. If the Big Bang Theory is right, and everything expanded from a single origin, then that would mean that 7 billion years ago the universe was a little more than half the size it is today, Right? That would be 13.7/2 or the size of the universe at that time was roughly 7 billion years wide. So at that time, if the GRB was 7 billion light years away from us that would put us near one edge of the universe, and the GRB near the opposite edge. You have to remember that the speed of light is not relative and does not take longer to get here from an object that is moving away from us.

That doesn't make sense because the background microwave or
WMAP is somewhat uniform around us. This is the after glow of the Big Bang which appears to me to be the same all around, which one might think that would put is near the center of the universe. The recently released image of the Two Micron All Sky Survey in the Astronomy Magazine article 1.5 million Galaxies Revealed also shows a uniform distribution of other galaxies around us, which also supports that.

This is enough to make your head hurt thinking about it, but all I know is that we are probably NOT near one of the edges of the universe and it would be presumptuous to think we are at the center of the universe. Good topic though.


reply posted on 1-4-2008 @ 12:28 PM by TheRedneck
reply to post by ben91069


Eh, sorry. I'll give it another go. It really is a difficult concept until you grasp it.

When you think of an explosion having a center, that's because you are standing outside the explosion, looking into it. In that context, there is a center. There is a single point that rapidly expands outward in all directions.

In the big bang, we are no longer outside looking in. WE are the explosion. There is no outside (that we know about) to look inward from. So from our point of view, since everything is at the 'center', there is, in effect, no center.

Try thinking of it as relative.

edit to add:
Originally posted by Hal9000
This is enough to make your head hurt thinking about it, but all I know is that we are probably NOT near one of the edges of the universe and it would be presumptuous to think we are at the center of the universe. Good topic though.


Agreed, excellent topic. Worthy of a flag, come to think of it.

TheRedneck


[edit on 1-4-2008 by TheRedneck]


reply posted on 1-4-2008 @ 12:32 PM by lonemaverick
Originally posted by ben91069
Originally posted by TheRedneck
reply to
post by ben91069


The same thing happens with a big bang universe. Everything is in the 'center'. The only way a center like you are thinking could exist is with an arbitrary definition of one point as 'This is our center'.

Now you should be seeing why I suggested sunglasses.

TheRedneck


You know that makes no sense to me at all, and I have no way to grasp it. I cannot conceive an explosion without a center. That just makes no sense and I don't even see how science can accept it as fact.

Ok, imagine you have a perfectly spherical balloon. Now, look at the surface. Where is the center of that surface? Not the center of the balloon, but the center of the surface of the balloon skin. There isn't one, unless you put some sort of a mark on the balloon, and say "There's the center." But that's not really the center, because what makes that point you chose different from any of the other points on the balloons surface?


reply posted on 1-4-2008 @ 01:36 PM by Hal9000
reply to post by TheRedneck


No, I understand that relative to our position, everything will appear to be moving away from us due to the expanding universe. That isn't what I had a problem with. What I was saying was that the light from the GRB took 7 billion years to reach us, and occurred 7 billion years ago, when the universe was smaller. Where I made my mistake was that I was assuming that the universe could not be more than 13.7 billion light years across because that would mean things were moving faster than the speed of light. Under that assumption, 7 billion years ago the universe had a size of 7 billion light years, which would mean the GRB was near one edge, and were were near another. I also didn't consider that 13.7 billion years is a radius so you would double it for the entire size.

Anyway, I found the answer to my problem in this article Universe Measured: We're 156 Billion Light-years Wide! which helps explain a lot. According to the article the speed of light is cumulative as the universe also expands.

I looked around for more info on where the Milky way is located in the universe, but there isn't much there. I did find this article.

It is difficult to say where in relation to the universe the Milky Way is located since we don't think that the universe has a centre, and that (on large enough) scales it is completely homogeneous and isotropic.

Where, in relation to the entire universe, is the Milky Way located?

Maybe this is what you (TheRedneck) were referring to about not having a center?



reply posted on 1-4-2008 @ 04:57 PM by nablator
reply to post by Hal9000



Interesting articles! But they don't tell you it's the size of the observable universe, not the real size of the universe. The volume of the universe may be infinite - by current theories. No one knows, actually, because we don't have any information about the shape of the hypersurface we call the universe. The curvature of space defined by General Relativity is irrelevant. A 2D analogy: a piece of paper with zero curvature (flat), still has zero curvature when crumpled in your pocket. Curvature is intrinsic to the space it describes, it does not help imagine what's outside the universe, or even if there's anything at all. So take the balloon analogy with a grain of salt, the universe is not a hypersphere.


reply posted on 2-4-2008 @ 02:56 AM by nablator
reply to post by MsSmartypants



As I already said, the balloon is a simple analogy, not a correct interpretation beyond the inflating, increasing its surface (analogy to volume in 3D). The universe is not a hypersphere. No one knows what's outside the universe, or even if there is anything.


reply posted on 2-4-2008 @ 12:08 PM by Hal9000
reply to post by nablator


I agree that no one knows for sure what the shape of the universe is, and from the article I posted they are calculating the size of the universe from measurements taken from the WMAP, which is the most distant object seen. So you are right, that it is the size of our observable universe, but since the microwave background radiation occurred 300,000 years after the BB, we are looking back in time to the beginning and there could not be much more beyond that in our universe. What could be beyond that is anyone's guess. I think that it would also be presumptuous to think ours is the only universe.

The article I posted also said that they also determined that the universe is "flat" based on the WMAP. I think this is misleading because "flat" does not mean flat as in a piece of paper. My interpretation is that when they say it is flat, it means it is not curved as you said, or if you look out into space, our line of sight is straight and does not bend. So when you look out into space you are looking at the edge of the universe no matter what direction you look. In other words, space does not curve around and an object would physically be closer to us than how they appear from our line of sight. I just don't see how you can say space is not curved, and use the analogy of crumpled paper, because that sounds like curved space to me.

Here is another explanation of a "flat" universe.

IMHO, the universe would have to be in the shape of a sphere, because it is "flat" or not curved, started at a single point of origin and has expanded in all directions from that point. At least that's my interpretation at this point and may be wrong. In fact I just read another article from Astronomy Magazine called What is the shape of our universe? and if you look at the image on the front cover, that is the shape of the universe including other dimensions or manifolds. This is way above my understanding, but thought it was interesting.

[edit on 4/2/2008 by Hal9000]
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