Stargazers’ nights numbered owing to glut of satellites

Scientists are also concerned about the sheer numbers of deorbiting satellites. Photo / AP

The night sky will be “crawling” with satellites by the end of the decade, blocking out the stars and leaving astronomers unable to make observations or detect alien life, experts have warned.

There are more than 8,000 satellites orbiting the Earth, a four-fold increase since 2019, and numbers are expected to grow exponentially in the coming decades.

Some 400,000 satellites have been approved globally for low Earth orbit, with SpaceX alone poised to launch another 44,000 for its Starlink internet constellation.

Satellites reflect sunlight back down to Earth, and astronomers are struggling to deal with the bright streaks of light they create as they drift in front of the optical field of telescopes. Internet satellites can also interfere with sensitive radio telescopes.

Tony Tyson, professor of physics and astronomy at the University of California, said: “If you just went out in a dark place somewhere and looked at the sky in 2030, it would be a very macabre scene. The sky will be crawling with moving satellites, and the number of stars that you would see are minimum, even in a very dark sky. It’s a major issue.”

The Royal Astronomical Society (RAS), the UK Space Agency and the Department for Business are so concerned they convened a Dark and Quiet Skies conference last week to call for regulation. Dr Robert Massey, deputy executive director of the RAS, said the world was seeing “a paradigm shift” in the use of space.

“There is the real prospect that we could see hundreds of thousands of satellites in orbit by the end of the decade,” he said.

“Frankly, searching for the origin of life may be a long shot, but detecting signals from other civilizations becomes harder if you have an incredibly powerful and noisy sky.”

Unlike light pollution, you cannot get away from it, because wherever you are on Earth, you can see the sky.

”If we leave this unchecked, I think this is also a cultural issue. If you get to the point where satellites make up about 10 per cent of the stars in the sky moving around, I think that’s fairly intrusive, and it is a damage to that natural landscape.”

The $10 billion ($15 billion) Vera Rubin telescope, located on the Cerro Pachón ridge in north-central Chile, is already facing major problems because of satellites.

The telescope, which begins a 10-year survey next year, is looking for tiny changes in the movements of 37 billion stars and galaxies. Yet early testing has shown that around 40 per cent of frames will be impacted during twilight hours.

Even telescopes in space are facing difficulties, with images from the Hubble often ruined by over-saturation as reflective satellites go past.

The downlink beams from internet satellites are also millions of times more powerful than the sensitive sources that radio telescopes are trying to detect, which could hugely hinder or confuse the ability to detect signals from space.

Not only would the glut of satellites damage astronomy, but it could change the night sky forever, experts warn. Scientists are also concerned about the sheer number of deorbiting satellites.

Ken MacLeod, an independent expert in what happens to satellites after they stop being functional, has calculated that when all the internet constellations are operational, there will be around 16,000 decaying internet satellites at any one time that will need to come out of orbit.

”They will cause re-entry fireballs,” he said. “If we really believe the numbers of how many are going to be falling, that’s about 60 every day, and that’s much brighter than magnitude seven [the faintest level of starlight visible with the naked eye], so they can cause troubles with all those observations.”