Tuesday at the European Week of Astronomy and Space Science meeting in Hatfield, England, astronomers announced a new milestone: an extrasolar planet with the lowest confirmed mass of any yet discovered around a normal star . “Confirmed” . . . “normal star” . . . seems like a lot of caveats, doesn’t it? Let me explain. The planet is called Gliese 581 e, and the research says it contains 1.9 times Earth’s mass. Earth-mass planets are the holy grails...

The discovery and optical imaging of Fomalhaut b , a planet orbiting the nearby star Fomalhaut, has wider implications for exoplanet science. I talked to NASA scientist Marc Kuchner about it. Kuchner works in the Exoplanets and Stellar Astrophysics Laboratory at Goddard Space Flight Center in Greenbelt, Maryland. He uses computer models to study the effect planets have on interplanetary dust. Kuchner (pictured at left below) and Christopher Stark...

They've discovered Earth ... again. The astronomy blogosphere is abuzz with news of "shrunken versions of our solar system" and "miniature worlds in the making," at least according to the press releases I've been reading. Nobody has called them " Hobbit solar systems" yet, but give them time. Alexander Scholz of the University of St. Andrews in Scotland , and Ray Jayawardhana from the University of Toronto reported...