More than 5,000 tons of extraterrestrial dust rain down on Earth each year, new research says

Scientists in France have determined that 5,200 tons of extraterrestrial dust particles from comets or asteroids reach Earth every year and account for the main source of extraterrestrial matter on our planet.

Over the course of nearly 20 years, a team of researchers, led by Jean Duprat of the French National Centre for Scientific Research (CNRS), collected extraterrestrial particles from a Franco-Italian Antarctic station - ranging from 30 to 200 micrometers in size - to measure their average annual fall from space. 

While it has always been known that extraterrestrial dust lands on our planet each year, it has been hard to determine how much. Data collected from the Antarctic over two decades was extrapolated to determine the annual fall on the planet as a whole each year. 

The researchers concluded that around 5,200 tons of extraterrestrial dust reach the ground annually, an estimated 80% of which comes from comets – which are made of dust and ice – and the remainder from asteroids – rock-like celestial bodies. Duprat and his team claim that extraterrestrial dust, therefore, represents the main source of extraterrestrial matter on our planet, far ahead of larger objects such as meteorites. 

The research, which will be available in the journal Earth & Planetary Science Letters from April 15, helps scientists better understand the role of extraterrestrial dust in supplying water and other materials to our planet.

If you like this story, share it with a friend!