Rosetta Comet Landing
The European Space Agency (ESA) logo is pictured in Darmstadt January 20, 2014. Comet-chasing ESA spacecraft Rosetta woke from nearly three years of hibernation on Monday to complete a decade-long deep space mission that scientists hope will help unlock some of the secrets of the solar system. Rosetta, which was launched by the ESA in 2004, is due to rendezvous with comet 67P/Churyumov-Gerasimenko and land a probe on it this year in an unprecedented manoeuvre. Reuters/Ralph Orlowski

The Rosetta spacecraft has found that the interplanetary dust particles that have fallen into Earth from the outer space were from comets. The discovery by the spacecraft, the first robotic space probe that was launched by the European Space Agency to study the comet 67P/ Churyumov-Gerasimenko in detail, could help interpret the origins of the Earth as well as the rest of the solar system, reported space.com.

COSIMA instrument is a dust-analysing instrument on the spacecraft. The Rosetta, with help from the COSIMA instrument, had been collecting as well as analysing the dust that flew from the comet 67P.

Rita Shulz is the lead author of the study and a space scientist at the European Space Agency in The Netherlands, an intergovernmental agency that is dedicated to space programmes. She said that comets could be thought of as either dirty snowballs or icy dirtballs. Usually, comets are said to consist of a mixture of both, ice and dust.

When comets get close to the sun, the ice on it turns from solid to gas or it sublimates. The closer the comets got to the sun, the more gas was given out, as a result of which more dust also gets out from the ice.

Shulz said that eventually, there was not enough pressure for the dust to get away because of which it got stranded on the surface of the comet, resulting in the formation of a layer of dust called the mantle. To complete an orbit, comet 67P takes 6.5 years, and within a span of four years, it was found that the comet built up a mantle.

Schulz said that scientists found that comets like the 67P/ Churyumov-Gerasimenko, were the origin of the interplanetary dust particles. The particles were said to rain down on Earth as well as the other bodies on the solar system.

Rosetta collected dust from the comet when it was at a distance of 3 astronomical units (AU) away from the sun. When the comet was a distance between 2.5 and 2.7 AU from the sun, the dust doubled, indicating that that was the time when the comet got rid of its mantle.

The grains of dust were fluffy and were more than 50 microns across. A lot of the grains shattered when it was collected then it became a size similar to the interplanetary dust particles. It was also discovered that the particles were rich in sodium which was a similar feature of the metoroids that fell on Earth.

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