The innermost planet, Mercury, is also the smallest of the
principal planets

Mercury Data:

Distance from the Sun:
mean 57.9 million km (0.387 a.u.)
max 69.7 million km (0.467 a.u.)
min 45.9 million km (0.306 a.u.)
Sidereal period: 87.969 days
Synodic period: 115.88 days
Rotation period: 58.6461 days
Mean orbital velocity: 47.87 km s−1
Axial inclination: negligible
Orbital eccentricity: 0.206
Orbital inclination: 7◦0015
.5
Diameter: 4878 km
Surface area: 7.475 × 107 km2
Apparent diameter from Earth:
max 12
.9
min 4
.5
Reciprocal mass, Sun = 1:6000 000
Density, water = 1: 5.44
Mass: 3.3 × 1026 g
Mass, Earth = 1: 0.055
Volume, Earth = 1: 0.056
Escape velocity: 4.25 km s−1
Surface gravity, Earth = 1: 0.38
Mean surface temperature:
day +350 ◦C
night −170 ◦C
Extremes of surface temperature:
day +427 ◦C
night −183 ◦C
Oblateness: negligible
Albedo: 0.06
Maximum magnitude: −1.9
Mean diameter of Sun, as seen from Mercury:
1◦2240