As the count of known planets in distant star systems continues to grow (the number now exceeds 400), so too does the number of ways we have to learn about them. Reporting in Nature this week, a team of astronomers say they have measured the makeup of an exoplanet's atmosphere using an Earth-based telescope for the first time. Mark Swain's team directed NASA's Infrared Telescope Facility toward HD 189733 b, a planet 63 light years away, discovered back in 2005.
HD 189733 b was already known from space-borne observations to harbor several specific molecules in its atmosphere: water, methane, carbon dioxide and carbon monoxide [Scientific American]
. Swain's analysis confirmed those previous findings using spectrography, in which the light from an object is broken down into its component wavelengths,
allowing the identification of atoms or molecules by their unique emission or absorption properties [Scientific American].
Swain's team also turned up ...
