Galaxies Floating on a Dark Matter Stream

Darkman, Walkin Dude writes "A team in Switzerland has discovered that most of the small satellite galaxies around the Milky Way's near-twin, Andromeda, are lined up in a single plane that slices through Andromeda's spiral disc. Using images from the Hubble space telescope, soon to be decommissioned, the researchers found that 9 of the 14 of Andromeda's satellites lay on a relatively narrow plane bisecting Andromeda. From the article: 'The team believes the plane could have formed in several ways. In one scenario, the galaxies may have fallen towards Andromeda along an invisible filament of dark matter. Computer simulations show these filaments can form a cosmic web along which galaxies flow.'"

Comments

Re:Hubble soon to be decommissioned

[NanoGator]

"North Korea is making far bigger noises about making their own nuclear bombs, but no one seems to make such a fuss ...."

[OT, Sorry.]

Um, yeah, that's because several countries have diplomatic relations with NK and are negotiating with them. The US is actually doing the right thing here (or at least what everybody wanted them to do with regards to Iraq), but nobody wants to acknowledge that because of the monkey in the White House.

Re:Sombrero Galaxies and You

[Ckwop]

Now, the slashdot community seems to be fairly educated and extremely opinionated so how about it--does dark matter exist? If so, since it is very difficult to detect, what are its defining properties?

If this is correct, then the Dark Matter riddle has been solved. Basically, it was due to the fact that scientists thought they could safely use the Newtonian limit to General Relativity with galaxies. They were wrong and Dark Matter is a result of this error.

This was reported on Slashdot not to many moons ago.

Simon

Re:Hubble Space Telescope

[wass]

Well let's see, NASA administrator Sean O'Keefe says it will never be visited by a space shuttle repair mission again

Um dude, O'Keefe has been gone from NASA for nine months now, your article link is almost a year old. One of the first things that the new administrator Michael Griffin did when he took over the reins was to try to figure out ways to keep Hubble alive. Griffin's an actual scientist, unlike O'Keefe who's a career-track manager. And thus sees the important of Hubble, which has been indispensible for astronomical research.

Direct from NASA's Hubble page , it says

"At his April, 2005 confirmation hearing before the U.S. Senate, as well as in subsequent statements, new NASA Administrator Michael D. Griffin testified to the extraordinary scientific value of Hubble. He indicated his desire to take the robotic servicing mission "off the plate" on the basis of mission complexity, and reconsider an SM4 Shuttle-astronaut mission to Hubble. His rationale is that after the Shuttle's Return to Flight ("RTF", currently scheduled for July of 2005), and in particular after all the Shuttle improvements that precede RTF, NASA will essentially have a "new" Shuttle vehicle and system in the context of astronaut and mission safety. After successes in RTF and the following flight, if analysis shows that the risk levels associated with a Hubble mission are sufficiently low and manageable, SM4 could be reinstated by the Administrator."

Hubble won't decommissioned soon

[amightywind]

In his zeal to take a political potshot Zonk has ignored the most recent developments. Don't be deceived. NASA administrator Michael Griffin has reconsidered earlier the earlier decision to scrap Hubble servicing. A shuttle crew will indeed have to risk their lives to extend Hubble's life for a few more years. Relax. There should still be lots of money left over to invest in Iraqi freedom, and to kill Al Qaida.

Re:Sombrero Galaxies and You

[Stalyn]

Might want to do some actual research on the subject. From that list there are no articles in support of the Cooperstock-Tieu model other than a response by the orginal authors. The theoretical arguments and evidence against the model are quite convincing.

Dark matter is just the best model we have right now. It also amazes me how much Slashdot is against the dark matter model. Why is that?

Re:Sombrero Galaxies and You

[drudd]

Dark matter has vast (let me repeat, VAST) amounts of evidence beyond rotation curves of galaxies. It is supported by weak and strong gravitational lensing measurements, the clustering of galaxies, flucutations in the cosmic microwave background, hot gas and random motions of galaxies in galaxy clusters...

All of this evidence is sufficient to say that either 1) dark matter exists or 2) our theory of gravity is broken in exactly the way necessary to seem like there's dark matter when there really isn't. #1 is the simplest, and as of yet, nobody has found a #2 that even comes close (although people are working on trying to find one). Cold dark matter has overcome nearly 40 years of people trying to poke holes in it, and it's stood the test of time.

In addition, it's not the kludge solution as it is portrayed by so many here on slashdot. There are good particle physics reasons to expect a heavy weakly interacting non-relativistic particle. Just because we don't know exactly what it is yet does not mean it's not a good theory.

We're already searching for dark matter annihilation signatures in the centers of dwarf galaxies, and we have direct detection experiments running here on Earth. So called direct detection of dark matter may only be years away. At the minimum we continually rule out parameter space of theories that do fit the observations, refining our understanding of what signatures to look for.

Doug