Since its launch in 2009, the Kepler Space Telescope has found a lot of "exoplanets," or planets that are orbiting a star, just as the Earth orbits the sun. The total number is said to be 1,000-plus. However, last year one exoplanet was discovered that has unusual properties—it is within the "habitable zone," i.e. the right distance from the right-sized star to potentially support water, and thus, life.
Following that discovery, more "habitable zone" exoplanets have popped up, bringing the total to eight. To commemorate these, NASA's Jet Propulsion Laboratory at the California Institute of Technology picked the three most promising—the dual-star-havin' "Kepler 16b," the heavy-gravity "HD 40307g" and the red-sky-boasting "Kepler 186f," and commissioned a series of WPA-like posters for each. Supposedly created by the "Exoplanet Travel Bureau," the posters are reminiscent of the ones urging Americans to travel to the Grand Canyon in the '30s and '40s.The posters each come with text beneath them that would be too small for you to read here, so we'll extract it for you:
Like Luke Skywalker's planet "Tatooine" in Star Wars, Kepler-16b orbits a pair of stars. Depicted here as a terrestrial planet, Kepler-16b might also be a gas giant like Saturn. Prospects for life on this unusual world aren't good, as it has a temperature similar to that of dry ice. But the discovery indicates that the movie's iconic double-sunset is anything but science fiction.
Twice as big in volume as the Earth, HD 40307g straddles the line between "Super-Earth" and "mini-Neptune" and scientists aren't sure if it has a rocky surface or one that's buried beneath thick layers of gas and ice. One thing is certain though: at eight time the Earth's mass, its gravitational pull is much, much stronger.
Kepler-186f is the first Earth-size planet discovered in the potentially 'habitable zone' around another star, where liquid water could exist on the planet's surface. Its star is much cooler and redder than our Sun. If plant life does exist on a planet like Kepler-186f, its photosynthesis could have been influenced by the star's red-wavelength photons, making for a color palette that's very different than the greens on Earth. This discovery was made by Kepler, NASA's planet hunting telescope.
Don't get too excited about visiting, though; the closest is some 475 light years away.