Research: artificial earth satellites significantly polluted the night sky with light
A team of scientists from Slovakia, Spain, and the United States reports that artificial objects that orbit the Earth can increase the overall brightness of the night sky by more than 10% compared to natural light levels. This exceeds the threshold for "light pollution" set over 40 years ago.
The researchers modeled the contribution of space objects to the overall brightness of the night sky, taking into account both functioning satellites and various debris, such as spent rocket stages. While telescopes often view space objects as individual points of light, the human eye sees only the combined effect of many such objects, which is an overall increase in the diffuse brightness of the night sky.
“Unlike ground-based light pollution, this kind of artificial light in the night sky can be seen from most of the Earth's surface,” explained John Barentin, a member of the International Dark-Sky Association and research participant. "Astronomers are building observatories away from city lights, but this form of light pollution has a much wider geographical reach."
In recent years, astronomers have expressed concern about the growing number of objects orbiting the planet, in particular the large fleet of communications satellites known as "mega-constellations." The emergence of this technology increases the likelihood of collisions between satellites and other objects, which will further generate space debris. In recent reports sponsored by the US National Science Foundation and the United Nations Office for Outer Space Affairs, mega-constellations have been identified as a threat to the continued use of astronomical objects on Earth and in low Earth orbit. In the UK, the Royal Astronomical Society has set up several working groups to understand the influence of mega-constellations on the optical means used by scientists to study stars and planets.
The results published today suggest a further increase in the brightness of the night sky in proportion to the number of new satellites launched and their optical characteristics in orbit. Satellite operators like SpaceX are working to reduce the brightness of their ships through design changes. However, despite these efforts, the dramatic increase in the number of rotating objects could change the perception of the night sky for many people around the globe.