more dark stuff - now we have dark galaxies

[MattEU]

Dark galaxy crashing into the Milky Way

THE Milky Way's neighbourhood may be teeming with invisible galaxies, one of which appears to be crashing into our own.

In 2008, a cloud of hydrogen with a mass then estimated at about 1 million suns was found to be colliding with our galaxy. Now it appears the object is massive enough to be a galaxy itself.

Called Smith's cloud, it has managed to avoid disintegrating during its smash-up with our own, much bigger galaxy. What's more, its trajectory suggests it punched through the disc of our galaxy once before, about 70 million years ago.

To have survived, it must contain much more matter than previously thought, in order to provide enough gravity to hold it together. Calculations by Matthew Nichols and Joss Bland-Hawthorn of the University of Sydney, Australia, indicate that it has about 100 times the previously estimated mass (arxiv.org/abs/0911.0684).

Many more such dark galaxies may be out thereMovie Camera, says Leo Blitz of the University of California, Berkeley. Simulations of galaxy formation suggest a galaxy the size of the Milky Way should feature about 1000 dwarf galaxiesMovie Camera, but only a few dozen have been found so far. Some of the missing dwarfs may be dark galaxies that are all but invisible, he says.

Dark galaxy crashing into the Milky Way

[Siggy_G]

Seems like the concept of dark clouds of hydrogen molecules can be backtracked to at least 2000:

http://home.pacbell.net/skeptica/H2.html

Article from Sky &Telescope January 2000 page 20.

"SEVERAL KINDS OF UNSEEN “Dark Matter” are either known or suspected to exist throughout the universe. One kind of invisible matter adds unseen mass to individual galaxies, above and beyond a galaxy’s visible stars and interstellar matter swarms of brown or white dwarfs, yet-to-be-discovered atomic particles called WIMPs or axions, and hypothetical “quark nuggets” have been proposed to account for it.

But the dark matter in galaxies may not be so exotic or even very dark. According to two Dutch astronomers, most or all of it may be ordinary molecular hydrogen (H2), which, unlike atomic hydrogen (H), is invisible except at certain infrared wavelengths." (...)

[nick c]

The latest TPoD:
[url2=http://www.thunderbolts.info/tpod/2009/ ... rkmode.htm]Dark Mode Galaxies[/url2]

[D_Archer]

Seems like the concept of dark clouds of hydrogen molecules can be backtracked to at least 2000:

http://home.pacbell.net/skeptica/H2.html

Article from Sky &Telescope January 2000 page 20.

"SEVERAL KINDS OF UNSEEN “Dark Matter” are either known or suspected to exist throughout the universe. One kind of invisible matter adds unseen mass to individual galaxies, above and beyond a galaxy’s visible stars and interstellar matter swarms of brown or white dwarfs, yet-to-be-discovered atomic particles called WIMPs or axions, and hypothetical “quark nuggets” have been proposed to account for it.

But the dark matter in galaxies may not be so exotic or even very dark. According to two Dutch astronomers, most or all of it may be ordinary molecular hydrogen (H2), which, unlike atomic hydrogen (H), is invisible except at certain infrared wavelengths." (...)

Mmmm, i like me some tasty Quark Nuggets!!!

[jjohnson]

The article's second illustration places the Sun near the center of this theorized rotating ring of bright stars. What are the chances of that? Do all these stars and loose star clusters revolve in this tipped orbit? How have they had sufficient time to observe and confirm that phenomenon? How does any of their posited dark stuff control this ring under gravitational theory? Is the ring remaining centered near our sun or is it translating away in some direction, eventually to leave the galaxy altogether? Making up "observations" like this poses many questions and raises extreme doubts that they have any idea about what is going on in the real universe.

[GaryN]

Is this the same structure ?

http://www.viewzone.com/milkyway.html

[jjohnson]

Sorry guys; I got sidetracked onto a related story with the original article, without paying attention. It's still dark matter etc. but off this subject. Disregard that last transmission!

[Harry Costas]

G'day

Hello JJ

It seems that Dark matter can be used and defined in what ever context.

Here is one view

http://arxiv.org/abs/0907.1912
Dark Matter Astrophysics

Authors: Guido D'Amico, Marc Kamionkowski, Kris Sigurdson
(Submitted on 10 Jul 2009)

Abstract: These lectures are intended to provide a brief pedagogical review of dark matter for the newcomer to the subject. We begin with a discussion of the astrophysical evidence for dark matter. The standard weakly-interacting massive particle (WIMP) scenario--the motivation, particle models, and detection techniques--is then reviewed. We provide a brief sampling of some recent variations to the standard WIMP scenario as well as some alternatives (axions and sterile neutrinos). Exercises are provided for the reader.

Interesting paper 33 pages pdf

[jjohnson]

That is interesting; I've saved it for deeper reading. "...Know thy enemy." I bookmarked the Krazy Kreationist website for similar reasons, although it is not actually helpful at all. I liked the introductory statement in the PDF which bases the need for dark matter on the "normal" baryonic mass "imbalance needed to satisfy the Li abundance predicted by the Big Bang theory. Well, that looks like a logical domino cascade to me (as usual) if you just tip the BB theory a little (thanks Eric Lerner and many others) and voila! Thanks, Harry.