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Author Topic:   Star Formation (Star Condensation)
Parasomnium
Member (Idle past 77 days)
Posts: 2191
Joined: 07-15-2003


Message 16 of 33 (391313)
03-24-2007 1:23 PM
Reply to: Message 15 by Taz
03-24-2007 1:01 PM


Superscript
Sorry to interrupt, but I noticed you didn't use superscript. Sentences with expressions like the ones you used are much easier to read if you do. Here's how yours turns out:

The volume of a typical interstellar cloud is 4.43*1044 m3. Divide that by 1057 and you get 4.43*10-13 m3. Each hydrogen gas takes up a volume of 6.2*10-31 m3. I'd hardly call that condensed.

It's a bit of a bore editing it, but your readers will thank you.


This message is a reply to:
 Message 15 by Taz, posted 03-24-2007 1:01 PM Taz has not yet responded

  
CTD
Member (Idle past 3250 days)
Posts: 253
Joined: 03-11-2007


Message 17 of 33 (391352)
03-24-2007 5:44 PM
Reply to: Message 15 by Taz
03-24-2007 1:01 PM


Sorry again
Can't help you there. Strictly speaking, I probably could go look up some things and study for a few days or weeks, but it's not that important.

It easy to see the history of the models. Way back when, they used to say gravity pulled the clouds in until stars formed. Then they discovered gravity wasn't enough, so they used shockwaves from supernova explosions.

Could be somebody made a mistake - maybe gravity is enough all by itself. Last I knew, it was pretty well agreed that it isn't; but I haven't done all the calculations and I don't intend to. They don't appear to be very easy. I always get confused about how pressure emulates temperature, and I'll bet that's a factor somewhere in the mess.

If people want to believe clouds can condense into stars without supernovas, I don't have a problem with it. I've tried to pitch in, and I may even be wrong about which model is now "preferred". If your model is newer, that's fine. If it's older but still correct, that's fine too.

Now if it's always been common knowledge that gravity alone could get the job done, why was the supernova model even invented? I hardly think any YEC would invent such a thing. And I'm a tad curious just how many gas clouds should be present if it's a "done deal" and they're all busily condensing into new stars.

There may be someone who would like to argue about this and mix numbers with you, but that would be someone other than myself. If it wasn't a very close thing, dark matter would've come into play long ago. Since it is a very close thing, and the math is complex, I see no point in arguing it. I cannot say at what point a gas reaches equilibrium and the pressure matches up with the gravity. Perhaps your gas wasn't condensed enough for that to happen yet. Maybe it never will... (at least maybe not prior to ignition!)

Again, your model might be good. It might be the best. But it comes to a conclusion that is the opposite of what was commonly believed not long ago. I'm not going to argue. One way or another, under Big Bang cosmology the gas clouds become stars. I understood they needed something to jump-start the process, but I really don't care very much either way. I am not infallible, and neither are those who performed similar calculations in the past.

My criticism of your model may have been erroneous. If it was, I am sorry. I was merely attempting to account for the discrepancy.


This message is a reply to:
 Message 15 by Taz, posted 03-24-2007 1:01 PM Taz has responded

Replies to this message:
 Message 18 by Taz, posted 03-25-2007 12:49 AM CTD has responded

    
Taz
Member (Idle past 672 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 18 of 33 (391439)
03-25-2007 12:49 AM
Reply to: Message 17 by CTD
03-24-2007 5:44 PM


Re: Sorry again
CTD writes:

Now if it's always been common knowledge that gravity alone could get the job done, why was the supernova model even invented?


Why not both? At the beginning when there were only hydrogen and helium (right after the big bang event), certain already dense regions accumulated into interstellar clouds and gravity eventually contract these gas clouds into newly formed stars. The hydrogen burning (or fusion) that occur within these stars create helium, then helium burning creates heavier elements, and so on and so forth. Eventually, some stars run out of fuel and is massive enough that when they collapse under their own weight they become supernovas. During these short violent events, even heavier elements are created while the explosions themselves send these elements back into the interstellar medium. These materials eventually condense again and form another generation of stars. And so on and so forth.

I'm not trying to pick on you, but so far your responses have been little better than "I heard somewhere that Darwin doubted his own theory, therefore evolution is false..."

your model might be good.

I'm sorry, but I have not presented any model to speak of. You are making this harder than it is.

Here's what happened so far. The thread started said that he thought gravity wasn't enough to overcome the gas's tendency to expand. I introduced honest to god math calculations that showed otherwise. You came in and said something like in the great scheme of things I'm wrong. I asked specifically why I was wrong and you answered that you heard somewhere that I was wrong, therefore I was wrong.

It would really help if you could be a little more specific than simply repeating "It is very well known that you're wrong, therefore you're wrong..." I mean, throw me a bone here. Tell me what's wrong?

Last I knew, it was pretty well agreed that it isn't.

May I propose the following explanation? Please note that it is only a hypothesis.

Is it possible that the community you refer to that "pretty well agreed" about this thing is the very same community that wants the young earth creationist model taught in school?

I know from personal experience that it was pretty well agreed that if the earth was a few miles from its current orbit that all life on earth would end immediately, proving that this razor thin region of space that earth occupies must be proof of divine intervention. To me, this "fact" remained pretty well known until I stopped being a fundamentalist christian and someone pointed out to me that earth is several million miles farther away from the sun during summer than during winter. After that, this pretty well known fact stopped being so well known.

What I'm saying is is it possible that, like me, you've been living a sheltered life?


This message is a reply to:
 Message 17 by CTD, posted 03-24-2007 5:44 PM CTD has responded

Replies to this message:
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 Message 21 by CTD, posted 03-25-2007 8:53 AM Taz has responded

  
anglagard
Member (Idle past 80 days)
Posts: 2157
From: Big Spring, TX, USA
Joined: 03-18-2006


Message 19 of 33 (391444)
03-25-2007 1:01 AM
Reply to: Message 18 by Taz
03-25-2007 12:49 AM


Re: Sorry again
Taz writes:

To me, this "fact" remained pretty well known until I stopped being a fundamentalist christian and someone pointed out to me that earth is several million miles farther away from the sun during summer than during winter.

Watch out, I understand that there may be Australians around here. :)


This message is a reply to:
 Message 18 by Taz, posted 03-25-2007 12:49 AM Taz has not yet responded

    
cavediver
Member (Idle past 1024 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 20 of 33 (391463)
03-25-2007 6:47 AM
Reply to: Message 8 by CTD
03-23-2007 5:58 AM


Re: More info
http://creationwiki.org/Star_formation
http://creationwiki.org/Nebula_hypothesis

The trouble with articles such as these is that is very difficult trying to ascertain the true propotions of stupidity, ignorance, lies by omission, and blatent falsehood that are fed into their creation.

Regarding the ang mom of the solar system:

quote:
Evolutionists understand the problem, so they propose that it has sun has slowed over time, but this fails to consider the true scope of the problem.

Take a moment to admire the eloquence of the writing!

And I think the word they are looking for is astrophysicists - not evolutionists. Or at least in my case, my first degree was in astrophysics, not evolution, which was when we sat around scratching our heads saying

"wow, that's a lot of ang mom to remove from the system - how do you think that happens? - oh, who cares, it obviously just works - yeah, the first creationist websites aren't due to arrive on the scene for at least another twelve years so we've plenty of time to hide our ignorance - heh, heh, who wants to know anyway, science is boring - too right, let's go get pissed - by the way, what's a website???"


This message is a reply to:
 Message 8 by CTD, posted 03-23-2007 5:58 AM CTD has not yet responded

  
CTD
Member (Idle past 3250 days)
Posts: 253
Joined: 03-11-2007


Message 21 of 33 (391480)
03-25-2007 8:53 AM
Reply to: Message 18 by Taz
03-25-2007 12:49 AM


Nah
If anything, I'm feeling overexposed these days. There's only so much I can take of stuff that's obviously untrue. Fortunately this isn't a case of obvious untruth. The more I look at it, the more complex it grows.

Here's some more links I dug up. I know there's better somewhere, but how to find it!? Anyhow, here's a couple from a fairly pro-banger forum. You'll need to find the "flat" button to view the whole threads. Then "find" words from my quotes below if you care enough.

http://uplink.space.com/showflat.php?Cat=&Board=sciastro&Number=637085&page=&view=&sb=&o=&vc=1
http://uplink.space.com/showflat.php?Cat=&Board=askastronomer&Number=593324&page=&view=&sb=&o=&vc=1

"Star formation is usually thought to require a fairly good sized and energetic event such as a supernova, which can compress a gas cloud and begin the process of gravitational collapse."

Then from the other:

"The cloud started out spinning. This spin was very slow, in fact the same rate of rotation as the Galaxy as a whole. However, as the cloud collapses, it spins faster. The centrifugal force created by the spin counters gravity and this should prevent the cloud from collapsing, since it increases faster than gravitational force.

This is called the 'angular momentum problem' and it was a vexing puzzle to astronomers throughout the 19th Century and into the earliest part of the 20th Century. In our solar system, the enormous Sun has over 98% of the mass of the system, and yet the planets orbiting around the sun have over 90% of the angular momentum (the spin). What mechanism could have carried away the spin?"

As if we didn't have enough to deal with, they throw angular momentum into the mix. Oh, and the first guy's pretty much saying what I've was saying earlier. These guys probably aren't experts, but I'd say they represent pretty well what's taught in the mainstream.

But here's a nice find for you! Ever hear of a fellow named James Hopwood Jeans? He worked out some relatively simple formulas about gas clouds collapsing.

http://en.wikipedia.org/wiki/James_Hopwood_Jeans

Be sure to take the links to Jeans Length and Jeans Instability while you're there. Good looking short-cuts, if you ask me. How's that for a bone?

And if you just can't get enough Wiki,

http://en.wikipedia.org/wiki/Molecular_cloud

The physics of molecular clouds are poorly understood and much debated. Their internal motions are governed by turbulence in a cold, magnetized gas, for which the turbulent motions are highly supersonic but comparable to the speeds of magnetic disturbances. This state is thought to lose energy rapidly, requiring either an overall collapse or a steady reinjection of energy. At the same time, the clouds are known to be disrupted by some process—most likely the effects of massive stars—before a significant fraction of their mass has become stars.

Which is why I'll save my energy for something else. There just aren't too many areas where the big official brains so obviously don't know what's going on. I mean no insult by that. It's very much to their credit that they don't make more of an effort to hide it.

I mean just after what little research I've done for my posts on this thread it's my opinion that anyone who just up and says "yes it will" or "no it won't" is probably not taking everything into consideration. At this point I would not be confident betting on either side, myself. Times are changing, and I don't consider you "wrong".

Here's another bone: if some YEC wants to say you need the supernovas, just whip out a little magnetism & electricity on 'im. There are other not-so-obvious factors. You don't have to fall back on dark matter, not for a long time. But be prepared for some surprises the other way too, if he's sharp & up-to-date.

Goodness! It's been a while since I learned so much about something I care so little about. But it was more fun than watching any Hollywood awards show.

Good Luck, TD. I look forward to clashing with you on an issue I do care about sometime.


This message is a reply to:
 Message 18 by Taz, posted 03-25-2007 12:49 AM Taz has responded

Replies to this message:
 Message 22 by Taz, posted 03-25-2007 10:03 PM CTD has not yet responded
 Message 25 by Son Goku, posted 03-26-2007 8:38 AM CTD has not yet responded

    
Taz
Member (Idle past 672 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 22 of 33 (391560)
03-25-2007 10:03 PM
Reply to: Message 21 by CTD
03-25-2007 8:53 AM


Re: Nah
CTD writes:

Be sure to take the links to Jeans Length and Jeans Instability while you're there. Good looking short-cuts, if you ask me. How's that for a bone?


According to your own link...

quote:
One of Jean's major discoveries, named Jeans length, is a critical radius of an interstellar cloud in space. It depends on the mass, size, temperature, and density of the cloud. A cloud that is smaller than its Jeans length will not have sufficient gravity to overcome the repulsive gas pressure forces and condense to form a star, whereas a cloud that is larger than its Jeans length will collapse.

Here's the calculation...

k = 1.38066 * 10-23 J/K
T = 20K
G = 6.67 * 10−11 N m2 /kg2
m = 1.7*1030 kg
p = m/((4/3)*pi*r3)
r = 4.73 * 1014 meters = .05 LY

λ = ((5*k*T*r3)/(G*m2)).5

Which comes out to be 2.75*10-14m

So... what's the problem?


This message is a reply to:
 Message 21 by CTD, posted 03-25-2007 8:53 AM CTD has not yet responded

Replies to this message:
 Message 23 by NosyNed, posted 03-26-2007 12:37 AM Taz has responded

  
NosyNed
Member
Posts: 8752
From: Canada
Joined: 04-04-2003
Member Rating: 10.0


Message 23 of 33 (391566)
03-26-2007 12:37 AM
Reply to: Message 22 by Taz
03-25-2007 10:03 PM


Surprising Jeans Length
I'm not checking the actual calculation but I find the result surprising.

We are discussing intersteller gas clouds and the crucial "length" with resonable parameters comes out to a jillion times less than a billionth of a meter?? This doesn't seem to make sense.

I'd have expected this to result in numbers that would actually separate "too small" clouds from large enough. Answers in 100,000's or much, much more meters is more like what I'd expect to see.

I don't get it at all is the probable conclusion I should arrive at.


This message is a reply to:
 Message 22 by Taz, posted 03-25-2007 10:03 PM Taz has responded

Replies to this message:
 Message 24 by Taz, posted 03-26-2007 2:43 AM NosyNed has not yet responded

  
Taz
Member (Idle past 672 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 24 of 33 (391570)
03-26-2007 2:43 AM
Reply to: Message 23 by NosyNed
03-26-2007 12:37 AM


Re: Surprising Jeans Length
NosyNed writes:

We are discussing intersteller gas clouds and the crucial "length" with resonable parameters comes out to a jillion times less than a billionth of a meter?? This doesn't seem to make sense.


My mistake. I blindly trusted that wiki article, which is wrong. If you know how to edit that wiki, you should do it. m refers to the mass of the particle, not the mass of the whole thing. So, the equation cannot be combined like that.

So, λ = 8.7*1014 m, which is I guess what he has been talking about. My mistake.

Edited by Tazmanian Devil, : No reason given.


This message is a reply to:
 Message 23 by NosyNed, posted 03-26-2007 12:37 AM NosyNed has not yet responded

  
Son Goku
Member
Posts: 1060
From: Ireland
Joined: 07-16-2005
Member Rating: 3.0


Message 25 of 33 (391575)
03-26-2007 8:38 AM
Reply to: Message 21 by CTD
03-25-2007 8:53 AM


Re: Nah
Which is why I'll save my energy for something else. There just aren't too many areas where the big official brains so obviously don't know what's going on. I mean no insult by that. It's very much to their credit that they don't make more of an effort to hide it.

I mean just after what little research I've done for my posts on this thread it's my opinion that anyone who just up and says "yes it will" or "no it won't" is probably not taking everything into consideration. At this point I would not be confident betting on either side, myself. Times are changing, and I don't consider you "wrong".


The quote you provided refers to how difficult it is to model the internal fluid dynamics of interstellar clouds, which does not cast any doubt on their ability to form Stars. Stellar formation is a much more generic feature.
This message is a reply to:
 Message 21 by CTD, posted 03-25-2007 8:53 AM CTD has not yet responded

  
Prototype
Junior Member (Idle past 1670 days)
Posts: 1
Joined: 06-30-2012


Message 26 of 33 (666841)
06-30-2012 9:31 AM


I come in a little late on this, but there is an important point that got missed in the discussion so far that must be mentioned.

Taz estimated the force on a hydrogen atom on the OUTER RIM of a gas cloud. In other words, he starts off with an extremely inhomogeneous gas distribution in space, where in one region of space is concentrated (astronomically speaking) all the matter, which is surrounded by vast regions of perfect vacuum.

The original question however was: How can we get from a uniform gas distribution to such an extremely clumpy system in the first place? This puzzling question has not be addressed here yet, at all.


Replies to this message:
 Message 27 by Dr Adequate, posted 06-30-2012 10:07 AM Prototype has not yet responded
 Message 28 by Alfred Maddenstein, posted 07-11-2012 5:25 PM Prototype has not yet responded

    
Dr Adequate
Member
Posts: 15753
Joined: 07-20-2006
Member Rating: 3.1


Message 27 of 33 (666845)
06-30-2012 10:07 AM
Reply to: Message 26 by Prototype
06-30-2012 9:31 AM


The original question however was: How can we get from a uniform gas distribution to such an extremely clumpy system in the first place? This puzzling question has not be addressed here yet, at all.

I think it has --- see message #3.

I am not a physicist (don't worry, I'm sure several of 'em will turn up any minute now). But I think the point is this: a perfectly uniform distribution of gas would indeed never become "clumpy". But this state is unstable: that is, any small deviation from perfect uniformity will be accentuated rather than reduced over time.

Edited by Dr Adequate, : No reason given.


This message is a reply to:
 Message 26 by Prototype, posted 06-30-2012 9:31 AM Prototype has not yet responded

  
Alfred Maddenstein
Member (Idle past 1348 days)
Posts: 565
Joined: 04-01-2011


Message 28 of 33 (667732)
07-11-2012 5:25 PM
Reply to: Message 26 by Prototype
06-30-2012 9:31 AM


The whole nebular idea even to be considered depends on taking the big bunk creationism for granted. That includes re-ification of the notion the Universe which means treating the Universe as a single, finite object uniformly evolving in linear time. That is, starting from a singularity that is everywhere, going next to the cloud of the simplest elements which in its turn collapses into the first stars and so on.
No reason to take that for granted. That is not possible at all. Cosmologically, time is another measurement of distance. That means distance in every direction as measured from any possible relative location. No common shared past for each and every location and no uniform evolution is implied by that at all.
This message is a reply to:
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 Message 29 by NoNukes, posted 07-11-2012 5:44 PM Alfred Maddenstein has responded

  
NoNukes
Member
Posts: 9431
From: Central NC USA
Joined: 08-13-2010
Member Rating: 2.8


(1)
Message 29 of 33 (667739)
07-11-2012 5:44 PM
Reply to: Message 28 by Alfred Maddenstein
07-11-2012 5:25 PM


Same wrong stuff, different day...
The whole nebular idea even to be considered depends on taking the big bunk creationism for granted.

No, the nebular idea does not depend on any particular theory for the universe. Regardless of whether you believe the universal is eternal, the sun and earth quite obviously are not. An endless, eternal universe might still include the birth and death of stars and galaxies.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison


This message is a reply to:
 Message 28 by Alfred Maddenstein, posted 07-11-2012 5:25 PM Alfred Maddenstein has responded

Replies to this message:
 Message 30 by Alfred Maddenstein, posted 07-11-2012 6:13 PM NoNukes has acknowledged this reply

    
Alfred Maddenstein
Member (Idle past 1348 days)
Posts: 565
Joined: 04-01-2011


Message 30 of 33 (667746)
07-11-2012 6:13 PM
Reply to: Message 29 by NoNukes
07-11-2012 5:44 PM


Re: Same wrong stuff, different day...
The stars and planets indeed may be recycled in any case so you are right to an extent. Though the actual process may never have started and its mechanism might have nothing to do with gravitational collapse.
Not so long ago, I have stumbled on an alternative hypothesis of planet formation that really impressed me. The hypothesis is very rough and might be off in many details but its general direction of thought is very interesting. It proposes that stars and planets are the same thing at different stages. That is, that planets are nothing but cooled stars. That would mean that giants like Jupiter are on their way of becoming earth-like and so on. Jeffrey Wolynski is the guy who came up with the conjecture.
This message is a reply to:
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Replies to this message:
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