More than 5,000 tons of space dust fall to Earth each year

Dust shed from comets and asteroids constantly rains down on our planet. How much of this extraterrestrial material lands on Earth’s surface?

Starry sky with fuzzy band of Milky Way and many short, narrow bright streaks.

View at EarthSky Community Photos | Chirag Bachani in Marathan, Texas, captured this photo of the Geminid meteor showe on December 14, 2020. He wrote: “The Geminid meteor shower produced a spectacular show with over 100 meteors per hour at the peak around 2 am local time on December 14th. This image displays over 40 meteors captured throughout the night from a Bortle Class 1 dark sky in Marathon, Texas. Many of the meteors lasted over 2 seconds and were typically green and blue.” Thank you, Chirag!

According to a new paper, over 5,000 tons of space dust fall on Earth every year. The study, published April 15, 2021, in the peer-reviewed journal Earth and Planetary Science Letters, is the result of a 20-year collection of extraterrestrial particles performed near the Concordia Research Station in Antarctica by an international team of researchers.

Dust shed from comets and asteroids constantly rains down on our planet. When these tiny bits of dust and rock pass through our atmosphere, they usually burn up, and the short-lived trail of light made by the burning debris is called a meteor.

If the meteor does not burn up completely, the remaining portion hits the Earth and is then called a meteorite. A special kind of tiny meteorites are known as micrometeorites: particles of a few tenths to hundredths of a millimeter in size.

Micrometeorites have always fallen on our planet. The goal of the new research was to determine how much of this interplanetary dust reaches Earth’s surface each year.

To collect and analyze micrometeorites, researchers undertook six expeditions over the past two decades, near the Franco-Italian station Concordia, on Antarctica’s Dome C, one of several summits or “domes” of the Antarctic Ice Sheet. Dome C is located in the heart of Antarctica, about 680 miles (1,100 km) inland. Dome C is an ideal place to collect micrometeorites, the researchers said, because of the low accumulation of snow and the virtual absence of ground dust.

Map of Antarctica, with scene of wide, deep, smooth-bottomed trench in snow.

On left, the location of the Concordia Research Station at Dome C in Antarctica. To the right, a view of a trench where micrometeorites were collected. Image via ScienceDirect/ J. Rojas et al.

Study co-author Jean Duprat is a cosmochemist at the French National Centre for Scientific Research (CNRS). Duprat told Popular Science:

Central Antarctica is a desert. So it’s totally isolated.

These six separate expeditions made it possible to collect enough extraterrestrial particles, with sizes between 30 and 200 micrometers, to measure their flux – the mass added to the Earth – per year.

According to a statement from the researchers:

By applying these results to the whole of our planet, the total annual influx of micrometeorites represents 5,200 tons per year. This is the main source of extraterrestrial matter on our planet, far ahead of that of larger objects such as meteorites, whose flux is less than ten tons per year.

Comparison of the flux of micrometeorites with theoretical predictions confirms that a majority most likely come from comets (80%) and the rest from asteroids.

White cylinders with black tops standing in a large snow trench.

Collection of micrometeorites in the central Antarctic regions, at Dome C, in 2002. Image via Jean Duprat/ Cécile Engrand/ CNRS.

A gray blob that looks like a cloud, on a black background.

Electron micrograph of a Concordia micrometeorite extracted from Antarctic snows at Dome C. The displayed scale (horizontal line) of ten micrometers (µm) is equal to 0.01 millimeters, or one hundredth of a millimeter (about a thousandth of an inch). Image via Cécile Engrand/ Jean Duprat/ CNRS.

Bottom line: A study, based on 20 years of collecting extraterrestrial particles in Antarctica, has concluded that more than 5,000 tons of space dust fall to Earth each year.

Source: The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial dust on Earth

Via CNRS

Via Popular Science

Eleanor Imster