Twin City Amateur Astronomers
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Overview Facts and Figures Missions to Mercury
Mercury is our solar system's closet planet to the Sun. Because it is so close to the Sun, Mercury is difficult to observe and can only be seen during twilight.

Orbiting the Sun in just over 88 days, Mercury is never more than 28° away from the Sun.

Mercury is a very dense planet and has a strong magnetic field which implies a solid metal core.

The surface of the planet is heavily cratered with several that exhibit prominent "rays" from the impact. The largest crater on Mercury is the Caloris Basin which formed from an ancient impact and is about 1300 km across.

There is little evidence of an atmosphere, so the nighttime temperature drops 600°C from the daytime temperature.