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Author Topic:   The expanding Universe and Galactic collisions
Jon
Inactive Member


Message 16 of 76 (430006)
10-23-2007 12:26 AM
Reply to: Message 6 by Kitsune
10-22-2007 4:34 PM


The Paraphrase according to Jon
I'm not sure why you say Taz's response is useless.
I think it was because of how it played out... which goes something like this paraphrase below:
Spektical: "I've always had this problem with my understanding of the BB theory, maybe someone here can clear it up."
Taz: "Why bring your problems of understanding to us? We don't care about furthering your understanding. I lack full understanding of geology, but you don't see me seeking further understanding, because I enjoy being an ignorant-ass pig. Why, Skeptical, can you not just be an ignorant-ass pig like me? Here, let me introduce to you all the ways I've justied being an ignorant-ass pig..."
Spektical: "I have no use for becoming an ignorant-ass pig, therefore, your information is of no use to me”it's useless."
Maybe someone can correct me if I'm wrong on my interpretation...
Jon
Edited by Jon, : No reason given.

In considering the Origin of Species, it is quite conceivable that a naturalist... might come to the conclusion that each species had not been independently created, but had descended, like varieties, from other species. - Charles Darwin On the Origin of Species
_ _ _ _ _ _ _ ____ _ _ _ _ _ _ _
En el mundo hay multitud de idiomas, y cada uno tiene su propio significado. - I Corintios 14:10
_ _ _ _ _ _ _ ____ _ _ _ _ _ _ _
A devout people with its back to the wall can be pushed deeper and deeper into hardening religious nativism, in the end even preferring national suicide to religious compromise. - Colin Wells Sailing from Byzantium

This message is a reply to:
 Message 6 by Kitsune, posted 10-22-2007 4:34 PM Kitsune has not replied

Replies to this message:
 Message 18 by kuresu, posted 10-23-2007 1:44 AM Jon has replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 17 of 76 (430010)
10-23-2007 12:44 AM
Reply to: Message 14 by Spektical
10-22-2007 11:45 PM


well first of all the universe is only 14.7 billion years old while Sol is 4.7 billion years old. How is this possible when the rate of the universe's expansion is increasing?
And I'm only 34, what's the problem.
And where is the centre of the BB or the point in space from which it originated?
There isn't one.
All this cannot be explained by a mere explosion.
Which the Big Bang was not.
The dynamics of an explosion of matter is way too linear imo.
Perhaps you mean something by this, but I'm not sure that it would mean anything to physicists.
And I do understand your point about the plant being green not because of its individual atoms being green. If they were the plant would probably be black.
That's an interesting use of the word "probably".
I guess the BB is the best theory scientists can come up with given all that is known.
Yes indeedy.
But I think there's more to it than just a simple explosion.
As any scientist would be willing to explain to you, there is.
Look, if you, having no knowledge of physics, can see flaws in your idea of your idea of some concept of physics, and physicists can't, this is almost certainly because you've got it wrong.
Why don't you get a book on cosmology and find out what the Big Bang is, instead of making up your own version and then complaining that it's wrong?

This message is a reply to:
 Message 14 by Spektical, posted 10-22-2007 11:45 PM Spektical has not replied

  
kuresu
Member (Idle past 2514 days)
Posts: 2544
From: boulder, colorado
Joined: 03-24-2006


Message 18 of 76 (430025)
10-23-2007 1:44 AM
Reply to: Message 16 by Jon
10-23-2007 12:26 AM


Re: The Paraphrase according to Jon
Yeah, I'd say you're totally off.
Taz's biggest point is that if you know practically nothing about a subject, then don't say anything until you do. After all, how can you disprove evolution (or physics, or geology, or chemistry, or any other science) until you actually understand what the other side is saying?
It also saves one from making a total fool of one's self.
I think you will find that Taz (and many others) does care about furthering the knowledge of other people. Not necessarily for "selfish" reasons (such as feeling good about yourself), but rather, for destroying one more idiot.

This message is a reply to:
 Message 16 by Jon, posted 10-23-2007 12:26 AM Jon has replied

Replies to this message:
 Message 19 by Jon, posted 10-23-2007 1:54 AM kuresu has not replied

  
Jon
Inactive Member


Message 19 of 76 (430028)
10-23-2007 1:54 AM
Reply to: Message 18 by kuresu
10-23-2007 1:44 AM


Re: The Paraphrase according to Jon
You are entitled to your opinion.

This message is a reply to:
 Message 18 by kuresu, posted 10-23-2007 1:44 AM kuresu has not replied

  
Annafan
Member (Idle past 4579 days)
Posts: 418
From: Belgium
Joined: 08-08-2005


Message 20 of 76 (430052)
10-23-2007 7:09 AM


These questions aren't easily answerable in a short forum post. I suggest you read "The Fabric of the Cosmos: Space. Time. And the Texture of Reality" by physicist Brian Greene. I'm currently reading it, and it goes into some detail (without maths, which means of course that it doesn't go into detail AT ALL, lol) about the current theories. Most of the concerns you have about (your personal ideas about) "the" Big Bang theory, have been addressed for some 30 years already by the concept of Inflation. Which basically is an extremely short period in the extremely young universe, in which space expanded exponentially (from a size smaller than an atom, to something in the order of magnitude of the size of the currently visible universe if I remember correctly). And Inflation (as often, there are different flavours of the theory) is not just a convenient assumption to make theory match observation. It actually predicted properties of the cosmic background radiation with astonishing accuracy. Green shows a graph of the prediction (a complex curve, not just something linear), and the same graph with the datapoints from measurements, and if it would be a test for God, I would now believe in God ;-)!

  
Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 21 of 76 (430054)
10-23-2007 8:37 AM
Reply to: Message 1 by Spektical
10-22-2007 2:24 PM


The relative velocities of different stellar objects are greater in magnitude than the rate of expansion.
That's all there is to it really.

This message is a reply to:
 Message 1 by Spektical, posted 10-22-2007 2:24 PM Spektical has not replied

  
Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 22 of 76 (430055)
10-23-2007 8:44 AM
Reply to: Message 14 by Spektical
10-22-2007 11:45 PM


well first of all the universe is only 14.7 billion years old while Sol is 4.7 billion years old. How is this possible when the rate of the universe's expansion is increasing?
Is it increasing? I thought that was still being determined. Either case, doesn't matter. Gravity is massively more powerful than expansion.
And where is the centre of the BB or the point in space from which it originated?
Everywhere. At t=0 (the bang) every point in the universe is in the same place. You're thinking of it like an explosion; it isn't like an explosion. There wasn't a bunch of space into which there was a big explosion.
I guess the BB is the best theory scientists can come up with given all that is known. But I think there's more to it than just a simple explosion.
Fortunately all the scientists would agree with you. Have a read through the Wikipedia article on it.

This message is a reply to:
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Replies to this message:
 Message 23 by Percy, posted 10-23-2007 9:15 AM Dr Jack has replied

  
Percy
Member
Posts: 22394
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 23 of 76 (430062)
10-23-2007 9:15 AM
Reply to: Message 22 by Dr Jack
10-23-2007 8:44 AM


Mr Jack writes:
Is it increasing? I thought that was still being determined. Either case, doesn't matter. Gravity is massively more powerful than expansion.
Yes, the rate of expansion is increasing, and no, gravity is not more powerful than expansion, except within regions no larger than local galactic groups.
--Percy

This message is a reply to:
 Message 22 by Dr Jack, posted 10-23-2007 8:44 AM Dr Jack has replied

Replies to this message:
 Message 24 by Dr Jack, posted 10-23-2007 9:25 AM Percy has replied

  
Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 24 of 76 (430063)
10-23-2007 9:25 AM
Reply to: Message 23 by Percy
10-23-2007 9:15 AM


It produces a more powerful force, no? I'd call that more powerful. It's the pervasiveness of expansionary effects that makes them more significant over larger scales, not their power. In the same way that the strong force is much more powerful than the gravitational force, but acts only over very short distances and so, on a larger scale, gravity comes to dominate.

This message is a reply to:
 Message 23 by Percy, posted 10-23-2007 9:15 AM Percy has replied

Replies to this message:
 Message 25 by Percy, posted 10-23-2007 9:49 AM Dr Jack has replied

  
Percy
Member
Posts: 22394
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 25 of 76 (430067)
10-23-2007 9:49 AM
Reply to: Message 24 by Dr Jack
10-23-2007 9:25 AM


When you said, "Gravity is massively more powerful than expansion," combined with your doubt that accelerating expansion has become accepted within mainstream cosmological circles, it sounded like an argument that the expansion would one day slow and reverse. It sounds like that's not what you were trying to say.
Maybe one of the cosmology buffs will check in and help us out here, but for my part I question the validity of likening the expansion of the universe (which is only postulated to be due to the effects of dark energy, not verified) to a force and then comparing it with the force of gravity, but perhaps it's just a preference for a different explanatory model that's at work in my mind.
--Percy

This message is a reply to:
 Message 24 by Dr Jack, posted 10-23-2007 9:25 AM Dr Jack has replied

Replies to this message:
 Message 26 by Dr Jack, posted 10-23-2007 10:15 AM Percy has not replied
 Message 27 by Spektical, posted 10-23-2007 10:19 AM Percy has not replied

  
Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 26 of 76 (430072)
10-23-2007 10:15 AM
Reply to: Message 25 by Percy
10-23-2007 9:49 AM


When you said, "Gravity is massively more powerful than expansion," combined with your doubt that accelerating expansion has become accepted within mainstream cosmological circles, it sounded like an argument that the expansion would one day slow and reverse. It sounds like that's not what you were trying to say.
Yes, that's not what I was trying to say.
Maybe one of the cosmology buffs will check in and help us out here, but for my part I question the validity of likening the expansion of the universe (which is only postulated to be due to the effects of dark energy, not verified) to a force and then comparing it with the force of gravity, but perhaps it's just a preference for a different explanatory model that's at work in my mind.
As I understand it, modelling gravity as a force is not quite accurate either, but both can be reasonably simplified to such - more precisely if you treat gravitational effects as curvature of spacetime, the expansion is modelled as a reverse curvature (if you treat expansion in the same way as the cosmological constant) and this can then be simplified to a force model. But, I'm neither a Physicist nor a Cosmologist, so I'm open to correction.

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 Message 25 by Percy, posted 10-23-2007 9:49 AM Percy has not replied

  
Spektical
Member (Idle past 5978 days)
Posts: 119
Joined: 10-16-2007


Message 27 of 76 (430073)
10-23-2007 10:19 AM
Reply to: Message 25 by Percy
10-23-2007 9:49 AM


Is it safe to say that gravity is a product of the universe? Also if the BB is not an explosion but an expansion, than what drives the expansion?

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 Message 25 by Percy, posted 10-23-2007 9:49 AM Percy has not replied

Replies to this message:
 Message 28 by Dr Jack, posted 10-23-2007 10:45 AM Spektical has not replied
 Message 29 by Spektical, posted 10-23-2007 10:45 AM Spektical has not replied
 Message 35 by EighteenDelta, posted 10-23-2007 11:34 AM Spektical has not replied

  
Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 28 of 76 (430079)
10-23-2007 10:45 AM
Reply to: Message 27 by Spektical
10-23-2007 10:19 AM


I suspect if you can answer that question, and provide proof for your answer, there's a nobel prize in it for us.

This message is a reply to:
 Message 27 by Spektical, posted 10-23-2007 10:19 AM Spektical has not replied

  
Spektical
Member (Idle past 5978 days)
Posts: 119
Joined: 10-16-2007


Message 29 of 76 (430081)
10-23-2007 10:45 AM
Reply to: Message 27 by Spektical
10-23-2007 10:19 AM


Also if the universe is unbounded, then how can it expand? What is the medium outside the universe?

This message is a reply to:
 Message 27 by Spektical, posted 10-23-2007 10:19 AM Spektical has not replied

Replies to this message:
 Message 30 by Annafan, posted 10-23-2007 10:47 AM Spektical has replied
 Message 32 by Dr Jack, posted 10-23-2007 11:00 AM Spektical has not replied

  
Annafan
Member (Idle past 4579 days)
Posts: 418
From: Belgium
Joined: 08-08-2005


Message 30 of 76 (430082)
10-23-2007 10:47 AM
Reply to: Message 29 by Spektical
10-23-2007 10:45 AM


Also if the universe is unbounded, then how can it expand? What is the medium outside the universe?
Another nobel prize if you answer this one

This message is a reply to:
 Message 29 by Spektical, posted 10-23-2007 10:45 AM Spektical has replied

Replies to this message:
 Message 31 by Spektical, posted 10-23-2007 10:57 AM Annafan has not replied

  
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