The planet closest to the sun has no atmosphere, oceans or visible signs of life.
While mostly very hot on its day side, the poles are cold enough to support megatons of water ice.
To an astronaut standing on its surface, Mercury would appear similar to the moon.
Gravity on Mercury is nearly the same as it is on Mars, about one-third the gravity on Earth, despite the fact that Mars is much larger. This means that Mercury is very dense.
Temperatures on Mercury range from minus 290 degrees Fahrenheit (minus 180 degrees Celsius) at the coldest, up to 800 degrees Fahrenheit (430 degrees Celsius) in the daytime.
Source SPACE.com: All about our solar system, outer space and exploration.
Source: http://www.space.com/26894-living-on-mercury-explained-infographic.html
