Astronomers called for limiting the number of satellites in Earth orbit

A few years ago, the main enemies of astronomers were clouds, urban glare and bad weather. Today, a new problem has been added to them — the rapid growth in the number of artificial satellites in Earth orbit. An international group of scientists has warned that up to 1.7 million spacecraft could appear around the planet in the coming years if all existing projects are approved. According to the researchers, this will not only significantly change the night sky, but also jeopardize the work of the world's largest telescopes. About why astronomers call the situation unprecedented and what role the unusual satellite project with mirrors plays in this is in the Izvestia article.

Why are astronomers talking about the threat?

Currently, there are about 14,000 active satellites orbiting the Earth. Most of them provide communication, navigation, Internet operation and scientific missions. However, according to the European Southern Observatory, the situation may change dramatically in the coming years: various companies have already applied to launch more than 1.7 million new devices.

It's not just about the usual communication satellites. Among the projects are new SpaceX mega—constellations, orbital data centers, as well as an unusual system from the American startup Reflect Orbital, which offers to use satellites with huge mirrors to reflect sunlight onto the Earth at night. It was such large-scale plans that forced astronomers for the first time to assess the consequences not of individual launches, but of the entire future satellite infrastructure.

How satellites interfere with the study of the universe

At first glance, it may seem that the satellites only add a few moving dots to the sky. In fact, the problem is much more serious. During long-term observations, spacecraft regularly cross the field of view of the telescopes, leaving bright streaks of light in the images. They literally overlap the images of distant stars, galaxies, and other objects for which observations are conducted.

So far, there are relatively few such cases, and scientists have learned how to partially compensate for such interference. However, if the number of satellites really increases hundreds of times, a significant part of astronomical observations, as stated, will be impossible.

The Reflect Orbital project is of particular concern. The company plans to put into orbit about 50,000 satellites equipped with mirrors that will be able to direct sunlight to certain areas of the Earth after sunset. It is assumed that this technology will help illuminate cities, construction sites and areas where additional light is required.

However, for astronomers, this particular initiative looks like one of the most dangerous. According to the researchers' calculations, even in normal mode, such devices will glow almost as brightly as Venus, and when reflecting sunlight, their brightness may exceed the brightness of the full moon by several times.

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What scientists suggest

The authors of the study emphasize that they are not opposed to the development of satellite communications or space exploration. On the contrary, modern orbital systems have already become an important part of the global infrastructure. However, in their opinion, the launch of new mega-constellations should be accompanied by international rules that will take into account the interests of science.

The study formed the basis for an official appeal by the European Southern Observatory, the International Astronomical Union and the Royal Astronomical Society of Great Britain to the US Federal Communications Commission. It is emphasized that this particular regulator is currently considering applications from SpaceX and Reflect Orbital to launch new satellite systems.

According to Eno, the level of about 100 thousand satellites in low-Earth orbit can be considered relatively safe, and they should be dim enough so as not to be distinguishable to the naked eye. If the number of spacecraft approaches the stated 1.7 million, the consequences for astronomy may be irreversible.

Betty Kyoko, a representative of the European Southern Observatory, stressed that this initiative poses an existential threat to optical astronomy. Scientists remind us that for the first time mankind found itself in a situation where it is able to change not only the surface of its own planet, but also the appearance of the night sky. If the current pace of satellite launches continues, future generations may see a completely different picture overhead — one where there will be almost more artificial objects than real stars.