Dark and Dusty Astronomy - Smashing!

Apparently lots of interesting things have been going on in the world of science the past few weeks, while I've been too busy to notice. Here are a few astronomy-related news stories. Hopefully soon, I'll post some physics and engineering ones, too.

BBC reports on dwarf spheroidal galaxies made mostly of dark matter.
The explanation of what happened to the ordinary matter in these galaxies is similar to that used to verify the existence of dark matter last summer: The ordinary matter interacts in the ordinary way, so when the dwarf galaxy crashed into another galaxy, the ordinary matter experienced drag and got left behind. Dark matter doesn't interact much, so it passed through mostly unscathed. The net result of losing most of the ordinary matter is a dark-matter dominated galaxy.

Also from the BBC, an article explaining how a dead star could have a dust cloud.
A star like our sun, at the end of its lifespan can no longer support fusion to produce heat and light. It then makes a transition to being a white dwarf star, gradually cooling to oblivion. In the process of transition, it will expand violently and blow off any dust that had surrounded it. How can new dust clouds develop around the dead star - doesn't dead mean unchanging? Nope. Apparently the violent expansion also destabilizes the orbits of the comets around the star. The comets then begin to crash into each other producing a dust cloud. Cool eyeball image!