Skip to comments.Dark Matter: Invisible, Mysterious and Perhaps Nonexistent -
Posted on 10/13/2005 8:20:08 AM PDT by UnklGene
Dark Matter: Invisible, Mysterious and Perhaps Nonexistent -
By Robert Roy Britt Senior Science Writer 10 October 2005
Galaxies don't have enough regular matter to keep them from flying apart, scientists have been telling us for years. So there must be a bunch of unseen "dark matter" lurking in every galaxy.
But dark matter has never been directly detected, and nobody knows what it might be made of. A few scientists remeain skeptical. To a lay person, it might sound downright crazy.
Now a new study suggests there may be no such thing as dark matter.
Fred Cooperstock of Northeastern University and Steven Tieu at the University of Victoria say Einstein's theory of general relativity can explain the cohesiveness of individual galaxies including our Milky Way.
Here's the thinking:
Newton's laws of physics explain why our solar system stays together. But the planets are negligible in the overall gravitational scheme, with the Sun being the total ruler and containing 99.86 percent of all the mass.
The same Newtonian physics were long ago applied to galaxies, and the rotation of stars couldn't be explained, so dark matter was invented to make theory work.
But a galaxy is much different than the solar system, Cooperstock explains. The conglomeration of all the matter -- stars, black holes, gas, and dust -- is collectively the source of the galactic gravity. Even a black hole at a galaxy's center typically packs less than 1 percent of the galaxy's overall mass.
The overall galaxy's gravity "feeds its own motion ... unlike the case of the solar system," Cooperstock told SPACE.com.
The science of the new argument is complex, but here goes:
"In the galaxy case, having rotation, we have found that general relativity provides a very important potential that is connected to the density of the galactic matter in what we call a 'nonlinear' manner,'" Cooperstock says. "This is unlike Newtonian physics."
This nonlinear effect has been noted before. "The interesting twist is that this holds also for the simpler steady rotational motion under gravity as in the galaxy," he said.
The upshot: The motions of stars in galaxies "is realized in general relativity's equations without the need to invoke massive halos of exotic 'dark matter' that nobody can explain by current physics," Cooperstock said.
A small percent of what used to be considered dark matter is made of burned-out stars that are hard to see. Predictions for how much of that material exists would not change.
Also, the new idea does not yet explain how large clusters of galaxies bind together. Further research by other theorists might solve that problem too, however, Cooperstock said. The new analysis has been submitted to the Astrophysical Journal but has yet to be reviewed by other scientists.
If it is right?
"This would remove about 25 percent of the mass of the universe, the ultimate weight-reduction program," Cooperstock said.
Let there be dark! And there was dark............And the cosmologists saw the dark and it was good........
nonlinear thinking bump
Thanks. I'm not sure about this one, but if it's right it's important. I'll ping the science list.
It's a slow day so far.
Lots of physics pings lately (no complaints here)!
Out for a bit today. Visiting elsewhere.
Which weighs more a pound of lead or a pound of feathers?
Most of the stuff missing is just stuff you can't see with telescopes...and there probably is a lot of it!
On the theory side, there are some really, really good software systems out there for doing detailed GR calculations for arbitrary distributions of matter. I'd be surprised to hear that they're all wrong.
It's too bad this couldn't have gone through peer review before hitting the press. But, well, that will come, unlike in an Intelligent Design result.
"unlike in an Intelligent Design result."
Just couldn't resist, could you?
Dark is hard to keep. They had a dark room at my college but some fool opened the door and it all leaked out.
I wasn't aware of any intelligent results.
Whatever the outcome, it will demonstrate the difference between hypotheses that can be tested, and ones that can't. It also demonstrates that science is teeming with people eager to upset prevailing opinion. All you need is some evidence.
Watch closely, because this may be taught in schools someday.
Ala cold fusion
Thanks for the ping!
I won't go there, because I don't know how the press got ahold of this. It's possible that it got uploaded to a preprint repository, word got around, and a reporter called him up. That would be very different from touting it at a press conference and scheduling interviews on the Today show.
Same reason my bank balance is always less than it should be.
It is only the fog. It is not a fire.
Nonexistent Matter? Dude, that's deep. Deep space deep!
Where can we find some of that?
Liberals - Dark Intelligence
We're doomed either way. Personally, I'm with Frost: I favor the Big Bust.
SOME say the world will end in fire, Some say in ice. From what Ive tasted of desire I hold with those who favor fire. But if it had to perish twice, 5 I think I know enough of hate To know that for destruction ice Is also great And would suffice. --Robert Frost--
I would bet he is right.. Or on the right track..
Just my personal opinion.. It's Free, so take it for what it's worth..
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