Meteorites Study: Mars, Earth, Moon Grew Up In Unique Planetary Nursery

March 20, 2008
Moon

A study of meteorites suggests that Mars, the Earth and the Moon share a common composition from ‘growing up’ in a unique planetary nursery in the inner solar system. The finding could lead to a rethink of how the inner solar system formed.

In the journal Nature the international team of scientists, which includes Professor Alex Halliday from Oxford University’s Department of Earth Sciences, report how they analysed 16 meteorites that fell to Earth from Mars. They found that the amounts of neodymium-142 these contain are subtly different from those of objects found in the asteroid belt. This isotopic fingerprint is proof that the chemistry of the inner solar system was different even for elements that are hard to vapourise.

Professor Halliday said: ‘The Earth, Moon and Mars appear to have formed in a part of the inner solar system with a ratio of samarium to neodymium that is around 5 per cent more than could be found in the asteroid belt. It is this ‘family resemblance’ that we see today when we compare oceanic basalts from Earth with Moon rocks and Martian meteorites. Such differences may be the result of the erosion of planetary crusts during formation events, alternatively, this composition arose from the sorting of clouds of partially melted droplets or grains - known as ‘chondrules’.’

Earth has a long geological history of recycling the materials that make up its crust and mantle, which could help explain why its composition is different from that of other planetary bodies – it could, for example, have deeply buried reservoirs of certain elements. However Mars and the Moon are believed to have been nothing like as active during their lifespan: making it much more difficult for any theory involving material recycling to explain why their composition should differ from other planetary bodies and yet have such similarities with the composition of the Earth.

Professor Halliday said: ‘What our results suggest is that the sorting of the elements that make up these planets may have happened at a much earlier stage than had been believed. It may even be that this sorting happened in the accretion disk out of which Mars and the early Earth first formed. What we can say is that the composition of these worlds is inconsistent with them simply forming out of large ‘lumps’ of stony meteorites, like those we see today in the asteroid belt.’

A report of the research, entitled ‘Super-chondritic Sm/Nd in Mars, Earth and the Moon’, is published in Nature on 20 March 2008. Co-author Alex Halliday is Professor of Geochemistry at Oxford University’s Department of Earth Sciences and Head of the MPLS Division. The international team included scientists from the Universite Denis Diderot, France, the ETH Zurich, Switzerland and the Ecole Normale Superieure de Lyon, France.

Source: Oxford University

Explore further: NASA selects CubeSat, SmallSat mission concept studies

Related Stories

NASA selects CubeSat, SmallSat mission concept studies

March 23, 2017

NASA has selected ten studies under the Planetary Science Deep Space SmallSat Studies (PSDS3) program, to develop mission concepts using small satellites to investigate Venus, Earth's moon, asteroids, Mars and the outer planets.

Earth's first example of recycling—its own crust

March 16, 2017

Rock samples from northeastern Canada retain chemical signals that help explain what Earth's crust was like more than 4 billion years ago, reveals new work from Carnegie's Richard Carlson and Jonathan O'Neil of the University ...

Martian winds carve mountains, move dust, raise dust

February 28, 2017

On Mars, wind rules. Wind has been shaping the Red Planet's landscapes for billions of years and continues to do so today. Studies using both a NASA orbiter and a rover reveal its effects on scales grand to tiny on the strangely ...

Recommended for you

Planetary waves, first found on Earth, are discovered on Sun

March 27, 2017

The same kind of large-scale planetary waves that meander through the atmosphere high above Earth's surface may also exist on the Sun, according to a new study led by a scientist at the National Center for Atmospheric Research ...

Stars born in winds from supermassive black holes

March 27, 2017

Observations using ESO's Very Large Telescope have revealed stars forming within powerful outflows of material blasted out from supermassive black holes at the cores of galaxies. These are the first confirmed observations ...

Timing a space laser with a NASA-style stopwatch

March 27, 2017

To time how long it takes a pulse of laser light to travel from space to Earth and back, you need a really good stopwatch—one that can measure within a fraction of a billionth of a second.

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

bobwinners
not rated yet Mar 20, 2008
It seems to me that the accretion disk which formed the all planets might have been sorted by gravity during the period of planetary formation. Is this what Halliday et al is proposing?
deepsand
3 / 5 (2) Mar 21, 2008
What Halliday suggests is that there was in fact some sorting of the elements in the acretion disk before the formation of certain planetary bodies, and that Mars, Earth & our moon where all born from the same portion of said disk subsequent to such sorting.

As for the mechanism that caused said sorting, he does not seem to be suggesting any particular one.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.