Mercury

Mercury is the closest planet to the sun & is the eight largest. Mercury is smaller but more massive than the two moons Ganymede & Titan. Mercury is 4,880 km in diameter & has a mass of 3.30e23 kg. Mercury was the believed to be the Greek god of commerce, travel & thievery, the counterpart of the Greek god Hermes messenger to the gods. Mercury most likely got its name because it travels so quickly across the sky. Since mercury is closer to the sun than earth it is harder to see it with a telescope. Temperatures on mercury rang from 90k to700k which is why scientists say that no life can be supported there. Mercury, like the moon, has many craters & no plate tectonics. Mercury is the second densest body major body in the solar system after earth. The only reason earth is denser than mercury is because of its gravitational compression. Mercury has a large iron core that dominates its interior structure; this core’s radius is about 1800-1900km & its crust is about 500-600km thick which is analogous to earth’s core mantle & crust. Mercury’s atmosphere is very thin; it is composed of atoms blown off the surface by solar wind; because it is so close to the sun these atoms are quickly blown into space; this makes the atmosphere unstable. Mercury has a magnetic field 1% the size of earths. One of the largest features on mercury is the Caloris Basin which is about 1,300km in diameter. The Caloris Basin is thought to be caused by an impact on the surface during the history of the solar system. In addition to the craters on its surface there are places on mercury with relatively smooth plains: scientists say this may be the result of ancient volcanic activity.