Mercury: a moon-scale body

Written by
Emily Lakdawalla
March 17, 2011
As I wait for the MESSENGER Mercury Orbit Insertion webcast to start, I thought I'd fiddle with some images to point out that Mercury is a bridge between the scales of planets and the scales of moons. Here's a collage of the eight bodies in the solar system that are between 2,500 and 6,000 kilometers in diameter. That's Mercury on the left, then the Moon, then the four Galilean moons of Jupiter, then Titan, then Triton. Both Ganymede and Titan are bigger than Mercury; Ganymede's actually the biggest but Titan appears bigger because of its puffy atmosphere.

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