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Ghostboo

The Universe theories

33 posts in this topic

The open Universe theory states that after the Big Bang,(For those who believe in that)the Universe started expanding forever and will never stop.

The closed Universe theory states that after the Big Bang,the Universe will expand until gravity reaches its limit(if there is one)and everything will be forced back to the middle of space again and fuze into one thing.Therefore awaiting yet another Big Bang.

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I say open.  But what I want to know is, if you are at the "edge" of the continuing expansion, with the universe behind you, what is in front of you?  In other words, what is the universe expanding into?  Is it pushing something else out of the way or what?  Man, makes me nausous to think about infinity! :s5  

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The answer to this question relies on whether the mean density of matter in the universe is greater or lower than the "Critical Density". If the matter in the universe has a lower mean density than the critical density, then it will continue to expand indefinately - an open universe. This would actual result in our universe undergoing "Heat Death" after a very long time, once all the stars in the universe have burned out, and all the materials required for star formation have been used up.

If however, the mean density of the matter in the universe is greater than the critical density, then gravity will halt the universe's expansion, and it will contract, resulting in a "Big Crunch".

Visible matter in the universe accounts for only about 20% of the critical density, however it is widely believed that a great deal more exists in the form of dark matter. If this were true, the actual density of the universe would be very close indeed to the critical density.

We will have to wait until more concrete methods for measuring and detecting dark matter become available, before the ultimate fate of our universe will be known for sure.

:sk

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i say closed.  i also believe that we are relative to everything, so even when the universe contracts we will never notice it at all.  

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To answer the original question, I believe the universe will expand forever. I say that only because the expansion of the universe is still accelerating, and by the time the acceleration stops(if it stops), the distances might be too great to contract. Without further information on dark matter, that's my position at this time(always subject to change as new evidense presents itself ;D)

DScwartz,

Everything is relative to everything else in the cosmos as it relates to space/time. The reason we won't notice the Big Crunch is because we will all be dead. The earth and the sun will both be dead, so of course we won't notice.

SaRuMaN,

It will be interesting to know if neutrinos have matter. Neutrinos are so numerous that even if their mass is only trace, it could answer a lot of questions about dark matter. Of course, if they do have mass, then the laws of physics will not only have a new chapter, but may have to be tweaked here and there to fit this exotic property of mass into the laws of known physics. Dark Matter against Dark Energy...which will prevail?

Pale_Horse,

I know what you mean. It's difficult to fathom nothingness. According to the theory, before the Big Bang, there was nothing. No time, no space. Just nothing. Even empty space is something, I guess. Is space that is void of all matter, such as a vacuum, subject to time? Although I contemplate it from time to time, it is beyond my comprehension.

Which leads me to this, is a vacuum void of all matter? Or does it have so little matter, that it has no gravitational influence? If space and time are related, and if a vacuum can be void of all matter, would there be time in the vacuum? If time requires matter to be present, does it matter how much matter? If there was a vacuum the size of the Grand Canyon, which had one atom in it, would it be considered a vacuum? Would it be subjected to time? :s9

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Stephen Hawkins has a theory that when the Universe finally contracts time will actually appear to move backwards, I should think it would be an interesting thing to experience.

(as Mr Hawkins appears to be one of the greatest minds of our time I,m going with the closed universe theory) :sq

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Is space that is void of all matter, such as a vacuum, subject to time? Although I contemplate it from time to time, it is beyond my comprehension- Homer.

i am astonished this could be beyond your comprehension, Homer.  after all, you seem to speak with such authority on these matters, as if you knew what you say to be an absolute certainty.  

please tell me how you know we will all be dead when the big crunch comes?  it could come tomorrow afternoon at 4:33:32 EST for all you know.  im glad you could enlighten us all with your omniscient knowledge of the ways of the cosmos.  maybe someone will take your words down for posterity's sake...

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DSchwartz,  

I speak with authority on either the things that I know to be true, or of things that are true in accordance with the current laws of astrophysics.  

 

If you point a gun straight up and shoot, will the time it takes the bullet to reach it's highest point be greater than or less than the time it takes for gravity to bring it back to the same level from which it was fired? Keep in mind gravity is the only force to bring it back, and gravity will be the only force to contract the universe as well. That being said, the universe has been expanding for about 15 billion years(give or take a few months ;D), and would be a mathematical impossibility for the crunch to happen in earths lifetime, much less tomorrow.  Of course I know you know this, and would rather put me to some test instead of answer a single question I asked.    

 

 

Kismit,  

Can you give more information on Hawking's theory? And what was it about the thoery that either impressed you or you found most believable?  

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[blue] :s2 <--- I'm laughing because although I took offence at Dschwartz's words to our good friend Homer, I realised that the total arrogance directed at him is supposed to be Dschwartz's attempt at 'humour'...

[/blue]

:s9

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Homer it would be a pleasure ,

I,t was a late night documentary called "Hawkings theories of or on the Universe" What Impressed me the most was the fact that he believed time would move backward when the Universe contracts unfortunately my meager I.Q didn't grasp a lot of the facts and I am certainly  not going to claim that I have any kind of grip on the Idea's of dark matter density's , but I'll check to see if I can find a site with the Info on it and attempt to post a link. :sq

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Thank you Kismit,

I seen that one before but didn't know if there was another more recent. Hawkings theory about the "no boundary universe" is very interesting. Using imaginary time, the theory states that the universe didn't begin with a singularity at all.

Thanks again Kismit  :)

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oh yes, the almighty 'current laws of astrophysics'.  just the fact that you say they are 'current' and not just the 'laws of astrophysics' proves my point exactly.  in 2002, we  happen to be at the peak of our understanding of astrophysics also, considering we all spend so much time in space studying it.  those laws couldnt possibly be wrong now could they?  when i made my statement about why i think we live in a closed universe i said 'i believe' and not 'i know' for precisely this reason.  i am glad you can be so confident that you feel you can put my belief down as wrong and your's as correct.  

please don't think you can belittle my statements at will, Homer.  i don't happen to ascribe to the belief that you have a superior intellect, as much as you wish i would.  

as for your little analogy of firing a gun up into the air, you are assuming that the universe follows the same rules of gravity that we experience on the earth.  how do you know the universe is affected by gravity?  you can't even prove it is expanding, much less that it will compress upon itself due to gravity.  also, you want me to answer a hypothetical question about a bullet where you rule out all the other possible influences on the bullet besides gravity alone?  is that reality, Homer?  i think not.  the fact that we do not live in a vacuum would affect the bullet, and as far as we understand the nature of the universe i see us as being in no position to make authoritative claims on anything.  you're an arrogant fool, Homer.   its one of the best types of fools to be, in comparison to say a bumbling fool or a jumping fool (who wants to be a jumping fool anyways?), but youre still a fool. :)

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DScwartz stated "oh yes, the almighty 'current laws of astrophysics'.  just the fact that you say they are 'current' and not just the 'laws of astrophysics' proves my point exactly.  in 2002, we  happen to be at the peak of our understanding of astrophysics also, considering we all spend so much time in space studying it.  those laws couldnt possibly be wrong now could they?"  You speak as if I have something to do with those laws. The laws are based on what we know about the physical properties of the universe based on experiments and instruments. But there are exotic materials in the universe that we know nothing about. Take my neutrino example. They are particles that pass through matter as if it wasn't there. Neutrinos from the sun pass right through the earth as if earth wasn't even there. It's not known for sure exactly what they are or if they are even made up of matter. That discovery could be very profound. The believed date of the universe has changed only this year. Does that mean it's an absolute certainly? Of course not, but it's using current evidence. Granted the laws didn't change with that discovery because it didn't change what we know about the physical properties, but it's still an important discovery in terms of how much expansion the universe has had.

You also stated "when i made my statement about why i think we live in a closed universe i said 'i believe' and not 'i know' for precisely this reason.  i am glad you can be so confident that you feel you can put my belief down as wrong and your's as correct"   I never put your belief about a closed universe down. In fact I myself stated that "I believe" and that my belief was subject to change when further evidence presents itself. So the reality is, that I didn't put down or disagree in anyway anything you said in your first post.

You also stated "how do you know the universe is affected by gravity?  you can't even prove it is expanding, much less that it will compress upon itself due to gravity."    Everything in the universe is affected by gravity. Everything. It has been PROVEN that the universe is expanding. Nobody can prove or disprove the universe won't compress upon itself, and I never stated the universe will compress upon itself due to gravity. What I stated was that if the universe does compress, it will be because of gravity. If you remember, my original reply was an open universe, meaning I don't believe the universe will compress.

So you have yet to prove me a fool, and I stand by everything that I have said. But I'm curious as to why you feel the need to insult me and challenge me.  

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i also believe that we are relative to everything, so even when the universe contracts we will never notice it at all. -DSchwartz

Everything is relative to everything else in the cosmos as it relates to space/time. The reason we won't notice the Big Crunch is because we will all be dead. The earth and the sun will both be dead, so of course we won't notice. -Homer

you sound an awful lot like a know-it-all to me here.  will you stop arguing now?  tossing around big words like neutrinos isnt making you sound any less a fool, btw.  im glad you felt like telling me what a neutrino was, since  im such an idiot i wouldnt know.  OMG, they can pass through the earth?  how is that possible?  OMG, that's amazing, Homer, thank you...

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Dschwartz,

I haven't said anything up till now, but you've got to stop picking fights with people - nobody can say anything any more without you coming down on them like a ton of bricks.

you sound an awful lot like a know-it-all to me here.  will you stop arguing now?

You are the only one arguing here. Disagreeing with other people's posts is fine - but it can be achieved without resorting to insulting comments and childish remarks like those in your last post.

I don't want to have to lock yet another thread because you won't stop having a go at someone.

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look, i didnt disagree with anyone's posts.  im not going to let Homer come down on my post like he speaks with some sort of authority on the matter.   this is a hypothetical topic, isnt it?

Saruman, if you read this topic from the start, you might see what im griping about.  Homer had this coming from me- as im getting tired of his insults.  if you think you need to lock a topic everytime i post something in it, youre going to be locking a lot of topics.  is this really doing any harm that it needs to be locked?  cant i choose to disagree with Homer and even call him a fool when he has said far worse about me?  i mean, wouldnt the definition of an arrogant fool be someone who acts like they understand the nature of the universe enough to tell others their opinions are incorrect while theirs are truth?  

how are you supposed to have discussions without disagreement?  it seems to me this forum works along some bizarre rule set, where one person can be insulting and another cannot.  i consider someone's correcting my opinions with theirs as grounds to argue.  i also consider people talking down to me to be offensive, especially since i know the reason Homer does.  can't you guys just back off and let a topic resolve itself?  its not like im swearing or threatening Homer in any way.  so what is the big deal?

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DSchwartz, some advice. We all have our differences with our opinions etc. You should just post what you think about the topic. Sometimes I see posts that are very "so-so" (not homer's) and I would love to just rip them apart (not saying that is your objective). I just try to be more observant and hopefully some people will agree with my posts and take me more seriously. I happen to see where you are coming from on many of your posts. It seems though that some of the others find it offensive. I realize many people here (including myself) have a lot of respect for each other, this forum, and other opinions. I love to keep it short and sweet, so that way it cannot be taken out of context. I rarely disagree with anyone just because it will be an ongoing debate/argument. Every unexplained topic on this forum is hypothetical and every post is speculation.

Mentalcase

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Thanks SaRuMaN and Mentalcase,

So anyways, because I think what Pale_Horse brought up is so interesting, I'll bring it up again.

What is on the other side of space/time? What is the universe expanding into? If you say nothing, then what is nothing? As a child, I always thought that space itself was infinite in both time and area, and that only the material inside space is finite. But that goes against the majority belief by the scientific community. Personally I can't fathom space and time as having a beginning. What was before the Big Bang? How long(time before time?) did it take the Big Bang to go "Bang" before filling nothing with matter(space before space)?

Does anyone have any ideas, because it's mind boggling to me :s01

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i believe that the universe is infinitely big and infinitely small  at the same time.  what we call the universe is actually a tiny part of a greater thing.  the space is enormous to us, but it is also even more enormous to a bacteria, or very small to a creature made up of galaxies.  we all live in a kind of equilibrium together.  just as we cannot exist without a cell sized structure, the universe cannot exist without galaxies.  

what is the big bang?  well, ask yourself if you can even explain where you came from first.  how can you exist from nothing?  there you'll find your universal answer.

just a side note... did you know that people are made of the same material that makes up stars?  the material that congregated into stars and planets also congregated into us too.  that must explain something :)

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Right DSchwartz, we are the universe asking about our own existence. I think that is a crazy, but cool notion.  

I always thought universes were like bubbles in a can of soda. Except the can of soda is infinite.  Another cool thought, and i'm not sure where i heard this..."the universe could be about the size of an atom under your finger nail."  So what is big to us may be small to something else.   :s9

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Also, gravity isn't explained yet, Einstein didn't explain it, neither did anyone else. He/they just knew about the physics. It just seems that the further matter moves away, the harder and less probable it would be that it would all reverse. Unless it lost speed, then of course gravity would do it's work. Maybe we are being stretched by many other universes with greater forces, including gravity. Does anyone know what I mean?

Plus I was thinking, solar systems (and systems alike) are vortex-like, galaxies are too.  Does that mean that our universe is also a vortex? If so, then why is matter expanding? And what is in the middle, a huge black hole?

Mentalcase :s8

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DSchwartz and Mentalcase,

I understand what you're saying, as I have thought of that since my early childhood and it still baffles me. The universe could actually be like an atom to another creature in it's own universe, which in turn is like an atom on the creature in another universe etc ect. The size of the universe, as it pertains to the question, isn't relevant. But if there was the biggest universe and a smallest universe, then there would eventually be an end. Consider this, if our universe isn't infinite, and there are more than one universe, then would they be connected? If not what would seperate them? If they are connected, then would they share the same beginning? If so, then why would they be different universes? Whether there is one universe or a million billion universes, the question would be the same. What is at the edge of the universe? What is nothing? What is the universe exapanding into? These questions would really only apply if one believed the universe wasn't infinite.

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People people,please!Calm down!Now I know how Logic feels about when I had an arguement with Magikman(which thankfully is over).DSchwartz,please don't take Homer too seriously.You're starting to act like me.Well,maybe not that horrible but still,pretty bad. ;D

And Homer...Well,I don't see much wrong with you.But there is one thing:When you said things that you know to be true,what do you mean?I'd like to hear about those things,and it'd be nice to hear some more theories.You seem to know a lot...Are you in college or a college graduate or what?

                 :sdboo

I am boo,hear me say......Boo......(Oh never mind). ;D

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:sd Boo,

We have already calmed down, you're a few days late.

:s09

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