Space

How Millimeter-Sized Stones in Space Formed Our Planet (VIDEO)

Catherine Griffin
First Posted: Apr 22, 2015 08:20 PM EDT

Scientists may have found out not only how asteroids formed, but also how our planet was created. They've discovered that a cosmic ocean of millimeter-sized particles that orbited the young sun were the building blocks that helped form our planet.

Fragments of asteroids regularly land on Earth as meteorites. If you examined these meteorites, you would see that they consist of millimeter-sized round stones, known as chondrules. While these small particles are believed to be the original building blocks of the solar system, researchers have been unable to explain how these chondrules formed asteroids in the first place.

In order to find out, the researchers developed a computer simulation for what the process may have looked like. The scientists made the assumption that the asteroids were formed in a kind of cosmic ocean of chondrules and that the asteroids started out much smaller than they are today.

So what did they find? According to the computer simulations, the asteroids grew quickly to a diameter of up to 1,000 km, the same size as those found today in the asteroid belt between Mars and Jupiter. The largest asteroids continued to grow to the same mass as the planet Mars, which has 10 percent of the mass of Earth.

"The chondrules are of exactly the right size to be slowed down by the gas that orbited the young sun, and they could then be captured by the asteroids' gravity," said Anders Johansen, one of the researchers, in a news release.

The rapid process of asteroid growth doesn't only say something about the formation of asteroids; it also ties in the formation of planets and, in particular, Earth.

"Our study shows that protoplanets may have formed very quickly from asteroids, by capturing chondrules in the same way as the asteroids did," said Martin Bizzarro, co-author of the new study.

The new theory is actually supported by studies of meteorites from Mars. These studies have shown that Mars was formed over a relatively short period of only 1 to 3 million years, which is within the same time span that the researchers obtained in the computer simulation.

The findings are published in the journal Science Advances.

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