Rebecca already posted an excellent video critique of Elon Musk’s Starlink concept, but as Skepchick’s resident astronomer, I thought I’d expand upon it a bit.
You all might know that I’m a radio astronomer, but I have at least a little bit of experience with visual observing as well. As an astronomy professor at a small college, I also run our tiny observatory, and I have plans to expand it. But will it be worth setting up a small research telescope if the night sky is about to become a lot more crowded?
Today, you can go out and see a satellite just about any night the sky is clear if you know where to look. Many satellites have solar panels that, when the angle is just right, cause them to reflect that light back to Earth, usually during the few hours after sundown and few hours before sun-up. They are spectacular to see when they are bright enough to view with the naked eye, and you can look like a real wizard if you use something like Heavens Above to predict their passing for passers-by.
Dimmer passes are more frequent than bright ones, so telescopes can pick up a lot more with their light gathering power. Even our little campus telescopes used in Astro 101 will pick up a few as you are gazing at something else, but the largest telescopes used today for astronomical research can pick up even more. These do often have techniques and algorithms for avoiding satellites when doing science, but the more satellites there are, the harder it gets. The sheer number and brightness of Starlink‘s satellites will bring the problem to an unprecedented level, interfering with cutting edge astronomical observations.
Astronomer Alex Parker modeled what what the full constellation of satellites would look like, and it sent most of astronomical twitter into a tizzy. To make matters worse, Musk responded to the criticisms showing an appalling lack of knowledge of astronomy and that he obviously did not consult with astronomers before planning these satellites. In addition to the “ISS has lights” mistake he made that Rebecca noted, he claimed that the satellites would only be visible so close to sunset and sunrise that the stars wouldn’t be out anyway. First off, that was clearly false, as observations of the first batch of satellites have shown. Secondly, astronomers require pictures of the sky during those times in order to calibrate the images that they will take with their instruments for the rest of the night.
Well, what about space telescopes, Musk and his legions of fanboys ask? Even the much revered Hubble telescope is not immune to satellite trails, as it orbits in Low Earth Orbit. But that doesn’t even touch the fact that, in the optical and radio parts of the electromagnetic spectrum it is far cheaper and more efficient and, in some cases, only possible, to do this astronomy from the ground. (Yes, satellites give off radio waves as well, causing issues for astronomers like me who prefer dishes and dipoles to mirrors, though there is at least some sign that SpaceX is working to mitigate the impact there.) Hubble is unique in that it was serviceable by astronauts, but telescopes like the upcoming infrared James Webb Space Telescope will orbit at a location inaccessible to humans for quite some time. Not to mention, cutting edge astronomy required BIG mirrors and dishes, the likes of which we don’t even know how to build and maintain in space. The recent black hole image, for example, took the combined power of several telescopes spread across the globe whose positions relative to each other had to be calibrated to the millimeter or better! That is a LOT harder to do with something in orbit. (If you want to get real nerdy on this, here is a very recent pre-print article on space radio interferometry.)
Okay, okay, so astronomers who do this work year in and year out have demonstrated that, yes Starlink will have a negative impact on visual and radio astronomy. “So what?” some say. Losing some niche areas of research is surely a small price to pay for global internet coverage, right? There are so many ways in which that is problematic…
First of all, at least some areas of astronomical research are highly practical. Remember those near-Earth asteroids that could wipe out cities, regions, or the whole of humanity? We need to spot those teeny tiny points of light well before they are close enough to cause damage if we’re going to nudge them out of the way. In at lease that one way, astronomical research is immediately practical.
Much of that work is also done by smaller telescopes and observatories which can scan larger areas of sky and for longer periods of time, and these will not have the satellite-avoidance measures available to large telescopes. That speaks to me as an educator as well, since it is on those smaller instruments that legions of STEM professionals get their first taste of science and engineering.
Next, the night sky is a global resource which is already being taken away from millions of people due to the problems of light pollution. These satellites would look pretty cool to the naked eye, but they would also compete with naked eye visible stars, completely changing the night sky that we all see, particularly in those hours just after sunset when most people are viewing them. I finally learned my Northern Hemisphere constellations in graduate school and still give sky tours to groups and my classes. Will the sky even be recognizable with so many visible satellites above the horizon? Just as Elon Musk didn’t ask astronomers for their input, he would be changing the night sky for the entire planet without asking for anyone’s input.
And that brings me to what I consider to be the most damaging aspect of this venture. As one planetary geologist put it, this project has a lot to do with colonialism. Here comes a powerful, wealthy, white dude who is going to benevolently give internet to the poor non-white people of the world without bothering to partner with them or ask what they want. It’s an old story, and one that many proponents of Starlink cling to mightily, as if this benevolence forgives all sins. Honestly, I’d encourage you to just read Divya M. Persaud’s entire Twitter thread on this because it sums up this problem so well.
And here is the kicker that ALSO ties into colonialism. Many of the arguments against Elon Musk’s Starlink by astronomers sound eerily like the arguments of indigenous Hawai’ians who are opposed to the building on the Thirty Meter Telescope in Mauna Kea, an act which has highlighted the problematic colonialism inherent in astronomical research. One can hope that enough people see the parallels to sway astronomer opinions on the TMT, but my hope is in short supply these days.
So, to wrap it up, astronomers have made a very good case for why Starlink is problematic, but we should also look internally upon our own attitudes where we are problematic for others in our pursuit of the universe.
With many thanks to all of the astronomers and other folks who are linked to in this post who have done the hard work of speaking out even when faced with obnoxious harassment.