NASA posters depict alien worlds

NASA has released three exoplanet posters in order to stir the public's curiosity about exoplanets discovered by the Kepler space telescope.

The three posters - created by Joby Harris and David Delgado, visual strategists at NASA's Jet Propulsion Laboratory, California in the US - contain artistic impressions of these alien worlds, reported Space.com.

One of the posters depicts Kepler 186f, a planet sometimes referred to as the 'Earth's cousin', which is larger than the Earth, and circles a star smaller and dimmer than the Sun.

Interestingly, the planet is shown to be covered with red grass.

"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 colour palette very different than the greens on the Earth," the poster's planet description reads.

Another poster shows a skydiver flying high above the super-Earth HD 40307g, an exoplanet that is eight times more massive than Earth.

"Prospects for life on this unusual world aren't good as it has a temperature similar to dry ice," the NASA poster said.

The third poster brings us Kepler-16b, an exoplanet which orbits a gravitationally bound pair of stars. That would mean any object on the surface, including a visiting space tourist, would cast two shadows.