Mercury Facts

DISTANCE FROM SUN: 36 million miles 
REVOLUTION AROUND SUN: 88 days
ROTATION: 59 days.
DIAMETER: 3,030 miles 
AVERAGE  TEMPERATURE: 800°F on day side, -270°F on night side.
SATELLITES: 0

It is the planet nearest the Sun. What would you guess about its temperature? 

 Mercury simply cannot make up its mind.   

At times it's REALLY hot ( 800°F!!!), and at times it is really cold. ( -270°F!!!)
How could it possibly get so cold on a planet that is so close to the sun? Go here for help.

 Mercury is really fast.  It can speed around the sun in only 88 days!  How long does it take the Earth to do the same thing?   
 

Mercury got its name because it is so fast.  The planet was named after the messenger of the ancient Roman gods. His name was Mercury. He had wings on his feet and on his head to speed him along. If you are going to be a messenger for the gods, you had better be fast!  The element, mercury, is also known as quicksilver.  

There is no air as we know it on Mercury.  There is only a very thin atmosphere of helium and sodium.  There is no water on this planet, so don't plan any vacations there!

The only planet that is smaller than Mercury is Pluto.  In fact, the planet Mercury is only a little larger than our moon.

Mercury is a rocky planet--very much like our moon. The surface of the planet is marked with craters and covered in dust as a result of meteors hitting it. Meteors do not burn up in such a thin atmosphere. There is no friction.  The meteorites leave huge dents when they hit the planet. Planets like Mercury and the other inner planets, Venus, Earth, and Mars, have a rocky surface and a metal core, or center.

Although Mercury revolves around the sun at a really high speed, Mercury rotates very slowly. In fact, Mercury takes almost 60 of our days to rotate one time.  How long does it take the Earth to rotate once?   Imagine not seeing the sun for almost 30 days at a time!  Imagine how cold it would be without sunlight for so long!  

Now let's warm you up. Imagine being the closest planet to the sun, and not turning away from the sun for 30 days!  As a result, the sunny side of the planet is baked constantly by a very strong sun. Daytime temperatures go up to 806°F.  At night, although the sun is just around the corner, the temperature plunges to -297°F.