Have you ever seen a satellite crossing the sky? It’s kind of cool. Satellites become visible because their solar panels and other reflective surfaces catch the light of the Sun and then reflect that light back down to Earth at night. How can they reflect the Sun when it is nighttime? Simple – the satellites are way up above the Earth, and from their vantage point, the Sun is still “visible” to them.
Most times when you see a satellite in the night sky it is relatively faint – a small, steady dot moving across the sky at a good clip. Sometimes, if you are lucky, you’ll see two satellites in similar orbits pass at the same time. And, if you are quite lucky indeed, one of them might flare, or rotate such that it reflects a lot of sunlight down at you briefly – sometimes even making the satellite the brightest thing in the sky for those few seconds.
Such sights are amazingly cool, and there is a whole subset of astronomers who enjoy satellite watching and deliberately plan their viewing sessions to see the best flares and passes. But what if such occurrences were no longer rare, but happened every night? What if you couldn’t look at the night sky without seeing a dozen or more satellites crossing the sky and flaring – all the time?
Many astronomers are concerned that this is where we are heading. On May 23rd, SpaceX launched the first 60 satellites in their Starlink Satellite Constellation designed to bring high speed internet coverage across the globe. These satellites all move together in a train. When they cross your sky, it’s not one dot you see…you see dozens! And they occasionally flare along the train as well – making the whole thing kind of sparkle a bit as it crosses the sky.
This might sound kind of pretty, but the constellation is just starting. In the end, SpaceX intends to have 12,000 such satellites in trains all over the sky. When finished, the Starlink Constellation will outnumber the visible stars in the night sky. Our nighttime view will have changed dramatically, with satellites zipping around quite often. Almost 7,500 of these satellites are expected to be in low Earth orbits, making them quite easily visible. And SpaceX is only one of several companies that are planning to set up large constellations of satellites.
Now, don’t get me wrong, I love to see satellites in our sky. But part of what I love about them is that they are rare. Special. A unique event not seen all the time. Giving up our already light-polluted skies to constant satellite passes does not seem like a positive thing to me. Already, even the small train of 60 satellites is causing problems for professional astronomers, as the light reflected from them leaves streaks across the images they take.
Maybe this seems like a silly concern to you. But then again, it’s hard to worry about saving what you never knew you had. Take a look at the night sky and maybe you’ll understand why I want to make sure we have it to look at for a long time to come. Join me at the Virginia Living Museum’s monthly Stargazing and Laser Light Night event on Saturday June 8. We’ll be setting up our telescopes beginning around 8pm for night sky viewing (weather permitting). The cafe will be open from 8 to 11:30pm for drinks and snacks. And in the planetarium, we’ll have three different shows – Virginia Skies, Laser Zeppelin, and Pink Floyd’s The Wall. There’s a charge for the planetarium shows, but stargazing is free. Come on out and explore the beauty of what’s right up above you. And who knows…we might even see a satellite cross the sky.