Piece of Missing Cosmic Matter Found

[Thom Young]

Astronomers have found a piece of the universe's puzzle that's been missing for a while: a type of extremely hot, dense matter that is all but invisible to us.

Engaging in something like cosmic accounting, astronomers have tried to balance the scant amount of matter that has been directly observed with the vast amount that remains unobserved. The latter constitutes about 90 percent of the universe's matter.

Galaxies, the stars within them, the planet we live on, and the chairs we sit on are made up of normal matter--the protons, electrons and neutrons that are collectively called baryons. Baryonic matter can be seen and directly observed, but it makes up only about 4 percent of the universe.

The rest of the universe is split up between dark matter (about 21 percent), a mysterious type of matter that has yet to be identified but that is thought to have played a critical role in the development of the first galaxies that formed after the Big Bang, and the even more mysterious dark energy (about 75 percent of the universe), which causes the accelerated expansion of the universe.

Dark matter remains a total mystery, but the new study squares the balance sheet a bit in regards to baryonic matter.

Previously, only about half of the baryonic matter in the universe was accounted for by the known gas, stars, and galaxies. A team of astrophysicists has now found evidence of part of the missing half in a bridge-like filament connecting two clusters of galaxies. The finding is detailed in the May 2008 issue of Astronomy and Astrophysics Letters.

Along with dark matter, the missing baryonic matter is thought to form an enormous spider web of tendrils that connect galaxy clusters, which sit on threads and knots in the web.

The missing part of this matter was thought to be a hot, ultra-thin gas haze of very low density between larger structures. Its hellacious temperature means that it only emits far-ultraviolet and X-ray radiation.

Some of this missing matter was found by the astrophysicists, who hail from the Max Planck Institute for extraterrestrial Physics (MPE) and the European Southern Observatory in Germany, as well as the SRON Netherlands Institute for Space Research. The team used the XMM-Newton, an X-ray space observatory, to observe a filament connecting two clusters of galaxies, Abell 222 and Abell 223.

"So far we could only see the clusters, the dense knots of the web. Now we are starting to see the connecting wires of the immense cosmic spider web," said MPE study team member Aurora Simionescu of the discovery of this missing baryonic matter.

A similar baryonic haze, 150 times hotter than the sun's surface, was indirectly detected surrounding the Milky Way* and connecting about three dozen other galaxies known collectively as the Local Group in 2003 by astronomers at Harvard and Ohio State Universities.

It is thought that these hot intergalactic hazes were created from material that did not fall into galaxies when they first formed more than 13 billion years ago. Finding and analyzing these filaments could help astronomers better understand what happened after the Big Bang and what forces are dominating the universe today.

* And, of course, when we fly starships through this baryonic haze that surrounds the Milky Way, anyone on board with ESP abilities will either be killed or transformed into gods.

Joking aside, this is very cool news that indicates that the universe has a web-like structure that connects ties galaxies together (at least clusters of galaxies).

[FlightlessAngel]

Sounds pretty cool
Dark Matter and Dark Energy? All sounds like it is from some kind of PS2 game where the dark forces try to take over the Universe!

[Thom Young]

Originally Posted by FlightlessAngel

Sounds pretty cool
Dark Matter and Dark Energy? All sounds like it is from some kind of PS2 game where the dark forces try to take over the Universe!

[seric26]

Originally Posted by Thom Young

* And, of course, when we fly starships through this baryonic haze that surrounds the Milky Way, anyone on board with ESP abilities will either be killed or transformed into gods.

I LOVE that episode. Back when the Trek women first wore pants! Sally Kellerman then looked like Gwyneth Paltrow now.

[Thom Young]

Originally Posted by seric26

I LOVE that episode. Back when the Trek women first wore pants! Sally Kellerman then looked like Gwyneth Paltrow now.

Yeah, that was the second pilot (after the Capt. Christopher Pike pilot that failed). However, it wasn't the first episode to air when the series began.

It has no Dr. McCoy, the equipment on the Enterprise is curved rather than angular, and Spock wears a gold uniform.

If you watch the episodes in the order in which they were aired, it's a bit disconcerting when you suddenly get to this episode (which is #3 or 4 in the sequence).

I sort of wish they had maintained the look that they had in this episode throughout the series. Short of that, I wish they would retcon this episode as the initial episode in the series.

[vark]

Originally Posted by Thom Young

Yeah, that was the second pilot (after the Capt. Christopher Pike pilot that failed). However, it wasn't the first episode to air when the series began.

It has no Dr. McCoy, the equipment on the Enterprise is curved rather than angular, and Spock wears a gold uniform.

If you watch the episodes in the order in which they were aired, it's a bit disconcerting when you suddenly get to this episode (which is #3 or 4 in the sequence).

I sort of wish they had maintained the look that they had in this episode throughout the series. Short of that, I wish they would retcon this episode as the initial episode in the series.

It has Scotty and that's all that matters to me. It was also the only Kirk episode with those cool phaser rifles. Where was the heavy ordnance when Horta heard a Who?

[kolchak]

Originally Posted by Thom Young

Yeah, that was the second pilot (after the Capt. Christopher Pike pilot that failed). However, it wasn't the first episode to air when the series began.

It has no Dr. McCoy, the equipment on the Enterprise is curved rather than angular, and Spock wears a gold uniform.

I'm pretty sure that had to do with network tampering. They saw the show as being too intellectual. We sure seem to be talking about Star Trek a lot lately

Ray

[Thom Young]

Originally Posted by kolchak

I'm pretty sure that had to do with network tampering. They saw the show as being too intellectual.

Yeah, which is why the Capt. Pike pilot wasn't given the go-ahead.

Still, even though the network wouldn't air the second pilot as the first episode, it's now become canon that it's the third Kirk episode after "The Man Trap" (McCoy's salt-sucking former lover) and "Charlie X" (the teenager with raging hormones who makes people disappear).

I was disappointed when I watched the remastered episode of "Charlie X." They cut a scene, which doesn't seem right in a "remastered" episode that is supposed to enhance the original not remove elements.

They cut the scene in the gym where Charlie watched one man slap the other on the butt after sparring with each other. It's what gave Charlie the idea of later slapping Yeoman Rand on the butt in the hallway.

I suppose the "remasterers" must have thought it was too "gay" for the man to have slapped the other on the butt.

[FlightlessAngel]

Is it really bad that i have never actually seen a single episode of Star Trek? The only parts I have seen are when my mum is watching the films when she is doing the ironing on a Sunday and they look alright, but I have never actually got around to watching anything of them.

[vark]

Hubble Survey Finds Missing Matter, Probes Intergalactic Web

Release No.: STScI-PR08-20
Credit: NASA, ESA, and A. Feild (STScI)

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 used 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 one of 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.

Graphical representation of the cosmic web This graphic represents a slice of the spider-web-like structure of the universe, called the "cosmic web." These great filaments are made largely of dark matter located in the space between galaxies. Credit: NASA, ESA, and E. Hallman (University of Colorado, Boulder)
> Larger image 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. 83 filaments were found laced with highly ionized oxygen in which five electrons have 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 shock wave 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.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA) and is managed by NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Md. The Space Telescope Science Institute (STScI) conducts Hubble Science operations. The institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc., Washington, D.C..

Officials refused to comment on rumours that both Galactus and the Beyonder have also been recently observed.