FIRST: Water found on Moon

William Atkins
Thursday, 10 July 2008 05:55

Science - Space

Because so much water was lost during volcanic activity on the Moon, these scientists think that early in the Moon’s history it may have contained about 750 water molecules per million, which is similar to what is presently found in the upper mantle of Earth.

James Van Orman, from Case Western Reserve University, was one of the group members of the study.

Orman wrote the numerical model that helped produce the discovery. He stated, "We looked at many factors over a wide range of cooling rates that would affect all the volatiles simultaneously and came up with the right mix. A droplet cooling at a rate of about 3° F to 6° F per second over 2 to 5 minutes between the time of eruption and when the material was quenched or rapidly cooled matched the profiles for all the volatiles, including the loss of about 95% of the water.”
 
The conclusions of this study—that very miniscule amounts of water are contained in moon rocks—may eventually led scientists to find water ice in dark areas of craters in the polar regions of the Moon—areas where the Sun does not shine.

The discovery is also important because it puts into question how the Moon was formed. Most planetary scientists contend that the “giant impact” theory holds the key to the Moon’s beginning. It states that a Mars-sized object collided with the Earth about 4.5 billion years ago.

The “giant impact” is theorized to have melted both bodies and, because of the collision, flung materials out and into orbit around the early Earth. Some of the material eventually formed the Moon. If this theory is true, then the intense heat from the collision would have vaporized the lightest of elements, including water.

However, scientist, now know based on this study, that water was not entirely vaporized in this so-called impact that formed the Moon. This new study now suggests that water may have come from the interior of the Moon and was eventually sent up to the lunar surface by volcanic action over three million years ago.

This study does not disprove the "giant impact" theory, only questions some parts of it.

The research is published in the July 10, 2008 issue of Nature.

Please read the EurekaAlert article “Moon water discovered: Dampens Moon-formation theory”, which contains additional information on this important discovery.

Other interesting articles on the discovery of water on the Moon include: Scientific American website “Moon Once Harbored Water, Lunar Lava Beads Show” and Sky and Telescope: “Water in Moon Dust Raises Questions”