If the name Alex Wolszczan (pronounced VOL-shtan) isn't immediately familiar, it may be because we've become so inured to new extrasolar planet discoveries that we've forgotten about the first. But it was Pennsylvania State University's Wolszczan who, in 1991, was the first to detect planets outside our Solar System, around the pulsar PSR B1257+12, an incredibly dense neutron star that is the remnant of a once massive star in the constellation Virgo some 1500 light years away. These were the first new planets discovered since Clyde Tombaugh's detection of Pluto in 1930, and Wolszczan was able to learn a surprising amount about them. Using the Arecibo radio telescope in Puerto Rico, he found that two of them were roughly similar in mass to the Earth, while the other corresponded roughly to the mass of the Moon. Their spacing around the primary corresponded to that between Mercury, Venus and the Earth around our Sun. Image: An artist's conception of one of the planets around the pulsar...

The 2005 Winter Conference on Astrophysics is now in session in Aspen, with papers running through tomorrow. The topics here make up a wish list for those interested in learning more about the next steps in extrasolar planet detection and analysis. Tomorrow's last session, for example, is on new technologies for detection, includng the Terrestrial Planet Finder mission. Earlier sessions have included everything from theories of giant planet formation to planetesimals and how they form in protoplanetary disks. But the first story out of the conference to hit the media was the detection of possible planets around a small brown dwarf called OTS 44, which is only 15 times the mass of Jupiter -- before now, the smallest brown dwarf implicated in debris disk formation was almost 30 times the mass of Jupiter. You can see how this hypothetical planetary system scales next to our own in the image below. OTS 44 is approximately 500 light years away in the Chameleon constellation. Image: This...