Mercury

Overview

Mercury, the smallest planet in our Solar System, shimmers just 58 million km (36 million miles) from the Sun. Its reflective, cratered surface flows between extremes: a molten 427°C (800°F) by day, freezing to -173°C (-280°F) by night.

Physical Properties

• Diameter: 4,879 km (3,032 miles)
• Mass: 3.3 × 10²³ kg (5.5% of Earth’s)
• Surface: Cratered, metallic sheen
• Core: Iron-rich, 85% of radius

Orbit & Flow

A swift, liquid dance:

• Orbit: 88 Earth days
• Rotation: 59 Earth days
• Resonance: 3:2 spin-orbit

Exploration

Earth’s probes:

• Mariner 10 (1974-1975): First reflection
• MESSENGER (2004-2015): Detailed mapping
• BepiColombo (2018-now): Current study