Average distance from the Sun: 36,000,000 mi.
Diameter of the planet: 3031 mi.

Mercury, the closest planet to the sun, is a barren, cratered vacuum that even without an atmosphere, has a temperature ranging from -315 degrees to 648 degrees farenheit.
These radical temperature changes are brought about because of this planets extremely slow rotation period of 59 of our days, or 1416 hours.
But just because of it's slow days, doesn't mean that it has slow years, one of it's revolutions around the sun only takes 88 days. Because of this planets slow rotation speed, the gravity is less than half of Earth's gravity, 38% actually. This means that your average 150 pound person on Mercury would only weigh 57 pounds. Mercury has a 0 axis tilt and is composed of helium, sodium and very little oxygen.