What shape is the universe?

Sekky · 2007-05-26 05:20:55

LQ wrote:

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.

Lol

Who are "they"? Link or this is nonsense.

Ricky · 2007-05-26 05:22:02

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.

There are no theories for what happened before, or at t=0. Many physicists come up with thought experiments which they mean for only "playing around", but people take these and think they are real science. They are not.

and it's the constant of proportionality that slowly decreases with time.

No, the constant is just that, constant. It does not decrease. Its currently thought to be somewhere around 71km/s for every parsec.

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.

I'm sorry, but I don't follow this logic.

LQ · 2007-05-26 05:22:56

Link to google search

URL condensed - Ricky

Sekky · 2007-05-26 05:24:17

Ricky wrote:

I'm sorry, but I don't follow this logic.

Gravity, there's your answer

Ricky · 2007-05-26 05:24:53

Sekky wrote:

Ricky wrote:
I'm sorry, but I don't follow this logic.
Gravity, there's your answer

Huh?

Ricky · 2007-05-26 05:26:18

LQ wrote:

Link to google search
URL condensed - Ricky

LQ, if you think science takes place on google searches, please, think again.

Sekky · 2007-05-26 05:27:54

Ricky wrote:

Sekky wrote:
Ricky wrote:
I'm sorry, but I don't follow this logic.
Gravity, there's your answer
Huh?

Suppose you have two planets travelling away from each other at some velocity, gravity accelerates each planet towards the other, decelerating the expansion of the universe over time (for an insane system of gazillions of planets)

LQ · 2007-05-26 05:36:55

Atleast they say that they didn't apply on tv. I know they do but that's what they say. They also say gravitons did not exist and that's directly from albert einsteins general relativity. Atleast from our science book we had in school. This would also mean that the mass didn't have the properties of relativity hence could travel as fast as they wanted, even though they must have known that it would make you mad.

Last edited by LQ (2007-05-26 05:47:36)

Ricky · 2007-05-26 05:47:58

LQ wrote:

Atleast they say that they didn't apply on tv. I know they do but that's what they say. They also say gravitons did not exist and that's directly from albert einsteins general relativity. Atleast from our science book we had in school. This would also mean that the mass didn't have the properties of relativity hence could travel as fast as they wanted, even though they must have known that it would make you mad.

Sources, please LQ.

LQ · 2007-05-26 05:54:39

Yes, w8 a moment and I'll check in my private library.

May I ask first, what difference would a source make?
My old physic book is in swedish you see.

Last edited by LQ (2007-05-26 06:10:04)

Sekky · 2007-05-26 05:55:50

LQ wrote:

They also say gravitons did not exist and that's directly from albert einsteins general relativity.

Gravitons have neither been proved or disproved, conjecturing that kind of theoretical physics serves no purpose, it's all CERN's fault.

Imho, it would be pretty if gravitons existed, but for now I'd prefer not to make the assumption.

It's like dark matter, all they're doing is attributing a cause to an observed property in the most non-controversial manner.

LQ · 2007-05-26 06:04:43

when you look so far out in space you look at past events the longer out in space and back in time you look the faster the rate of expansion you see, conclusion we can draw from red shift.
What do you say, does that sound right? hence the expresion lightyear

Last edited by LQ (2007-05-26 06:09:05)

Identity · 2007-05-26 06:40:51

Hmm I just came up with an ill-advised hypothesis:

There is no clearly defined 'boundary' of the universe, that is to say, it is infinitely large. Therefore, couldn't it have been possible that the universe has been here all along, but just that all the stars and planets erupted from one explosive from a point in this forever-existing universe? The observations by Hubble just state that everything is moving away from each other. This doesn't mean that it is the universe is expanding, it might not have anything to do with that?

Ricky · 2007-05-26 06:57:04

The observations by Hubble just state that everything is moving away from each other. This doesn't mean that it is the universe is expanding, it might not have anything to do with that?

We know for a fact that it is space which is expanding. We know this because the speed at which something moves away from us is directly proportional to the distance it is. Furthermore, Einsteins equations derived from Relativity predicted that the universe is expanding. He fudged his equations because he believed this had to be incorrect. Later, he called it his biggest blunder.

all the stars and planets erupted from one explosive from a point in this forever-existing universe?

If this is the case, then one of our most fundamental laws of physics, the 1st and 2nd law of thermodynamics, is incorrect. For if this universe is infinitely old, then all energy should in the universe should be spread out evenly. It's not.

luca-deltodesco · 2007-05-26 07:18:23

einstein also hated quantum mechanics, because of entanglement ' strange action at a distance ' i believe.

LQ · 2007-05-26 07:26:39

Identity wrote:

Hmm I just came up with an ill-advised hypothesis:
There is no clearly defined 'boundary' of the universe, that is to say, it is infinitely large. Therefore, couldn't it have been possible that the universe has been here all along, but just that all the stars and planets erupted from one explosive from a point in this forever-existing universe? The observations by Hubble just state that everything is moving away from each other. This doesn't mean that it is the universe is expanding, it might not have anything to do with that?

Let's bend this to the better, shall we?

It's not infinitely old, then we wouldn't have come to experience this yet. Let's instead say that the size of the universe is infinit, for instance, time and space can be infinit even though we have not experienced the time ahead of us yet. That is definitely possible, we can call it destiny and eternity. Moreover, the infinite dimensional dot split to space and matter, that were non vanishing continous vector fields. in other words into something that could last. That we call the big bang. the universe might still be expanding some, but probably as you say, it is just us that move into eternity and destiny. Is that okay/nice?

LQ · 2007-05-26 07:53:18

Ricky wrote:

and it's the constant of proportionality that slowly decreases with time.
No, the constant is just that, constant. It does not decrease. Its currently thought to be somewhere around 71km/s for every parsec.

Yes he knows. He meant: and it's the constant of proportionality that makes a slow decreases of expansion speed with time.

mathsyperson · 2007-05-26 08:34:57

I think it does decrease, but so slowly that the decrease is negligible.

Let's go back to near(ish) the start of the universe, at something like t = 1 million years. (I'm not certain about timings of the start of the universe, but I'm guessing that that's long enough for planets to have started to form. If not, please pretend that I'd had a more educated guess. )

So, two planets A and B are a distance x1 apart. They are also travelling at a relative speed v1 to each other. A and C are a distance x2 apart and travelling at v2 away from each other, and so on. Then, v1/x1 = v2/x2 = v3/x3 = ...

So there is a constant of proportionality there, λ say, so that λx = v.
The planets would all be travelling at roughly the same speed that they still are today (overall, that is. Their speed will change if they get hit by an asteroid or sink into a sun, but if we only consider "lucky" planets that don't do that then it will be right.)

However, as they've been moving away from each other for all that time, their distance from each other will have increased greatly. That means that for λx = v to still work, then λ must have decreased. It's constant for all planets at any one point in time, but it's not constant with time itself.

Now that the universe is very very very very very old, however, the decrease of λ is far too slow to be noticeable. It probably hasn't even decreased an amount worth mentioning since the origin of humans, but it still has nonetheless. That's why astronomers can accurately approximate it to be constant and measure it. But what they shouldn't do is use that approximation as an argument to show that the universe's expansion is accelerating.
There's no reason why it would, and it would take far too long to get evidence, considering that if it was speeding up then it would be doing so extremely slowly.

Ricky · 2007-05-26 09:09:46

I think you misunderstand what I mean by increasing. The rate at which the universe expands is constant. That is, x meters per km of space per year. But as the universe becomes larger, there is more space that is expanding. As such, the amount in which the universe expands increases.

Does that make sense?

I think it does decrease, but so slowly that the decrease is negligible.

Why do you think this?

mathsyperson · 2007-05-26 11:57:01

That's what I thought you meant, but I don't agree. I just think that the whole universe expands by a constant amount each year.

If we believe in the Big Bang, then the universe is really just an explosion. A very grand explosion indeed, but still an explosion. As such, each particle of 'debris' gets hurled away from the point of origin at a certain constant speed, and the furthest particles from the origin define how big the explosion is at a certain time. But as those particles are moving at a constant speed, then the universe is also expanding at a constant speed.

I think it does decrease, but so slowly that the decrease is negligible.
Why do you think this?

I can't really see how else to explain it other than how I already did in the previous post. Sorry.

LQ · 2007-05-26 15:18:47

Mathsyperson means that whatever you say, the opposit is true since your claim is based on the wrong assumption
For instance, if we look back in time we will see the past. You argue that if we look out in space we just see the bigger picture, that is a wrong assumption.

2 bodies:

0 <---> 0
^
move away from eachother

diagram: now--------------------------------------------X--------big bang
^
faster when the universe was young

diagram: big---------------------------------------------X--------small
^
ie. faster when the universe was small(er)

Last edited by LQ (2007-05-27 07:19:31)

LQ · 2007-05-26 15:25:24

Ricky wrote:

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.

diagram: slow-------------------------------x-------fast movement
diagram: later-------------------------------x-------earlier time

Sorry for the dada gogo comment, i thought Ricky quoted me from another forum at an early occasion from another forum.

Last edited by LQ (2007-05-27 07:22:25)

Ricky · 2007-05-27 04:13:57

However, as they've been moving away from each other for all that time, their distance from each other will have increased greatly. That means that for λx = v to still work, then λ must have decreased. It's constant for all planets at any one point in time, but it's not constant with time itself.

I have yet to work the math out, but I believe that no matter what constant we pick, it must decrease extremely rapidly.

LQ, I can't make heads or tails of any of your last two posts.

LQ · 2007-05-27 07:26:54

Ever occured to you that the small red shifted young far away exploding universe might have expanded faster then it expands today?

Stanley_Marsh · 2007-05-27 08:02:32

Consider this , A quantity of water placed in a dam , and there are some solids objects floating a the in water(in not on) , when the dam breaks , the displacement of water in certain time is greater than those of the objects. Maybe the universe structure is like darkmatter as water and planets like the object floating in it.

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Re: What shape is the universe?

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