Cover image for Highlights in Chemical Science

Highlights in Chemical Science

News from across RSC Publishing.

Where on Earth has our water come from?

22 October 2010

Evidence that water came to Earth during its formation from cosmic dust, rather than following later in asteroids, has been shown by a group of international scientists.

The origin of the abundant levels of water on Earth has long been debated with the main differences in the theories being the nature of the material that carries the water, and whether the water came during or after planet formation.

Now, Nora de Leeuw at University College London, UK, and colleagues have used molecular-level calculations to prove that dissociative chemisorption of water onto the surface of olivine rich minerals, such as forsterite, is highly exothermic. And so when these mineral dust particles came together during Earth formation, gas-solid interactions could have resulted in water being adsorbed onto the surface of the dust particles. This means that water could have been part of the Earth from the very beginning.

fosterite minerals

Water could have been adsorbed onto minerals that created the Earth

'Our calculations indicate that it is viable for water to become adsorbed at the surfaces of dust particles in the interstellar medium, where planets are formed. The water is thus trapped and becomes incorporated into the Earth,' says de Leeuw.

De Leeuw's work challenges the common assumption made by astronomers that the Earth's water originated from bodies in the asteroid belt. 'The work will be of tremendous interest to those modelling the geology and habitability of extrasolar terrestrial planets,' comments Philip Armitage, an expert in astrophysical and planetary sciences at the University of Colorado, Boulder, US.

Rebecca Brodie 

Enjoy this story? Spread the word using the 'tools' menu on the left or add a comment to the Chemistry World blog. 

Link to journal article

Where on Earth has our water come from?
Nora H. de Leeuw, C. Richard A. Catlow, Helen E. King, Andrew Putnis, Krishna Muralidharan, Pierre Deymier, Marilena Stimpfl and Michael J. Drake, Chem. Commun., 2010, 46, 8923
DOI: 10.1039/c0cc02312d

Also of interest

Volatile elements locked in moon rock

Theory that the Moon is depleted of volatile elements challenged as lunar mineral samples suggest levels are the same as on Earth

Planets' birthplace harbours chemical seeds of life

Organic molecules observed in the planet-forming region of a star resembling our own Sun

A Titan discovery

European researchers step closer to explaining hydrocarbon formation on Saturn's largest moon.