Mercury  
MESSENGER image of Mercury with three visible colors mapped to 1000 nm, 700 nm, and 430 nm wavelengths
Designations
Pronunciation i/ˈmɜrkjəri/
Adjective Mercurian, Mercurial
Orbital characteristics
Epoch J2000
Aphelion
  • 69,816,900 km
  • 0.466 697 AU
Perihelion
  • 46,001,200 km
  • 0.307 499 AU
Semi-major axis
  • 57,909,100 km
  • 0.387 098 AU
Eccentricity 0.205 630
Orbital period
  • 87.969 1 d
  • (0.240 846 a)
  • 0.5 Mercury solar day
Synodic period 115.88 d
Average orbital speed 47.87 km/s
Mean anomaly 174.796°
Inclination
  • 7.005° to Ecliptic
  • 3.38° to Sun’s equator
  • 6.34° to Invariable plane
Longitude of ascending node 48.331°
Argument of perihelion 29.124°
Satellites None
Physical characteristics
Mean radius
  • 2,439.7 ± 1.0 km
  • 0.3829 Earths
Flattening 0
Surface area
  • 7.48×10
  • 0.147 Earths
Volume
  • 6.083×10
  • 0.056 Earths
Mass
  • 3.3022×10
  • 0.055 Earths
Mean density 5.427 g/cm
Equatorial surface gravity
  • 3.7 m/s2
  • 0.38 g
Escape velocity 4.25 km/s
Sidereal rotation
period
  • 58.646 day
  • 1407.5 h
Equatorial rotation velocity 10.892 km/h (3.026 m/s)
Axial tilt 2.11′ ± 0.1′
North pole right ascension
  • 18 h 44 min 2 s
  • 281.01°
North pole declination 61.45°
Albedo
  • 0.068 (Bond)
  • 0.142 (geom.)
Surface temp.
   0°N, 0°W
min mean max
100 K 340 K 700 K
80 K 200 K 380 K
Apparent magnitude −2.6
Angular diameter 4.5" – 13"
Atmosphere
Surface pressure trace
Composition
  • 42% Molecular oxygen
  • 29.0% sodium
  • 22.0% hydrogen
  • 6.0% helium
  • 0.5% potassium
  • Trace amounts of argon, nitrogen, carbon dioxide, water vapor, xenon, krypton and neon

Get more info about Mercury in Wikipedia

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Mercury, which is released under the Creative Commons Attribution-Share-Alike License 3.0