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Earth’s Water Origins

November 17, 2015

Lava found deep below the earth reveals the origins of earth’s water.

Transcript

Lydia Hallis

Scanning electron microscope images showing a Baffin Island rock sample. Large olivine mineral grains dominate this rock (mid-gray colored grains in image A). These olivine grains contain trapped pockets of glass, known as melt inclusions (image B), and this glass contains tiny amounts of water. (Lydia Hallis)

BOB HIRSHON (host):

H20’s origins. I’m Bob Hirshon and this is Science Update.

Our planet is covered with oceans, lakes, and rivers, but where did all that water come from? An analysis of H20 trapped inside lava from deep within earth’s mantle suggests it’s been around since the formation of the solar system. While at the University of Hawai’i, Glasgow University planetary scientist Lydia Hallis compared the hydrogen composition of these ancient samples to that of water from different planetary bodies.

LYDIA HALLIS (Glasgow University):

We found was that the hydrogen composition was most similar to the disk of dust and gas before any of the planets formed.

HIRSHON:

That suggests it arrived as earth was forming from that disk, rather than via a comet or asteroid.

HALLIS:

I think that’s really incredible that the water that we drink was originally from this really huge ball of gas in space.

HIRSHON:

The study appears in Science magazine. I’m Bob Hirshon, for AAAS, the science society.