Violence Shaped the Night Sky - not the kind we know

[seanoz]

Ok, even ridicule erupts in the beginning of their own articles now, this is getting so ridiculous, like the AGW crowd eventually mainstream cosmologists and most astrophysicists they will be seen as thumb twiddling blood (money) sucking bludgers, (Australian colloquialism for worthless incompetent).

Just attempt to read this and not laugh, I mean please, it is pathetic, I am not a degree holder, but even my studies have shown me enough of a capacity to question consensus to be sure I don't go this far off on a tangent!

http://www.newscientist.com/article/mg2 ... ?full=true

Sean.

[MattEU]

In the middle of the 19th century, the English astronomer John Herschel noticed that we are surrounded by a ring of bright stars. But it was Boston-born Benjamin Gould who brought this to wider attention in 1874. Gould's belt, as it is now known, supplies bright stars for many famous constellations including Orion, Scorpius and Crux, the Southern Cross...
It is a sizeable structure, some 3000 light years across, and can be traced as a bright band of stars tilted at about 20 degrees to the Milky Way. Within it are several thousand high-mass stars as well as up to a million low-mass ones. Most importantly, these stars appear to have formed separately from the rest of the stars in the galaxy - and that's what makes them so interesting.

He estimates that in the halo surrounding the Milky Way - which is a pretty typical sort of galaxy - there could be a million billion (1015) such clumps of dark matter.

Crucially, this substructure is remarkably durable. Inside the halo, clumps of ordinary matter tend to radiate energy away, and this allows them to settle onto the disc of the galaxy. Dark matter clumps do not normally emit radiation, and so continue to circulate in the same orbits into which they were born - and this means that from time to time a clump of dark matter will come crashing through the disc of the Milky Way.

Dark collisions

For Kenji Bekki of the University of New South Wales in Sydney, Australia, this line of thinking was encouragement enough to set to work. He cranked up a computer model and began simulating what happened as clump after clump of dark matter smashed into one giant molecular cloud after another. Sure enough, he found that it was child's play to generate something resembling a Gould's belt. "The tilt is easy to reproduce," he says. "These collisions may be entirely natural.

Childs play indeed.

But there are some intestesting things it mentions...

The Large Magellanic Cloud (LMC) sits just 186,000 light years away, and at first sight it appears to be a mess of stars with no obvious structure. Closer inspection, however, has revealed a bar-like structure of older stars buried near its heart.

...Bekki wondered whether a collision with a piece of halo substructure could be the cause - and in his simulations, it could. He found that a clump of dark matter with 100 million times the mass of the sun - which equates to about 1 per cent of the mass of the LMC itself - could reproduce the offset bar. It would do this not by moving the bar itself, but by rearranging the surrounding stars so that the bar appears to be off-centre. "The results strongly suggest that apparently isolated dwarf galaxies develop off-centre bars from interactions with dark matter clumps," he says.

Evidence for similar collisions is starting to turn up even further afield. Bekki is casting a critical eye at dwarf galaxy NGC 6822, which has a noticeable hole about 5000 light years across. "It looks like a collision to me," he says.

Meanwhile, Comerón has also found something that he believes to be a Gould's belt in another galaxy. Down in the south-east quadrant of the magnificent spiral galaxy M83 is a bright burst of stars, sitting in an otherwise dark lane between spiral arms. It is about 1500 light years across. "The complex stands out clearly from the spiral pattern of the galaxy, and its size and age make it look like a Gould's belt," he says.

Power bands in the sky. What could cause a line of stars to be brighter and in the wrong place?