Astronomy

`Note that the above numbers are valid for a 2 km asteroid made out of wood.' - Daniel Silevitch <dmsilev@eta.pha.jhu.edu> on sci.astro (taken quite out of context)

I have a great fascination with astronomy, and consider myself lucky to live in a time when my species is making so many amazing astronomical discoveries. If I had my life to live over again, I might well become an astronomer. (At the moment it's an unlikely leap, since I have a particularly deficient background in math.)

Here are some of my favourite astronomy-related web sites:

Pretty pictures

• I visit the Astronomy Picture of the Day almost every day (and check out their archive for anything I've missed). Robert Nemiroff and Jerry Bonnell do an excellent job of selecting (often topical, and usually beautiful) astronomy pictures and writing up descriptions of them, replete with links. You can learn a lot at this site, and by following its links to others. Or you can just look at the pretty pictures.
• The Hubble Heritage Project presents pictures from the Hubble Space Telescope.

Extrasolar planets

• Extrasolar Visions is a site devoted to speculation about actual extrasolar planets. A number of extrasolar planets have been discovered so far (mostly by detecting the slight wobble they cause in the star they orbit, but also by gravitational lensing, and one has been confirmed by noticing the dip in brightness as it passes in front of its star). The Extrasolar Visions site starts with the actual data about these planets (mass and orbit of planet and type of parent star) and adds a whole bunch of imagination to produce pictures and descriptions of what those planets or their moons might be like. A lot of it is (and has to be, at this point) completely made up, but it's interesting nonetheless, and based on kernels of fact. One nice feature at this site is a three-dimensional starmap (in perspective drawing) showing the spacial relationships of the stars with planets discovered around them to our sun. Unfortunately, the site is very slow and requires Java and/or Javascript.
• A more strictly factual site is the Extrasolar Planets Encyclopaedia at the Observatoire de Paris (also available in French). This page has news of recent detections and publications, announcements of meetings and conferences, and the like.
• Michael Matessa has a page about extrasolar planets, and a table of known exoplanets, which can be sorted by various parameters (mass, distance from primary, etc.)
• Most of the planets have been detected by Geoff Marcy and Paul Butler, who pioneered the technique, and they maintain a web page for the SFSU planet-search project.

Sky maps

• NASA's SkyView site lets you browse various digitized sky surveys (in various wavelengths)
• Heavens-Above generates current sky maps showing the position of satellites and planets (as well as stars), so you can figure out when you can go outside, look up, and see the International Space Station or an Iridium satellite passing overhead.

General astronomy education

• Phil Plait has a page about Bad Astronomy - astronomical misconceptions or gaffes in newspapers, TV, movies, and popular culture. It's a great place to learn some good astronomy, as well as have a laugh, and the site also has a series of bite-sized astronomy essays on various topics.