The Interior of Mercury Target Name:   Mercury Spacecraft:   Mariner 10 Produced by:   Calvin J. Hamilton Copyright:  © 2001 Calvin J. Hamilton Date Released:  3 December 2001 (Publisher Permission Request)

• Mercury

Most of what is known about the internal structure of Mercury comes from data acquired by the Mariner 10 spacecraft that flew past the planet in 1973 and 1974. Mercury is about a third of the size of Earth, yet its density is comparable to that of Earth. This indicates that Mercury has a large core roughly the size of Earth's moon or about 75% of the planet's radius. The core is likely composed of 60 to 70% iron by mass. Mariner 10's measurements of the planet reveals a dipolar magnetic field possibly produced by a partially molten core. A solid rocky mantle surrounds the core with a thin crust of about 100 kilometers.

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