OK, while I was so busy with the party and the con, a few interesting and timely astronomy stories broke.
SPACE.com -- Obscure Comet Brightens Suddenly
Naked eye comets don't happen all that often (remember Hale-Bopp, or do we forget so quickly?). Holmes was a known comet, unlike Hale-Bopp, and brightened without warning. Probably a reaction to Bruce Willis approaching, no doubt.
In a more recent update, the comet is apparently developing a tail, as expected.
SPACE.com -- Scientists Say Dark Matter Doesn't Exist
OK, this one is about a forthcoming paper now available as a preprint. After results last year on the Bullet Cluster seemed to be a direct proof of the existence of dark matter, a couple of modified gravity theorists have gone through some contortions to argue that modified Newtonian gravity can still explain the results. I've printed the paper to take a look, but I'm skeptical. This is a case where dark matter offers an immediate and predictable explanation, but modified gravity must struggle after the fact. In my opinion, without a close read. I'm also suspicious of the submission/revision history. The paper was apparently submitted the first time to the preprint server before being refereed, a very bad practice, then resubmitted after acceptance, and resubmitted a third time after additional unspecified revisions. Funny that it's only now getting popular press, at least that I've seen.
Anyway, their basic idea is that if you take out the dark matter, and modify gravity to account for the lensing, you can somehow account for the separation in the center of the lensing mass and the center of the baryonic mass (dominated by the hot X-ray gas rather than the galaxies).
Some interesting commentary about this modified galaxy (MOG) theory and the bullet cluster results can be found here. My own bias as a simple-minded observer is that the MOG people are jumping through a lot of hoops with some extra parameters that might not be fair, while the very straightforward interpretation favors dark matter.