I'm a great believer in getting the most out of older systems. The computer I do most of my work on is now eight years old. I have access to newer equipment, but I built this box with an eye toward longevity and I'm still happy with it. With the pace of technological change, it's definitely gotten creaky despite additional memory, a new video card and various other upgrades. That means that Windows gets slower and slower on it, but then, I rarely use Windows, being an open source guy to the bone. Linux has always been my choice. Now the nice thing about Linux is that, no matter which version I run (and I've run quite a few by now), I can get snappy performance out of this old box. The astronomical analogy isn't too far to seek -- these days we're talking about building larger and larger Earth-based telescopes, and in fact have just inaugurated the Gran Telescopio Canarias on a 7,874-foot mountaintop in the Canary Islands, an instrument that has the largest segmented mirror -- 10.4...

Protoplanetary disks may not raise the same level of excitement that the discovery of new planets does, but to me, the idea of watching a planetary system form is awe-inspiring. I can't help but wonder whether, going back about five billion years or so, astronomers around some distant star weren't watching the early signs of planetary formation around our own star. Disks in their various stages give us a sense of the continuity of solar system development. Continuity, that is, in the sense that stars seem to form planets as a matter of course. But we're seeing yet more evidence this week that protoplanetary disks can vary markedly from star to star. Now comes news of the dust cloud around 51 Ophiuchi, which turns out to be not one but two distinct disks, an inner one with grains 10 micrometers and larger in diameter (based on infrared observations), and an outer one made up of primarily 0.1 micrometer grains. Image: This graphic compares the inner and outer disk of the 51 Ophiuchi...

?I love to run into genuine enthusiasm when someone is doing cutting-edge science, and Didier Queloz (Observatoire de Geneve) has not let me down. Here the astronomer is discussing CoRoT-7b, which new studies have determined is a rocky world: "This is science at its thrilling and amazing best. We did everything we could to learn what the object discovered by the CoRoT satellite looks like and we found a unique system." Amazing indeed. We knew from CoRoT's transit measurements that the radius of this planet was about twice that of Earth. Queloz and team went to work with the HARPS spectroscope (High Accuracy Radial velocity Planet Searcher) at ESO's La Silla site in Chile, gathering fully seventy hours of observations on the system. What emerged was the best mass measurement for an exoplanet yet. Combining that revealed mass -- five times that of the Earth -- with CoRoT's radius readings, we can deduce that CoRoT-7b is about as dense as Earth, and thus almost certainly a rocky world....

The exoplanet hunt has entered a significant new phase, one focused on transiting planets and the useful things we can learn about their physical properties and atmospheres through such events. Driven by CoRoT and Kepler, we're now in position to use those transits to spot smaller worlds than ever, down to terrestrial size, and naturally the focus is on Earth analogs located in the habitable zones of their stars. So think of it this way: We've gone from a broad-brush approach based largely on radial velocity methods to a more selective hunt, one that will take us to the realm of planets that can have liquid water on their surfaces and aren't so different from our own. Not that the continuing work on characterizing planetary systems is of any less importance, but we've found plenty of gas giants, and now we're trying to learn something about how common these smaller worlds may be. Putting an exclamation point on this focus is a conference called Pathways Towards Habitable Planets, to...