Nasa Discovers Dark Matter!

[Atheist God]

http://www.nasa.gov/home/hqnews/2006/aug/H...ark_matter.html

As the article states above this is the real deal. Nasa has discovered dark matter, this could possibly be one of the more larger scientific discoveries we have had in a long time.

There really isn't a whole lot of info available on NASA's website as they won't be having the press teleconference until Monday at 1:00pm EDT

Here is a link to wikipedia on dark matter for those here who may not be sure as to what the theories are so far.

http://www.nasa.gov/home/hqnews/2006/aug/H...ark_matter.html

[rice]

wow!...i havent read the article yet but it sounds very interesting...didnt they say that dark matter is found around all galaxies and stuff like that? ah wells..ima start reading...thnx for the post and article ganja!

[Atheist God]

wow!...i havent read the article yet but it sounds very interesting...didnt they say that dark matter is found around all galaxies and stuff like that? ah wells..ima start reading...thnx for the post and article ganja!

Thanx rice...

I use Digg for news like this all the time it's great to have it on RSS for shizzle. If you haven't been to Digg it's essentially a user submitted news service in which users post news. It is the most popular on the webernet.

Digg

[Startraveler]

I didn't catch that and I haven't seen much about this anywhere but it sounds like this is a discovery about dark matter and not a direct detection of dark matter. The day a dark matter particle is definitively directly detected it'll be all over the place. Assuming they exist.

[Waspie_Dwarf]

NASA Finds Direct Proof of Dark Matter

The press release is reproduced below:

Aug. 21, 2006

Michael Erica Hupp
Headquarters, Washington
202-358-1237

Steve Roy
Marshall Space Flight Center, Huntsville, Ala.
256-544-6535

Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
617-496-7998

RELEASE: 06-297

NASA Finds Direct Proof of Dark Matter

Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies. The discovery, using NASA's Chandra X-ray Observatory and other telescopes, gives direct evidence for the existence of dark matter.

"This is the most energetic cosmic event, besides the Big Bang, which we know about," said team member Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

These observations provide the strongest evidence yet that most of the matter in the universe is dark. Despite considerable evidence for dark matter, some scientists have proposed alternative theories for gravity where it is stronger on intergalactic scales than predicted by Newton and Einstein, removing the need for dark matter. However, such theories cannot explain the observed effects of this collision.

"A universe that's dominated by dark stuff seems preposterous, so we wanted to test whether there were any basic flaws in our thinking," said Doug Clowe of the University of Arizona at Tucson, and leader of the study. "These results are direct proof that dark matter exists."

In galaxy clusters, the normal matter, like the atoms that make up the stars, planets, and everything on Earth, is primarily in the form of hot gas and stars. The mass of the hot gas between the galaxies is far greater than the mass of the stars in all of the galaxies. This normal matter is bound in the cluster by the gravity of an even greater mass of dark matter. Without dark matter, which is invisible and can only be detected through its gravity, the fast-moving galaxies and the hot gas would quickly fly apart.

The team was granted more than 100 hours on the Chandra telescope to observe the galaxy cluster 1E0657-56. The cluster is also known as the bullet cluster, because it contains a spectacular bullet-shaped cloud of hundred-million-degree gas. The X-ray image shows the bullet shape is due to a wind produced by the high-speed collision of a smaller cluster with a larger one.

In addition to the Chandra observation, the Hubble Space Telescope, the European Southern Observatory's Very Large Telescope and the Magellan optical telescopes were used to determine the location of the mass in the clusters. This was done by measuring the effect of gravitational lensing, where gravity from the clusters distorts light from background galaxies as predicted by Einstein's theory of general relativity.

The hot gas in this collision was slowed by a drag force, similar to air resistance. In contrast, the dark matter was not slowed by the impact, because it does not interact directly with itself or the gas except through gravity. This produced the separation of the dark and normal matter seen in the data. If hot gas was the most massive component in the clusters, as proposed by alternative gravity theories, such a separation would not have been seen. Instead, dark matter is required.

"This is the type of result that future theories will have to take into account," said Sean Carroll, a cosmologist at the University of Chicago, who was not involved with the study. "As we move forward to understand the true nature of dark matter, this new result will be impossible to ignore."

This result also gives scientists more confidence that the Newtonian gravity familiar on Earth and in the solar system also works on the huge scales of galaxy clusters.

"We've closed this loophole about gravity, and we've come closer than ever to seeing this invisible matter," Clowe said.

These results are being published in an upcoming issue of The Astrophysical Journal Letters. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass. For additional information and images, visit:

http://chandra.nasa.gov

- end -

--------------------------------------------------------------------------------

Source: NASA Press Release 06-297

[Waspie_Dwarf]

A Matter of Fact

As a rule, scientists seek certainty. So it's rather unusual that for more than 70 years, many astronomers have wagered the universe is primarily made of dark matter -- a mysterious and unproven substance.


Image above: A purple haze shows dark matter flanking the "Bullet Cluster."
Image Credit: X-ray: NASA/CXC/M.Markevitch et al. Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al. Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.
+ View High-res Image

It's a bet that finally paid off, because a team of scientists working with NASA's Chandra X-ray Observatory has found direct evidence that dark matter is as real as the rings around Saturn.

The discovery cements dark matter's status as the biggest building block in the universe, while also putting to rest the nagging worries of many astronomers that they gambled wrong.

Dark matter's murky nature has always sat a bit uneasily with astronomers. "It is uncomfortable for a scientist to have to invoke something invisible and undetectable to account for 90 percent of the matter in the universe," said Maxim Markevitch, a Chandra astrophysicist and researcher with the study.

One of the main arguments for the existence of dark matter involves galaxies and their clusters. Galaxies whip through space at enormous speeds and are searing with hot clouds of gas. Speed and heat of galaxies should cause them to fly apart, but they don't. A leading explanation for this is that the gas and stars are held together by the gravity of dark matter. Belief in dark matter is widespread across the scientific community, but astronomers don't know what it's made of. Still, they believe it acts like it has mass and exerts gravity, yet is invisible and can't bump, touch or crash into anything.

Like determining the origin of the universe or how black holes work, dark matter is one of the holy grails of astronomy. "Little is known about it; all that the numerous searches for dark matter particles have done is rule out various hypotheses, but there have never been any 'positive' results," said Markevitch.

Doug Clowe, leader of the study, set out to see if believing in dark matter was wishful thinking or informed faith. "A universe that's dominated by dark stuff seems preposterous, so we wanted to test whether there were any basic flaws in our thinking," said Clowe.

What's the Matter?
Clowe and astronomers with Chandra, the Hubble Space Telescope, the European Southern Observatory's Very Large Telescope and the Magellan telescopes all set their sights on a galaxy cluster nicknamed the "Bullet Cluster." The cluster was an exciting target because of its unique distribution of gas clouds and stars and potential for harboring dark matter.


Image above: The Bullet Cluster is made of two colliding groups of galaxies.
Image Credit: NASA/STScI
+ View High-res Image

The amount of matter, or "mass," in a galaxy is made up mostly of the gas that surrounds it. Stars, planets, moons and other objects count too, but a majority of the mass still comes from the hot, glowing clouds of hydrogen and other gases.

When the Bullet Cluster's galaxies crossed and merged together, their stars easily continued on their way unscathed. This may seem a bit perplexing, because the bright light of stars makes them appear enormous and crowded together. It would be easy to expect them to smash into each other during their cosmic commute. But the truth is, stars are actually spaced widely apart and pass harmlessly like ships on an ocean.

The gas clouds from the merging galaxies, however, found the going much tougher. As the clouds ran together, the rubbing and bumping of their gas molecules caused friction to develop. The friction slowed the clouds down, while the stars they contained kept right on moving. Before long, the galaxies slipped out of the gas clouds and into clear space.

With the galaxies in open space, Chandra scientists found dark matter hiding.

Dark Matter Weighs In
When the stars separated from the clouds, they gave astronomers a lucky chance to estimate their total mass and gravity without the hot gas. The astronomers used their telescopes and various methods to measure the mass of the galaxies.


Image above: The Hubble Space Telescope was used to observe how the Bullet Cluster bent light coming from background stars.
Image Credit: NASA/CXC/M. Weiss
+ View High-res Image

Dark matter revealed itself when the team tried a technique called "gravitational lensing." This neat trick was inspired by Albert Einstein's prediction that stars and galaxies of high mass can bend light toward them from other sources. The amount of extra light can be calculated and tells astronomers about the size of the galaxy.

An odd thing happened in this case: the galaxies lit up far too much for their size.

Hidden Influence
The scientists had already calculated the masses of the galaxies using other measuring methods. Yet the results from gravitational lensing showed the galaxies are bending much more light toward themselves than they should be able to. The astronomers knew something was amiss. An unseen force, substance or object had escaped the clouds along with the galaxies and was helping to bend more light.

For the first time in history, astronomers caught dark matter at work.

"These results prove that dark matter exists," declared Clowe.

So there it is, bright as starlight: Dark matter matters, as a matter of fact.

Charlie Plain
NASA's Chandra X-ray Observatory and John F. Kennedy Space Center

Source: NASA - Exploring the Universe - Stars and Galaxies

[RamboIII]

This is an interesting and highly beneficial find. These certain theories with hard evidence are constantly overlooked by the ignorant who praise NASA's doom.

[Science_Guy]

I knew they'd find it. I mean, gravity from the mass of the stars aren't enough to hold them together as a galaxy, as well as galaxies in a cluster, so dark matter has to contribute to the missing mass!

[Startraveler]

This is big news, no doubt, but it seems like they're being a bit careless with headlines like "NASA Finds Direct Proof of Dark Matter."

"Little is known about it; all that the numerous searches for dark matter particles have done is rule out various hypotheses, but there have never been any 'positive' results," said Markevitch.

This remains true. The direct detection of a particle of dark matter will certainly qualify as "direct proof of dark matter." This particular discovery, while extremely significant, is better described by the sentence toward the end of the second article:

For the first time in history, astronomers caught dark matter at work.

A lot of people are saying this is proof of dark matter (and by that I'm assuming they mean some new kind of nonbaronic matter, as is usually meant) but I'm not so sure this line is true:

Despite considerable evidence for dark matter, some scientists have proposed alternative theories for gravity where it is stronger on intergalactic scales than predicted by Newton and Einstein, removing the need for dark matter. However, such theories cannot explain the observed effects of this collision.

Even if it turns out that current modified gravity models can't account for this that doesn't necessarily mean no such model can ever deal with this. I'll admit those ideas will start to look pretty unappealing (and a lot of people already found them unappealing as it is) if they have to keep on jumping through hoops and piling on complexities to keep working but I'm just not convinced at this point that this proves they can't work.

This is just another piece in the puzzle--a big one--not the final one by a long shot.

[Moon*Ghost]

So, in simpler terms, what does this discovery mean?

[Waspie_Dwarf]

So, in simpler terms, what does this discovery mean?

The relationship between gravity and mass is fairly well understood. However the way that galaxies are held together requires considerably more mass than we can observe (things we can see includes stars gas clouds etc). It has been theorised that most of the mass in the universe is of a type we can't see. This is known as dark matter. It is this dark matter that NASA has found evidence of.