More than 5,000 tonnes of extraterrestrial dust falls to Earth every year

·1-min read
Researchers from the CNRS traveled to the Antarctic to collect galactic dust.

According to a new study from the French National Center for Scientific Research (CNRS), every year, around 5,200 tonnes of galactic dust penetrates our atmosphere to land on planet Earth. Created by comets and asteroids, when it enters the atmosphere, the dust particles can flare up, giving rise to shooting stars.

Reaching the ground in the form of micrometeorites, the dust is a phenomenon that has always existed, but one that had yet to be quantified. Most of the time, it is composed of tiny particles, of the order of a few tenths to hundredths of a millimetre, which have managed to pass through the atmosphere to reach the surface of the planet.

To collect and analyze these micrometeorites, over the last 20 years, the CNRS has organized several expeditions to an area near the French-Italian research station Concordia (Dome C) a little more than a thousand kilometers from the coast of Adélie Land in the heart of Antarctica. This site was selected by the scientists because of the near absence of terrestrial dust.

Extrapolating from the results of sampling at the collection site, the research team estimates that around 5,200 tonnes of micrometeorites land on the planet every year. This is much greater than the annual flux of larger extraterrestrial objects like meteorites, which is estimated at around ten tonnes per year.

This is one of the key findings from an extensive study conducted by a consortium of French organizations including the National Center for Scientific Research (CNRS), the Paris-Saclay University, the National Museum of Natural History and the French Polar Institute. The full study will be published in the journal Earth & Planetary Science Letters on April 15.

David Bénard