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Author Topic:   The expanding Universe and Galactic collisions
Spektical
Member (Idle past 4087 days)
Posts: 119
Joined: 10-16-2007


Message 1 of 76 (429922)
10-22-2007 2:24 PM


I have mediocre knoweldge about astronomy and physics, but for some reason the Big Bang theory doesn't quite sit well with me. If according to the BB theory the universe is in fact expanding and bodies of matter are moving away from each other, how do you explain galactic collisions?

Of course one answer could be that the relative mass and proximity of two galactic bodies attract one another to the point of collision. This would also mean that the expansion of the universe is slowing/cooling down.

Another question is: could the universe have originated from a gigantic Black hole, and if so could that be where this universe is heading to?

Edited by Spektical, : No reason given.


Replies to this message:
 Message 3 by Taz, posted 10-22-2007 3:15 PM Spektical has responded
 Message 6 by Kitsune, posted 10-22-2007 4:34 PM Spektical has responded
 Message 21 by Dr Jack, posted 10-23-2007 8:37 AM Spektical has not yet responded
 Message 38 by Rahvin, posted 10-23-2007 11:55 AM Spektical has responded
 Message 39 by EighteenDelta, posted 10-23-2007 12:08 PM Spektical has not yet responded

    
AdminNem
Inactive Member


Message 2 of 76 (429924)
10-22-2007 2:31 PM


Thread moved here from the Proposed New Topics forum.
  
Taz
Member (Idle past 1402 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 3 of 76 (429928)
10-22-2007 3:15 PM
Reply to: Message 1 by Spektical
10-22-2007 2:24 PM


Spektical writes:

I have mediocre knoweldge about astronomy and physics, but for some reason the Big Bang theory doesn't quite sit well with me.


I have a mediocre knowledge of geology, but you don't see me sharing my opinion that plate tectonic doesn't sit well with me. I have a mediocre knowledge of spinal surgery. Yet, I didn't say a word when my aunt had spinal surgery some weeks ago.

So, you see, there are a lot of things in this world, and outside of this world, that we don't completely understand. This is why we have experts.

If according to the BB theory the universe is in fact expanding and bodies of matter are moving away from each other, how do you explain galactic collisions?

You answered your own question with..

Of course one answer could be that the relative mass and proximity of two galactic bodies attract one another to the point of collision.

In logic, we would call your question the composition fallacy. An example is since the atom of a plant is colorless then we must assume that the plant is colorless. This is, of course, absurd.

Just because 2 galaxies attract each other and collide doesn't mean that the universe as a whole isn't expanding.

Another question is: could the universe have originated from a gigantic Black hole, and if so could that be where this universe is heading to?

Don't know for the first question.

For the second question, if the universe has enough mass for gravity to overcome the expansion, then it will ultimately end up in a big crunch. If the universal mass is below the critical point, then it will ultimately wither away with light years seperating each atom. If it's just the right mass, it could last forever.

The better question is why are you worried about this right now? You still have tens of billions of years before you start to see any obvious signs of either doomsday scenario. You plan to live that long?


Disclaimer:

Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!


This message is a reply to:
 Message 1 by Spektical, posted 10-22-2007 2:24 PM Spektical has responded

Replies to this message:
 Message 4 by Spektical, posted 10-22-2007 3:58 PM Taz has responded

  
Spektical
Member (Idle past 4087 days)
Posts: 119
Joined: 10-16-2007


Message 4 of 76 (429932)
10-22-2007 3:58 PM
Reply to: Message 3 by Taz
10-22-2007 3:15 PM


Thank you for the completely useless and non-thought provoking response taz. I'm not worried...go play tornado somewhere else.
This message is a reply to:
 Message 3 by Taz, posted 10-22-2007 3:15 PM Taz has responded

Replies to this message:
 Message 5 by jar, posted 10-22-2007 4:09 PM Spektical has not yet responded
 Message 7 by Percy, posted 10-22-2007 4:49 PM Spektical has not yet responded
 Message 9 by Taz, posted 10-22-2007 6:16 PM Spektical has responded

    
jar
Member
Posts: 30936
From: Texas!!
Joined: 04-20-2004


Message 5 of 76 (429933)
10-22-2007 4:09 PM
Reply to: Message 4 by Spektical
10-22-2007 3:58 PM


Not all forces are equal
Maybe it would help if I point out that not all forces are equal. While gravity seems to be one of the weakest of forces, it also seems to operate over greater distances than many of the others. We have trees and buildings and mountains because some forces are stronger than gravity, and because those operate over shorter distances than gravity.

While space does seem to be expanding, the force driving the expansion does not seem to be stronger than other forces, therefore we see different forces controlling local effects.

The result is the universe we see.


Aslan is not a Tame Lion
This message is a reply to:
 Message 4 by Spektical, posted 10-22-2007 3:58 PM Spektical has not yet responded

  
Kitsune
Member (Idle past 2410 days)
Posts: 788
From: Leicester, UK
Joined: 09-16-2007


Message 6 of 76 (429937)
10-22-2007 4:34 PM
Reply to: Message 1 by Spektical
10-22-2007 2:24 PM


I'm not sure why you say Taz's response is useless. He's explained a few points to you, including the one about the relationship between not knowing much about something and it "not sitting well" with you. There's a wealth of information on astronomy to tap into on the web.

For one thing, why should two galaxies colliding make the universe slow down in its expansion? The whole of space-time is expanding, carrying matter and energy along with it. It matters not what the matter and energy are doing, they do not prevent the expansion of space-time. Dark energy seems to be causing the acceleration. You can read about it here.

About the idea that the universe could have originated from a black hole. Some people have suggested this. It does seem that the universe started out as a singularity, a point almost infinitely small and infinitely dense. A black hole is also a singularity, albeit of much less mass (the largest so far detected contain the mass of a few million suns). The problem there, though, is that the universe exploded. You would have to come up with a mechanism that described how a black hole would suddenly explode, when every black hole yet observed has only consumed matter and energy. Black holes are believed to emit something called Hawking radiation, but it would take billions and billions of years for a black hole to radiate all of its mass in this way; it is a very slow and gradual process.

That isn't to say that some brilliant mathematician might not be able to describe one day how a black hole could theoretically explode. Maybe Dr. Adequate will stop by and share some of his insights.


This message is a reply to:
 Message 1 by Spektical, posted 10-22-2007 2:24 PM Spektical has responded

Replies to this message:
 Message 8 by kuresu, posted 10-22-2007 4:53 PM Kitsune has not yet responded
 Message 10 by Spektical, posted 10-22-2007 10:15 PM Kitsune has not yet responded
 Message 16 by Jon, posted 10-23-2007 12:26 AM Kitsune has not yet responded

    
Percy
Member
Posts: 18377
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.9


Message 7 of 76 (429939)
10-22-2007 4:49 PM
Reply to: Message 4 by Spektical
10-22-2007 3:58 PM


Spektical writes:

Thank you for the completely useless and non-thought provoking response taz. I'm not worried...go play tornado somewhere else.

Maybe not the best way to motivate people to address your questions?

--Percy


This message is a reply to:
 Message 4 by Spektical, posted 10-22-2007 3:58 PM Spektical has not yet responded

    
kuresu
Member (Idle past 623 days)
Posts: 2544
From: boulder, colorado
Joined: 03-24-2006


Message 8 of 76 (429941)
10-22-2007 4:53 PM
Reply to: Message 6 by Kitsune
10-22-2007 4:34 PM


There's a wealth of information on astronomy to tap into on the web

Good. Then maybe you can find what's wrong with these statements:

A black hole is also a singularity, albeit of much less mass (the largest so far detected contain the mass of a few million suns).

AND

The problem there, though, is that the universe exploded

AND

every black hole yet observed has only consumed matter and energy

Pay particular attention to the second quoted statement.


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

    
Taz
Member (Idle past 1402 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 9 of 76 (429948)
10-22-2007 6:16 PM
Reply to: Message 4 by Spektical
10-22-2007 3:58 PM


Spektical writes:

Thank you for the completely useless and non-thought provoking response taz.


You're welcome.

I'm not worried...go play tornado somewhere else.

The reason I asked why you are worrying (or concern yourself) about this is because you seem to be lacking in the most basic knowledge of physics. My mentor used to tell me that in order to be an artist one must first learn how to use a paint brush. You simply can't understand the BB theory unless you first have to familiarize yourself with the basic stuff.

Not only is the universe expanding, the rate of expansion is increasing. Astronomy currently doesn't have a clue as to why this is, and some are attributing this to dark energy, a very hypothetical form of energy that is responsible for the acceleration outward.

Do you understand the implication of this? Some unknown force is driving the accelerated rate of expansion of the universe while a very well known force (gravity) is locally grouping objects together.

Other than that, I don't know what to tell you.


Disclaimer:

Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!


This message is a reply to:
 Message 4 by Spektical, posted 10-22-2007 3:58 PM Spektical has responded

Replies to this message:
 Message 11 by Spektical, posted 10-22-2007 10:27 PM Taz has responded

  
Spektical
Member (Idle past 4087 days)
Posts: 119
Joined: 10-16-2007


Message 10 of 76 (429980)
10-22-2007 10:15 PM
Reply to: Message 6 by Kitsune
10-22-2007 4:34 PM


I was being cautious about my extent of knowledge about astronomy...just spoke out loud. His comments were useless because the didn't answer the questions as much as they tried to dismantle the question itself which is besides the point.

Anyways, my apologies to Taz for sounding harsh or rude.

Edited by Spektical, : No reason given.


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

Replies to this message:
 Message 12 by Taz, posted 10-22-2007 10:35 PM Spektical has not yet responded

    
Spektical
Member (Idle past 4087 days)
Posts: 119
Joined: 10-16-2007


Message 11 of 76 (429983)
10-22-2007 10:27 PM
Reply to: Message 9 by Taz
10-22-2007 6:16 PM


No you explained it pretty eloquently. I know this information as well, and I guess the mystery is the fact that the universe is expanding at an increasing rate, which goes against our current linear perspective of how the universe works.

This is why the big bang theory doesn't fit. I think there is a much more complex mechanism by which the universe evolved or became the way it is now.

I read an article not too long ago on Universe Today or space.com...unfortunately I forgot the title of the article...but basically it hypothesizes a different theory from the BB and one that I think has to do with other universes and strings etc.

I have to go back and rummage for it.

Edited by Spektical, : No reason given.


This message is a reply to:
 Message 9 by Taz, posted 10-22-2007 6:16 PM Taz has responded

Replies to this message:
 Message 13 by Taz, posted 10-22-2007 10:39 PM Spektical has responded
 Message 74 by cavediver, posted 10-27-2007 6:28 AM Spektical has not yet responded

    
Taz
Member (Idle past 1402 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 12 of 76 (429986)
10-22-2007 10:35 PM
Reply to: Message 10 by Spektical
10-22-2007 10:15 PM


Spektical writes:

His comments were useless because the didn't answer the questions as much as they tried to dismantle the question itself which is besides the point.


To be fair, let me explain a little further why I decided to dismantle your question rather than answer it directly. Consider the following question.

If a plant is green, how come the plant's atoms are colorless?

Can this question be answered directly? Sure, it can. But one can't really answer this question honestly without pointing out the obvious logical fallacy of division. Just because the plant is green doesn't necessarily mean its atoms are green. Trying to apply the behavior of the whole on the individual components is never a good idea. And neither is trying to apply the behavior of the individual components onto the whole system.

My other main point in my first reply to you is that I really really really hope you will learn to refrain from having an opinion about everything. We live in an age where everyone seems to have an opinion on everything. Having been an educator and is now considering going back to it permanently, I've seen too many cases of students not agreeing with something as simple as gravity only to later show they know nothing about it. How on earth can you disagree with something you know little to nothing about? So, I guess my goal has always been to try to convince people that a little humility here and there wouldn't hurt. And by example, you will find that I hardly ever comment on geology. Even a middle schooler would know more about geology than I do.

You don't have to agree with everything the experts say. In fact, you can disagree all you want. Just remember that you have the power to vote like everyone else. At least show the experts the courtesy of learning a little about the subject before having and sharing your opinion on it.

(Otherwise, we'd get another Bush in the oval office in 2008.)


Disclaimer:

Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!


This message is a reply to:
 Message 10 by Spektical, posted 10-22-2007 10:15 PM Spektical has not yet responded

  
Taz
Member (Idle past 1402 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 13 of 76 (429987)
10-22-2007 10:39 PM
Reply to: Message 11 by Spektical
10-22-2007 10:27 PM


Spektical writes:

This is why the big bang theory doesn't fit. I think there is a much more complex mechanism by which the universe evolved or became the way it is now.


Mind expanding on this a little more?


Disclaimer:

Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!


This message is a reply to:
 Message 11 by Spektical, posted 10-22-2007 10:27 PM Spektical has responded

Replies to this message:
 Message 14 by Spektical, posted 10-22-2007 11:45 PM Taz has responded

  
Spektical
Member (Idle past 4087 days)
Posts: 119
Joined: 10-16-2007


Message 14 of 76 (430002)
10-22-2007 11:45 PM
Reply to: Message 13 by Taz
10-22-2007 10:39 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? what I mean is how did all the different galaxies form so quickly and with such complexity? And where is the centre of the BB or the point in space from which it originated?

Also what is the purpose of dark matter? All this cannot be explained by a mere explosion. The dynamics of an explosion of matter is way too linear imo.

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.

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.


This message is a reply to:
 Message 13 by Taz, posted 10-22-2007 10:39 PM Taz has responded

Replies to this message:
 Message 15 by Taz, posted 10-23-2007 12:02 AM Spektical has not yet responded
 Message 17 by Dr Adequate, posted 10-23-2007 12:44 AM Spektical has not yet responded
 Message 22 by Dr Jack, posted 10-23-2007 8:44 AM Spektical has not yet responded

    
Taz
Member (Idle past 1402 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 15 of 76 (430003)
10-23-2007 12:02 AM
Reply to: Message 14 by Spektical
10-22-2007 11:45 PM


Spektical writes:

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? what I mean is how did all the different galaxies form so quickly and with such complexity?


Look up the idea of inflation as a modification to the BB.

And where is the centre of the BB or the point in space from which it originated?

Well... I know you've heard this a million times before, so I guess one more time wouldn't hurt.

You are thinking too 3-dimensionally. Imagine that the universe is 2-dimensional and that it exists solely on the surface of an expanding balloon. There are many dots on the surface of this balloon. As the balloon expands, these dots grow further apart from each other.

If you were to ask where the center of this two dimensional universe is, noone can really give you an answer. There is no center. I know you are tempted to say the inside of the balloon is the center, but in this scenario you've wandered outside of the universe.

Also what is the purpose of dark matter?

Dark matter pretty much is a hypothetical form of matter that accounts for 2/3 of the total mass of the universe. It's probably non-baryonic in nature, but I guess we'll never know until we get ourselves some dark matter to analyze.

All this cannot be explained by a mere explosion. The dynamics of an explosion of matter is way too linear imo.

Well, explosion isn't exactly the best way to describe what happenned at the beginning of time. Try to think of it more as an expansion of space-time from a single point.

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.

It wasn't so much as an explosion as simply a sudden expansion of space-time and matter. And yes, we could always improve on the current model :)

Just remember that the BB made at least one very prominent prediction. It predicted the existence of a cosmic background radiation that should exist everywhere in the universe. And voila, we have detected exactly the cosmic background radiation predicted by the theory. So, I guess it's not perfect but it does explain a lot and have some very powerful predictive power.


Disclaimer:

Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!


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

  
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