Europa

A moon of Jupiter, Europa lies a mere 44.5 light-minutes away (about 800.5 million km/497.4 million miles), a relatively small distance in comparison with the vastness of space.

Despite Europa’s 25 kilometer (15 mile) thick ice, scientists are hopeful that Europa may harbor life in an under-ice ocean. With possible thermal vents similar to ones here on Earth and friction on the ice caused by Jupiter’s massive gravitational pull, a salty ocean may have formed at the underneath Europa’s frozen surface.

Image via Star Walk