This week, NASA released images of the first cloud map of any planet beyond our solar system. The planet, known as Kepler-7b, is one of more than 150 exoplanets discovered by the Kepler telescope, and lies about 1,000 light years away from Earth.
The news follows a study of the exoplanet, more than three years in the making, which utilized data from both the Kepler and Spitzer space telescopes. In its latest findings, published in this month’s Astrophysical Journal Letters, researchers have produced a low-resolution map that depicts “a remarkably stable climate” on Kepler-7b, according to Thomas Barclay from NASA’s Ames Research Center. Rather than frequently shifting cloud patterns, like those found on Earth, scientists believe the exoplanet has consistently clear skies in the east and high cloud coverage in the west.
Scientists first began looking into the planet’s climate after the Kepler telescope picked up an anomaly on the planet’s western hemisphere. Unable to determine whether the bright spot they were seeing was a heat spot on the planet or cloud coverage above it, they called in the Spitzer telescope to get an accurate reading of the planet’s atmosphere. Spitzer, capable of detecting infrared light, allowed NASA to get its first temperature readings of Kepler-7b, estimated to be between 1,500 and 1,800 degrees Fahrenheit.
That’s certainly hot—but not nearly as hot as NASA would have expected, given the planet’s close proximity to its own star, far closer than the Earth is to the Sun. With a heat spot ruled out, the team was able to confirm that the western half of the planet experiences nearly continuous cloud coverage; clouds which are reflecting back much more light that most other planets of a comparable size.
This isn’t the first peculiarity scientists have discovered about Kepler-7b. They had already determined that the planet is 1.5 times the size of Jupiter—but only has half that planet’s mass—leading NASA to dub Keplar-7b one of the “puffiest” planets ever discovered. Its low mass allows the planet to whip around its star at a dizzying speed—a year on Keplar-7b lasts less than five days—and if the planet could be placed into a massive intergalactic bathtub, it would float.
The Keplar mission was launched in March 2009, and Kepler-7b was one of the first exoplanets it discovered. Since then, it has helped NASA identify more than 150 exoplanets, including one of the darkest planets yet discovered (Kepler-1b), as well as one of the smallest (Kepler-37b). In April of 2013, NASA announced the discovery of three Earth-like “water worlds” in the Lyra constellation, more than 1,2000 light years away, that fall into the category of “Goldilocks” planets, where conditions may be “just right” to support life.
Just weeks later, however, a malfunction with the Kepler telescope’s reaction wheels, which help focus its fixed field of view towards planetary bodies, caused a cessation in the collection of scientific data. After a failed attempt at fixing the two wheels, NASA remains uncertain about the mission’s fate, which was due to last until 2016. The Spitzer telescope, crucial to the latest discovery about Kepler-7b, is itself operating at partial capacity. First launched in 2003 with a mission length of 2.5 years, it more than doubled that before its onboard liquid helium supply ran out in 2009, rendering all but its infrared technology no longer usable.