The work of one of the world’s largest ground-based observatories, tasked with scanning the skies for exploding stars and menacing asteroids, is being marred by streaks of light left behind by SpaceX’s Starlink satellites.
The Californian observatory, called the Zwicky Transient Facility (ZTF), began observing the whole sky in 2017. The telescope captures comprehensive, detailed images of the sky every two days, focusing on bright objects and any entities that appear in space that are suddenly and briefly visible. It usually finds light from supernovas and asteroids that may be passing low Earth orbit.
However, the wide range of Starlink satellites launched from has brought a new wrinkle to the work Elon Musks SpaceX program, as a new review of ZTF images shows over time.
The ZTF study was published in the Astrophysical Journal Letters on Monday, January 17th. The study showed that as early as 2019, streaks were visible in the images, which are the hallmarks of the satellites as they move through the sky.
In a statement to the press on Thursday, the scientists said the images they take of the twilight sky during the times of sunrise and sunset are most at risk from this visual contamination, in a statement.
Unfortunately, these are the most important types of images, as they are very important for capturing and tracking asteroids coming from the direction of the sun.
Of course, there has always been some visual interference with images that astronomers have taken of Earth; However, the percentage of such contaminated images has skyrocketed in recent years — years that correlate with the launch of Starlink satellites.
From just 0.5% at the end of 2019, the proportion of these images with streaks rose to a worrying 20% at the end of 2021.
Worse still, the Starlink satellites already in the sky are just a taste of the vast array of 12,000 that will eventually be part of the Starlink constellation. Only 15% of all deployed Starlink satellites have been put into orbit.
And not only that — Musk said so SpaceX intends to have up to 42,000 satellites as part of its global telecom offering; Complicating the situation further are the plans of other companies like OneWeb, Amazon and China’s SatNet to have essentially the same telecom orbiters in the sky.
So far there are 1,469 Starlink satellites in our skies and SpaceX just launched 49 new satellites on Tuesday, January 18th.
Study shows Starlink satellites affect images of twilight sky
Przemek Mróz, the study’s lead author, explained: “We don’t expect Starlink satellites to affect images outside of the twilight hours, but if other companies’ satellite constellations move to higher orbits, it could cause problems in after-twilight observations.”
Mroz is also a former postdoctoral fellow at the California Institute of Technology (Caltech), which runs the ZTF.
Scientists were stunned to discover an incredible 5,301 satellite streaks in images taken during the period in question.
However, as reported in Scientific American, there is – literally – hope on the horizon. SpaceX is already aware of the problem and has already begun building “visors” into its satellites that reduce the brightness they reflect by a factor of five.
While the streaks don’t pose as much of a problem as clouds in obtaining these photographic images, they are still important in helping astronomers see what might be out there threatening Earth.
Caltech physics professor Tom Prince, a co-author of the study, explained
“There is a small chance that we might miss an asteroid or other event hidden behind a satellite streak, but compared to weather influences like a cloudy sky, these are rather small impacts on the ZTF.”
But any physical object that either blocks scientists’ view of other celestial bodies or drives them to frantically hunt for flashes of light that are nothing more than satellite tracks should be avoided if possible.
Astronomers have been asking questions about the Starlink satellites’ placement and the impact they could have on discovering new celestial objects since they were first launched into orbit in May 2019.
The visible “strings of pearls” in the sky are indeed impressive and beautiful to behold, but their novelty was short-lived when the International Astronomical Union called on the United Nations to protect the world’s night sky as a natural heritage of the human race.
Satellite “mega-constellations” potentially harmful
The American Astronomical Society chimed in, saying the potential damage such “mega-constellations” of satellites could suffer was similar to that from light pollution, a phenomenon that is now well known and that businesses and government agencies want as much as possible limit with new downward lighting.
As recently seen when China blown up Elon Musk’s SpaceX for its array of satellites clogging the skies, the sheer number of them needed to provide the telecommunications Musk promised is already posing a problem.
Scientific American reports that Starlink satellites are already the cause of more than 50% of space-satellite collisions, according to Professor Hugh Lewis, Europe’s leading authority on space debris.
Of course, with the production of such gigantic arrays, there is always an environmental impact on earth and in our atmosphere.
Megaconstellation owners, including SpaceX, say they plan to replace their communications satellites with newer, upgraded versions and do away with the older models by dropping them and burning them up in the atmosphere.
However, all of these events produce particles and substances that may have unknown effects on the atmosphere itself and the Earth below.