Re: News: Galactic clash sheds light on dark matter.

<tgdenning@xxxxxxxxxxxxx> wrote:

On Aug 30, 5:32 pm, Ye Old One <use...@xxxxxxxxx> wrote:
On Sat, 30 Aug 2008 13:24:03 -0700, Timberwoof
<timberwoof.s...@xxxxxxxxxxxxxxxxxxxxx> enriched this group when s/he
wrote:

In article <0c5jb49fjtkluddjvanmb1josro6uo0...@xxxxxxx>,
Ye Old One <use...@xxxxxxxxx> wrote:

As the two clusters merged at speeds of millions of miles per hour,
the hot gas in each cluster collided and slowed down, the astronomers
said. The dark matter, however, did not.

This would mean that the rotation rate of stars in such galaxies should
now change because they're in a differently-massive galaxy than before.

Which then brings up the question of simulated galaxy collisions: Do
they take dark matter into account? (I'm sure later ones do.)

Well..... Since few can yet agree on exactly what effect DM is having
on galactic evolution it is still hard to model it. You think you get
it right modeling what you see in one galaxy and then find it doesn't
work on another. Some have seriously asked the question "Is there more
than one type of DM?"

--
Bob.

Can you elaborate on the reasoning in this collision model? Is the DM
supposed to be moving along with the non-DM until the collision, and
then passing through the collision area---so the stuff on the left
side of the image was originally on the right side, associated with
the NDM moving from the right?

That's the only way the picture makes sense, I think. But then what is
the interaction of the DM with the NDM?

-tg

Ungh. My head just exploded.
--
macaddicted
Wisdom is radiant and unfading and she is easily discerned
by those who love her and is found by those who seek her.
Wisdom 6:12 (NRSV)

.

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