What shape is the universe?

LQ · 2007-05-24 21:32:38

Imagine a line with beginning and end, now imagine something infinitely slow moving on it, and that is all there is. Does the line have an end?

Daniel123 · 2007-05-24 21:39:49

Wouldn't 'infinitely slow' imply it is not moving at all?

LQ · 2007-05-24 21:51:39

Atleast I meant that it would take an infinity for it to reach the other end. I just had breakfast, sorry for the interruption.
I guess the answer is that for the thin moving on the line, the line is never ending, but what about for the line?

Last edited by LQ (2007-05-24 21:54:49)

Daniel123 · 2007-05-24 21:55:58

Its ok. I find it impossible to understand the concept of 'infinity'. I dont think anyone can. So, it feels more logical if that 'line' is in fact a circle - so we are not going 'infinitely' slowly, yet we can never reach the end, as there is no end.

LQ · 2007-05-24 22:10:38

ok, there is no end and if there was one it wouldn't be relevant/important anyway. I just look of it as every time exists or will exist anyway.

Last edited by LQ (2007-05-24 22:11:39)

Ricky · 2007-05-25 02:29:01

I dont think it was the 'Big Bang'. The big bang theory says the universe started from an extremely hot and dense state, and has been expanding for around 14 billion years. But where did the material that started the big bang come from? And if there was no universe, what was it in?

Do you know the evidence for the Big Bang? A scientist came up with the theory to explain some observations, did some calculations, and came up with a new prediction. He predicted the existence of background radiation. They went to look for it, and sure enough, found it, and in just about the right amount too.

There is much other evidence for Big Bang, such as the ratio of light elements to heavy. Look into the actual evidence behind something before you dismiss it just because you don't like it.

The Big Bang doesn't explain everything. It does not explain how the universe started a t=0. Rather, the Big Bang starts just a few microseconds after this. How the universe started? No one knows, and some scientists believe it is impossible to know.

Sekky · 2007-05-25 03:17:27

Ricky wrote:

I dont think it was the 'Big Bang'. The big bang theory says the universe started from an extremely hot and dense state, and has been expanding for around 14 billion years. But where did the material that started the big bang come from? And if there was no universe, what was it in?
Do you know the evidence for the Big Bang? A scientist came up with the theory to explain some observations, did some calculations, and came up with a new prediction. He predicted the existence of background radiation. They went to look for it, and sure enough, found it, and in just about the right amount too.
There is much other evidence for Big Bang, such as the ratio of light elements to heavy. Look into the actual evidence behind something before you dismiss it just because you don't like it.
The Big Bang doesn't explain everything. It does not explain how the universe started a t=0. Rather, the Big Bang starts just a few microseconds after this. How the universe started? No one knows, and some scientists believe it is impossible to know.

I went to a very well presented seminar not so long back where it was claimed that there is no t=0, as if you were to reverse time, space-time would degress to such a dense state that the "speed" at which time flowed would tend to zero, thus no discernable beginning.

LQ · 2007-05-25 03:36:20

Let me get this straight, In the beginning, time did not pass, cause everything was so incredibly dence. Then after some time had past, everything exploded into a non existing room. Suddenly, gravitons where created from some special particle fusion, even though they had no reason to do so and got control over the universe. what more, electrons and protons got created and ever since then they have been attracted to eachother.

The question then remains, why didn't they settle this in the beginning?

Sekky · 2007-05-25 03:38:48

LQ wrote:

Let me get this straight, In the beginning, time did not pass, cause everything was so incredibly dence. Then after some time had past

Last edited by Sekky (2024-06-24 07:43:15)

LQ · 2007-05-25 03:46:52

It was intended. It was also partly a joke.

Last edited by LQ (2007-05-25 03:48:33)

Ricky · 2007-05-25 05:40:39

I went to a very well presented seminar not so long back where it was claimed that there is no t=0, as if you were to reverse time, space-time would degress to such a dense state that the "speed" at which time flowed would tend to zero, thus no discernable beginning.

Interesting hypothesis. It sounds mostly like a thought experiment, was any evidence presented to back it up?

LQ · 2007-05-25 06:33:23

"Philosophy is a game with objectives and no rules. Mathematics is a game with rules and no objectives."

Honestly. It sounds good but it isn't.

Anyway, I find it hard to see how a continuum can lack a beginning. Another conclusion I have also drawn: Beginnings begin and if it is not the beginning that begin, then it is not the beginning. But I employ you to draw the conclusion that we move through the entire time continuum, not "all - 1 plank length". -Gngngngnnnh almost, but not quite!

Last edited by LQ (2007-05-25 06:52:03)

LQ · 2007-05-25 07:07:42

Okay, let me make a guess myself, the universe firstly was inf dimensional, but not a non-vanishing continuous vector field. So it decayed into such and by doing so, it split into space and matter, not to mention exotic matter of all kinds. Obviously this caused a big bang, since all things firstly existed on the same spot. now instead, all things, surounded with nothing but eachother, hence next to eachother, only experienced the dimensions that they had and not those who were before. Which in its turn led to the experience of a neverending space and an unteeming amount of matter, almost instantly.

Stanley_Marsh · 2007-05-25 07:57:13

Daniel123 wrote:

If the universe is expanding, what happens when you get to the edge of it? And i dont see how it can be both infinite and expanding - because if it was expanding, there must be and edge that is expanding, but if it was infinite then there would be universe already beyond that edge. Does anyone understand what i mean?

Got a simply answer , the universe is infinite because it's expanding. Expanding

infinite.

LQ · 2007-05-25 08:13:59

Ah, that question. Honestly, I don't think the universe is expanding much more now, It's just the heavy mass in the universe from the big bang that continues expanding into the universe.

Ricky · 2007-05-25 10:13:34

Ah, that question. Honestly, I don't think the universe is expanding much more now, It's just the heavy mass in the universe from the big bang that continues expanding into the universe.

The universe is increasing its rate of expansion. And we also know its not just matter moving around. Everything is moving away from everything else. The only way this is possible is if space itself is expanding.

luca-deltodesco · 2007-05-25 10:18:02

Ricky wrote:

Interesting hypothesis. It sounds mostly like a thought experiment, was any evidence presented to back it up?

i remember reading something, showing that even taking into account massive innacuracies in calculations, the speed of light is infact decreasing, but perhaps it isnt that its 'speed' is decreasing in the whole scheme of things, but that under our dimensions, time is speeding up, and so to us, it appears to be slowing down.

then again, i did a quick google search on it, and it appears the only people stating this, are young earthers, so you can completely disregard all of that.

Last edited by luca-deltodesco (2007-05-25 10:19:18)

Sekky · 2007-05-25 10:58:49

Ricky wrote:

Interesting hypothesis. It sounds mostly like a thought experiment, was any evidence presented to back it up?

Much, albeit the majority was theoretical physics beyond my comprehension, but the guys gave some decent analogies for the most part. Actually that presentation was part of a larger seminar on astrophysics, most of which I didn't understand, but I damned well enjoyed pretending I did

LQ · 2007-05-25 20:33:50

Ricky wrote:

Ah, that question. Honestly, I don't think the universe is expanding much more now, It's just the heavy mass in the universe from the big bang that continues expanding into the universe.
The universe is increasing its rate of expansion. And we also know its not just matter moving around. Everything is moving away from everything else. The only way this is possible is if space itself is expanding.

"The universe is increasing its rate of expansion."

Why don't you show me how this experiment was done. I mean it is not working with andromeda and the milky way, cause they are moving towards eachother, and that's odd, cause they are the somewhat latest in time: there is a lot of difference between negative escape velocity and faster then overlightspeed. Cause the big bang expanded in overlight speed. Or, yes, you want to refute that now. Who doesn't, I have also, it's just that it wasn't welcomed.

Ricky · 2007-05-26 04:34:57

Why don't you show me how this experiment was done. I mean it is not working with andromeda and the milky way, cause they are moving towards eachother, and that's odd, cause they are the somewhat latest in time: there is a lot of difference between negative escape velocity and faster then overlightspeed.

The first thing to realize is that the universe is a big place, and of course there will be things moving towards each other. For example, I'm almost certain we are getting closer to some planet in our solar system right now.

But way back in the day, Hubble discovered something really cool. He discovered that how fast something moves away from us is proportional to the distance it is from us. This means that if something is really far away, it will be moving away from us much faster than something close to us. Of course, actual movement of matter (not from the expansion of space) can counter act this.

So what does this mean? Well, try a little example. In this example, I'm going to use a dash (-) as space, and its going to expand by doubling every year, cause this makes the math easy.

We have two objects, x and y, relatively not moving at all, at a distance of 10:

x----------y

The first year passes and the space between doubles:

x--------------------y

Now the second year passes:

x----------------------------------------y

And just to make it obvious, a third year passes:

x--------------------------------------------------------------------------------y

You should start to see a curve. The distances are: 10, 20, 40, 80. This means that y is accelerating away from x. This means that as the universe expands, it's rate of expansion increases simply because the distance between and two given objects is, on the average, going to be greater.

Ricky · 2007-05-26 04:39:22

Cause the big bang expanded in overlight speed.

I've never heard anything like this, where did you get that from?

And I can almost assure you its wrong, because according to Einsteins equations, if matter is traveling faster than the speed of light, then as it looses energy, it starts traveling even faster.

Daniel123 · 2007-05-26 04:43:32

Another factor that suggests the rate of expansion is increasing is red shift. When we look at light from distant galaxies, we find that all the frequencies are shifted towards the red end of the spectrum. In other words, the frequencies are all slightly lower than they should be. It's the same effect as a car horn sounding lower-pitched when the car is travelling away... this is known as the Doppler effect. Measurements of the red shift suggest that all the galaxies are moving away from us very quickly - and it's the same in whichever direction you look in. However, more distant galaxies have greater red shifts than nearer ones - which means that the more distant galaxies are moving away faster than nearer ones. Following the pattern, it is almost definite that galaxies even further away (ones which we cannot see) are moving away even faster (otherwise nearer ones would collide with them). So if the further galaxies are moving away faster, then the further out you go, the faster the rate of expansion - so the universe is expanding with an increasing rate.

LQ · 2007-05-26 05:05:03

Daniel123 wrote:

Another factor that suggests the rate of expansion is increasing is red shift. When we look at light from distant galaxies, we find that all the frequencies are shifted towards the red end of the spectrum. In other words, the frequencies are all slightly lower than they should be. It's the same effect as a car horn sounding lower-pitched when the car is travelling away... this is known as the Doppler effect. Measurements of the red shift suggest that all the galaxies are moving away from us very quickly - and it's the same in whichever direction you look in. However, more distant galaxies have greater red shifts than nearer ones - which means that the more distant galaxies are moving away faster than nearer ones. Following the pattern, it is almost definite that galaxies even further away (ones which we cannot see) are moving away even faster (otherwise nearer ones would collide with them). So if the further galaxies are moving away faster, then the further out you go, the faster the rate of expansion - so the universe is expanding with an increasing rate.

You don't say? might I add that when you look so far out in space you look at past events? wouldn't it then be logic that the longer back in time you go the faster the rate of expansion? So you are infact NOT making any sence what so ever.

mathsyperson · 2007-05-26 05:08:20

I don't think Ricky's example works.

Yes, it's been measured that the observed speed of a planet is roughly proportional to its distance from us, but that doesn't mean that a planet gets faster as it gets further from us. Instead, each planet moves at a roughly constant speed, and it's the constant of proportionality that slowly decreases with time.

Besides, if we assume that Ricky's model does show how the planets move, then if anything that would imply that the Universe's expansion was slowing down.
The further planets would be moving quickly, and because light takes longer to reach us from there, that means that a long time ago the universe was expanding quickly. The closer planets are moving more slowly, which means that now it isn't expanding as fast.

Edit: Post collision. But at least I collided with an agreement.

LQ · 2007-05-26 05:14:46

Ricky wrote:

Cause the big bang expanded in overlight speed.
I've never heard anything like this, where did you get that from?
And I can almost assure you its wrong, because according to Einsteins equations, if matter is traveling faster than the speed of light, then as it looses energy, it starts traveling even faster.

Even if you are right, that is not the current view of the universe, since the scientist claims that the laws of physics were not invented by the time of the big bang. They claim that overlightspeed were legal back then.

Math Is Fun Forum

#51 2007-05-24 21:32:38

Re: What shape is the universe?

#52 2007-05-24 21:39:49

Re: What shape is the universe?

#53 2007-05-24 21:51:39

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#54 2007-05-24 21:55:58

Re: What shape is the universe?

#55 2007-05-24 22:10:38

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#56 2007-05-25 02:29:01

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#57 2007-05-25 03:17:27

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#58 2007-05-25 03:36:20

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#59 2007-05-25 03:38:48

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#60 2007-05-25 03:46:52

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#61 2007-05-25 05:40:39

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#62 2007-05-25 06:33:23

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#63 2007-05-25 07:07:42

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#64 2007-05-25 07:57:13

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#65 2007-05-25 08:13:59

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#66 2007-05-25 10:13:34

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#67 2007-05-25 10:18:02

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#68 2007-05-25 10:58:49

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#69 2007-05-25 20:33:50

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#70 2007-05-26 04:34:57

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#71 2007-05-26 04:39:22

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#72 2007-05-26 04:43:32

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