But in constructing the first atmospheric model that has the orbital dynamics of a star-planet-moon system fully included, astronomers Duncan Forgan, at the Royal Observatory in Edinburgh, and David Kipping, at the Harvard Smithsonian Center for Astrophysics in Cambridge, turn that idea on its head.

FORBES: Earth-Like Exo-Moons Can Lurk Well Beyond Planetary Habitable Zones, Say Astronomers

Kepler-37b is a tad larger than our heavenly dance partner, the Moon, and whizzes round a star much like our Sun, with two larger planets in its system for company.

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Stewart's co-star Robert Pattinson doesn't make our list because he is over 21, but New Moon's Taylor Lautner does.

FORBES: Hollywood

In their paper, the co-authors argue that gravitational tidal heating caused by the gravitational friction of an earth-like exo-moon on an eccentric orbit around a Jupiter-like planet lying at a Jupiter-like distance from its parent star, could, in fact, create habitable conditions.

FORBES: Earth-Like Exo-Moons Can Lurk Well Beyond Planetary Habitable Zones, Say Astronomers