S o l a r S y s t e m There are 8 planets in our Solar System. What are they? Let's find out. Solar System 1/ Mercury Planet Mercury What is the planet Mercury? In our Solar System , there is a planet named Mercury. This is the first planet from the sun. The smallest planet in the solar system, and also the closest to the sun is Mercury. Mercury goes around the sun 1 time in 88 days. One day on Mercury equals 59 days on Earth. It has no moon. Mercury's surface looks like Earth's moon. How did Mercury get its name? The Romans believed that Gods and Goddesses were in charge of everything on Earth. Mercury is the name of the messenger for their gods. The Roman Mercury had wings on his helmet and shoes. He can travel quickly around the world. The planet Mercury goes quickly around the sun. That is how it got its name. Temperature? The day side of the planet reaches temperatures of up to 800 degrees Fahrenheit