Science & Technology

Micrometeorites: More Than 5,000 Tons of Extraterrestrial Dust Falls to Earth Each Year

Electron micrograph of a Concordia micrometeorite extracted from Antarctic snow at Dome C. Credit score: © Cécile Engrand/Jean Duprat

Yearly, our planet encounters mud from comets and asteroids. These interplanetary mud particles cross by way of our ambiance and provides rise to taking pictures stars. Some of them attain the bottom within the kind of micrometeorites. A world program carried out for practically 20 years by scientists from the CNRS, the Université Paris-Saclay and the Nationwide museum of pure historical past with the assist of the French polar institute, has decided that 5,200 tons per yr of these micrometeorites attain the bottom. The research was revealed within the journal Earth & Planetary Science Letters on April 15, 2021.

Micrometeorites have at all times fallen on our planet. These interplanetary mud particles from comets or asteroids are particles of a couple of tenths to hundredths of a millimeter which have handed by way of the ambiance and reached the Earth’s floor.

To gather and analyze these micrometeorites, six expeditions led by CNRS researcher Jean Duprat have taken place during the last 20 years close to the Franco-Italian Concordia station (Dome C), which is positioned 1,100 kilometers off the coast of Adélie Land, within the coronary heart of Antarctica. Dome C is a perfect assortment spot due to the low accumulation fee of snow and the close to absence of terrestrial mud.

Gathering micrometeorites within the central Antarctic areas, at Dome C in 2002. Snow sampling. Credit score: © Jean Duprat/ Cécile Engrand/ CNRS Photothèque

These expeditions have collected sufficient extraterrestrial particles (starting from 30 to 200 micrometers in dimension), to measure their annual flux, which corresponds to the mass accreted on Earth per sq. meter per yr.

If these outcomes are utilized to the entire planet, the whole annual flux of micrometeorites represents 5,200 tons per yr. That is the primary supply of extraterrestrial matter on our planet, far forward of bigger objects resembling meteorites, for which the flux is lower than ten tons per yr.

A comparability of the flux of micrometeorites with theoretical predictions confirms that the majority micrometeorites in all probability come from comets (80%) and the remainder from asteroids.

That is precious data to higher perceive the position performed by these interplanetary mud particles in supplying water and carbonaceous molecules on the younger Earth.

Reference: “The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial mud on Earth” by J. Rojas, J. Duprat, C. Engrand, E. Dartois, L. Delauche, M. Godard, M. Gounelle, J. D. Carrillo-Sánchez, P. Pokorný and J. M. C. Aircraft, 10 February 2021, Earth & Planetary Science Letters.

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