Too Much of a Good Thing?

 Away from our city lights, the night skies over our planet glisten with thousands of stars. Those we can see with our eyes are only the tip of a nearly infinite stellar iceberg. While the starry night sky provides us with breathtaking beauty, astronomers with their telescopes study much more. They examine the stars, the galaxies that stars reside in, and the space between galaxies. They use these telescopes to peer billions of years back in time, all looking for clues to how the universe works, where it came from, how it’s changing, how we came to be.

Occasionally when you share in the beauty of our night sky, you might see a “star” moving among all the others. These artificial satellites, the biggest of which is currently the International Space Station, might even elicit some level of excitement.

But, imagine you’re an astronomer studying a distant galaxy, looking for clues to how the universe came to be when one of these satellites slides across the view of your telescope disrupting the precious data your instruments are taking. That would be a big nuisance to that astronomer’s studies.

You might think, hey, it’s one little blip and there are so few, what harm can they do? But, for every satellite you notice at night, there are many more that you can’t see but which can interfere with astronomical data.

SpaceX, a private space launch company, uses its Falcon 9 rocket to launch satellites for private communications companies to orbit. One of its biggest customers, Starlink, uses thousands of satellites to provide internet access around the world. Each Falcon 9 can launch 50 or more Starlink satellites. It’s certainly a fascinating sight to watch this train of satellites traveling across your night sky as they slowly separate and move to their individual orbits. Such satellite trains initially led to many UFO reports, although the sight is common enough that they rarely generate such reports anymore. Once in their final orbit, they shine so faintly that the human eye can barely discern them.

But astronomical telescopes easily spy them. And they are more than just a nuisance. They produce bright trails on images taken by those telescopes. They can block out a star of particular interest or cause brief, transient phenomena, like the poorly understood gamma-ray bursts, to be totally missed.

Satellite tracks in an image from Cerro Tololo Inter-American Observatory in Chile 

Credit CTIO-NOIRLab-NSF-AURA

Recently, Amazon’s Blue Origin launched the first of one hundred, Blue Walker satellites. It is the largest commercial satellite ever launched, roughly half the size of a tennis court, and it rivals the brightest stars in the night sky. The fully operational Blue Walker satellites may be even larger and brighter.

I remember as a child how exciting it was to glimpse the rare satellites moving across my night sky. But for astronomers trying to understand the workings of our universe, these are becoming much more than an annoyance. All too often, they cause the loss of rare, often irretrievable astronomical data.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

This is reprinted with permission from the Oklahoman and Oklahoman.com.