First stage of planet formation took place 4568 million years ago

December 20th, 2007 - 2:43 pm ICT by admin  

Washington, Dec 20 (ANI): A new research has dated the earliest step in the formation of the solar system when microscopic interstellar dust combined into mountain-sized chunks of rock to 4,568 million years.

The research was carried out by Frederic Moynier, postdoctoral researcher, Qing-zhu Yin, assistant professor of geology, and graduate student Benjamin Jacobsen from the UC (University of California) Davis.

The physics and timing of this first stage of planet formation are not well understood. So, putting time constraints on the process should help guide the physical models that could be used to explain it, said Yin.

The researchers established the dates by analyzing a particular type of meteorite, called a carbonaceous chondrite, which represents the oldest material left over from the formation of the solar system.

Carbonaceous chondrites are made up of globules of silica and grains of metals embedded in black, organic-rich matrix of interstellar dust. The matrix is relatively rich in the element manganese, and the globules are rich in chromium.

Looking at a number of different meteorites collected on Earth, the researchers found a straight-line relationship between the ratio of the amount of manganese to that of chromium, the amount of matrix in the meteorites, and the amount of chromium-53.

These meteorites never became large enough to heat up from radioactive decay, so they have never been melted, said Yin. They are cosmic sediments,” he added.

By measuring the amount of chromium-53, they could work out how much of the radioactive isotope manganese-53 had initially been present, giving an indication of age, said Yin. They then compared the amount of manganese-53 to slightly younger igneous (molten) meteorites of known age, called angrites, he added.

The UC Davis researchers estimate the timing of the formation of the carbonaceous chondrites at 4,568 million years ago, ranging from 910,000 years before that date to 1,170,000 years later.

“We’ve captured a moment in history when this material got packed together,” said Yin. (ANI)

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