An international team of scientists has found that each year, 5,200 tons of dust falls from space to Earth. This far outweighs the larger meteorites that fall to our planet, reaching just 9 tons each year, making these tiny particles the most abundant source of extraterrestrial material on Earth.
Over 20 years, researchers led by physicist Jean Duprat from the French National Centre for Scientific Research (CNRS) have made six expeditions to Antarctica to collect particle samples. There, layers of space dust are preserved well enough for researchers to estimate how much falls to Earth each year.
To access these layers, over the 20 year period, the researchers dug out several large trenches of snow weighing 20 kilograms each and returned them to the lab in their research station. There, they melted away the snow and collected the remaining dust particles before sorting them and removing contaminants like fibers from the researchers'researchers' gloves.
In doing so, they were able to extrapolate their findings to estimate that 5,200 tons of small particles ranging from 30 to 200 micrometers in diameter fall to Earth every year. As most of the space rock that enters the Earth's atmosphere burns up, the researchers estimated that around 15,000 tons of space dust enter the atmosphere each year, with just a third reaching the Earth'sEarth's surface.
They further said that around 80% of the dust likely originates from comets called Jupiter-period comets- small comets controlled by Jupiter'sJupiter's gravity. Meanwhile, the remaining 20% of dust likely comes from asteroids.
The researchers said that understanding more about how extraterrestrial material makes its way to Earth could help us better understand how different elements and molecules necessary for life, like carbon and water, arrived on our planet. Knowing this would in turn allow us to better understand how life originally emerged on Earth.