In astrophysicist Fred Hoyle classic 1957 science fiction novel The Black Cloud, an enormous gas cloud enters our solar system and obscures the sun, stopping its radiation from reaching Earth. In the book, the titular cloud’s impending arrival is first noted by astronomers, who sound the alarm. Now, more than 60 years after Hoyle’s book was first published, astronomers are once again voicing their concerns about the sky being blocked out — only this time, it’s for real. And while they’re not talking about the end of life as we know it, their fears could certainly sound the death knell for much Earth-based astronomy.
Unlike Hoyle’s novel, in 2019 the threat comes from humans, rather than any kind of extraterrestrial force. It involves the proposed launch of tens of thousands of satellites into low-Earth orbit where they will form a mega-constellation, making much of our present astronomical efforts impossible. Earlier this month, SpaceX launched another 60 of its Starlink satellites as part of its plan to provide high-speed internet to every part of the planet. However, as useful as this may sound, an astronomer who spoke to Digital Trends said that there are plenty of potential negative ramifications.
“Even as professional astronomers, we’ve only just woken up to the fact that [this had the potential to be] a serious problem in the near future,” said Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics.
A major change to the environment
McDowell has long been an enthusiastic proponent of satellite launches. Since 1989, he has written and edited Jonathan’s Space Report, a free internet newsletter which documents technical details of satellite launches. “I’m a little sad to be on the other side of the coin, but I think it’s an important issue that needs to be talked about,” he said.
McDowell’s fear — shared by others in his field — is that the sheer number of satellite launches set to take place in the coming years will make it virtually impossible to carry out particular types of ground-based astronomy. Already astrophysicists carrying out long exposures, lasting around 15 seconds, frequently have their images ruined by a satellite trail passing overhead. Many times brighter than the “super faint galaxy” an astronomer might be looking for, this essentially ruins the image.
An image of the NGC 5353/4 galaxy group made with a telescope at Lowell Observatory in Arizona, USA on the night of Saturday 25 May 2019. The diagonal lines running across the image are trails of reflected light left by more than 25 of the 60 recently launched Starlink satellites as they passed through the telescope’s field of view. Although this image serves as an illustration of the impact of reflections from satellite constellations, please note that the density of these satellites is significantly higher in the days after launch (as seen here) and also that the satellites will diminish in brightness as they reach their final orbital altitude. Victoria Girgis/Lowell Observatory
“That’s an annoyance, but you work around it,” McDowell said. “You take multiple images, trusting that at least one of them will not have the trail. But when we get to the point where there are tens of thousands of very bright satellites in low orbit, the worry is that almost every image you take will have these trails on it… At some point certain types of astronomical observation will just not be feasible any more.”
Those fears aren’t based on overblown concerns about a worst case scenario. SpaceX boss Elon Musk has already said that he is in the process of requesting permission from the Federal Communications Commission (FCC) to install up to 30,000 satellites, in addition to the 12,000 that have already been approved. This would bring SpaceX’s satellite haul to more than 8x the total number in orbit right now.
“With Starlink as currently envisaged, when it’s fully deployed there will be more naked eye-visible satellites in the sky than there are stars,” McDowell continued. “You won’t notice this if you’re in a big city with bright lights where you can barely see the stars anyway. But if you are out in an area away from the lights of cities you can see down to what is called magnitude six, the faintest stars that you can see with the naked eye. Even at that level the satellites will outnumber the stars. The sky will be seething instead of static. That is a [major] change to our environment.”
Can’t we just replace them with space telescopes?
Nor is McDowell confident about the possibility of replacing ground-based observation with alternative approaches such as orbital telescopes and probes. “The problem is that there are many more ground-based telescopes than space telescopes,” he said.
Even launching several more Hubble-style space telescopes would only equal a fraction of the observing time currently available on Earth.
Starlink satellites ready to deploy. SpaceX
“Maybe in an ideal world, Elon’s Starship brings the cost of launching things down by a factor of 10 or [even] a factor of 100,” McDowell said. “But that doesn’t bring down the cost of actually building the space-capable payload. You’re still talking billions of dollars for a telescope anything comparable to the big ground-based telescopes. Each one is a few tens of millions on the ground, but would be tens of billions to do in space, even if the launch was free. There is no possible plausible budgetary environment in which we can move all of our ground-based observatories to space.”
Of course, any technological advance comes with negatives along with positives. For instance, industrialization brings large numbers of people out of subsistence living, but comes with its own slew of problems. As one of my favorite cultural theorists, Paul Virilio, once wrote: “The invention of the ship was also the invention of the shipwreck.” Is massive damage to our ability to look out at the universe, via ground-based observations, a worthy tradeoff for greater levels of connectivity? There’s probably a debate to be had that it is. The point, however, is that it’s a debate that, right now, isn’t being had.
A problem the UN should be talking about
“What I’m arguing is that this should be something where the United Nations, in its avatar as the Committee on the Peaceful Uses of Outer Space, has an appropriate role to weigh in,” McDowell said.
The Committee on the Peaceful Uses of Outer Space (COPUOS) was established in 1959. That’s around half a decade before the launch of Telstar 1, the first commercial satellite, whose mission was to transmit television signals across the Atlantic Ocean. COPUOS has started to consider issues of sustainability in space. To date, however, these have predominantly focused on the (also very important) issue of space debris.
“They don’t currently talk about light pollution and that’s an oversight because we didn’t see this coming,” McDowell continued. “I think it’s time to add light pollution to the list of environmental impacts that heavy use of low-Earth orbit entails.”
McDowell suggests that launch applications for satellites should require companies to make forecasts about the level of light pollution that they will cause. He also suggests a limit to the number of launches until we have a better idea of how they will impact the night sky.
“We are entering a new era of the space age; the era of massive space industrialization,” he said. “These internet mega-constellations are only the beginning. It’s not just SpaceX Starlink; there are many other companies that are planning to do similar things. Beyond that, I expect there will be other uses of space that will lead to bigger and larger sets of satellites being placed into Earth orbit. The problem is that regulation hasn’t really caught up with the winds of change.”