Scientists have long believed that burning space debris in Earth’s atmosphere creates air pollution that could affect the planet’s climate. Now, for the first time, they have managed to detect the presence of these pollutants in the air above our planet.

A team of researchers flew high-altitude NASA planes over Alaska and the U.S. mainland to study the chemistry of the thin air in the stratosphere, the second lowest layer of Earth’s atmosphere, which extends from about 10 to 50 kilometers (6 miles to 30 miles). ) above the planet’s surface.

NASA’s WB-57 and ER-2 aircraft allowed researchers to reach an altitude of 11.8 miles (19 km), about five miles (9 km) above the cruising altitude of commercial airliners.

Sensitive sensors in the plane’s nose analyzed chemical compounds diluted in rarefied, pristine stratospheric air, beyond the reach of sources of air pollution on Earth. Researchers found traces of lithium, aluminum, copper and lead in air samples. The detected concentrations of these compounds were much higher than concentrations that would be caused by natural sources such as the evaporation of space dust. meteors when they encounter the atmosphere. In fact, the concentrations of these pollutants reflect the proportion of chemical compounds found in the alloys used in the production of satellites. in the statement researchers

“We’re finding this man-made material in what we thought was a pristine part of the atmosphere,” said Dan Cizzo, a professor of Earth, Atmospheric and Planetary Sciences at Purdue University in Indiana and one of the study’s authors. phrase “And if something is changing in the stratosphere (stationary region of the atmosphere), it deserves a closer look.”

In recent years, scientists have become alarmed about the possible consequences of growth number of missiles launched and repeated entries of satellites into the upper layers of the Earth’s atmosphere.

For example, aluminum oxide, which results from the burning of aluminum-based alloys, is known for its ozone-destroying properties. Coincidentally, the ozone layer, which protects life on the planet from harmful ultraviolet (UV) radiation, is located in the stratosphere where pollutants are found. The ozone layer is just beginning to recover from the damage caused by the previous use of ozone-depleting substances in refrigerators and aerosol sprays, and contamination from space debris may slow the healing process.

In addition, Aaron Boley, an associate professor of astronomy and astrophysics at the University of British Columbia in Canada, told Space.com in an earlier interview that aluminum oxide particles could change Earth’s albedo, the planet’s ability to reflect light. Therefore, very high concentrations of aluminum oxide in the stratosphere can lead to temperature changes in the stratosphere, which can lead to unpredictable consequences on the Earth’s climate.

The problem, Boley warned, is that particles dispersed at high altitudes will probably never fall to Earth, meaning their concentrations will only increase over time.

The emergence of megaconstellations and large satellite systems such as SpaceX’s Starlink has led to a dramatic increase in the number of satellites launched into orbit in recent years. Most of these satellites are designed to fall back to Earth and burn up in the atmosphere after completing their mission. Dozens or even hundreds of satellites could be launched in the next decade; This means a sharp increase in the number of re-entry satellites and therefore in the concentration of chemicals produced by their burning in the upper atmosphere.

“Changes in the atmosphere can be difficult to study and understand,” Chitso said. “But this study shows us that the impact of human activity and human spaceflight on the planet may be significant, perhaps more significant than we imagined. Understanding our planet is one of the most urgent research priorities.”

Research It was published Monday, October 16, in the journal Proceedings of the National Academy of Sciences.