Nasa offers out of this world vacations

When packing for a vacation on Kepler 16-b, it's good to remember the sunscreen. It does, after all, have two suns.

OK, so a long weekend visiting a planet 1,200 trillion miles away, may not be a realistic prospect just yet, but that hasn't stopped scientists at NASA from dreaming.

To mark the exciting discovery of a slew of potentially distant habitable worlds by its Kepler space observatory, the U.S. space agency's Jet Propulsion Laboratory at the California Institute of Technology has created a series of posters advertising imaginary vacations to some of them.

Rendered in the retro style of classic travel billboards of the 1920s, '30s and '40s, the posters depict these distant worlds as pleasurable destinations.

The image for Kepler 16-b -- previously compared to the fictional "Star Wars" planet of Tatooine because of its dual suns -- shows a space-suited figure basking in the light from the twin orbs overhead.

"Relax on Kepler 16-b," the poster says. "The land of two suns ... Where your shadow always has company."

Although the planet is depicted as a rocky, terrestrial world, Nasa says it could also be a gas giant like Saturn with freezing temperatures that would make it hostile to known lifeforms.

A second poster shows an astronaut free-falling to experience the powerful gravity over HD 40307g, a "Super Earth" 44 light years -- or 264 trillion miles -- away.

The third depicts Kepler-186f (even further away at 500 light years) with a scene of red trees held back by a white picket fence.