Earth Has It, But Does Our Moon Have It?

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Earth Has It, But Does Our Moon Have It? -

Described by Galileo Galilei as "a most beautiful sight to behold" and, contradicting many philosophers of his time, as "uneven, full of hollows and protruberances" Earth's natural satellite has always been an object of wonder and interest. Since Galileo's time, continually improved telescopes, and modern exploratory space flights, have revealed information about the nature of the Moon that is fascinating both to laymen and scientists.

We now know for example that the Moon is like, but also not like, Earth. It has many of the same elements in its core, mantle, and crust but does not have air, nor oceans. There are no plants and people have never lived there although a few lucky ones have visited. Between 1964 and 1972 NASA sent 22 scientific missions to the Moon. But, despite these explorations, much of the Moon remained a mystery and scientists have been anxious to return to the Moon to prospect for additional information.

So, on January 6, 1998, Lunar Prospector, NASA's first dedicated lunar mission in 25 years blasted off to the Moon aboard a three-stage rocket called Athena II. After a four-day journey to the Moon and entry into lunar polar orbit, the unmanned, tiny, drum-shaped spacecraft successfully started its eighteen-month mission circling the moon once every 118 minutes first at a distance of 63 miles and later only 6 miles above the Moon's surface.

The Prospector's main job was to map lunar resources, gravity, magnetic fields, and gases released from the lunar interior. At the end of its mission, in July 1999, the Prospector was deliberately crashed into the Lunar surface while astronomers around the world watched carefully with sensitive spectrometers to detect the effects of the impact.

1) What did the astronomers hope to detect?
2) What led them to think this might be a possibility?
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What did scientists and astronomers hope to detect?


Answer: 1) Evidence of the presence of water


MORE:
2) What has led scientists to think that water might exist on the Moon?

Although we believe that the Moon does not have any water of its own, it has been bombarded by comets -- mixtures of dust and ice -- for billions of years. We would expect that ice deposited on the lunar surface in the Moon's thin atmosphere and bathed in warm sunlight would evaporate. However, such cometary ice deposits would be unlikely to melt in very cold craters near the Moon's south pole, where the Sun never shines. If water is found on the Moon, it is likely to be deep in these craters.


On March 5, 1998 Prospector scientists announced the discovery of a definitive signal for water ice at both of the lunar poles, possibly as much as 300 million metric tons mixed into the lunar soil at each pole.

Did the Prospector mission confirm these hopes?

The worldwide observations of the Prospector's crash near the south pole of the Moon on July 31, 1999 were focused primarily on using sensitive spectrometers tuned to look for the ultraviolet emission lines expected from the hydroxyl (OH) molecules in the rock and dust kicked up by the impact of the 354- pound spacecraft.

Disappointingly, no observable signature of water was detected, according to scientists examining data from Earth-based observatories and from the Hubble Space Telescope.

This leaves open the question of whether ancient cometary impacts delivered ice that remains buried in permanently shadowed regions of the Moon, as suggested by the large amounts of hydrogen measured indirectly from lunar orbit by Lunar Prospector during its main mapping mission and by the Department of Defense's Clementine Mission as it flew by the Moon in 1994.

[Information taken from NASA's web site at http://lunar.arc.nasa.gov/ ]

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