Scientists discover how Earth was formed

Scientists have found that our planet was formed much like asteroids, by cosmic ocean of millimetre-sized particles that orbited the sun.

According to a new study led by Lund University in Sweden, fragments of asteroids regularly land on Earth as meteorites. It comprises millimetre-sized round stones, known as chondrules. These small particles are believed to be the original building blocks of the solar system.

Dr Anders Johansen, an astronomy researcher at Lund University said that the chondrules were 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." Co-author Mordecai-Mark Mac Low added that this caused them to fall down and accumulate like sand piling up in a sandstorm.

The research community had previously believed that the Earth was formed through collisions between protoplanets, of the size of Mars, over a period of 100 million years. However, the researchers have not yet understood how the protoplanets themselves were formed.

Martin Bizzarro, an expert on chondrules from Copenhagen University and co-author of the paper, said that the study showed that protoplanets may have formed very quickly from asteroids, by capturing chondrules in the same way as the asteroids did.

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

The study is published in the journal Science Advances.