An anonymous reader writes with this excerpt from Cosmos:
"Astronomers have made the first direct capture of a spectrum of light from a planet outside the Solar System and are deciphering its composition. The light was snared from a giant planet that orbits a bright young star called HR 8799 about 130 light-years from Earth, said the European Southern Observatory (ESO). ... The find is important, because hidden within a light spectrum are clues about the relative amounts of different elements in the planet's atmosphere. 'The features observed in the spectrum are not compatible with current theoretical models,' said co-author Wolfgang Brandner. 'We need to take into account a more detailed description of the atmospheric dust clouds, or accept that the atmosphere has a different chemical composition from that previously assumed.' The result represents a milestone in the search for life elsewhere in the universe, said the ESO. Until now, astronomers have been able to get only an indirect light sample from an exoplanet, as worlds beyond our Solar System are called. They do this by measuring the spectrum of a star twice — while an orbiting exoplanet passes near to the front of it, and again while the planet is directly behind it. The planet's spectrum is thus calculated by subtracting one light sample from another."