latest stories:   Super-Earth GJ 1214 b  Paul A. Kempton   In
the meantime, astronomers are honing their techniques on the
closest thing available—so-called super-Earths, just a few times
the mass of our own planet, which are too hot to be habitable
but are interesting in their own right. To that end, a team of
researchers has managed to capture the light spectrum of a
super-Earth backlit by its host star. The measurements provide
an unprecedented glimpse of the atmosphere of a relatively small
planet; most worlds that have been located in other planetary
systems are behemoths more massive than Jupiter. The research
appears in the December 2 issue of Nature. (Scientific American
is part of Nature Publishing Group.)  The few known super-Earths
whose orbits are fortuitously aligned so that they transit—pass
in front of their host star—from Earth's vantage point provide a
unique laboratory for planetary investigations. As a transiting
planet moves through its orbit, starlight filtering through its
atmosphere or