Astronomy Picture of the Day

Explanation: Do other rich planetary systems exist? Our Solar System has the most planets of any known star, most probably because it is so hard to detect planets around other stars. Sensitive measurements, though, have now uncovered a slight but complex wobble of the Sun-like star HD 10180 indicating that it has at least five planets and possibly more, making it the richest extra-solar planetary system yet known. HD 10180's planets were discovered in years of data using the sensitive HARPS spectrograph attached to the ESO's 3.6-meter telescope in La Silla, Chile. The planetary system appears quite different than our Solar System, since all of HD 10180's discovered planets have Neptune-like masses but orbit inside the distance of Mars. An artist's depiction of flying into this system is shown in the above video. In the future, more sensitive data taken over longer time periods may extend the star-wobble detection technique into the realm of uncovering more distant and more Earth-like planets.