A few weeks ago, I was helping out with a stargazing night at Mount Stromlo when I spotted something interesting in the sky.
I mentioned to my guests to quickly come outside of the dome we were using to look up at a trail of very bright white dots, moving across the sky like a celestial conga line.
Everyone (including myself) was very impressed at this sight and I told them they were lucky to see it. However, reflecting back on it, I wonder whether in the future it will be the case that we will be lucky to not see it.
You may have seen this yourself lately - this line of lights in the sky. The objects in question were the Starlink satellite constellation. They are aiming to launch a large number, about 12,000, small satellites made by SpaceX. They aim to provide high-speed satellite internet to the entire world.
These satellites would whiz around the Earth about 500km above our head - known as low Earth orbit, which takes 90 minutes to do a lap of the globe. Over 700 of them have already been launched with testing of the network underway. People are getting around 100 Mb/s and it should only get faster.
While this sounds like a fantastic idea, providing internet access to disadvantaged and unreached areas of the planet and a competitive pricing to other service providers, there are a number of issues that give astronomers pause.
The first is light pollution; a term normally used as the rationale for observatories to be set up away from bright cities and their lights.
Starlink satellites are quite reflective, as I saw for myself a few weeks ago, and with 12,000 or more of them to go up it is quite likely these satellites will streak across many an astrophotographer's camera.
This is especially problematic for radio astronomers, many of which reside in Australia. All of these satellites will be communicating with ground stations and between each other, the signals of which will pollute the signals coming from stars and galactic sources that astronomers want to research.
Elon Musk, CEO of SpaceX has committed to reducing the reflectivity of his satellites, but they will still cause an impact regardless.
The second issue is space debris. With so many satellites flying in such a small space, the likelihood of a collision with another satellite is quite high. The resulting debris from a collision can be devastating (especially if you are Sandra Bullock in the movie Gravity). Even a fleck of paint at that altitude can act like a bullet due to its speed, causing even more damage.
Other companies also plan to join SpaceX's venture, including Amazon and Samsung with their own 1000s of satellites, and so it may be inevitable that our night sky will be filled with celestial conga lines. But whether the loss of a clear night sky is worth the global internet access is a question that governing authorities, and the public, will have to consider - and soon.
- Jonah Hansen is a PhD student specialising in space interferometry at Mount Stromlo Observatory at the Australian National University.