Mercury
Mercury is the closest planet to the Sun and the smallest planet in our solar system. It races around the Sun faster than any other planet and looks a lot like a gray, cratered rock.
Weather and air
Mercury has almost no air to breathe or to hold heat. Its days are extremely hot while its nights are extremely cold because the thin air cannot keep warmth.
A few interesting things
- Mercury orbits the Sun in only 88 days, the fastest of all planets.
- It has very big temperature swings — scorching in daytime and freezing at night.
- Mercury has almost no atmosphere, so meteors hit the surface and make many craters.
- The surface looks similar to our Moon with lots of round impact craters.
- Scientists have found water ice hiding in permanently shadowed craters at the poles.
- Even though Mercury is small, it has a magnetic field like Earth does.
Moons
Mercury does not have any moons.
A few details
- Diameter: 4,880 km
- Type: rocky
- Distance from sun: 57.9 million km
- Day length: 4,224 hours
- Year length: 88 days