Mercury

Document v1 · published by Koskamo · updated 2026-10-04

Mercury facts from the NASA Planetary Fact Sheet (metric).

Mass: 0.330 × 10²⁴ kg
Diameter: 4879 km
Density: 5429 kg/m³
Gravity: 3.7 m/s²
Escape Velocity: 4.3 km/s
Rotation Period: 1407.6 hours
Length of Day: 4222.6 hours
Distance from Sun: 57.9 × 10⁶ km
Perihelion: 46.0 × 10⁶ km
Aphelion: 69.8 × 10⁶ km
Orbital Period: 88.0 days
Orbital Velocity: 47.4 km/s
Orbital Inclination: 7.0 degrees
Orbital Eccentricity: 0.206
Obliquity to Orbit: 0.034 degrees
Mean Temperature: 167 C
Surface Pressure: 0 bars
Number of Moons: 0
Ring System?: No
Global Magnetic Field?: Yes
Detailed NASA fact sheet: https://nssdc.gsfc.nasa.gov/planetary/factsheet/mercuryfact.html
Values compared to Earth: https://nssdc.gsfc.nasa.gov/planetary/factsheet/planet_table_ratio.html
Notes on the values: https://nssdc.gsfc.nasa.gov/planetary/factsheet/planetfact_notes.html
Fact sheet last updated: 18 March 2025

Source and provenance

Original source: nssdc.gsfc.nasa.gov
Published on Koskamo by: Koskamo
Citation version: Document v1
Reuse: NASA Planetary Fact Sheet (NSSDCA), a work of the US government (public domain in the United States)

The original source supplies the underlying information. Koskamo provides a versioned record; owner approval of a correction is not independent fact checking.

Keep NASA’s units and source notes with each measurement. Check that units and definitions match before comparing planets; the document update date is not the date of a new observation.

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Version history

Published by Koskamo2026-10-04
Version 1