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Old 09-25-2012, 06:04 AM
Location: Wasilla, Alaska
17,825 posts, read 20,496,555 times
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Astronomers Discover Milky Way's Hot Halo

Our galaxy — and the nearby Large and Small Magellanic Clouds as well — appears to be surrounded by an enormous halo of hot gas, several hundred times hotter than the surface of the Sun and with an equivalent mass of up to 60 billion Suns, suggesting that other galaxies may be similarly encompassed and providing a clue to the mystery of the galaxy’s missing baryons.


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.

Source: Astronomers Discover Milky Way’s Hot Halo
I just recently read the above article, but apparently this discovery was made more generally in 2005. The baryonic matter they are finding around the Milky Way appears to have been an accidental discovery.

The discovery of the missing baryonic matter should not be confused with Dark Matter. The universe consists of 70% Dark Energy, 25% Dark Matter, and 5% baryonic matter. Yet the stars, galaxies, and everything we see only accounts for 50% of that baryonic matter. The other 50% of missing baryonic matter has not been discovered until recently.

Around the Milky Way there appears to be a very large halo of hot (1.0-1.5 million degrees Kelvin) oxygen gas with a mass of approximately 60 billion solar masses. The Milky Way, by comparison, has approximately 1,250 billion solar masses. So while they may have found a piece of the puzzle, they still have to account for 1,190 billion solar masses of missing baryonic matter.

Astronomers find missing baryons - physicsworld.com
The Missing Baryons in the Milky Way and Local Group
Missing Baryons and the Warm-Hot Intergalactic Medium

Last edited by Glitch; 09-25-2012 at 06:15 AM..
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