PlanetQuest is a distributed computing project aimed at using spare computer cycles to search for extrasolar planets. The search will use the transit method, in which a planet is detected when it crosses the face of its primary as seen from Earth. That requires subjecting the data from thousand of stellar images to analysis, a job that would tax the largest supercomputer, but perhaps not the kind of distributed network that SETI@Home has already put to work in its search for extraterrestrial intelligence.

Nobody knows for sure how many stars have planets that line up edge-on to our own line of sight, but estimates run between 0.5 and 10 percent. Instead of studying a single star for long periods, as is done in the radial velocity method that has found most extrasolar planets so far, the transit approach has to rely on images of highly crowded star regions, where tens of thousands of stars can be viewed at once. The best area, then, is in the plane of the Milky Way. Stars captured in the project’s images will be be analyzed to determine their light curve, with PlanetQuest’s transit detection algorithms testing for the presence of a planet.

A beta version of the software should be available at the PlanetQuest site by the end of 2005, with the project going live in 2006. PlanetQuest notes that while finding terrestrial planets around Sun-like stars is beyond current capabilities, it may well be possible to find such planets around M-class red dwarfs. Another bonus: PlanetQuest may be able to detect optical SETI signals, a significant addition to existing efforts in that area.

A list of research articles by members of the PlanetQuest team can be found here. And Wired Magazine wrote the project up in a recent article by Amit Asaravala.