Galaxies are big. Our own Milky Way contains about fifty billion solar masses of stars, and another ten billion of interstellar gas, roughly speaking. The average star is maybe half a solar mass, so crudely speaking, that’s one hundred billion stars. Give or take. For comparison, the population of the Earth has not quite reached eight billion humans.

I am a white American male. As such, I realize that there is no way for me to grasp and viscerally appreciate all the ways in which racism afflicts black Americans. Or, for that matter, all the ways in which sexism afflicts women. But I can acknowledge that these things exist. I can recognize when it happens. I’ve seen it happen to others, both friends and strangers. I can try not to be part of the problem.

I started this blog as a place to discuss science, and have refrained from discussing overtly political matters. This is no longer possible. Today is June 10, 2020 – the date set to strike for black lives. I want to contribute in a tiny way by writing here. If that seems inappropriate to you or otherwise makes you uncomfortable, then that probably means that you need to read it and reflect on the reasons for your discomfort.

Predictive power in science isn’t everything. It’s the only thing.

I haven’t written much here of late. This is mostly because I have been busy, but also because I have been actively refraining from venting about some of the sillier things being said in the scientific literature. I went into science to get away from the human proclivity for what is nowadays called “fake news,” but we scientists are human too, and are not immune from the same self-deception one sees so frequently exercised in other venues.

I was contacted today by a colleague at NASA’s Goddard Space Flight Center who was seeking to return some photographic plates of Halley’s comet that had been obtained with the Burrell Schmidt telescope. I at first misread the email – I get so many requests for data, I initially assumed that he was looking for said plates.

I happened to visit this blog as a visitor from a computer not mine. Seeing it that way made me realize how obnoxious the ads had become. So WordPress’s extortion worked; I’ve agreed to send them a few $ every month to get rid of the ads. With it comes a new domain name: tritonstation.com. Bookmarks to the previous website (tritonstation.wordpress.com) should redirect here. Let me know if a problem arises, or the barrage of ads fails to let up.

Britain and America are two nations divided by a common language. attributed to George Bernard Shaw Physics and Astronomy are two fields divided by a common interest in how the universe works. There is a considerable amount of overlap between some sub-fields of these subjects, and practically none at all in others.

I haven’t written here since late January, which not coincidentally was early in the Spring semester. Let’s just say it was… eventful. Mostly in an administrative way, which is neither a good way, nor an interesting way. Not that plenty interesting hasn’t happened. I had a great visit to Aachen for the conference Dark Matter & Modified Gravity. Lots of emphasis on the philosophy of science, as well as history and sociology.

There is a tendency when teaching science to oversimplify its history for the sake of getting on with the science.

This Thanksgiving, I’d highlight something positive. Recently, Bob Sanders wrote a paper pointing out that gas rich galaxies are strong tests of MOND. The usual fit parameter, the stellar mass-to-light ratio, is effectively negligible when gas dominates. The MOND prediction follows straight from the gas distribution, for which there is no equivalent freedom.