PLANET OF THE WEEK : mercury

Mercury is the closest planet to the sun.

Mercury is a battered and baked planet just larger than Earth's moon. Evidence of heavy bombardment from the chaos of the formation of the solar system is left in the hundreds of craters and resulting lava flows on this small, barren planet. The largest crater is Beethoven at 643 km in diameter and is the largest in the solar system. The largest feature, Caloris Basin, is 1300 km in diameter and was probably caused by an impact from an object larger than 100 km in diameter. Some craters have ice in them even though the planet is so hot because the sun never reaches into the shadows due to the planet's tilt and orbit. With no atmosphere, there is a temperature difference of about 600 degrees between the coldest spots and hottest spots on the planet.
Mercury orbits the sun in about 88 Earth days but takes 58 Earth days to rotate once. On this planet a year takes a (Mercury) day and a half!