The upper atmosphere disturbs the trajectory of space debris

Nasa

Since the 1980s, scientists have believed that the increase in the atmospheric concentration of greenhouse gases would cause a general cooling and contraction of the very high atmosphere. This phenomenon has just been demonstrated by a group of researchers who have published their results in the Journal Of Geophysical Research: Atmosphere. This is the first study to establish the presence of widespread cooling and contraction of the upper atmosphere. 

 
The cooling upper atmosphere is evidence that the current climate change is the result of an increase in the greenhouse effect, which in turn is induced in particular by carbon dioxide emissions from human activities. The region concerned is that between the upper and lower atmosphere, between fifty and one hundred kilometres above sea level. 
 
To demonstrate the existence of this phenomenon on a global scale and its extent, the researchers used recent satellite data to update the upper atmosphere temperature databases. The results show that between 2009 and 2012, the upper atmosphere contracted by 1.3 kilometres due to cooling between 2˚ and 19˚C depending on altitude. According to the researchers, only a portion of this estimated 340-metre contraction is attributable to the concentration of carbon dioxide in the atmosphere. 
 
The remaining contraction observed at higher altitudes, above sixty kilometres, is due to a decrease in solar activity over the study period, as the cold air is denser. While the phenomenon has two distinct origins, the difference between the effects of greenhouse gases and solar activity is that the latter is reversible by cycle. 
 
This cooling has very real consequences in addition to causing the upper layers of the atmosphere to sink and being an indicator of the role of greenhouse gases. In particular, it means a decrease in drag and a longer lifetime for space debris in orbit around the Earth. Density decreases with altitude and as friction from air molecules weakens, it influences the trajectory of objects in low orbit. The study’s lead author, Martin Mlynczak, says that the positive aspect is that satellites will stay in orbit longer but so will debris, which will probably increase the risk that individual space objects, such as satellites, will have to adjust their trajectories to avoid collisions. This, he says, could increase the costs of space insurance and be a major factor in future space legislation and policy decisions. 
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unnamed - 2022-12-06T091505.933

The upper atmosphere disturbs the trajectory of space debris

Nasa Since the 1980s, scientists have believed that the increase in the atmospheric concentration of greenhouse gases would cause a general cooling and contraction of the very high atmosphere. This phenomenon has just been demonstrated by a group of researchers who have published their results in the Journal Of Geophysical Research: Atmosphere. This is the first study to establish the presence of widespread cooling and contraction of the upper atmosphere. 
 
The cooling upper atmosphere is evidence that the current climate change is the result of an increase in the greenhouse effect, which in turn is induced in particular by carbon dioxide emissions from human activities. The region concerned is that between the upper and lower atmosphere, between fifty and one hundred kilometres above sea level. 
 
To demonstrate the existence of this phenomenon on a global scale and its extent, the researchers used recent satellite data to update the upper atmosphere temperature databases. The results show that between 2009 and 2012, the upper atmosphere contracted by 1.3 kilometres due to cooling between 2˚ and 19˚C depending on altitude. According to the researchers, only a portion of this estimated 340-metre contraction is attributable to the concentration of carbon dioxide in the atmosphere. 
 
The remaining contraction observed at higher altitudes, above sixty kilometres, is due to a decrease in solar activity over the study period, as the cold air is denser. While the phenomenon has two distinct origins, the difference between the effects of greenhouse gases and solar activity is that the latter is reversible by cycle. 
 
This cooling has very real consequences in addition to causing the upper layers of the atmosphere to sink and being an indicator of the role of greenhouse gases. In particular, it means a decrease in drag and a longer lifetime for space debris in orbit around the Earth. Density decreases with altitude and as friction from air molecules weakens, it influences the trajectory of objects in low orbit. The study's lead author, Martin Mlynczak, says that the positive aspect is that satellites will stay in orbit longer but so will debris, which will probably increase the risk that individual space objects, such as satellites, will have to adjust their trajectories to avoid collisions. This, he says, could increase the costs of space insurance and be a major factor in future space legislation and policy decisions. 
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