Dark Matter Detected?

[Menolly]

Has dark matter finally been detected?

Hunt may well be over for a mysterious and invisible substance that accounts for three-quarters of the matter in the universe
Ian Sample, science correspondent


A computer simulation shows how invisible dark matter coalesces in halos (shown in yellow). Photograph: Science Photo Library

For 80 years, it has eluded the finest minds in science. But tonight it appeared that the hunt may be over for dark matter, the mysterious and invisible substance that accounts for three-quarters of the matter in the universe.

In a series of coordinated announcements at several US laboratories, researchers said they believed they had captured dark matter in a defunct iron ore mine half a mile underground. The claim, if confirmed next year, will rank as one the most spectacular discoveries in physics in the past century.

Tantalising glimpses of dark matter particles were picked up by highly sensitive detectors at the bottom of the Soudan mine in Minnesota, the scientists said.

Dan Bauer, head of the Cryogenic Dark Matter Search (CDMS), said the group had spotted two particles with all the expected characteristics of dark matter. There is a one in four chance that the result is due to some other effect in the underground detectors, Bauer told a seminar at the Fermi National Accelerator Laboratory, near Chicago.

Rumours that Bauer's group was on the verge of making an announcement surfaced on physicists' blogs a few weeks ago. Though tentative, tonight's results triggered an immediate wave of excitement in the science community.

"If they have a real signal, it's a seriously big deal. The scale on which people are looking for dark matter is vast," said Gerry Gilmore at Cambridge University's institute of astronomy. "Dark matter is what created the structure of the universe and is essentially what holds it together. When ordinary matter falls into lumps of dark matter it turns into galaxies, stars, planets and people. Without it, we wouldn't be here," Gilmore said.

Scientists have debated the existence of dark matter since 1933, when the Swiss astronomer Fritz Zwicky argued that a distant cluster of galaxies would fall apart were it not for the gravitational pull of some vast but invisible cosmic substance. It was named dark matter because it does not reflect or absorb light, making it impossible to observe with telescopes.

Last year, the Hubble telescope photographed indirect evidence in the form of a ghostly halo around a distant galaxy, caused by clumps of dark matter bending light from stars as it passed by. A year before that, scientists led by the British astronomer Richard Massey, at the California Institute of Technology, published the first 3D map of dark matter, which revealed how it clung around galaxies and held clusters of them together.

Dark matter is likely to be made up of a variety of invisible particles that not only explain the missing mass of the universe, but shed light on some of the most profound mysteries in science.

Some dark matter particles could explain why ordinary matter is not radioactive, while others may help scientists understand why time – so far as we know – always runs forward.

"The real impact of this is psychological, in that it shows we're getting close to being able to do a whole new kind of physics," Gilmore said. "We know there are properties of the universe that should correspond to new families of particles. One of the great mysteries is why time only goes in one direction, and one candidate to explain that is a dark matter particle."

Many scientists believe dark matter particles will turn out to be proof of a theory called supersymmetry, which predicts that every kind of particle in the universe is paired with a heavier twin. Finding evidence for supersymmetry is one of the major goals of the Large Hadron Collider at Cern, in Switzerland.

Dark matter particles are peculiar because they pass through objects as if they were not there. Their aloof nature has led scientists to name them weakly interacting massive particles, or Wimps. Vast amounts of these are thought to be constantly moving through the Earth and everything on it, us included, as the solar system spins around our galaxy.

The detectors at the Soudan mine are buried underground to shield them from other kinds of particles that bombard Earth from space. To detect dark matter, scientists have to wait for the extremely rare occasion when a dark matter particle knocks into an atomic nucleus in the detector and makes it vibrate.

Detectors in the mine will be upgraded in the new year before the search for more dark matter continues, Bauer said.

The hunt for dark matter
What is dark matter?

The night sky might seem full of stars and planets, but what we see is only 4% of the stuff of the universe. Some three-quarters is dark matter, an invisible substance that scientists believe is there because of the gravitational force it exerts.

What does dark matter do?

Dark matter stretches throughout space where it attracts ordinary matter that coalesces into galaxies of billions of stars and planets. It forms a kind of cosmic skeleton that gives the universe its structure. Many scientists believe they will find a family of invisible dark matter particles, each of which plays a different role in nature. Some may even explain why time always goes in the same direction.

Who came up with the idea?

The Swiss astronomer Fritz Zwicky postulated dark matter in 1933. He noticed that a distant cluster of galaxies would fall apart were it not for the extra gravitational pull of some mysterious unseen mass in space. Astronomers verified his prediction by showing that stars swirling around distant galaxies zipped around so fast they must be held in place by extra gravitational forces.

Does everyone believe in dark matter?

A minority of astronomers and physicists dismiss dark matter as a fudge. Instead, they suspect that the strength of gravity varies from place to place, in a way that explains why stars do not hurtle out of spinning galaxies. The theory is known as Modified Newtonian Dynamics (Mond).

[matrixman]

Wow! That is a stupendous breakthrough if true. Exciting times in astronomy!

[Vraith]

Perfect slow thread for posting this in:

news.yahoo.com/elusive-dark-matter-pervades-intergalactic-space-211404372.html

[Prebe]

On the basis of this gravitational interaction, physicists have inferred that dark matter constitutes 22 percent of the matter-energy content of the universe, while ordinary detectable matter constitutes just 4.5 percent.

So, what about the last 73,5 % Poindexter?

[I'm Murrin]

The other half of matter-energy. (And most of that is dark energy!)

[Vraith]

And here we are again [my last was dark matter, too!]
news.yahoo.com/milky-way-haze-may-dark-matter-signature-204405915.html

"The radiation cannot be explained by the structural mechanisms in the galaxy, and it cannot be radiation from supernova explosions," study co-author Pavel Naselsky, of the Niels Bohr Institute at the University of Copenhagen in Denmark, said in a statement.
"We believe that this could be proof of dark matter," he added. "Otherwise, we have discovered [an] absolutely new (and unknown for physics) mechanism of acceleration of particles in the galactic center."

I'm not sure if it would be cooler to get closer to proving it's real, or cooler that it's something completely unknown.

[Fist and Faith]

If it doesn't absorb or reflect light, as stated in the first post, then, when we get our hands on it, we can coat ourselves with it, and be invisible! And I'm telling you right now, no women's locker room will be safe again.

So if it's everywhere, in greater quantity than regular matter, why am I not bumping into it all the time?

[Vraith]

If it doesn't absorb or reflect light, as stated in the first post, then, when we get our hands on it, we can coat ourselves with it, and be invisible! And I'm telling you right now, no women's locker room will be safe again.

So if it's everywhere, in greater quantity than regular matter, why am I not bumping into it all the time?

That's actually pretty easy, if it is what they think: it only could affect you through gravity...but gravity is so weak you'd need a huge ball of it to feel it...but since it is its own anti-particle, you can't make a great big ball of it.

[Orlion]

If it doesn't absorb or reflect light, as stated in the first post, then, when we get our hands on it, we can coat ourselves with it, and be invisible! And I'm telling you right now, no women's locker room will be safe again.

So if it's everywhere, in greater quantity than regular matter, why am I not bumping into it all the time?

That's actually pretty easy, if it is what they think: it only could affect you through gravity...but gravity is so weak you'd need a huge ball of it to feel it...but since it is its own anti-particle, you can't make a great big ball of it.

Well isn't THAT convenient! It's its own anti-particle, so we can't have, like, more than one particle of it at a time... sounds like loser talk!

[Vraith]

If it doesn't absorb or reflect light, as stated in the first post, then, when we get our hands on it, we can coat ourselves with it, and be invisible! And I'm telling you right now, no women's locker room will be safe again.

So if it's everywhere, in greater quantity than regular matter, why am I not bumping into it all the time?

That's actually pretty easy, if it is what they think: it only could affect you through gravity...but gravity is so weak you'd need a huge ball of it to feel it...but since it is its own anti-particle, you can't make a great big ball of it.

Well isn't THAT convenient! It's its own anti-particle, so we can't have, like, more than one particle of it at a time... sounds like loser talk!

This is [what I'm about to say, not what's been said] COMPLETELY histori-satirical/ironic so no one can misinterpret and get offended!!!.....

The universe wrote:

We can't just let the darkies get together like normal particles, it will destroy civilization.

[Orlion]

That's actually pretty easy, if it is what they think: it only could affect you through gravity...but gravity is so weak you'd need a huge ball of it to feel it...but since it is its own anti-particle, you can't make a great big ball of it.

Well isn't THAT convenient! It's its own anti-particle, so we can't have, like, more than one particle of it at a time... sounds like loser talk!

This is [what I'm about to say, not what's been said] COMPLETELY histori-satirical/ironic so no one can misinterpret and get offended!!!.....

The universe wrote:

We can't just let the darkies get together like normal particles, it will destroy civilization.

umm....err, I mean.... we are not amused... ....*smirk*

[Fist and Faith]

[Vraith]

Just a new tidbit on this [I didn't link the article cus it doesn't provide any actual information...just that information will be coming.]

Though Ting was coy about just what, exactly, the experiment has found, he said the results bear on the mystery of dark matter, the invisible stuff thought to outnumber regular matter in the universe by a factor of about six to one.
"It will not be a minor paper," Ting said, hinting that the findings were important enough that the scientists rewrote the paper 30 times before they were satisfied with it.

[Hashi Lebwohl]

If you have to rewrite your paper 30 times before you are satisfied with it then either a) you don't understand the subject matter and you are bullshitting or b) you understand the subject but you do not understand the experimental results you obtained.

I can see 3 rewrites, even 5, but 30? No, they are simply making it up as they go along just to get published.

[Avatar]

If you have to rewrite your paper 30 times before you are satisfied with it then either a) you don't understand the subject matter and you are bullshitting or b) you understand the subject but you do not understand the experimental results you obtained.

Maybe you just can't write?

--A