If you ever go to Mercury, bring your sunscreen because it is the planet closest to the Sun. You'll also need a pair of thermal underwear because at night Mercury cools down fast. Temperatures can drop to as low as -292 degrees F! Now that's cold! You will also need a pair of hiking boots so you can travel and climb in and out of the craters that cover Mercury's scarred landscape.

Diameter: 3,000 miles Location: 1st planet from
Sun Average Distance from Sun: 35 million miles
Average Surface Temperature: 330 degs. F
Number of Moons: 0
Orbital Period: 88 Earth days
Characteristics: fastest orbit of any planet in solar system, atmosphere is the thinnest, and its temperatures, ranging from 180 to 450 degrees C, are the most extreme in the solar system

Image credits: main image: courtesy of JPL, California Institute of Technology and NASA; quote, © AMNH.