Seeing a planet around another star means finding a way to mask the overwhelming glare that swamps the faint image. The job is, as a news release from the American Institute of Physics reminds us, something like trying to see the light of a match held next to an automobile's headlight from a distance of 100 meters. Consider that the Earth is ten billion times less bright than the Sun at optical wavelengths and you see the enormity of the problem. Among the possible solutions is an approach taken by Grover Swartzlander and his colleagues at the University of Arizona. Swartzlander eliminates excessive starlight by feeding it through a helical 'mask' -- a kind of lens. The result is what the team calls an optical vortex coronagraph. From the news release: The process works in the following way: light passing through the thicker and central part of the mask is slowed down. Because of the graduated shape of the glass, an "optical vortex" is created: the light coming along the axis of the...

The search for planets around small stars seems to be gaining in intensity. Now a team of French and Swiss astronomers has announced the discovery of a Neptune-class planet around the star Gliese 581. The Gliese catalog lists all known stars within 25 parsecs (81.5 light years) of the Sun, making its listings of significant interest in the hunt for exoplanets and, long-term, in our thinking about robotic interstellar probes. Also catching the eye is the fact that this star is a red dwarf, confirming the notion that such stars are ripe for exoplanetary investigation. Gliese 581 is 20.5 light years away in the constellation Libra. Red dwarfs like it make up about 70 percent of the galactic population; in fact, of the 100 stars closest to the Sun, fully 80 are red dwarfs. Earlier surveys of red dwarfs have revealed few with planets, but Stéphane Udry (Geneva Observatory), a co-author of the paper on the new find, believes the earlier surveys may have operated with insufficient...