Hubble Finds Missing Matter

[Martian]

Hubble Survey Finds Missing Matter, Probes Intergalactic Web   click to show 

Although the universe contains billions of galaxies, only a small amount of its matter is locked up in these behemoths. Most of the universe's matter that was created during and just after the Big Bang must be found elsewhere.

Now, in an extensive search of the local universe, astronomers say they have definitively found about half of the missing normal matter, called baryons, in the spaces between the galaxies. This important component of the universe is known as the "intergalactic medium," or IGM, and it extends essentially throughout all of space, from just outside our Milky Way galaxy to the most distant regions of space observed by astronomers.

The questions "where have the local baryons gone, and what are their properties?" are being answered with greater certainty than ever before.

"We think we are seeing the strands of a web-like structure that forms the backbone of the universe," Mike Shull of the University of Colorado explained. "What we are confirming in detail is that intergalactic space, which intuitively might seem to be empty, is in fact the reservoir for most of the normal, baryonic matter in the universe."

Hubble observations made nearly a decade ago by Todd Tripp and colleagues first reported finding the hottest portion of this missing matter in the local universe. That study utilized spectroscopic observations of one quasar to look for absorbing intergalactic gas along the path to the quasar.

In the May 20 issue of The Astrophysical Journal, Charles Danforth and Shull report on observations taken along sight-lines to 28 quasars. Their analysis represents the most detailed observations to date of how the IGM looks within about four billion light-years of Earth.

Baryons are protons, neutrons, and other subatomic particles that make up ordinary matter such as hydrogen, helium, and heavier elements. Baryonic matter forms stars, planets, moons, and even the interstellar gas and dust from which new stars are born.

Astronomers caution that the missing baryonic matter is not to be confused with "dark matter," a mysterious and exotic form of matter that is only detected via its gravitational pull.

Danforth and Shull, of the Department of Astrophysical and Planetary Sciences at the University of Colorado in Boulder, looked for the missing baryonic matter by using the light from distant quasars (the bright cores of galaxies with active black holes) to probe spider-web-like structure that permeates the seemingly invisible space between galaxies, like shining a flashlight through fog.

Using the Space Telescope Imaging Spectrograph (STIS) aboard NASA's Hubble Space Telescope and NASA's Far Ultraviolet Spectroscopic Explorer (FUSE), the astronomers found hot gas, mostly oxygen and hydrogen, which provide a three-dimensional probe of intergalactic space. STIS and FUSE found the spectral "fingerprints" of intervening oxygen and hydrogen superimposed on the quasars' light.

The bright quasar light was measured to penetrate more than 650 filaments of hydrogen in the cosmic web. Eighty-three filaments were found laced with highly ionized oxygen in which five electrons have been stripped away.

The presence of highly ionized oxygen (and other elements) between the galaxies is believed to trace large quantities of invisible, hot, ionized hydrogen in the universe. These vast reservoirs of hydrogen have largely escaped detection because they are too hot to be seen in visible light, yet too cool to be seen in X-rays.

The oxygen "tracer" was probably created when exploding stars in galaxies spewed the oxygen back into intergalactic space where it mixed with the pre-existing hydrogen via a shockwave which heated the oxygen to very high temperatures.

The team also found that about 20 percent of the baryons reside in the voids between the web-like filaments. Within these voids could be faint dwarf galaxies or wisps of matter that could turn into stars and galaxies in billions of years.

Probing this vast cosmic web will be a key goal for the Cosmic Origins Spectrograph (COS), a new science instrument that astronauts plan to install on Hubble during Servicing Mission 4 later this year.

"COS will allow us to make more robust and more detailed core samples of the cosmic web," Shull said. "We predict that COS will find considerably more of the missing baryonic matter."

"Our goal is to confirm the existence of the cosmic web by mapping its structure, measuring the amount of heavy metals found in it, and measuring its temperature. Studying the cosmic web gives us information on how galaxies built up over time."

The COS team hopes to observe 100 additional quasars and build up a survey of more than 10,000 hydrogen filaments in the cosmic web, many laced with heavy elements from early stars.

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Perhaps it's just the cosmology nerd in me, but I think this is very exciting stuff. The matter found was baryonic, but it highlights the cosmic web, which is highly interrelated with dark matter theory. I've always thought dark matter seemed like a bit of a sham, but this actually lends quite a bit of credence to it.

There's still a lot of baryonic matter that's unaccounted for, but I imagine this is going to be a very important discovery in the coming months and years.

(Mods, relocate this as appropriate)

[SSJTWIZTA]

Woah! thats pretty rad. when i first seen the title of this thread the first thing that popped into my mind was that they actually found dark matter, but thats not the case. still, it's very interesting. like you i had my doubts about the whole dark matter thing but this article is nudging me into a different direction.

i cant wait to see where this goes, they better get on those quasars.
its nice to see that those things arent just being used as a standard candles.

[thingstodo]

They found "does it?"

[BadNick]

Another small step...

Unless somethings dramatically more pop out of this discovery, it still leaves a huge deficit of matter (or other "stuff") that can account for our observations, at least based on what we think we know.

I'm basing my comment on this part of the report: "...Baryons are protons, neutrons, and other subatomic particles that make up ordinary matter such as hydrogen, helium, and heavier elements. Baryonic matter forms stars, planets, moons, and even the interstellar gas and dust from which new stars are born.

Astronomers caution that the missing baryonic matter is not to be confused with "dark matter," a mysterious and exotic form of matter that is only detected via its gravitational pull..."

[Hain]

That's pretty cool.

Originally Posted by Martian

Perhaps it's just the cosmology nerd in me, but I think this is very exciting stuff.

Nah this isn't nerdy.

View: Professor makes black hole breakthroughs, ballads
Source: CNN
This post created with FASS

Abstract: "'Attracted by your gravity, your body's so compact / Pulling me inward, prepare for close contact,' Boston University astronomer Alan Marscher sings in his song about a deep-space object known as a black hole."   click to show 

Professor makes black hole breakthroughs, ballads
3 hours, 40 minutes ago
by Elizabeth Landau


(CNN) -- "Attracted by your gravity, your body's so compact / Pulling me inward, prepare for close contact," Boston University astronomer Alan Marscher sings in his song about a deep-space object known as a black hole.
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Alan Marscher, professor at Boston University, sings about black holes and other astronomy concepts.
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Marscher once used other rock groups' songs to illustrate scientific concepts for his students, such the Einsteinian "'39" by Queen.

Then he began writing his own songs tailored to specific lectures like "Superluminal Lover," a black hole ballad full of physics and innuendo. Video Watch him sing "Superluminal Lover" »

The song may not have won him much fame, but an international team of researchers that Marscher leads has just published some breakthrough research on the same black hole phenomena he sings about.

Black holes are somewhat like vacuum cleaners in space. These collapsed stars suck in anything and everything in their immediate vicinities and don't let anything escape, not even light.

The vacuum cleaner idea of a black hole isn't perfect. Astronomers have also detected jet streams of particles traveling at nearly the speed of light, as well as X-rays and gamma rays, shooting out from black holes.

Using radio telescopes set up all over the world, Marscher and colleagues studied a black hole nearly 1 billion light years away (one light year is about 5.9 trillion miles). They found evidence supporting one theory of why the black hole has these jet streams.

As matter falls into a black hole, it swirls around like water going down a drain, Marscher said. The closer things get to the black hole, the faster they begin to orbit.

The magnetic field then twists, like a spring that coils up, he said. This magnetic field propels particles along the black hole's rotational poles.
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Marscher's team found direct evidence to support this explanation, detecting the twisted magnetic field and the polarized light that results from it.

"This paper represents a significant advance in the field," said Marc Lacy, an associate research scientist at Caltech's Spitzer Science Center. "The authors make a convincing case that what they'd see is what you'd expect to see in this model of jet formation."

Lukasz Stawarz, a researcher at the Stanford Linear Accelerator Center, said Marscher's team's observations contribute significantly to our understanding of this type of black hole and provide evidence of a model that had little confirmation before.

"Observations reported by Alan Marscher and collaborators, although not definitive, are very convincing and novel in this respect," he said.

The researchers eagerly await results from NASA's Gamma-ray Large Area Space Telescope, a space observatory that may provide even more insight into black holes' jet streams. The spacecraft will launch no later than June 3, NASA said.

Black holes cannot be seen because they do not emit any light, but astronomers have found substantial evidence of them. Still, no existing telescope is powerful enough to observe exactly what goes on so close to a black hole, Lacy said.

"These are very rare objects, and so it's not until we look a great distance away that we see one whose jet pointing almost right at us," Marscher said. "Then, when we see a jet pointing almost right at us, the jet beams its radiation, like a halogen flashlight."

Although astronomers have detected black holes only in deep space, there is speculation that a black hole could be generated at the Large Hadron Collider, the multibillion-dollar particle accelerator under development at the European Organization for Nuclear Research in Geneva, Switzerland.

The idea that a black hole could emerge in these experiments is far-fetched, Marscher said. But even if the accelerator did create a black hole, it wouldn't necessarily be harmful, he said. See what's planned for the collider »

"If you made a little tiny black hole in a laboratory, it wouldn't have that much gravity. It wouldn't suck in everything that's on the Earth; it would just suck in stuff that's within, say, a few millimeters of it," he said. "It wouldn't be the devastating danger that science-fiction writers would say, because it'd be a real tiny mass."

Still, even a laboratory-made black hole shouldn't be kept around for long. By its nature of sucking things up, it could just grow and grow, accumulating more mass and more power to pull in more things.

"I think I would put it into something that had a lot of mass and then just toss it off into space, so it wouldn't come into contact with very much matter so it wouldn't grow." Marscher said.

From the time he was a pre-teen, he was interested in astronomy. But he didn't think he could do it for a living, so he signed up for engineering at Cornell University.
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Still, he ended up in astronomy, despite the low odds of making it into graduate school and earning a faculty position.

"My philosophy has always been that even if you have only a low probability of succeeding in a career, you should try anyway, so that you don't wake up when you're middle-aged and wonder what could have been," he said.

Though he was in a rock band in high school, Marscher wasn't too tempted to become a professional musician. He wrote his dozen science songs to complement his teaching in a course called "The Evolution of the Physical Universe and of the Earth," part of Boston University's core curriculum for undergraduates.

"Anybody's attention span during an hourlong period doesn't really focus on someone just lecturing," he said. The music "really does help to liven up the lectures."

Now that is nerdy... Something I cannot deny doing either...

[PayUp]

Amazing stuff. I can't even find the remote to my dvd player.

[SaltPork]

I wonder if any of the scientists said: "so THAT'S where i left it". I would have.

[SSJTWIZTA]

Originally Posted by SaltPork

I wonder if any of the scientists said: "so THAT'S where i left it". I would have.

Cosmology Zing!

[pan6467]

What does the study of cutting hair have to do with space?????????