Ancient meteorites reveal creation of Solar System

Scientists have discovered evidence of chemical processes over 4.6 billion years old

Published: July 24, 2012 at 12:00 pm

The meteorites are likely to have come from the asteroid Vesta. NASA/JPL-Caltech/UCLA/MPS/DLR/IDA


Space rocks can tell us a lot about how our world came to be.

Analysing the composition of meteorites has always given scientists the opportunity to study Earth’s earliest geological history.

Now, a team from the Carnegie Institution for Science in the US has studied a particularly ancient type of meteorite called a diogenite and discovered some of the earliest chemical processes in our Solar System.

After terrestrial planets like Earth began to take on material from the surrounding Solar System, in a process called accretion, they developed a familiar structure – a metallic core, a silicate mantle and a crust.

The unfathomable processes that created these planets – the decay of short-lived radioisotopes and the impact of large objects – produced tremendous amounts of heat.

During the formation of a planet’s core certain elements including osmium, iridium, ruthenium, platinum, palladium, and rhenium are displaced into the core.

But studies have shown that the mantles of the Earth, Moon and Mars contain more of these elements than they should.

In order to discover the reasons for this anomaly, scientists decided to analyse diogenite meteorites.

As diogenites are likely to have come from the asteroid Vesta, or a similar body large enough to undergo the same chemical reacctions as Earth – in many respects they form scale models of terrestrial planets.

But after examining seven diogenites from Antarctica and two from the African desert, they discovered that the meteorites underwent heat-related chemical processing reactions over 4.6 billion years ago, only 2 million years after the formation of the oldest solids in the Solar System.


With this new data, scientists hope to gain a clearer picture of the earliest days of our Solar System and a better understanding of the Earth’s birth and infancy.

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