Mercury
Mercury is the smallest planet in the solar system and the closest to the Sun, with a diameter of about 4,880 kilometers and a fast orbit speed of 47.87 kilometers per second. It has a slow rotation, with one day equaling about 59 Earth days. Mercury's surface is heavily cratered and has many ridges and cliffs, as well as large areas of smooth plains, covered in a layer of fine dust. Its extremely thin atmosphere mostly consists of helium, sodium, potassium, and oxygen. Due to its proximity to the Sun, temperatures on Mercury can reach up to 427 degrees Celsius during the day, while dropping to -173 degrees Celsius at night.
