Astronomers' Warning About Satellites Impact On Night Sky Dives Beyond Astronomy

There are too many satellites above — that's the call that astronomers made yet again about the increasingly diminishing darkness of night skies. Beyond being a hindrance to the field of astronomy, the issue dives deeper even into human culture.

In a series of papers published recently, astronomers warned again about the increasing problem of light pollution from the ever-growing number of satellites being deployed into space.

"Orbital space near the Earth has been transformed radically since the launch of the first artificial satellite in 1957," the scientists wrote in one of the papers. "The number of functional satellites in low Earth orbit (LEO) has more than doubled since early 2019 due to the advent of large groups of satellites informally known as megaconstellations."

Indeed, the Low Earth orbits have increasingly grown congested, and the skies have grown brighter. As of Spring 2022, there were about 5,800 satellites in orbit, but it was estimated that an additional 58,000 more would be launched by 2030.

To put into perspective the speed at which more satellites have been deployed in just the last couple of years, this number was just around 3,000 in 2019-2020. And large satellite constellations are said to be among the main drivers of this increase.

Dimming Astronomy With Bright Lights

Naturally, one of the main fields that have been impacted by this issue is astronomy.

In late 2022, for instance, astronomers called out a bright, new "cell phone tower in space" that ended up outshining "all but the brightest stars" in the sky. They noted then that it could also interfere with radio astronomy, having the potential to "compromise" their "ability to do science."

And although strange sightings of mysterious lines of lights due to constellation launches like Starlink may be quite an interesting view for the casual viewer, these sightings may also be highlighting the kind of impact that these objects in orbit may be having on the darkness of the sky.

In 2022, researchers found more than 5,000 satellite streaks attributable to the Starlink satellites from November 2019 to September 2021 observations of the Zwicky Transient Facility (ZTF) at the Palomar Observatory in California.

"Today, due to the rise of light pollution, there are almost no more remote places available on Earth that simultaneously meet all the characteristics needed to install an observatory (namely, the absence of light pollution, a high number of clear nights, and good seeing)," scientists wrote in Nature Astronomy, calling their fellow scientists to "do more to stand up to 'big light' and 'big space' to preserve this natural resource."

For the Vera Rubin Observatory being built in Chile, for instance, it's estimated that even the darkest part of the night sky would be brightened by 7.5% in the next decade, reported AFP News. This means that the number of stars that the observatory could see, as powerful as it is, may also be reduced by 7.5% — while also adding millions to the cost.

Sadly, this could also mean losing out on some incredible celestial events that scientists would have captured had the skies been left to their natural darkness.

In 2020, astronomer Jonathan McDowell released a paper discussing the potential impact of the rapid changes due to the constellation of thousands of Starlink satellites. By 2021, several other constellations had been planned and proposed, potentially leading to thousands more satellites expected to enter the Earth's orbit.

Clouding Humanity's Link To The Skies

Beyond the complexities and intricacies of these impacts on science and astronomy, this may also have an impact on humanity's long-standing relationship with the skies. The night sky has played an important role for humanity, from navigation and time-keeping to inspiring works of art and music, wrote Jessica Heim of the University of Southern Queensland in a piece on The Conversation.

"The night sky transcends science or utility; it is equally a source of inspiration, connection to nature and recreation. For some cultures, sky traditions are a prominent aspect of their social customs, cultural traditions and religious beliefs," Heim and colleagues wrote in their paper. "As such, it represents a form of intangible human heritage that deserves intentional preservation and safeguarding for future generations."

Indeed, whether one is an astronomy enthusiast or simply a sky watcher who loves the natural beauty of dark night skies sprinkled with brilliant celestial bodies, watching the night sky and marveling at its beauty is one of the things that humans throughout history have had in common.

"The projected increase in night sky brightness will make it increasingly difficult to see fainter stars and the Milky Way, both of which are important in various cultural traditions," said Heim.

So even though these changes may not be quite as visible to the casual sky watcher, brightened skies and altered views of the cosmos may, in some ways, cloud that connection. There is that somber sense that we are no longer viewing the same grand skies that our ancestors were seeing. Just as what we have done here on Earth, we may have altered the skies in ways we have yet to fully conceive.

More Satellites Could Also Mean More Collisions — And More Debris

As you put more and more things in orbit, the possibility of collisions naturally also increases. One of the tricky things about such collisions in orbit is that they can end up creating a problematic chain of collisions that, as it continues, becomes a bigger problem to solve.

Take note that even the smaller debris as a result of these collisions can be problematic, as they can also cause damage to functioning satellites. In 2022, it was estimated that there were tens of thousands of objects larger than 10 centimeters in orbit. There could be even more of the smaller debris that is too small to even be tracked, and it's said that even an impact of tiny debris with a spacecraft such as the International Space Station and the SpaceX Crew Dragon "could create big problems."

"The number of centimeter-sized objects that could seriously damage satellites in collisions is probably around 1,000,000," the scientists wrote.

As NASA explained, even small flecks of paint could end up damaging a spacecraft because of how fast they move. And these threats don't seem to be diminishing over time, just because a piece had been in orbit for a long time.

In 1996, for instance, a French satellite sustained damages because of debris from a rocket that had exploded already a decade before. Earlier this year, a secret Russian spy satellite reportedly broke up and left its orbital debris to circle the planet, possibly for over a hundred years. That's a pretty long time, and just for one of the thousands of satellites.

Even at a time when the satellite population wasn't yet as large as it is today, NASA had already noted the need to mitigate debris.

"In particular, we show...that even if launch operations were to cease today, the population of space debris would continue to grow," the agency noted in a report that was published in 2006. (F)uture emphasis should be placed on finding new remediation technologies for solving this growing problem"

'It's not too late to stop this'

This issue, in some ways, offers a grander view of how much light pollution we have polluted the planet with. As humanity progresses, one of the things that continue to grow with us is the amount of light pollution that we produce.

Here on land, excessive light pollution has had a multitude of impacts on humans, the wild and even the environment. For instance, it has been found to affect people's natural circadian rhythms and also ends up affecting and confusing animals' behavior.

The brightening skies from all of these objects humans have deployed into space perhaps show an extension of that influence.

"(W)e humans have amazing capacity to underestimate our own influence on the environment," planetary astronomer Aaron Boley of the University of British Columbia said in 2022, according to Physics Today.

Still, the astronomers are hopeful that there's still a chance to make a change, noting that action "should be taken in all countries, more urgently so in those who bear a larger share of responsibility in the present process of deterioration of the global night sky."

"As it is not too late to stop this, we as scientists and first as citizens should act to stop this attack, from above with satellites and from below with ALAN (artificial light at night), on the natural night and on the intangible cultural heritage of humankind's starry skies," they wrote in the Nature Astronomy piece, calling their fellow scientists to take action.

"Now is the time to consider the prohibition of mega-constellations and to promote a significant reduction in ALAN and the consequent light pollution. Our world definitely needs a 'new deal' for the night."