Scientists have long thought that the burning up of space junk in Earth’s atmosphere creates air pollution that may affect the planet’s climate. Now, for the primary time, they’ve managed to detect the presence of those pollutants within the air high above our planet.
A team of researchers flew high-altitude NASA aircraft over Alaska and the U.S. mainland to sample the chemical composition of the skinny air within the stratosphere, the second-lowest layer of Earth’s atmosphere, which extends from about 6 miles to 30 miles (10 to 50 kilometers) above the planet’s surface.
The planes, NASA’s WB-57 and ER-2 aircraft, allowed the researchers to achieve altitudes of as much as 11.8 miles (19 km), which is about five miles (9 km) above the cruising altitude of economic airliners.
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Sensitive sensors within the nosecones of the planes analyzed the chemical compounds diluted in the skinny, pristine stratospheric air, which is out of reach of Earth-based air pollution sources. The researchers found traces of lithium, aluminum, copper and lead within the sampled air. The detected concentrations of those compounds were much higher than what could possibly be brought on by natural sources, similar to the evaporation of cosmic dust and meteorites upon their encounter with the atmosphere. The truth is, the concentrations of those pollutants reflected the ratio of chemical compounds present in alloys utilized in satellite manufacturing, the researchers said in an announcement.
“We’re finding this human-made material in what we consider a pristine area of the atmosphere,” Dan Cziczo, a professor of Earth, atmospheric, and planetary sciences at Purdue University in Indiana and one in every of the authors of the study, said within the statement. “And if something is changing within the stratosphere — this stable region of the atmosphere — that deserves a more in-depth look.”
In recent times, scientists have been sounding alarm bells in regards to the possible effects of the rising variety of rocket launches and satellite re-entries on the upper layers of Earth’s atmosphere.
For instance, aluminum oxide, a product of the burn-up of aluminum-based alloys, is understood for its ability to destroy ozone. Coincidentally, Earth’s ozone layer, which protects life on the planet from harmful ultraviolet (UV) radiation, resides within the stratosphere, where the pollutants were found. The ozone layer has only just begun recovering from the destruction brought on by the sooner use of ozone-depleting substances in fridges and aerosol sprays, and the pollution from space junk may set back its healing process.
On top of that, aluminum oxide particles can alter Earth’s albedo, the planet’s ability to reflect light, Aaron Boley, an associate professor of astronomy and astrophysics on the University of British Columbia in Canada, told Space.com in an earlier interview. Too-high concentrations of aluminum oxides within the stratosphere could due to this fact result in temperature changes within the stratosphere which could, in turn, have unexpected consequences for Earth’s climate.
The issue is that particles dispersed at high altitudes are probably never going to fall to Earth, Boley warned, which suggests that their concentrations are only going to rise with time.
The arrival of megaconstellations, large systems of satellites similar to SpaceX’s Starlink, has led to a steep increase within the variety of satellites launched into orbit in recent times. Most of those satellites are designed to fall back to Earth and burn up within the atmosphere at the tip of their missions. Tens and even a whole lot of satellites could also be launched in the approaching decade, and which means a pointy increase in satellite re-entries and thus within the concentrations of chemicals created by their burn-up within the upper layers of the atmosphere.
“Changes to the atmosphere might be difficult to review and sophisticated to know,” Cziczo said. “But what this research shows us is that the impact of human occupation and human spaceflight on the planet could also be significant — perhaps more significant than we have now yet imagined. Understanding our planet is one of the urgent research priorities there may be.”
The study was published within the journal Proceedings of the National Academy of Sciences on Monday (Oct. 16).