|Interesting Facts about Mecury|
|Mass||.3302 x 1024|
|Volume||6.085 x 1010 km3|
|Equatorial Radius||2440 km|
|Rotation Period||1407.6 hours|
|Surface Gravity||3.7 m/s2|
Mercury is the second smallest planet in this solar system and also the closest to the sun. It has a diameter of only 3,031 miles (4,878km). It makes one complete orbit around the sun in only 88 earth days. Mercury is also one the brightest planets visible to us on earth. However, since it is so close to the sun it is only visible just before sunrise and sunset. At its closest point to the sun (perihelion) it is 29 million miles or 47 million kilometers away. The aphelion, the farthest position of orbit, is 44 million miles (71 million km). Strangely, Mercury rotates around its orbit in 59 earth days (Remember, earth rotates around its axis once in 24 hours). Mercury does not have an atmosphere but does contain a thin atmospheric layer of sodium and helium.
This mosaic of Mercury was taken by the Mariner 10 spacecraft during its approach on 29 March 1974
|Another mosiac of Mercury|
Another mosiac of Mercury showing the impact craters
Another mosiac of Mercury in the shape of a semi-circle
Composition: Mercury is believed to be 70% iron and 30% rock from other elements such as silicates.
Asteroid Impact: An asteroid approximately 62 miles wide struck mercury and created an impact basin about 810 miles wide. The basin is called the Caloris Basin and was once covered with molten lava.
This mosaic shows the Caloris Basin (located half-way in shadow on the terminator). Caloris is Latin for heat and the basin is named this because it is near the subsolar point (the point closest to the sun) when Mercury is at perihelion (the closest point in its orbit to the sun).
Mercury was visited by the Mariner 10 spacecraft that returned images on March 29, 1974. The spacecraft flew by two more times in 1975 and managed to take pictures that covered approximately 45% of the planet. It revealed a landscape similar to the moon with impact craters.
The surface temperature on Mercury varies more than 630 degrees Celsius (1,130°F) Before sunrise, Mercury is at 300°F (-184°C) and at noon, it is almost 800°F (427°C)!
Since Mercury has a highly elliptical orbit, the view of the sun would be strange. The sun would seem to stop moving east to west and reverse directions, then reverse again.
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