Galaxies Made Of Nothing?

Ant writes: "There's an interesting article from theorists attempting to explain some of the "missing mass" in the universe now say there may be entire galaxies that are dark. The new idea, proposed by Neil Trentham of the University of Cambridge, along with colleagues Ole Moller and Enrico Ramirez-Ruizof, suggests that for every normal, star-filled galaxy, there may be 100 that contain nothing, or at least nothing that we understand."

Re:URL for paper

[calcfreak901]

Could the image also show matter flowing off to a supermassive black hole, rather than a dark galaxy?

Re:Oh, no!

[RareHeintz]

I so wish that I could mod that up as funny...

Nice one, HM.

OK,
- B
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whoa....

[insane penguine]

hey, that's pretty impressive. but what would happen if you accidentally blundered into one? would you suddenly not be able to see any thing? would that mean you could run into planets or what ever? would you become non-existant?

Some mindless nothings

[jd]

The net mass of quantum foam exceeds the theoretical mass of this "Dark matter".

It's also known to exist.

IMHO, "Dark Matter" is the invention of physicists who indulge in eating curiously-coloured mushrooms far too often. In science, the best theories are the simplest, not the most elusive.

URL for paper

[bcrowell]

The original paper is here. [arxiv.org]
The Assayer [theassayer.org] - free-information book reviews

Re:URL for paper

[bcrowell]

First off, you have to realize that you can't necessarily tell the motion of the stars when you look at a distant galaxy. They don't cover enough angle per year for motion to be directly detectable, and Doppler shifts are not always measurable. So what they see is a feature, but not necessarily a pattern of flow.

Also, it's a common misconception that black holes are like cosmic vacuum cleaners. Stuff normally just orbits past a black hole without passing through the event horizon. That haze in the photo is stars, not gas, so there's no friction to help stuff slow down instead of orbiting past.

For persepective, try going to this page [dao.nrc.ca] and typing in a random NGC galaxy number (ngcxxx, where the x's are random digits). If you do a few of these, you'll probably notice a lot of them have funky shapes. Sometimes this can be attribited to something like a recent collision, and sometimes you just have to say it's a funky-shaped galaxy and we don't know why. I skimmed their paper, and they don't even refer to this particular galaxy in it.
The Assayer [theassayer.org] - free-information book reviews

Oh, no!

[Happy Monkey]

The Nothing is bigger than it has ever been before! Save us, Atreyu and Bastion!
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I like it!

[KjetilK]

I find the idea of very dark galaxies appealing. For instance you have the binary quasar 2345+007 [harvard.edu], which can be a gravitational lens. If it is a gravitational lens, the lensing object is very dark, and it is also very massive. There has been some reports that a lensing galaxy has been seen, but no generally accepted conclusion has been drawn as to the nature of this quasar. So, this is exciting stuff!

Re:URL for paper

[Black Parrot]

And here [bbc.co.uk] is a news article with a picture.

No, not a picture of a dark galaxy... a picture of a visible galaxy with a trail of material streaming off like it has just had a brush with another, though there's no other in sight.

BTW, the /. topic is typically misleading (do they do that on purpose?) -- dark matter != "nothing".

And while we're on the topic, there are several cosmology articles in the January Scientific American, which was still on the shelves 2-3 days ago.

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