Could our oceans have an extraterrestrial origin?

November 12th, 2009 - 5:03 pm ICT by IANS  

London, Nov 12 (IANS) Water did not originate on Earth as believed, but came into being from the turbulence caused by giant planets in the outer solar system, according to a new theory.
Ice-covered asteroids thus reached the Earth around a 100 million years after the birth of the planets, says Francis Albar├Ęde from the French Laboratoire des Sciences de la Terre.

This water, seemingly originated from an extraterrestrial source, perhaps facilitated plate tectonics even before life appeared. Space agencies have got the message: wherever there is life there has to be water.

Around 4.5 billion years ago, the earth was bequeathed with sufficient water for oceans to form and for life to find favourable niches in the seas and on the continents resulting from plate tectonics.

Conversely, the Moon and Mercury are dry, mortally cold deserts, Mars dried up very quickly and the surface of Venus is a burning inferno.

Going by books, the ocean and the atmosphere were formed from volcanic gases and the Earth’s interior is the source of volatile elements.

However, the rocks of the earth’s mantle are deficient in water. The same is true on earth’s sister planets, Venus and Mars, says a release of the Laboratoire des Sciences.

The main reason proposed by Albar├Ęde is that, during the formation of the Solar System, the temperature never dropped sufficiently between the Sun and the orbit of Jupiter for volatile elements to be able to condense with planetary material.

The arrival of water on earth therefore corresponds to a late episode of planetary accretion, which governs the growth and therefore the final mass of the planet, concludes Albarede.

These conclusions were published in Nature.

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