The In-Depth April National Geographic Story on how light pollution is generally getting worse can be found HERE. With the proposed release of thousands of near Earth orbit SpaceX "Starlink" satellites, astronomers and dark sky advocates fear the worst, but are hoping for the best.
Statement from the International Dark-Sky Association
Tucson, AZ – On May 23, 2019, the spacecraft company, SpaceX launched a group of sixty satellites into low Earth orbit (LEO). Due to their reflective solar panels and other metal surfaces, the satellites are visible to the naked eye at night. In the days since they were launched, sightings have been reported all around the world. The visibility of the satellites, combined with a rapid increase in the number of satellites in LEO has caused concern in the astronomy and stargazing communities. Questions about the impact of this newly deployed technology are rippling through the natural nighttime conservation network.
To date, the U.S. Federal Communications Commission has already approved the operation of more than 7,000 SpaceX satellites in low Earth orbit. At least three other companies have expressed interest in launching large groups of similar new satellites, which are intended to provide reliable broadband internet service to people all over the world. These plans could easily lead to tens of thousands of satellites in low Earth orbit.
The rapid increase in the number of satellite groups poses an emerging threat to the natural nighttime environment and our heritage of dark skies, which the International Dark-Sky Association (IDA) has worked to protect since 1988. We do not yet understand the impact of thousands of these visible satellites scattered across the night sky on nocturnal wildlife, human heritage, or our collective ability to study the cosmos.
Some early reports have caused concern. James Lowenthal, a professor of astronomy at Smith College, was training undergraduate students for a summer astronomy outreach internship in New Hampshire when the SpaceX satellite grouping crossed their path in the night sky. “We were gathered around the telescope when one of them shouted, ‘WHAT is THAT?’” he tells IDA. Lowenthal calls the satellites a “shocking and devastating sight.”
The number of low Earth orbit satellites planned to launch in the next half-decade has the potential to fundamentally shift the nature of our experience of the night sky. IDA is concerned about the impacts of further development and regulatory launch approval of these satellites. We therefore urge all parties to take precautionary efforts to protect the unaltered nighttime environment before deployment of new, large-scale satellite groups.
SpaceX Satellites Pose New Headache For Astronomers
Issam Ahmed, Physics.org
It looked like a scene from a sci-fi blockbuster: an astronomer in the Netherlands captured footage of a train of brightly-lit SpaceX satellites ascending through the night sky this weekend, stunning space enthusiasts across the globe.
But the sight has also provoked an outcry among astronomers who say the constellation, which so far consists of 60 broadband-beaming satellites but could one day grow to as many as 12,000, may threaten our view of the cosmos and deal a blow to scientific discovery.
The launch was tracked around the world and it soon became clear that the satellites were visible to the naked eye: a new headache for researchers who already have to find workarounds to deal with objects cluttering their images of deep space.
"People were making extrapolations that if many of the satellites in these new mega-constellations had that kind of steady brightness, then in 20 years or less, for a good part the night anywhere in the world, the human eye would see more satellites than stars," Bill Keel, an astronomer at the University of Alabama, told AFP.
The satellites' brightness has since diminished as their orientation has stabilized and they have continued their ascent to their final orbit at an altitude of 550 kilometers (340 miles).
But that has not entirely allayed the concerns of scientists, who are worried about what happens next.
Elon Musk's SpaceX is just one of a several companies looking to enter the fledgling space internet sector.
To put that into context, there are currently 2,100 active satellites orbiting our planet, according to the Satellite Industry Association.
If another 12,000 are added by SpaceX alone, "it will be hundreds above the horizon at any given time," Jonathan McDowell of the Harvard Smithsonian Center for Astrophysics told AFP, adding that the problem would be exacerbated at certain times of the year and certain points in the night.
"So, it'll certainly be dramatic in the night sky if you're far away from the city and you have a nice, dark area; and it'll definitely cause problems for some kinds of professional astronomical observation."
Musk's puzzling response
The mercurial Musk responded to the debate on Twitter with contradictory messages, pledging to look into ways to reduce the satellites' reflectivity but also saying they would have "0% impact on advancements in astronomy" and that telescopes should be moved into space anyway.
He also argued the work of giving "billions of economically disadvantaged people" high-speed internet access through his network "is the greater good."
Keel said he was happy that Musk had offered to look at ways to reduce the reflectivity of future satellites, but questioned why the issue had not been addressed before.
If optical astronomers are concerned, then their radio astronomy colleagues, who rely on the electromagnetic waves emitted by celestial objects to examine phenomena such as the first image of the black hole discovered last month, are "in near despair," he added.
Satellite operators are notorious for not doing enough to shield their "side emissions," which can interfere with the observation bands that radio astronomers are looking out for.
"There's every reason to join our radio astronomy colleagues in calling for a 'before' response," said Keel.
"It's not just safeguarding our professional interests but, as far as possible, protecting the night sky for humanity."
Lights In The Sky From Elon Musk's New Satellite Network Have Stargazers Worried
Michael J. I. Brown, The Conversation
UFOs over Cairns. Lights over Leiden. Glints above Seattle. What's going on?
The launch of 60 Starlink satellites by Elon Musk's SpaceX has grabbed the attention of people around the globe. The satellites are part of a fleet that is intended to provide fast internet across the world.
Improved internet services sound great, and Musk is reported to be planning for up to 12,000 satellites in low Earth orbit. But this fleet of satellites could forever change our view of the heavens.
Starlink's ambitious mission
Starlink is an ambitious plan to use satellites in low Earth orbit (about 500km up) to provide global internet services.
This is different from the approach previously used for most communication satellites, in which larger individual satellites were placed in high geosynchronous orbits—that stay in an apparently fixed position above the Equator (about 36,000km up).
Communications with satellites in geosynchronous orbits often require satellite dishes, which you can see on the sides of residential apartment buildings. Communication with satellites in low Earth orbit, which are much closer, won't require such bulky equipment.
But the catch with satellites in low Earth orbit, which move quickly around the world, is they can only look down on a small fraction of the globe, so to get global coverage you need many satellites. The Iridium satellite network used this approach in the 1990s, using dozens of satellites to provide global phone and data services.
Starlink is far more ambitious, with 1,600 satellites in the first phase, increasing to 12,000 satellites during the mid-2020s. For comparison, there are roughly 18,000 objects in Earth orbit that are tracked, including about 2,000 functioning satellites.
Starlink satellites travel silently across the skies of Leiden.
Lights in the sky
It's not unusual to see satellites travelling across the twilight sky. Indeed, there's a certain thrill to seeing the International Space Station pass overhead, and to know there are people living on board that distant light. But Starlink is something else.
The first 60 satellites, launched by SpaceX last week, were seen travelling in procession across the night sky. Some people knew what they were seeing, but the silent procession of light also generated UFO reports. If you're lucky, you may see them pass across your skies tonight.
If the full constellation of satellites is launched, hundreds of Starlink satellites will be above the horizon at any given time. If they are visible to the unaided eye, as suggested by initial reports, they could outnumber the brightest natural stars visible to the unaided eye.
Astronomers' fears were not put to rest by Musk's tweets:
Satellites are very definitely visible at night, particularly in the hours before dawn and after sunset, as they are high enough to be illuminated by the Sun. The Space Station's artificial lighting is effectively irrelevant to its visibility.
In areas near the poles, including Canada and northern Europe, satellites in low Earth orbit can be illuminated throughout the night during the summer months.
Hundreds of satellites being visible to the unaided eye would be a disaster. They would completely ruin our view of the night sky. They would also contaminate astronomical images, leaving long trails across otherwise unblemished images.
The US$466 million Large Synoptic Survey Telescope, based in Chile, is an 8-metre aperture telescope with a 3,200-megapixel camera. It's designed to rapidly survey the sky during the 2020s.
Will we lose the night sky to city lights and satellites? Credit: Jeff Sullivan, CC BY-NC-NDWith the full constellation of Starlink satellites, many images taken with this telescope will contain a Starlink satellite. Longer exposures could contain dozens of satellite streaks.
Dark skies or darkened hopes?
Is there any cause for optimism? Yes and no.
Musk has produced some amazing feats of technology, such as the SpaceX Falcon and Tesla cars, but he's also disappointed some on other projects, such as the Hyperloop tunnel transport plan.
While Starlink certainly blew up on Twitter, for now at least, Musk is 11,940 satellites short of his 12,000.
Also, initial reports may have overestimated the brightness of the Starlink satellites, with the multiple satellites closely clustered together being confused with one satellite.
While some reports have indicate binoculars are needed to see the individual satellites, they also report that Starlink satellites flare, momentarily becoming brighter than any natural star.
If the individual satellites usually are too faint to be seen with the unaided eye, that would at least preserve the natural wonder of the sky. But professional astronomers like myself may need to prepare for streaky skies ahead.
I can't say I'm looking forward to that.
Cloudy Nights contributor t image created the graphic animation below to simulate the visibility of the SpaceX satellites:
Thanks to the code written by Astronomy Live's youtube channel owner, I generated TLE's for 66 satellites in 24 orbital planes at 550km to simulate the planned first shell of Starlink satellites.
I created an animation from an arbitrary location, I chose Long Island, New York since it is near a large population.
This is if there were 1,584 Starlink satellites up and place right now, each frame is a 10 minute change in time, as can be read. Note the promise that you won't be able to see them deep into a summer night is not necessarily factual.
The satellite icons shown indicate they will be reflecting Sunlight. However, their brightness may be in the range of mag. 4- mag 10 or dimmer, depending on time/location/orientation. Flares are also not animated as the operational orientation is not yet known thus not making them predictable. Expect flares to be up to mag. 1 or brighter depending on reports so far...