- For every 2 orbits of the Sun, which takes around 88 Earth days, Mercury completes three rotations of its axis.
- Every seven years or so, Mercury can be seen from earth passing across the face of the Sun.
- It is named for the Roman god Mercury, the messenger to the gods – most likely related to the orbiting speed of the planet.
- After the Earth, Mercury is the second densest planet.
- The planet has just 38% of the gravity on Earth. This means that Mercury isn’t able to hold the atmosphere it has and it instead gets blown away by solar winds.
- Mercury has no moons or rings because of its low gravity and lack of atmosphere.
- It was once believed that a planet called Vulcan existed between the orbit of Mercury and the sun.
- Mercury is only the second hottest planet because Venus is the hottest planet.
- The range from -170°C (-280°F) during the night to 430°C (800°F) during the day.
- Mercury has a large iron core that is around 40% of its volume.