Rising levels of carbon dioxide in Earth’s atmosphere could exacerbate efforts to rid our increasingly cluttered atmosphere of orbiting space junk.
According to two new studies, greenhouse gases have contributed significantly to the shrinking of the upper atmosphere. This contraction has been speculated for decades. Now, for the first time, it’s really being noticed.
Some visible shrinkage is normal and will recover; But scientists say the carbon dioxide contribution could be permanent.
This means that dead satellites and other pieces of old technology in LEO are likely to last longer due to reduced atmospheric drag, cluttering the area and causing problems for new satellites and space observations.
“One of the results is that the satellite will last longer, which is good, because people want the satellite to be idle,” explained geoscientist Martin Mlenjak From NASA’s Langley Research Center.
“But the debris will also last longer and potentially increase the likelihood that satellites and other valuable space objects will have to adjust their trajectories to avoid collisions.”
Descriptions of the Earth’s atmosphere generally specify a layer at a certain height, but in reality the volume of gas that surrounds our world is not constant. It expands and contracts in response to various influences, perhaps the greatest of which is the sun.
Now, the sun doesn’t stop either. past activity cycle, from top to bottom, and vice versa, approximately every 11 years. At the moment we are in the middle 25th session so Since the start of the count, the cycle that started in December 2019 is approx. The previous cycle, the no. 24, was unusually faint even at peak solar activity, allowing Mlynczak and his colleagues to measure atmospheric contraction.
Their attention was focused on two layers, collectively known as the MLT: the mesosphere, which begins at an altitude of about 60 kilometers (37 miles); and the lower thermosphere, which begins at about 90 km.
Information from NASA temporary The satellite, an observatory that collects data in the upper atmosphere, provided them with pressure and temperature information for the MLT for nearly 20 years, from 2002 to 2021.
In some layers of the lower atmosphere, carbon dioxide creates a warming effect by absorbing and re-emitting infrared radiation in all directions, effectively blocking a part of it.
However, some of the infrared radiation emitted by carbon dioxide escapes into space, effectively carrying away heat and cooling the upper atmosphere. The higher the carbon dioxide level, the colder the atmosphere.
We already know This cooling causes the stratosphere to shrink. We can now see that it does the same thing to the mesosphere and the thermosphere above it. Using TIMED data, Mlynczak and his team found that the MLT shrunk by about 1,333 meters (4,373 feet). About 342 meters of it are the result of radiation cooling caused by carbon dioxide.
“There has been a lot of interest to see if we can actually observe this cooling and shrinking effect of the atmosphere.” Meleng said.
“We have finally presented these observations in this article. We are the first to demonstrate this type of atmospheric contraction, globally.”
Considering that the thermosphere extends several hundred kilometers, 342 meters may not seem like a lot. However, AJ Document published in September Physicist Ingrid Knusen of the British Antarctic Survey in the UK has shown that cooling of the thermosphere could lead to a 33% decrease in atmospheric drag by 2070.
It is this atmospheric drag that helps satellites and rocket stages clear orbits after their missions are completed. Cnossen found that this cloud reduction could extend the orbit of defunct space junk by 30% by 2070.
As more satellites are launched into low Earth orbit, this will become a growing problem, with no real mitigation measures, either to reduce the number of satellites or the amount of carbon dioxide.
“With each rise, there is a cooling and deflation that we attribute in part to rising carbon dioxide,” Meleng said. “As long as carbon dioxide increases at the same rate, we can expect this rate of temperature change to also remain constant, about half a degree Kelvin.” [of cooling] by contract.
Research published in Geophysics Research Journal: Atmosphere.
