begining of the universe

[shalasz]

We know that the universe is expanding. Is all matter expanding from the point of the big bang? If it is then we should know where the big bang occurred and there should be a void there?

 

[nimbus]

That's not how it works. Space expands in no particular direction.<br />http://www.damtp.cam.ac.uk/user/gr/public/bb_pillars.html <div class="Discussion_UserSignature"> </div>

 

[deapfreeze]

IMO space would have to expand away from the bang. If space were to expand into itself would it not be destroyed? <div class="Discussion_UserSignature"> <p><font size="2" color="#0000ff"><em>William ( deapfreeze ) Hooper</em></font></p><p><font size="1">http://deapfreeze-amateur-astronomy.tk/</font></p><p> </p> </div>

 

[SpeedFreek]

Well, firstly try not to consider the "big-bang" as some sort of explosion, in space. Consider that an expanding volume <b>of</b> space came into being, containing all the matter. The dimensions inside that volume were created with it, and we reside within those dimensions. But, my impossible viewpoint here is "outside" our universe, although as residents of this universe we actually have no conception of that dimension, or what shape our universe might take up within that dimension.<br /><br />So, a universe, the dimensions it is comprised of, the space and matter within it, come into being in an expanding volume. Where is the centre of expansion? Nobody within that universe can detect the centre, as their universe was originally a point (as seen from outside) which then expanded as a volume of space and matter. If you consider that the point contained everything, as you imagine it becoming an expanding volume, the point would actually be spread all over the surface of that volume for the purposes of this example.<br /><br />From outside, whatever shape the universe is, we might determine our local view of where the original point was, in relation to the expanding volume we can now see, but from the inside, that universes residents have no means to determine that point, and the point would seem irrelevant as they see all the oldest objects at the edges of their universe in <b>every</b> direction, which is understandable as the original point was spread all over the "outside" of that volume.<br /><br />This is all just an example to help you visualise the abstract nature of the problem. <img src="/images/icons/laugh.gif" /><br /><br />Another is to consider the <b>surface</b> of a sphere as a 2 dimensional universe. If that sphere is expanding, then the surface is expanding and points on that surface are all moving apart equally. But to the 2 dimensional residents of that 2 dimensional universe, there is no centre of expansion on that surface. They have no idea that the surf <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>

 

[deapfreeze]

OK now I have a question? If all the oldest stars are at the edge of the universe could we not just find the youngest stars to find the beginning? The place where everything begins and then expands out toward the edge? Sounds logical to me. There has to be a point where you look in all directions and everything is older than where you are. Would this not be the beginning? <div class="Discussion_UserSignature"> <p><font size="2" color="#0000ff"><em>William ( deapfreeze ) Hooper</em></font></p><p><font size="1">http://deapfreeze-amateur-astronomy.tk/</font></p><p> </p> </div>

 

[SpeedFreek]

Sorry, I should have made it more clear. The term "older" can be misleading I can see.<br /><br />The objects we see at the furthest distances we see as they were over 13 billion years ago, when the universe was very young. They were the first objects that appeared in the universe, the ones we see at the furthest distances. That image we see is 13 billion years old, so I refer to them as the oldest objects we can see.<br /><br />The thing to remember is that galaxies evolve and change over time, as they collide with others and swirl around! The first galaxies appeared <i>throughout</i> the expanding universe, and just as we see those distant galaxies as they were 13 billion years ago, someone there in that distant place, in whatever kind of galaxy might now be there, would look in our direction and see what was here 13 billion years ago. It probably wouldn't look anything like what is here today!<br /><br />The universe expanded a quite a lot before the first galaxies formed, something around 500 million years after the big-bang. When we look at the those most distant galaxies, we can tell by their size that they were a lot closer to us when they emitted that light that we see now, 13 billion years later.<br /><br />Their light left those galaxies, and as it travelled towards us, the space it was journeying through was expanding, increasing the distance that light had to travel. It finally reached us 13 billion years later, with those galaxies looking a lot dimmer than they did when the light left them. Their light was dimmed during its journey through expanding space which also stretched the light as it travelled in a measurable way (redshift), which when we combine it with that apparent dimness, allows us to estimate their distance and age.<br /><br />Now then, this means that the most distant galaxies, the ones at the edge of our observable universe, we see them as they were closest to the beginning of time. The further we look, the older, the closer to the beginning is <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>

 

[deapfreeze]

Ok so let me see if I get this Big Bang. First there was nothing from it emerged nearly all of the matter and radiation that we now see. But still I have to believe there is going to be a starting point the begining It went from nothing to something I see this but it happened somewhere and that is the begining. There has to be a way of determining this point. <div class="Discussion_UserSignature"> <p><font size="2" color="#0000ff"><em>William ( deapfreeze ) Hooper</em></font></p><p><font size="1">http://deapfreeze-amateur-astronomy.tk/</font></p><p> </p> </div>

 

[derekmcd]

"<i>But still I have to believe there is going to be a starting point...</i>"<br /><br />There was a starting point. If the Universe was infinately small and expanded, the starting point is <i><b>everywhere</b></i>. This is why using the balloon analogy can be misleading. You have to ignore the inside of the balloon... there is no inside. As with the Universe, there is no center. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[siarad]

Always puzzling, I guess the starting point expands too so we're <i><b>in</b></i> it

 

[deapfreeze]

"the starting point is everywhere."<br /><br />If this is the case would the end also be everywhere? Is the beginning the end? <div class="Discussion_UserSignature"> <p><font size="2" color="#0000ff"><em>William ( deapfreeze ) Hooper</em></font></p><p><font size="1">http://deapfreeze-amateur-astronomy.tk/</font></p><p> </p> </div>

 

[SpeedFreek]

It depends what you mean by the end.<br /><br />It seems to me you are thinking of all the matter in the universe as having expanded away from a certain point in space as if it flowed out of that point in all directions, through the space surrounding that point. This won't help you.<br /><br />Try thinking of it as if all the matter and the space are <b>inside</b> that point, and the point itself (with all the space and matter inside it) is expanding into a dimension outside of our universe.<br /><br />Now we cannot actually imagine all the dimensions in our universe as a shape. But think of it as an abstract concept. There is the possibility that universe has no edge. That if you were able to travel far enough and beat the rate of expansion you might eventually end up back where you started, although in the time your journey took the place where you started would now look totally different as it would have aged billions of years!<br /><br />If light itself were able to move faster than the rate of expansion, you might end up with a universe that billions of years in the future might have a geometry such that if you look in opposite directions you are looking at the same piece of space, but seeing it as it was at different times.<br /><br />But it seems that the rate of expansion will preclude light from ever propagating throughout the universe, so we will never know if this is the case. If the universe did indeed have a geometry where it curves back on itself dimensionally, where would the centre of it be?<br /><br />This is a similar scenario to the balloon analogy, where we consider the surface of a sphere or balloon to be a 2 dimensional universe. People living within that 2D surface would only be able to move in 2 dimensions, along that surface. They can circumnavigate their universe if they can move fast enough and beat the rate it is expanding and eventually come back to where they started. That 2D surface has no centre of expansion or point that can be considered as th <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>

 

[lukman]

So it takes more than 3D to understand the universe, then how many dimesion it takes to be able to map the universe including the center? 5D enough? -) <div class="Discussion_UserSignature"> </div>

 

[SpeedFreek]

Well, if the whole universe did have a centre I think it would be an arbitrary geographical point, having no more relation to the origin of the universe or "place where the big-bang happened" than any other point.<br /><br />If you crack an egg into a frying pan, once cooked you might measure the fried egg and find it's absolute centre, but what purpose would it have? Would it bear any relation to that eggs origin? Would it even represent the place on that fried egg that first touched the frying pan? It's the shell that's important, but that already went down the waste disposal! <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>

 

[deapfreeze]

I was reading an article by Sten Odenwald.<br />http://www.astronomycafe.net/ . In one of his articles he talks about the possibilities of 10 plus dimensions so 5 might not do it. I think I am starting to get it. It makes more sense now than a few days ago any ways...lol <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font size="2" color="#0000ff"><em>William ( deapfreeze ) Hooper</em></font></p><p><font size="1">http://deapfreeze-amateur-astronomy.tk/</font></p><p> </p> </div>