Chunk of Universe's Missing Matter Found

[pmbryant]

From Scientific American:

Chunk of Universe's Missing Matter Found

In recent years, astronomers have found themselves faced with a nagging inventory problem. Received wisdom holds that dark matter and dark energy make up 95 percent of the universe, and ordinary matter, or baryons--the subatomic particles the forms planets, stars and the like--account for the remainder. The problem is, the luminous matter detected with the aid of optical telescopes has amounted to a mere 10 percent of the expected ordinary matter, and the baryons inferred by other means bring that total to only 50 percent.

New findings are helping to bridge this gap between prediction and observation. In a paper published today in the journal Nature, scientists report having identified the probable source of the rest of this missing matter. Data from the Chandra X-ray Observatory, it appears, indicate that the lost baryons may be swimming in diffuse rivers of gas in the intergalactic medium too hot to see with an optical telescope.

Previous work had suggested that baryons might be inhabiting an infernally hot intergalactic gas, but the researchers did not know enough about the density of the baryons to draw firm conclusions about how many might be there. In the new study, Fabrizio Nicastro of the Harvard-Smithsonian Center for Astrophysics and his colleagues obtained high-quality spectra of the gas while it was illuminated by the flaring of the quasarlike galaxy Markarian 421 (see image). Based on those spectra, the team determined that the density of the baryons in the gas was sufficient to account for the missing matter.

But whether the region sampled in this study is representative of the rest of the universe is not known. ...

A little more: http://www.scientificamerican.com/article.cfm?chanID=sa003&articleID=00048DA2-5C8A-1201-947F83414B7F4945

EDIT: Here's an article with some more details: http://researchnews.osu.edu/archive/foundmat.htm

[davidinalameda]

1. my cats took it and it's under my bed

I haven't cleaned for a while

[papau]

2. Cool article - but "inferred" &"may be" and even "probable" with

a "perhaps not representative region of space" makes for a lot of room for future PHD work!

but still neat!

:-)

[pmbryant]

3. So many questions....

Alas, it's hard to solve all the mysteries of the Universe with one paper.

:-)

--Peter

[Beetwasher]

4. So, This Would Mean Dark Matter is Essentially A "Myth"

and that the mass of the universe can be mostly accounted for by regular matter?

[pmbryant]

5. Not at all. This study doesn't say anything about Dark Matter

Excerpts from the more detailed article above: http://researchnews.osu.edu/archive/foundmat.htm

According to current theories, when the universe began, it contained a certain amount of normal matter, a cache of protons and neutrons that today make up all normal atoms -- “stuff” as we know it.

Astronomers can use optical telescopes to look back in time and see what happened to the normal atoms, called baryons. Around 10 billion years ago, when half of the baryons became stars and galaxies and lit up the sky, the other half just seemed to disappear.

This new study shows that the missing baryons are still out there, Mathur said, they’re just floating in gas that is too hot to see with an optical telescope.

...

As to how the missing baryons ended up where they are, Mathur suspects that they were drawn there by the gravity of a different kind of matter, known as dark matter. Astronomers know that some unseen material provides most of the gravity of the universe, though they disagree on what dark matter is actually made of.

If Mathur and her colleagues are right, then their finding supports a dramatic theory: that dark matter provides a kind of backbone to the universe, where the structure of normal matter like galaxies follows an underlying structure of dark matter.

[Beetwasher]

6. Ooops! Nevermind! I Misread It!

That's what you get when you scan an article a bit too quickly!!

[bmbmd]

7. I believe the Heechee

took it into their home black hole.