An exoplanet is defined as a planet orbiting a star other than our own. The first exoplanet was discovered in 1992. Since then, almost 2000 exoplanets have been discovered with many more candidates waiting to be confirmed. Because of the vast distances between us and exoplanets we do not know much about their properties with current technology. Fortunately technology is improving and we are learning more about exoplanets.
Using NASA’s Kepler Space Telescope, planetary scientists have analyzed the climate of six exoplanets. The six planets are all very large relative to Earth’s size. These large planets are all close in to their parent star and as a result are very hot making them excellent for studying changes in atmosphere. The temperature on the surface of these planets is as high as 2900 degrees Fahrenheit!
Scientists measures changes in atmosphere in day and night cycles as the planets rotate on their axis and around their star. Lead author of the study Lisa Esteves describes the study:
“We traced each of them going through a cycle of phases in which different portions of the planet are illuminated by its star, from fully lit to completely dark.”
Using this technique, the daily climate cycle has been mapped. The counter clockwise rotation of these planets causes cloud cover to move eastward across the planets. The result of this is a cloudy sky during the night that clears up in the day.
Unfortunately these planets cannot support life as they are not terrestrial (have a solid surface) and are much too hot. The encouraging part of this study however is that, as our telescopes improve, we will be able to use this technique on smaller, Earth sized planets. Knowing the climate and atmospheric properties of smaller planets would be vital in determining whether or not a planet could support life.