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Mercury (mag. up to -0.5). Mercury appears four times as a morning star in 2004, and three times as an evening star. The apparition in late March will be the best one of the year at least for me: I have a great view towards western horizon from my windows, and on the other hand, I hate waking up too early to see the morning stars, although several of the morning apparitions of Mercury will be quite good in 2004. |
| Quality | Unit | Value |
|---|---|---|
| Mass | kg | 3.3 x 10^23 |
| Diameter | km | 4878 |
| Mean density | kg/m^3 | 5420 |
| Escape velocity | m/sec | 4300 |
| Average distance from Sun | AU | 0.387 |
| Rotation period (length of day) | Earth days | 58.65 |
| Revolution period (length of year) | Earth days | 87.97 |
| Obliquity (tilt of axis) | degrees | 0 |
| Orbit inclination | degrees | 7 |
| Orbit eccentricity | deviation from circular | 0.206 |
| Mean surface temperature | ēK (ēC) | 452 (+179) |
| Maximum surface temperature | ēK (ēC) | 700 (+425) |
| Minimum surface temperature | ēK (ēC) | 100 (-170) |
| Visual geometric albedo | ratio (0 to 1) | 0.12 |
| Largest known surface feature diameter Caloris Basin |
km | 1350 |
| Atmospheric components | trace amounts of | hydrogen helium |