MERCURY, THE WINGED MESSENGER
Mercury was known to the Romans as the messenger to the gods.
It is the closest planet to the sun and hurtles round our star every 88 days. It is the second smallest planet, after Pluto. Mercury has an iron core that extends three quarters of the way to its surface. This suggests that at one time Mercury was considerably larger. It appears that a hefty blow from a stray object in its distant past may have blown much of its original rocky shell off into space. This is not the only scar Mercury displays from major collisions. The Caloris Basin is one of the largest impact craters in the solar system. At 800 miles across it is bigger than the British Isles. The impact was so great that the shock waves created rocky ridges on the other side of the planet.
Although the Mercurian year is very short, the days (and nights) drag on. Mercury spins on its axis quite slowly and only fits in one and a half days to its year. If you were to visit the planet you would have to suffer interminably long nights where the temperature drops to -280 degrees Farenheit. At dawn the temperature would quickly soar and as the huge sun edged its way across the sky the barren landscape would heat up to 800 degrees farenheit.
A visitor to the planet would also witness some of the most peculiar sunsets in the solar system.
Sometimes Mercury's rapid motion round the sun outpaces it's genteel rotation. If this happens at sunset, the sun will dip below the horizon then pop back up again for a couple of days before sinking back down again plunging you into the long cold night.
| Mercury Statistics
|
|---|
|
|
|---|
| Equatorial radius (km) | 2,439.7
|
|---|
| 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 surface temperature | 179°C
|
|---|
| Maximum surface temperature | 427°C
|
|---|
| Minimum surface temperature | -173°C
|
|---|
Atmospheric compositionHeliumSodiumOxygen
Other
42%
42%
15%
1%
| |
|---|
OBSERVING MERCURY
Mercury is one of the hardest planets to see. Most of the time it is lost in the glare of the sun and only on a few occasions each year does it become visible.
