SpaceX satellites pose new headache for astronomers
SpaceX satellites pose new headache for astronomers
Washington (AFP) - 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."
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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."
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