https://astronomy.com/news/2021/04/satellite-skyglow-may-mean-light-pollution-is-unavoidable?utm_source=Yesmail&utm_medium=email&utm_email= [login to see] &utm_campaign=News0_ASY_210430_000000
The downside to satellites
In the past few years, astronomers have raised concerns about the growing number of satellites being launched — especially the megaconstellations launched by companies like SpaceX. When satellites streak overhead, they can disrupt naked-eye observing and astrophotography, as well as observations by professional telescopes.
Now, a paper published online March 29 in the Monthly Notices of the Royal Astronomical Society highlights another concern: Even when satellites and other objects in orbit are too dim to be resolved by the naked eye, they collectively scatter enough light back into the atmosphere that it produces a diffuse glow similar to light pollution from cities.
According to the researcher’s calculations, this light pollution from satellites and other small objects in orbit, such as debris and particles, can increase the natural sky brightness by 10 percent — a threshold that the International Astronomical Union (IAU) warned in 1979 was too high for astronomical observatories — when overhead.