1 in 15 lights in the sky could soon be a satellite, warns an astronomer

I’m out on my rural farm in Saskatchewan, talking to my neighbors, whom I’ve invited to appreciate the night sky through a telescope.

After exclamations and open-mouthed amazement at Saturn’s rings and the light that has traveled through space for more than two million years to reach our eyes in the Andromeda Galaxy, our conversation inevitably turns to the pandemic, our working arrangements. home and complaints about the rural internet. My neighbor mentions that they just switched to using Starlink for their internet provider.

I look up and see a bright satellite moving in the sky, almost certainly a Starlink, because it now represents almost half of the nearly 4,000 operational satellites and is extremely bright. I take a deep breath and think carefully about how to talk about the substantial cost we will all have to pay for Starlink internet.

I don’t blame my neighbors for the change. Here, as in many rural areas of North America, there are no great internet options, and with so many people working and taking home classes during the pandemic, anything that makes life easier is immediately accepted.

But I know exactly how high this cost could be. My forthcoming work Astronomical Journal, has predictions about what the night sky will look like if satellite companies fulfill their current plans.

I also know that because of the geometry of the sunlight and the orbits that have been chosen, 50 degrees north, where I live, will be the worst affected part of the world.

Without any regulations, I know that in the near future, one of the 15 points you can see in the sky will actually be constantly crawling satellites, not stars. This will be devastating for astronomy research and will completely change the night sky around the world.

The future is too, too bright

To find out how badly the night sky will be affected by the sunlight reflected by the planned megaconstellations of satellites, we built an open source computer model to predict the brightness of satellites seen from different places on Earth at different hours of the night. different seasons.

We also built a simple web application based on this simulation.

Our model uses 65,000 satellites in the orbits of four mega-constellation companies: SpaceX Starlink and Amazon Kuiper (USA), OneWeb (UK) and StarNet / GW (China). We calibrated our simulation to fit the measurements of the Starlink satellite telescope, as they are by far the most numerous.

Starlink has so far taken a few steps toward blurring satellites since its first launch, but most are still visible to the naked eye.

Our simulations show that from anywhere in the world, every season, there will be tens to hundreds of satellites visible for at least an hour before sunrise and after sunset.

Right now, it’s relatively easy to get rid of dark urban light pollution while camping or visiting your cottage, but our simulations show that you can’t get rid of this new satellite light pollution anywhere on Earth, even at the North Pole.

The worst-hit locations on Earth will be 50 degrees north and south, near cities such as London, Amsterdam, Berlin, Prague, Kiev, Vancouver, Calgary and my own home. At the summer solstice, at these latitudes, there will be almost 200 satellites visible to the naked eye all night.

I’m studying the orbital dynamics of the Kuiper Belt, a belt of small bodies beyond Neptune. My research is based on long exposure, wide field images to discover and track these small bodies to learn about the history of our Solar System.

Telescope observations that are key to learning about our Universe are about to become much, much more difficult due to the unregulated development of space.

Astronomers are creating some mitigation strategies, but they will require time and effort that should be paid for by mega-constellation companies.

Unknown environmental costs

Starlink may seem cheaper than other rural options, but this is due to the high cost. An immediate cost is air pollution from the hundreds of rocket launches needed to build and maintain this system.

Each satellite deployment drops rocket-worn bodies and other debris into Earth’s already crowded orbit, increasing the risk of a collision. Some of this space debris will eventually fall back to Earth, and those parts of the globe with the highest satellite densities above the head will also be most likely to be literally affected.

Starlink plans to replace each of the 42,000 satellites after five years of operation, which will require the de-orbit of an average of 25 satellites per day, about six tons of material. The mass of these satellites will not disappear – it will be deposited in the upper atmosphere.

Because satellites are mainly made up of aluminum alloys, they can form alumina particles as they vaporize in the upper atmosphere, potentially destroying ozone and causing changes in global temperature.

This has not yet been studied in depth, as the Earth’s low orbit is not currently subject to any environmental regulations.

Sky adjustment

Currently, the low orbit of the Earth, where all these satellites are planned to operate, is almost completely unregulated. There are no rules about light pollution, air pollution from launches, air pollution from re-entry or collisions between satellites.

These megaconstellations may not even be financially viable in the long run, and internet speeds can slow down to a crawl when many users connect at the same time or when it is raining.

But companies are launching satellites right now at a frantic pace, and the damage they do to the night sky, the atmosphere and the safety of the Earth’s low orbit will not be undone even if the operators go bankrupt.

There is no doubt that rural and remote internet users in many places have been left behind by the development of internet infrastructure. But there are many other options for online delivery that will not lead to such extreme costs.

We cannot accept the global loss of access to the night sky, which we have been able to see and which we have been able to connect with as long as we are human.

With cooperation instead of competition between satellite companies, we could have far fewer in orbit. By changing the design of the satellites, they could be much weaker, with less impact on the night sky. We should not make a choice between astronomy and the internet.

But without regulations that impose these changes or strong consumer pressure to indicate the importance of the night sky, our view of the stars will soon change forever.

Samantha Lawler, Assistant Professor of Astronomy, Queen’s University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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