| Consider the following statements regarding the recent discovery of ICE on planet Mercury's surface: |
| 1. Even though mercury is quiet close to sun, the presence of ice is attributed to impacts of comets and possibly asteroids. |
| 2. This discovery was made by NASA's spacecraft, Messenger. |
| 3. It is the second mission to successfully reach Mercury, after Mariner 10 which was launched in 1973. Which of the above statements is or are correct? |
A) 1, 2, 3
B) 2, 3
C) 1, 2
D) 1, 3
Correct Answer: A
Solution :
[a] Missions to Mercury are difficult because the planet is deep in the Sun's gravitational well. The only mission to visit Mercury was Mariner 10 which had three flybys in 1974 and 1975. Each of these flybys occurred when the same portion of the planet was lit by the Sun, so only about half the planet was imaged. By their very nature, the interiors of shadowed craters are too dark to image, so these pictures do not shed any light on whether or not ice exists inside these craters. A mission to Mercury called MESSENGER launched in 2004 went into orbit around Mercury in 2011. There are only two significant sources for ice on Mercury: meteorite bombardment and planetary outgassing.
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