One of the world’s major ground-based observatories which is tasked with scanning the heavens for exploding stars and threatening asteroids is having its work compromised by light streaks left by SpaceX’s Starlink satellites.
The California observatory, called the Zwicky Transient Facility (ZTF) started its full-sky observations back in 2017. Taking comprehensive, in-depth images of the heavens every two days, the telescope hones in on bright objects and any entities in space that appear suddenly and are only visible for a short time. Normally, it finds light from supernovas and asteroids that may be passing near-Earth orbit.
However, a new wrinkle has been put into the works as a result of the vast array of Starlink satellites launched by Elon Musk’s SpaceX program, as shown in a new review of the ZTF’s images over time.
The ZTF study was published in the Astrophysical Journal Letters on Monday, January 17. The study indicated that as far back as 2019, streaks have shown up in the images that are the hallmarks of the satellites as they move through the skies.
In a statement to the press on Thursday, the scientists explained that the images they make of the twilight sky during the times of sunrise and sunset are the most at risk of this visual contamination, in a statement.
Unfortunately, these are the most crucial types of images since they are very important in picking up and tracking asteroids coming from the direction of the sun.
Of course, there has always been some visual interference with images astronomers take from Earth; however, the percentage of such contaminated images has skyrocketed in the last several years — years which correlate to the launch of Starlink satellites.
From only 0.5% in late 2019, the ratio of these streaked images spiked to a disturbing 20% in late 2021.
What’s worse is that the Starlink satellites already in the sky are only a foretaste of the vast array of 12,000 that will eventually be part of the Starlink constellation. Only 15% of all the Starlink satellites that are to be used have been put into orbit up to the present.
And not only that – Musk has stated that SpaceX intends to have as many as 42,000 satellites as part of its worldwide telecommunications array; making the situation even more complex are the plans of other firms, such as OneWeb, Amazon, and the Chinese SatNet to have much the same telecommunications orbiters in the skies.
So far, there are 1,469 Starlink satellites in our skies and SpaceX just launched 49 new satellites on Tuesday, Jan. 18.
Study finds that Starlink satellites affect images of the twilight sky
Przemek Mróz, the lead author of the study, stated “We don’t expect Starlink satellites to affect non-twilight images, but if the satellite constellation of other companies goes into higher orbits, this could cause problems for non-twilight observations.”
Mroz is also a former postdoctoral scholar at the California Institute of Technology (Caltech), which operates the ZTF.
The scientists were dismayed to detect an incredible 5,301 satellite streaks on the images taken during the period in question.
However, as reported in Scientific American, there is hope – literally – on the horizon. Already sensitized to the issue, SpaceX has already begun to install “visors” in its satellites, bringing the brightness they reflect down by a factor of five.
Although the streaks do not pose as much problem as clouds in getting these photographic images, they are still important in helping astronomers detect what is out there that may threaten the earth.
Caltech physics professor Tom Prince, a co-author of the study, stated
“There is a small chance that we would miss an asteroid or another event hidden behind a satellite streak, but compared to the impact of weather, such as a cloudy sky, these are rather small effects for ZTF.”
But any physical object which either blocks the scientists’ vision of other heavenly bodies that may be out there – or that makes them go on wild goose chases after flashes of light that are nothing more than satellite trails – are to be avoided if at all possible.
Astronomers raised questions about the array of Starlink satellites and the impact they might have on the discovery of new celestial objects since they were first launched into orbit in May of 2019.
The visible “string of pearls” in the sky are indeed awe-inspiring and beautiful to gaze at, but their novelty was short-lived when the International Astronomical Union called on the United Nations to protect the world’s night skies as a natural heritage of the human race.
Satellite “mega-constellations” potentially damaging
The American Astronomical Society weighed in, saying that the potential damage such satellite “mega-constellations” could incur is similar to that of light pollution, a phenomenon that is well known now and which businesses and governmental entities are limiting as much as they possibly can with new, downward-directed lighting.
As seen recently, when China blasted Elon Musk’s SpaceX for its string of satellites clogging up the skies, the sheer number of them needed to provide the telecommunications Musk promises is already posing a problem.
Scientific American reports that Starlink satellites are already the cause of more than 50% of space collisions between satellites, according to Professor Hugh Lewis, Europe’s lead authority on space debris.
Of course, there is always an environmental impact on Earth and in our atmosphere with the manufacture of such gigantic arrays as well.
Megaconstellation owners including SpaceX say they plan to replace their communications satellites with newer, upgraded versions, doing away with the older models by way of allowing them to fall and burn up in the atmosphere.
However, all such events produce particles and substances that may have unknown ramifications for the atmosphere itself and the Earth under it.