Mercury is the innermost densest planet in our solar system. It orbits the sun in 87.969 days and revolves about it's axis in two-thirds of the orbital period, 58.646 days. Mercury like Venus, does not have a natural satellite. When compared to other planets, Mercury exhibits two other important peculiarties, It's orbit has a very large eccentricity (e=0.206), and the orbital plane is inclined to the ecliptic by the angle of 7 degrees. Mercury is a very bright object because of its particular position in the Solar System; at perihelion, it recieves ten times as much solar radiation as our Moon. The flux of thermal energy emitted in the infrared from the surface was measured very precisely during the first and third encounters of Mariner 10 with the planet. During a Mercurian 'day' the temperature may reach 430° C in the vicinity of the subsolar point (where the sun is at the zenith), while the minimum night side temperature is about -170° C. |
| Mercury Statistics | |
|---|---|
| Mass (kg) | 3.303e+23 |
| Mass (Earth = 1) | 5.5271e-02 |
| Equatorial radius (km) | 2,439.7 |
| Equatorial radius (Earth = 1) | 3.8252e-01 |
| Mean density (gm/cm^3) | 5.42 |
| Mean distance from the Sun (km) | 57,910,000 |
| Mean distance from the Sun (Earth = 1) | 0.3871 |
| Rotational period (days) | 58.6462 |
| Orbital period (days) | 87.969 |
| Mean orbital velocity (km/sec) | 47.88 |
| Orbital eccentricity | 0.2056 |
| Tilt of axis (degrees) | 0.00 |
| Orbital inclination (degrees) | 7.004 |
| Equatorial surface gravity (m/sec^2) | 2.78 |
| Equatorial escape velocity (km/sec) | 4.25 |
| Visual geometric albedo | 0.10 |
| Magnitude (Vo) | -1.9 |
| Mean surface temperature | 179°C |
| Maximum surface temperature | 427°C |
| Minimum surface temperature | -173°C |
| Atmospheric composition
42% 42% 15% 1% | |
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If you wish to learn more about the planet Mercury here are some excellent resources.
| Nasa Planet Guide |
| NSSDC Photo Gallery: Mercury |
