Every year, 5,200 tons (4,700 metric tons) of interplanetary dust particles reach the Earth’s surface, a new study reports.
These new findings suggest that cosmic dust is the main source of extraterrestrial material on Earth, far exceeding the input of larger and more visible meteorites, which are thought to bring less than 10 tons (nine metric tons) of material to Earth. every year.
This information can help scientists understand the role that interplanetary dust has played in supplying water and carbon molecules to a young Earth at the beginning of our planet’s history.
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Interplanetary particle hunting is by no means an easy task. First of all, how do you find micrometeorites that measure only a few tenths to a hundredth of a millimeter? (Human hair, for example, is about 70 micrometers in diameter.)
Crucially you need a blank, empty cloth of earth dust. For this, researchers are looking at the heart of Antarctica.
For the past 20 years, physicist Jean Duprat of the French National Center for Scientific Research (CNRS) has led six research expeditions to the Franco-Italian Concordia station (Dome C), which is located 1,100 kilometers off the coast of Adélie Land, Antarctic.
Dome C offers the perfect hunting ground for cosmic dust due to the low snow rate and clean snow conditions, CNRS said in a statement.
The team collected samples of pure snow from trenches over 2 meters deep, located in the wind direction of the research station, to avoid any human contamination of the samples.
Over two decades, researchers have collected enough micrometeorites (30 to 300 micrometers) to calculate how much extraterrestrial dust falls on Earth each year.
Scientists have estimated that a total of 15,000 tons (13,600 metric tons) of cosmic dust rains annually on Earth, although most of the material is lost at the entrance as it burns in the Earth’s atmosphere. This leaves 5,200 tons (4,700 metric tons) of interplanetary dust to settle on the surface of our planet every year.
The culprits for a majority (about 80%) of this interplanetary dust are the comets of the Jupiter family. These cosmic snowdrops of frozen gas, rocks and dust originate mainly in Kuiper belt, just beyond orbit Neptune.
While the rest of space is believed to come from asteroids; the small rocky bodies left over from our formation solar system.
The discoveries are the result of the collaboration of scientists from CNRS, the University of Paris-Saclay and the National Museum of Natural History, with the support of the French Polar Institute.
The research was published on April 15 in the journal Earth & Planetary Science Letters.
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