Astronomers' horizons are closing: space pollution caused by the increase in the number of satellites in orbit is interfering with telescope observations to the point of threatening the future of the profession, warns research cited by BTA, whose authors are calling for an "awakening".

With the emergence of mega-constellations of thousands of satellites launched in groups launched by the US company SpaceX in 2019, the number of satellites has more than doubled, and projects to deliver high-speed data from space are multiplying.

This colonization of low Earth orbit (up to 2,000 kilometers) congests traffic, increasing the risk of collisions.

Through a chain reaction, these collisions generate more debris, which in turn shatters into even smaller fragments, increasing the cloud of space debris gravitating overhead.

We have polluted Mars without even setting foot on the planet

The implications are "dramatic" for professional astronomy, which is facing an "unprecedented" transformation of the night sky, according to research published in the journal Nature Astronomy. 

For the first time, astronomers have attempted to measure the decline in observational efficiency resulting from this contamination and calculate the cost.

By reflecting sunlight, satellites increase the effect of light pollution from Earth.

Some companies, including SpaceX, tried to dim the brightness of their spacecraft to mitigate the inconvenience. 

However, the effects of small debris are even more problematic, as below a certain size ground-based telescopes cannot detect them individually.

Major science projects such as the Vera Rubin Observatory under construction in Chile are suffering as a result, as models predict a 7.5 percent increase in sky brightness at its zenith over the next decade.

This, in turn, will lead not only to additional costs, but also to a reduction by the same percentage of the number of stars that can be observed.

The impact could be even worse because current measurements of light pollution underestimate this phenomenon, according to another study published in the journal Nature Astronomy. 

Another cost is the loss of opportunities to detect rare and unknown astrophysical phenomena.

Some of them, such as the passage of meteorites, are so "secret" that they can only be observed under completely clear skies.

As light pollution on Earth continues to rise, suitable places to build telescopes are shrinking, some researchers complain.

However, the phenomenon goes beyond the scope of science and affects humanity's "ancestral connection" with the firmament, which should be seen as its "intangible heritage", according to astrophysicist Aparna Venkatesan of the University of San Francisco. 

"The loss of darkness poses a threat both to the environment and to our cultural heritage," alarmed astronomers and issued a "wake-up call".

To stop this "madness", the authors of the studies call for a significant restriction or even ban on satellites, stressing that any other "mitigation" measures will be ineffective.

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