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Infall towards protostars

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  • oxmixmudd
    replied
    Originally posted by Jorge View Post
    Ah ... one of the most active individuals guilty of continuously misrepresenting my position makes a cameo appearance. Tell me, Jim, do you know the difference between actually "observing" something and "extrapolating an observation"?
    Prove I have ever 'misrepresented' your position. Case in point. You say below you don't think stars can form naturally. I think that is stupid. We can observed it happening. We can't observe a redwood grow from seeding to 300ft tall giant either, but no one in his right mind doubts they did, or that they do.

    Let me tell you why no one has ever OBSERVED a star collapsing: because it takes to darn long, that's why! Using the very models that you place your faith in, the process would take many, many thousands of years - far longer than what we humans have ever observed.
    To bad you can't read. I said that in my post. The point is, we CAN observe in the local cosmos all the extant phases of star formation, from collapsing cloud to mature star. It doesn't take a genius to figure out the rest.


    Do you even listen to yourself? "On the verge of fusion" ... and you know that, HOW??? Once again, you are merely e-x-t-r-a-p-o-l-a-t-i-n-g what you observe via a model and worldview that you have assumed.
    By observing the spectra and other characteristics of the protostar. Fusion ignition occurs at certain temperatures and pressures. If we observe a hot ball of gas where those temperatures and pressures don't yet exist in its core, then we can know it's not there yet - up to a point of course. The problem for you is that you set absurd standards of proof and then hide behind them because your world view collapses if the universe is really billions of years old.


    DITTO



    You are mixing the issues involving planets with that of stars.
    These aren't the same issues nor do I regard them as such.
    Planets form out of the same gas clouds that stars form from. It's all a singular process Jorge. We observe that process at all possible stages across the sky. In fact, we can see most stages in a single place - the Orion Nebula, 1500 light years hence.


    "Filling in the gaps ..." -- boy, is that EVER a loaded phrase!!!



    The loaded phrase "fill in the gaps" is used here again plus you're performing unrestrained extrapolation based on a model, a worldview and lots of assumptions. To top it off, you say that "... the physics and chemistry that govern the processes is sufficiently understood" I nearly fell off my chair after that one. Let me school you - other than conjecture, no one has a C-L-U-E as to how stars may form naturally. In addition, much of the solid physics that we DO know argues against it ever happening.

    "But it must happen since the stars are there and they must have formed naturally."

    You just can't stop yourself from being an ally to Materialists, can you, Jim?

    Jorge
    Silly Jorge. I guess you don't believe the big tall redwoods grew up on their own either. God had to make the really tall ones, but the little ones we see growing today, they came from the seeds because we can observe that process from its beginning to its present state. But we would be foolish to assume that just because we can extrapolate that if they continue growing one of these little guys can grow into one of the big fellas they actually did. Right?




    Jim
    Last edited by oxmixmudd; 02-20-2014, 10:42 AM.

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  • Jorge
    replied
    Originally posted by oxmixmudd View Post
    Observing large gas clouds in the process of collapse is not a 'just so story'
    Ah ... one of the most active individuals guilty of continuously misrepresenting my position makes a cameo appearance. Tell me, Jim, do you know the difference between actually "observing" something and "extrapolating an observation"?

    Let me tell you why no one has ever OBSERVED a star collapsing: because it takes to darn long, that's why! Using the very models that you place your faith in, the process would take many, many thousands of years - far longer than what we humans have ever observed.

    Observing very hot balls of gas in the center of large gas clouds on the verge of fusion ignition is not a 'just so story'
    Do you even listen to yourself? "On the verge of fusion" ... and you know that, HOW??? Once again, you are merely e-x-t-r-a-p-o-l-a-t-i-n-g what you observe via a model and worldview that you have assumed.


    Observing stars which match the theoretical characteristics of what would be a recently formed star surrounded by dense circumstellar dust disks is not a 'just so story'
    DITTO

    Observing stars surrounded by circumstellar rings of similar dust where the inner sections has been cleaned and where planets can be observed is not a 'just so story'.
    You are mixing the issues involving planets with that of stars.
    These aren't the same issues nor do I regard them as such.

    Filling in the gaps between these observations with the rather obvious consequences of continued progression of the same processes we observe in action is not a 'just so story'.
    "Filling in the gaps ..." -- boy, is that EVER a loaded phrase!!!

    We observe across the galaxy and across the universe all possible phases of what theory would tell us is the process of natural star formation. We simply don't have enough observation time to have observed the process on a single object from start to finish. There is little difference between this and composing the life cycle of a redwood tree by observing the various phases of its growth in a forest. We don't have enough direct observing time to observe a single instance from seedling to full height there either. But the physics and chemistry that govern the processes is sufficiently understood to fill in the gaps in observation.

    Jim
    The loaded phrase "fill in the gaps" is used here again plus you're performing unrestrained extrapolation based on a model, a worldview and lots of assumptions. To top it off, you say that "... the physics and chemistry that govern the processes is sufficiently understood" I nearly fell off my chair after that one. Let me school you - other than conjecture, no one has a C-L-U-E as to how stars may form naturally. In addition, much of the solid physics that we DO know argues against it ever happening.

    "But it must happen since the stars are there and they must have formed naturally."

    You just can't stop yourself from being an ally to Materialists, can you, Jim?

    Jorge
    Last edited by Jorge; 02-20-2014, 09:08 AM.

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  • oxmixmudd
    replied
    Originally posted by Jorge View Post
    Wonder who that may be?

    I personally have never been "afraid" of the possibility that stars may form naturally or that extrasolar planets may exist. Almost invariably here on TWeb, my position on those matters was misrepresented time and time again. For the record my position is this: I do NOT believe that the first stars could have formed naturally - no way at all. I do NOT believe that subsequent stars form naturally but I do not rule out the possibility. If (IF!) it is possible, I have not yet encountered any mechanism that stands up to scrutiny - it's all handwaving and just-so stories (coincidentally, just like Evolution). Of course, to Materialists and their ideological allies, natural star formation is an ideological prerequisite. Regarding extrasolar planets, pretty much the same thing. 'Nuff said.

    Jorge
    Observing large gas clouds in the process of collapse is not a 'just so story'

    Observing very hot balls of gas in the center of large gas clouds on the verge of fusion ignition is not a 'just so story'

    Observing stars which match the theoretical characteristics of what would be a recently formed star surrounded by dense circumstellar dust disks is not a 'just so story'

    Observing stars surrounded by circumstellar rings of similar dust where the inner sections has been cleaned and where planets can be observed is not a 'just so story'.

    Filling in the gaps between these observations with the rather obvious consequences of continued progression of the same processes we observe in action is not a 'just so story'.

    We observe across the galaxy and across the universe all possible phases of what theory would tell us is the process of natural star formation. We simply don't have enough observation time to have observed the process on a single object from start to finish. There is little difference between this and composing the life cycle of a redwood tree by observing the various phases of its growth in a forest. We don't have enough direct observing time to observe a single instance from seedling to full height there either. But the physics and chemistry that govern the processes is sufficiently understood to fill in the gaps in observation.


    Jim
    Last edited by oxmixmudd; 02-20-2014, 07:52 AM.

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  • Jorge
    replied
    Originally posted by rwatts View Post
    Warning

    For those who are as afraid of stars being able to form naturally as they are afraid of extra solar planets, best not to open this at all.
    Wonder who that may be?

    I personally have never been "afraid" of the possibility that stars may form naturally or that extrasolar planets may exist. Almost invariably here on TWeb, my position on those matters was misrepresented time and time again. For the record my position is this: I do NOT believe that the first stars could have formed naturally - no way at all. I do NOT believe that subsequent stars form naturally but I do not rule out the possibility. If (IF!) it is possible, I have not yet encountered any mechanism that stands up to scrutiny - it's all handwaving and just-so stories (coincidentally, just like Evolution). Of course, to Materialists and their ideological allies, natural star formation is an ideological prerequisite. Regarding extrasolar planets, pretty much the same thing. 'Nuff said.

    Jorge

    Leave a comment:


  • Outis
    replied
    Originally posted by rwatts View Post
    Or "How natural processes make stars from stuff (which is not the same as stars coming from nothing)"
    Interesting. Yes, quite a slog, but observations on the process (especially the bit about inflow exceeding outflow by a magnitude of three) makes a considerable amount of sense.

    Leave a comment:


  • rwatts
    started a topic Infall towards protostars

    Infall towards protostars

    Or "How natural processes make stars from stuff (which is not the same as stars coming from nothing)"




    Gidday folk,


    It’s been an ongoing problem scientists have been wanting to solve. Just as natural processes make clouds, snow, and rain, so how do similar kinds of processes make stars?

    In a broad scope, a theory has been around for over a hundred years, namely that stars are born via a process of gravitational collapse. And for a long time there has been some evidence to support the idea.

    Over the past decades, thanks to ever sophisticated instrumentation and data processing abilities, scientists have been able to address questions regarding the nitty-gritty of the process. However, one observation has always been somewhat elusive, namely the infall of material from the surrounding gas and dust cloud, toward the protostar itself.

    For a while now, and somewhat to everyone's surprise, paradoxical outflows from collapsing stars have been observed. Inflows have been another matter altogether. There has been evidence of these processes but it has never been conclusive.

    Now, thanks to even better technology, particularly satellite instrumentation, the situation is beginning to change.

    The following paper reports on some key observations regarding this:-

    Waterfalls around protostars: Infall motions towards Class 0/I envelopes as probed by water

    The paper is technical and hence a slog, but enough of it is understandable by a layperson such as myself to get something from it. For those of you who have a better understanding of physics, particularly of the physics as it relates to this kind of study, well hopefully you will get even more from it.

    Some points are:-

    1) To go from the interstellar medium to a gas cloud, the density must increase from around 0.001 ions (atoms) per cc to around 10,000 ions per cc. To go from the gas cloud to a very dense clumps within a cloud, the density must increase form around 10,000 ions per cc to 1,000,000 ions per cc. But to get from the dense clump to the star, the density has to go from 1,000,000 ions per cc to 1,000,000,000,000,000,000 ions per cc. Ouch!!!


    2) The formation of the protostar by gravitational collapse is what is thought to bring about this massive increase in density.


    3)A gas cloud is rotating and as matter moves in towards the central dense globule (the future star), it picks up rotational velocity and eventually enough of this gas forms a flattened disk which orbits the star. It is thought that gas then falls from this disk into the future star. This disk may be stable or it may be unstable.


    4) So, in general, there are three major components - a large external enveloping cloud from which matter falls onto a flat accretion disk which orbits a central dense globule which later becomes the star. Matter falls from this accretion disk onto the globule and when the globules density is high enough, it becomes hot enough to be a star.


    5) Another component, already mentioned, is an outflow - a strong beam of material escaping as a jet from each pole of the cocooned protostar.


    6) Various molecules are used to follow the motions of gas within the cocoon that encloses the protostar. With respect to infall, the molecules are CS, HCO+, N2H+ etc.


    7) Infall gives a specific kind of signature called an “asymmetric line profile” which has a bit more blue than red shifted light in the profile. The signature can be modified by foreground gas clouds and by outflow from the protostar itself.


    8) However, infall has, unlike outflow, been hard to verify. (I suspect because infall occurs inside the cocoon, while outflow actually breaks out of and moves well beyond the protostar cocoon).


    9) The authors of this study decided that H2O (water) would make a better tracer.


    10) Because of the particular water spectral line being examined, they had to use satellite observations, owing to the fact that the earth’s atmosphere absorbed that particular wavelength, making earth bound observations impractical.


    11) The observations covered a region from 1,000 AU out to 11,000 AU from the central protostar. (1AU = 93,000,000 miles).


    12) Data from a model of protostar formation was matched against observations. The best fit model was for infall over the whole of the gas shell surrounding the protostar and its accretion disk.


    13) They discuss the case of IRAS4A using it as their representative model.


    14) Infall exceeded outflow by one to three orders of magnitude.


    15) Infall seemed to be slowing at the accretion disk, suggesting that the accretion disk was increasing in mass and would therefore become unstable.


    Anyway, the paper might make something of an interesting read for those with appropriate knowledge. Otherwise it can be an informative paper just to scan over, while paying attention to the introductory sections and the conclusion.


    Warning

    For those who are as afraid of stars being able to form naturally as they are afraid of extra solar planets, best not to open this at all.
    Last edited by rwatts; 02-17-2014, 02:05 PM.

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