Solar System

☿ Inner Solar System

Mercury

The solar system's smallest planet. Its most brutal.

Mercury is the runt of the inner solar system — and also its most brutal. Stripped of any meaningful atmosphere, it endures temperature swings of over 600 degrees between its sun-scorched days and frozen nights. No wind. No weather. Just rock, craters, and silence. The solar system's smallest planet is also its fastest, racing around the Sun in just 88 Earth days, as if it cannot bear to stay still.

"No wind. No weather. Just rock, craters, and silence."
57.9 million km

Distance from Sun

59 Earth days

Day Length

88 Earth days

Year Length

−180° to 430° C

Surface Temperature

0

Moons

47.4 km/s

Orbital Speed

4,879 km diameter

Diameter

3.7 m/s²

Surface Gravity

One Remarkable Thing

Mercury's core makes up 85% of its radius — proportionally the largest iron core of any planet in the solar system. It should not exist the way it does.

Earth
Mercury

Mercury's diameter is just 4,879 km — about 38% of Earth's. It is smaller than Jupiter's moon Ganymede.