What's new
Troll Kingdom

This is a sample guest message. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Nascent Drama

Saal's group measured the beads' elemental makeup to ensure they came from lunar volcanic activity and not from the impact event that formed the moon.
 
The researchers also ruled out the chance that such beads could have become contaminated by outside forces such as hydrogen — an element of water — from the solar wind.
 
Others had tried and failed earlier to find water in similar samples, but one of Saal's collaborators had developed improved detection methods using a technique called secondary ion mass spectrometry (SIMS).
 
"For the past four decades, the limit for detecting water in lunar samples was about 50 parts per million (ppm) at best," said Erik Hauri, geochemist at the Carnegie Institution in Washington, D.C. and co-author on the study.
 
The group found up to 46 ppm of water within the glass beads. Saal and his collaborators then used modeling to estimate how much water originally existed in the magma within the moon's interior, knowing some water would have escaped the molten droplets as a gas on the surface.
 
That led to estimates that the glass beads may contain 745 ppm of water — strikingly similar to solidified lava that came up from the Earth's upper mantle through undersea vents. However, Saal's group gives 260 ppm of water as the most certain figure for now.
 
Just finding water at all could lead to a sea-change in how scientists view the early moon — either the moon held onto water from Earth during its violent creation, or else water gathered from elsewhere within 100 million years of the impact event as the moon solidified.
 
Modeling done on the Earth impact event suggests that our planet would have held onto much of its water, Canup explained. But such models say little about how much the moon could have held onto, and other questions remain unanswered even from this latest study.
 
"The major uncertainty I see is whether they're sampling something that tells us about the bulk composition of the moon, or whether they have sampled materials produced by a more limited water-rich part of the moon's interior," Canup said.
 
Knowing whether water is highly abundant or relatively scarce within the moon could also have implications for lunar exploration, but not for near-future missions such as NASA's Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS). The latter mission is slated to crash two spacecraft into the moon's south pole in early 2009, in an attempt to find evidence of water ice hidden in the lunar craters.
 
Any surface water ice likely formed from comets and other external bodies crashing into the moon and releasing their water, Bussey said, although he acknowledged the chance that some water vapor drifted to the poles during the moon's early history.
 
Saal's group will attempt to clear up some of those questions as they examine samples from more Apollo missions. For now, their work stands as an example of continuing to squeeze science out of an unexpected link between the past and future.
 
You must log in or register to reply here.
Back
Top