Visiting Chicago for the annual meeting of the Astronomical Society of the Pacific, I attended a one-day session on astronomy visualization (the usual suspects). Lots of things caught my attention, but I thought I’d highlight the Wolfram Demonstrations Project, a collection of visual (non-Java) applets that utilize the free Mathematica Player.

The image above is a snapshot of the “day and night world clock” from the collection. Nothing too special about it, particularly as a snapshot, but within the player, you can fiddle with the time of year and time of day to see how the dividing line between day and night changes over the course of the year. As a kid, I was always fascinated by the Geochron clock at my local planetarium, so perhaps I’m just being nostalgic. Still, I enjoy watching the terminator’s projection on the flat surface, bending through the course of a year.

Among the other demonstrations, I like the Cepheid light curve, too, as well as the hydrogen orbitals and the inverse Hilbert matrices.