The Spitzer Space Telescope has been measuring temperatures, atmospheres and orbits of planets light-years from Earth since 1993:
Spitzer Space Telescope
and To some extent so does the Kepler, Chandra X-ray telescope, Compton Gamma-Ray Observatory , and of course the Hubble telescope.
For those that want more information in science's search for life and habitable planets:
PlanetQuest: Exoplanet Exploration
Exoplanet Exploration Program