Mercury

Mass:  3.303×1023 kg., .0553 of Earth's mass

Equatorial Radius:  2439 km., .382 of Earth's radius

Flattening:  0.0

Mean Density:  5.43 gm./cm.3

Acceleration of Gravity:  3.79 m./sec.2, .387 of Earth's

Escape Velocity: 4.3 km./sec.

Sidereal Period of Rotation:  58.6462 Days

Sidereal Period of Revolution: 87.969 Days

Eccentricity:  .206

Orbital Velocity:  47.89 km./sec. or 107,127 mi./hr.

Albedo:  .11

Distance from the Sun: .387099 AU or 35,983,107 mi.

SPECIAL CHARACTERISTICS

  1. a)  Spin-Orbit coupling (2/3)

  2. b)  Caloris Basin and the "weird terrain"

  3. c)  Magnetic Field 1% of the Earth's field

  4. d)  Difficult to see telescopically from the Earth

  5. e)  No natural satellites

  6. f)  Trace atomsphere of helium (1×10-9 millibars)

  7. g)  Mariner 10 flyby in 1974

  8. h)  Long lobate scarps

  9. i)  Test for general relativity, time dilation in the gravitational field

  10. j)  Maximum temperature is +430°C (806°F) to a minimum night-time temperature of -170°C (-270°F)

  11. k) 7 degree inclination to the Ecliptic

OTHER DATA--The minimum flyby distances for the three Mariner 10 encounters are 756 km., 48,069 km., and 327 km. (470 mi., 29,869 mi., and 203 mi. respectively).  The mosaic is from a distance of 210,000 km. or 130,488 mi.