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Boyle's Gas Law, What is it?


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#41 Adam Nagy

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Posted 06 July 2009 - 09:05 PM

A.Sphere can you answer the question that I posed to Percy? How do astronomers tell the difference between a 'fresh' star forming nebulae and a nebulae that is a nova remnant?

#42 A.Sphere

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Posted 06 July 2009 - 09:27 PM

The last time I checked the whole reason convection currents occur is because a heat imbalance is seeking neutral by rising away from the gravitational center since the heated gas is less dense than the cooler gas, it rises away from the heat source, in our case the center of activity, the gravitational well. In your example this necessarily indicates that what is at the center of your heated gas cloud will follow a convection path away from the center before it can collapse. What is going to get those molecules to collapse into an even tighter configuration when any increased heat will excite the molecules in a way that promotes faster convection and greater convection cycles away from this proposed gravitational well that still has no solid core because of what our gas is doing thermally as it is compressed.

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This is a seperate issue. First you must concede that the gas law is not violated because T is decreasing.

But to be brief - the convection cells will rise to the boundary and release heat and then flow back down to the core - since the system is not closed we will not see a compression and expansion perpetually because the heat is radiated into space not a closed system. This is not overlooked at all and you can find extensive literature on convection during star formation.

#43 Adam Nagy

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Posted 06 July 2009 - 09:34 PM

This is a seperate issue.  First you must concede that the gas law is not violated because T is decreasing.

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It's not a separate issue. The whole point of what I proposed is to demonstrate the importance of why "T" is decreasing and where this decreasing "T" occurs, away from the hypothetical gravitational core.

#44 A.Sphere

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Posted 06 July 2009 - 09:41 PM

A.Sphere can you answer the question that I posed to Percy? How do astronomers tell the difference between a 'fresh' star forming nebulae and a nebulae that is a nova remnant?

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The ISM is constantly replenished by nebulae from dying stars. Are you asking how can an astronomer determine whether or not a baby star is really just a dying star in its own nebula? If its a white dwarf, neutron star, or black hole inside a gaseaous nebula it is a system at the end of stellar evolution. These remnants give off different signatures. Study up on HR diagrams for detailed info.

#45 Percy

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Posted 07 July 2009 - 04:29 AM

Hi Adam,

I see A. Sphere has joined the discussion, and I'll try to join in later. I'm off this week, but I've got some chores and errands I'm going to take care of now. But before I do that I want to clear up a misunderstanding.

This isn't true. They do mention it, just not by name. They mention the principle thereof:

http://www.answersin...ern-astronomy-1

However, when gas is compressed, it heats up. This higher temperature creates extra pressure which resists further compression. The collapse would have a tendency to stop before the star ever formed.

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Yes, of course what they describe is consistent with Boyle's law. My point was that they disagree with you that Boyle's law prevents the formation of stars. Their description when they say "gas is compressed" is where you and AiG part company, because you believe that Boyle's law states that a gas's resistance to being compressed cannot be overcome by gravity.

Your position that Boyle's law holds that gases will disperse even in the presence of gravity is incorrect, as is self evident just from the fact that planetary bodies with sufficient mass are able to retain atmospheres through their gravity. And the gas in interstellar nebula are just as subject to gravity as all gases everywhere, including the gravity they themselves produce.

Boyle's law describes the relationship between gas pressure and volume in a closed system but this demonstration shows an unusual characteristic of gas. It resists being compressed.

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I wouldn't characterize gases resisting compression as "an unusual characteristic" (even kids know this just from puffing out their cheeks), but the rest of this is correct for this level of detail.

Boyle's gas law is a factor in all of this and anyone who says it isn't is trying to exclude it for mere convenience and to support untestable assumptions.

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Neither you nor I are claiming that Boyle's law isn't followed in the process of star formation. You believe Boyle's law prevents star formation, apparently because you think a gas's resistance to compression is too strong for gravity to overcome. Others are explaining to you why this is incorrect.

--Percy

#46 Adam Nagy

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Posted 07 July 2009 - 05:09 AM

Yes, of course what they describe is consistent with Boyle's law.  My point was that they disagree with you that Boyle's law prevents the formation of stars.  Their description when they say "gas is compressed" is where you and AiG part company, because you believe that Boyle's law states that a gas's resistance to being compressed cannot be overcome by gravity.

Your position that Boyle's law holds that gases will disperse even in the presence of gravity is incorrect, as is self evident just from the fact that planetary bodies with sufficient mass are able to retain atmospheres through their gravity.  And the gas in interstellar nebula are just as subject to gravity as all gases everywhere, including the gravity they themselves produce.

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There are a couple of things here. First, I don't believe that there is no such thing as gravity in a gas only environment. I'm saying that gravity and gas have an observable pattern of interaction which A.Sphere actually lent to the thought experiment for why I consider the idea of natural star formation, at the very least, extremely problematic with current understanding.

Neither you nor I are claiming that Boyle's law isn't followed in the process of star formation.  You believe Boyle's law prevents star formation, apparently because you think a gas's resistance to compression is too strong for gravity to overcome.  Others are explaining to you why this is incorrect.

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Their explanations are not based on repeatable science. It is based on some assumptions. The explanations are based on the assertion that; "Stars must form naturally because only our naturalistic ideas are allowed any consideration. Even if our current ideas are total bunk, there must be some similar cause for what we see." It's the same origins mindset that drives the fanciful stories associated with biological evolution.

I've heard it so many times; "Even if evolution is proven false, it must still be something like evolution that explains all the animals." This isn't science. It's speculation based on an artificially limited perspective.

#47 Adam Nagy

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Posted 07 July 2009 - 05:10 AM

The ISM is constantly replenished by nebulae from dying stars.  Are you asking how can an astronomer determine whether or not a baby star is really just a dying star in its own nebula?  If its a white dwarf, neutron star, or black hole inside a gaseaous nebula it is a system at the end of stellar evolution.  These remnants give off different signatures.  Study up on HR diagrams for detailed info.

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So you admit that all nebulae that we are looking at today are nova remnants?

#48 Adam Nagy

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Posted 07 July 2009 - 05:34 AM

Dear Percy,

Please address this post for the forum:

http://www.evolution...indpost&p=34583

#49 jason78

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Posted 07 July 2009 - 08:23 AM

There are a couple of things here. First, I don't believe that there is no such thing as gravity in a gas only environment.

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The sun is a gas only environment consisting mostly of hydrogen (73.46%) and helium (24.85%). Where does it's gravity come from?

#50 Adam Nagy

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Posted 07 July 2009 - 08:46 AM

The sun is a gas only environment consisting mostly of hydrogen (73.46%) and helium (24.85%).  Where does it's gravity come from?

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Putting the cart before the horse again Jason? Yes the star is there and it is a nuclear furnace made up of liquid hydrogen. We aren't arguing whether stars exist or whether their gravitational fields exist. We are arguing over whether we have a sufficient scientific explanation for how stars form in the first place?

#51 A.Sphere

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Posted 07 July 2009 - 09:10 AM

Putting the cart before the horse again Jason? Yes the star is there and it is a nuclear furnace made up of liquid hydrogen. We aren't arguing whether stars exist or whether their gravitational fields exist. We are arguing over whether we have a sufficient scientific explanation for how stars form in the first place?

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Yes but why isn't the Sun in hydrostatic equilibrium due to ideal gas pressure alone? Why is the thermal pressure caused by gas pressure and radiation pressure? Obviously the Sun exists in a state where gravitational pressure has collapsed the Sun far enough that thermal pressure is holding off gravitational pressure. Are you saying that God created all stars just as they are with thermal pressure and gravitational pressure in equilibrium? Are you saying the Sun is maintained by magic?

If your disagreement with star formation had to do with convection currents creating outward pressure - why didn't you say so in the beginning? Why didn't you tell us that what really upsets you about star formation is based on your recollection of advance fluid dynamics? In brief - you are forgetting that cooling happens via convection, conduction, and radiation. These processes do not work independently but with each other. Also, once the convection cells reach the boundary layer they release heat and flow back to the core because of gravity where they heat up once more. Convection is not a problem for Star formation and there is info available in the literature on this very subject.

Edit: Once last thing - once the gas blob is dense enough convection can only occur within a certain region.

#52 Adam Nagy

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Posted 07 July 2009 - 09:23 AM

Yes but why isn't the Sun in hydrostatic equilibrium due to gas pressure?  Are you saying the Sun is maintained by magic?

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As a created item, the Sun is in a gravitational well based on its own mass working perfectly well within known physical/chemical/nuclear laws.

You see you're trying to explain away the origin of the sun with naturalistic assumptions but in turn your are also ignoring known physical laws to pretend you can explain where the sun came from by understanding how it works.

#53 A.Sphere

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Posted 07 July 2009 - 09:28 AM

As a created item the Sun is in a gravitational well based on its own mass working perfectly well withing known physical laws.

You see you're trying to explain away the origin of the sun with naturalistic assumptions but in turn your are also ignoring known physical laws to pretend you can explain where the sun came from by understanding how it works.

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I was elaborating while you were responding - so my post above is different from this quote - just to let you know.

Anyway, but those known physical laws involve a system in which the inward gravitational pressure is balanced by outward thermal pressure. It is a state that is already in an extreme tug of war between thermal pressure and gravitational pressure.

#54 Adam Nagy

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Posted 07 July 2009 - 09:35 AM

I was elaborating while you were responding - so my post above is different from this quote - just to let you know.

Anyway, but those known physical laws involve a system in which the inward gravitational pressure is balanced by outward thermal pressure.  It is a state that is already in an extreme tug of war between thermal pressure and gravitational pressure.

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I agree but the weak force... gravity... is in this case a substantial force because of it's already present super massive state.

It's kind of like this. Forces must receive different levels of consideration in say the design of a bridge depending on many factors.

How come wind is not a substantial factor in the design of this bridge?...

Posted Image

...but it was a major factor in this bridge? (well, it should have been :lol: )...

j-zczJXSxnw

You're basically trying to convince us that the stone bridge is doomed to collapsing with a gust of wind by convincing us that the evidence of the Tacoma Narrows Bridge will apply in the same way eventually to the small stone bridge.

#55 A.Sphere

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Posted 07 July 2009 - 09:47 AM

I agree but the weak force... gravity... is in this case a substantial force because of it's already present super massive state.

It's kind of like this. Forces must receive different levels of consideration in say the design of a bridge depending on many factors.

How come wind is not a substantial factor in the design of this bridge?...

Posted Image

...but it was a major factor in this bridge? (well, it should have been :lol: )...

j-zczJXSxnw

You're basically trying to convince us that the stone bridge is doomed to collapsing with a gust of wind by convincing us that the evidence of the Tacoma Narrows Bridge will apply in the same way eventually to the small stone bridge.

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But the blob of gas is also super massive and it is cooling which means its contracting so our super mass is being squeezed into a tighter ball by gravity...

Gravity is weak unless mass is large. In the cases we are talking about the mass is very large.

#56 Adam Nagy

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Posted 07 July 2009 - 10:16 AM

But the blob of gas is also super massive and it is cooling which means its contracting so our super mass is being squeezed into a tighter ball by gravity...

Gravity is weak unless mass is large.  In the cases we are talking about the mass is very large.

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Again, you are assuming a dense object (which a gas cloud is not) before it exists based on forces that you can't demonstrate.

It's just like assuming the effects of wind on the small stone bridge based on the observation of the Tacoma Narrows bridge.

A.Sphere can you answer this post when you get a chance?

http://www.evolution...indpost&p=34615

#57 Adam Nagy

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Posted 07 July 2009 - 11:37 AM

I think what is interesting about this conversation is how linear and simplistic the defense of how gas clouds could collapse is presented. Watch this video of the unusual dynamics of water in zero gravity:

ZyTwLAW-Z8c

#58 b00tleg

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Posted 07 July 2009 - 11:37 AM

deleted

#59 Adam Nagy

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Posted 07 July 2009 - 11:39 AM

b00tleg,

How do you identify these Giant molecular clouds as other than nova remnants?

Edit: Never mind then. :lol:

#60 b00tleg

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Posted 07 July 2009 - 11:52 AM

Again, you are assuming a dense object (which a gas cloud is not) before it exists based on forces that you can't demonstrate.

It's just like assuming the effects of wind on the small stone bridge based on the observation of the Tacoma Narrows bridge.

A.Sphere can you answer this post when you get a chance?

http://www.evolution...indpost&p=34615

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http://en.wikipedia....iki/Gas#Density
Because the molecules are free to move about in a gas, the mass of the gas is normally characterized by its density. Density is the mass per volume of a substance or simply, the inverse of specific volume. For gases, the density can vary over a wide range because the molecules are free to move. Macroscopically, density is a state variable of a gas and the change in density during any process is governed by the laws of thermodynamics. Given that there are many particles in completely random motion, for a static gas, the density is the same throughout the entire container. Density is therefore a scalar quantity; it is a simple physical quantity that has a magnitude but no direction associated with it. It can be shown by kinetic theory that the density is proportional to the size of the container in which a fixed mass of gas is confined.

http://en.wikipedia....molecular_cloud
Vast assemblages of molecular gas with masses of 104–106 times the mass of the sun are called Giant molecular clouds (GMC). The clouds can reach tens of parsecs in diameter and have an average density of 10²–10³ particles per cubic centimetre (the average density in the solar vicinity is one particle per cubic centimetre). Substructure within these clouds is a complex pattern of filaments, sheets, bubbles, and irregular clumps.[4]

The densest parts of the filaments and clumps are called "molecular cores", whilst the densest molecular cores are, unsurprisingly, called "dense molecular cores" and have densities in excess of 104–106 particles per cubic centimeter. Observationally molecular cores are traced with carbon monoxide and dense cores are traced with ammonia. The concentration of dust within molecular cores is normally sufficient to block light from background stars such that they appear in silhouette as dark nebulae.[6]

GMCs are so large that "local" ones can cover a significant fraction of a constellation such that they are often referred to by the name of that constellation, e.g. the Orion Molecular Cloud (OMC) or the Taurus Molecular Cloud (TMC). These local GMCs are arrayed in a ring around the sun called the Gould Belt.[7] The most massive collection of molecular clouds in the galaxy, the Sagittarius B2 complex, forms a ring around the galactic centre at a radius of 120 parsec. The Sagittarius region is chemically rich and is often used as an exemplar by astronomers searching for new molecules in interstellar space.[8]

Do you still purport that gas can't form dense objects, ir is this information biased naturalistic assumptions?




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