Mercury is the smallest planet in our solar system. It is the first planet from the sun but still Venus is the hottest planet of our solar system. Mercury is named after the roman god of speed because it revolves to fast that it’s one year lasts 88 Earth days. Mercury’s one day lasts 176 Earth days. Mercury is grey in color. Most common elements found on Mercury’s surface are sodium, calcium and nickel. Just like Earth it have an active core made up of molten rock, Mercury’s structure also resembles Earth by having a crust, mantle and core. In day time Mercury’s temperature rises to 400 degrees Celcius and in night it falls to -20 degrees Celcius. Mercury’s surface is full of craters.