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Thread: Missing Baryons Found?

  1. #1 Missing Baryons Found? 
    Forum Masters Degree MrMojo1's Avatar
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    Could this discovery account for what is labeled dark matter? If so, does this begin to explain dark energy?

    If the size and mass of this gas halo is confirmed, it also could be an explanation for what is known as the "missing baryon" problem for the galaxy....Measurements of extremely distant gas halos and galaxies indicate the baryonic matter present when the universe was only a few billion years old represented about one-sixth the mass and density of the existing unobservable, or dark, matter. In the current epoch, about 10 billion years later, a census of the baryons present in stars and gas in our galaxy and nearby galaxies shows at least half the baryons are unaccounted for.

    NASA - NASA's Chandra Shows Milky Way is Surrounded by Halo of Hot Gas

    NASA - Exploring the Invisible Universe: Chandra X-ray Observatory


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    I don't think so; it doesn't seem to be enough by itself. It might reduce the amount of dark matter required slightly - but most of this halo is well outside the galaxy and so won't affect rotational velocities.

    Astronomers Discover Milky Way’s Hot Halo
    Quote Originally Posted by Universe Today
    Unrelated to dark matter or dark energy, the missing baryons issue was discovered when astronomers estimated the number of atoms and ions that would have been present in the Universe 10 billion years ago. But current measurements yield only about half as many as were present 10 billion years ago, meaning somehow nearly half the baryonic matter in the Universe has since disappeared.


    ei incumbit probatio qui dicit, non qui negat
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    it is missing as we didn't know where it was. the BBT predicts the amount of matter that the universe contains, flat, open or closed, so we knew there was some baryonic matter we hadn't accounted for.
    Sometimes it is better not knowing than having an answer that may be wrong.
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    Part of the confusion might be that theory indicates baryonic matter is around 4-5% of the universe, but visible stars, etc. make up of about 1/10 th of the 4-5%.
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    A Huge Reservoir of Ionized Gas around the Milky Way: Accounting for the Missing Mass? - Abstract - The Astrophysical Journal Letters - IOPscience

    So, if our galaxy, and presumably the others as well, is surrounded by a giant cloud of hot ionized particles (plasma), what is the source of the million K heat, and how is it sustained?

    Hint: There is an analogous process going on in our own solar system.

    Respectfully submitted,
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    Last edited by Dotini; September 25th, 2012 at 02:08 PM.
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  7. #6  
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    Quote Originally Posted by MrMojo1 View Post
    Could this discovery account for what is labeled dark matter? If so, does this begin to explain dark energy?

    If the size and mass of this gas halo is confirmed, it also could be an explanation for what is known as the "missing baryon" problem for the galaxy....Measurements of extremely distant gas halos and galaxies indicate the baryonic matter present when the universe was only a few billion years old represented about one-sixth the mass and density of the existing unobservable, or dark, matter. In the current epoch, about 10 billion years later, a census of the baryons present in stars and gas in our galaxy and nearby galaxies shows at least half the baryons are unaccounted for.
    The article I read said they estimated the amount of new plasma they found to be about as much mass as in the observable galaxy. For dark matter they need maybe 4 or 5 times more matter as observed within the galaxy. It was also discovered in a halo surrounding our galaxy with varying relative motions rather than having the orbital rotation rates needed for dark matter.

    It does, however, help close the gap in predictive theory concerning the amount of baronic matter that accordingly should exist within and surrounding the Milky Way galaxy.
    Last edited by forrest noble; September 26th, 2012 at 01:31 PM.
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    Let us suppose the galaxy is the source of the galactic plasma cloud - in a way analogous to the Sun accelerating electrons in the solar wind, with the ions and neutrals following along. Recent discoveries in heliophysics point to "shocks and instabilities" in plasma that are are able to generate the fabulous heat of the solar corona - precisely the heat observed in the galactic plasma cloud. Coincidence?

    NASA - Heliophysics Nugget: Riding the Plasma Wave
    So, this suggests that shocks and the instabilities they create may play a larger role in transferring the energy from the plasma's bulk movement into heat, than previously thought. Wilson believes that the instabilities caused something called perpendicular ion heating – a process that increases the random kinetic energy of the positively-charged ions in a direction perpendicular to the background magnetic field. The waves also added energy to the negatively-charged electrons -- with the greatest effects observed not being heating, the random kinetic energy, but bulk acceleration in a direction parallel to the magnetic field.

    "The same type of wave-particle interaction is thought to happen in solar flares, the heating of the sun's corona, and supernova blast waves," says Wilson. "All of these energizations have very similar properties. Now we have evidence that these Whistler-like fluctuations may be causing heating in all these places."


    Respectfully submitted,
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    Dotini,

    Let us suppose the galaxy is the source of the galactic plasma cloud - in a way analogous to the Sun accelerating electrons in the solar wind, with the ions and neutrals following along. Recent discoveries in heliophysics point to "shocks and instabilities" in plasma that are are able to generate the fabulous heat of the solar corona - precisely the heat observed in the galactic plasma cloud. Coincidence?
    The expulsion of plasma from stars seems like a pretty good bet concerning plasma far outside the galactic plane. Another speculative but possible source might be the central galactic black hole and the related torus. Just like the two gamma ray bubbles in the Milky Way that appear to have been generated from the central black hole and surroundings.

    .....Wilson believes that the instabilities caused something called perpendicular ion heating – a process that increases the random kinetic energy of the positively-charged ions in a direction perpendicular to the background magnetic field. The waves also added energy to the negatively-charged electrons -- with the greatest effects observed not being heating, the random kinetic energy, but bulk acceleration in a direction parallel to the magnetic field.

    "The same type of wave-particle interaction is thought to happen in solar flares, the heating of the sun's corona, and supernova blast waves," says Wilson. "All of these energizations have very similar properties. Now we have evidence that these Whistler-like fluctuations may be causing heating in all these places."
    ....with the greatest effects observed not being heating, the random kinetic energy, but bulk acceleration in a direction parallel to the magnetic field.
    Thanks for the interesting link. Such a magnetically induced process for galaxies has long been predicted by Plasma Cosmology (PC) which has proposed that galactic magnetic fields play a much bigger role in galaxy formation, internal and external mechanics, including some PC models proposing influences on galaxy rotation curves induced by such a process. In time it would seem that much of this external matter would eventually get drawn into the galactic plane while giving off energy, and upon cooling off via radiation and conduction, could reform new stars.

    I also read that the density of this plasma is so low that the same plasma spheroidal halo could not be observed (if it existed) even for the closest galaxies such as Andromeda.
    Last edited by forrest noble; September 26th, 2012 at 02:27 PM.
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