Rising levels of carbon dioxide in the Earth’s atmosphere could lead to a doubling of efforts to clean up our increasingly cluttered atmosphere.
Greenhouse gases have contributed significantly to the shrinking of the upper atmosphere, which scientists have assumed for decades, according to two new studies. And here, for the first time, it was really noticed.
Some of this observed decline is normal and will recover, but the scientists say the carbon dioxide contribution is likely to be permanent.
This means that failed satellites and other pieces of old technology in LEO are likely to stay in place longer as we loosen atmospheric drag, cluttering up the area and creating problems for new satellites and space observations.
“One of the results will be that satellites will last longer, which is great because scientists want their satellites to stay operational,” explains geospatial data scientist Martin Melengak of NASA’s Langley Research Center. potentially increase. It is possible that satellites and other valuable space objects will need to adjust their trajectory to avoid collisions.”
Descriptions of the earth’s atmosphere usually indicate layers at certain heights, but the truth is that the volume of gases surrounding our world is not constant, and it expands and contracts in response to various influences, perhaps the largest of which is the influence of the sun. .
The sun is also not stationary, it goes through cycles of activity, from maximum to minimum and back again, approximately every 11 years. We are currently in the middle of the 25th such cycle since the beginning of the reckoning, a cycle that began around December 2019.
The previous cycle #24 was unusually weak even at the peak of solar activity, which allowed Melengak and his colleagues to measure atmospheric deflation.
Their attention was focused on two layers, collectively known as the MLT: the mesosphere, which begins at an altitude of about 60 km, and the lower thermosphere, which begins at an altitude of about 90 km.
Data from NASA’s TIMED satellite, an observatory that collects data on the upper atmosphere, has provided the MLT with pressure and temperature information for almost 20 years, from 2002 to 2021.
In some of the lower atmosphere, carbon dioxide creates a warming effect by absorbing and re-radiating infrared radiation in all directions, effectively capturing some of it.
However, some of the infrared radiation emitted by carbon dioxide escapes into space, effectively carrying heat away and cooling the upper atmosphere. The more carbon dioxide, the colder the atmosphere.
Scientists warn that incessant carbon is compressing Earth’s upper atmosphere https://t.co/yhfK8pyD9v
— ScienceAlert (@ScienceAlert) November 22, 2022
“We already knew that this cooling leads to compression of the stratosphere,” the team noted. “Now we can see that the same thing happens with the mesosphere and the thermosphere above it.” Using TIMED data, Melniak and his team found that the MLT had decreased by about 1333 meters. Approximately 342 meters of them were formed as a result of radiative cooling caused by carbon dioxide.
“It was very interesting to see if we could actually observe this cooling and contraction of the atmosphere,” says Mlenjak. “Finally, we presented these observations in this paper. We are the first to show this kind of atmospheric contraction, on a global basis.”
Given that the thermosphere extends over several hundred kilometers, 342 meters may not sound like much. However, a paper published last September by physicist Ingrid Knusen of the British Antarctic Survey in the UK showed that atmospheric cooling could lead to a 33% reduction in atmospheric drag by 2070.
Atmospheric drag is what helps satellites and rocket stages get into orbit after their mission is complete. Knussen found that this cloud reduction could extend the lifespan of extinct space debris by 30 percent by 2070.
As more satellites are launched into low Earth orbit, this problem will only increase, and there are no real mitigation measures in sight – neither to reduce the number of satellites, nor to reduce the amount of carbon dioxide.
Source: Science Alert
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