Alien plant. Artwork of an alien plant adapted to live on a planet with high surface gravity. The plant differs to those found on Earth. Its short, thick, stocky appearance allows it to survive the crushing pressures of high gravity. A rocky planet that is 1.2 times the diameter of Earth would have twice the mass and three times the surface gravity of Earth. It would have a thick atmosphere causing a greenhouse effect. For life to exist, it would need to be sufficiently far from its parent star to avoid a runaway greenhouse effect, such as on the planet Venus.