FYI

Winnipeg Free Press - PRINT EDITION

Water throws wrench into moon-origin theories

  • Print

LOS ANGELES -- Scientists picking up signs of water on the moon's surface typically attribute them to deposits left by comets, asteroids and other heavenly objects. But a new analysis of lunar samples brought back to Earth by Apollo astronauts in the early 1970s indicates the moon's interior may have been a little damp in its early days.

The findings, published online Sunday in the journal Nature Geoscience, support mounting evidence the moon once contained some "native" water -- throwing a wrench into current beliefs about how Earth's companion formed.

Prevailing theories hold that the moon was created when a Mars-sized body crashed into the young Earth and broke off debris that eventually coalesced. In the process, much of the water would have evaporated into space, leaving Earth's new satellite quite arid.

"It's thought that the moon's formation involved the materials getting very hot," said Paul Warren, a University of California, Los Angeles cosmo-chemist who was not involved in the new study. "It's usually assumed that little water would have survived through that."

Indeed, the samples returned by the Apollo missions that visited the lunar highlands seemed to confirm Earth's cold, rocky companion was bone-dry, said University of Notre Dame geologist Hejiu Hui, who led the new analysis.

But work in the last five years has challenged that notion, as scientists have used more advanced methods to look for increasingly tiny concentrations of water in glass beads that are thought to have been formed by volcanic eruptions in the moon's early days.

Some experts have argued those glass beads could have been exposed to alien water sources after they had been ejected from the moon's interior. So Hui and his colleagues decided to look at a type of rock called plagioclase, which is thought to have formed in a magma ocean inside the moon. Although the rocks later floated to the surface to form the crust, they contain a chemical time capsule from inside the young moon. To further rule out any outside source of water, Hui's team looked past the surface of these rocks and into their centres.

After examining the samples under a microscope equipped with a spectrometer, the researchers found the rocks contained six parts per million of water. That's drier than an Earth desert, but far more than expected to survive in a rock from the moon's once-molten centre.

The samples should have been bone-dry, Hui said, but "somehow we still detect this amount of water, so that makes things interesting."

The findings could have interesting implications for theories about the moon's origin, Warren said.

"It's thought that the moon's formation involved the materials getting very hot, and it's usually assumed that little water would have survived through that," he said. If the new study is right, "It opens up quite a mystery as to how the moon came through what we think was a very hot genesis process with this much water."

-- Los Angeles Times

Republished from the Winnipeg Free Press print edition February 23, 2013 J14

Fact Check

Fact Check

Have you found an error, or know of something we’ve missed in one of our stories?
Please use the form below and let us know.

* Required
  • Please post the headline of the story or the title of the video with the error.

  • Please post exactly what was wrong with the story.

  • Please indicate your source for the correct information.

  • Yes

    No

  • This will only be used to contact you if we have a question about your submission, it will not be used to identify you or be published.

  • Cancel

Having problems with the form?

Contact Us Directly
  • Print

You can comment on most stories on winnipegfreepress.com. You can also agree or disagree with other comments. All you need to do is be a Winnipeg Free Press print or e-edition subscriber to join the conversation and give your feedback.

You can comment on most stories on winnipegfreepress.com. You can also agree or disagree with other comments. All you need to do is be a Winnipeg Free Press print or e-edition subscriber to join the conversation and give your feedback.

Have Your Say

New to commenting? Check out our Frequently Asked Questions.

Have Your Say

Comments are open to Winnipeg Free Press print or e-edition subscribers only. why?

Have Your Say

Comments are open to Winnipeg Free Press Subscribers only. why?

The Winnipeg Free Press does not necessarily endorse any of the views posted. By submitting your comment, you agree to our Terms and Conditions. These terms were revised effective April 16, 2010.