Big mirrors in area to mirror daylight at evening? No thanks, astronomers say

Imagine it: You’ve labored an extended shift, turned the lights out and settled into mattress, when impulsively the sky outdoors your window lights up as if it’s daylight.

This is what might occur if a U.S. firm has its method.

Reflect Orbital is seeking to ship large mirrors in area to “sell sunlight after dark.” 

It’s a plan that’s inflicting alarm amongst astronomers who’re already involved concerning the lack of the evening sky on account of satellite tv for pc constellations — lots of to 1000’s of satellites belonging to 1 firm, most frequently offering web companies — and general mild air pollution. 

But the California startup says their plan might assist resolve vitality points in addition to present lighting for conditions like catastrophe rescue plans and extra. 

Astronomers aren’t shopping for it.

Aaron Boley, an astronomer and affiliate professor on the University of British Columbia, stated there are “basic misunderstandings or willful misrepresentations” on the corporate’s web site.

“They were talking about reducing light pollution by having this giant light from space. And it really seems like they’re trying to suggest that because it’s natural sunlight, it’s not like pollution.”

The company — which filed a request with the U.S. the Federal Communication Commission to launch its first satellite, EARENDIL-1 — is proposing using the satellites to beam down reflected sunlight on specific locations, such as solar farms after the sun has set.

Reflect Orbital has proposed a few different sizes of satellites, ranging from 10 x 10 metres, 18 x 18 metres and even 54 x 54 metres. 

But even at the top size, some experts say that in order to provide enough sunlight to a solar farm, thousands of satellites would be needed.

“If you were to do the midday sun for instance, you would need a mirror that — from the ground — looked like it was the same size as the sun itself in the sky,” said Michael Brown, an associate professor in astronomy at Monash University in Melbourne, Australia.

“That’s many kilometres across when it’s up in orbit. Now, no one’s going to launch a mirror that’s many kilometres across, so what they do is they launch multiple smaller mirrors. And Reflect Orbital’s talking about 54-metre-square mirrors. And to just produce 20 per cent of the midday sun, it looks like you need about 3,000, possibly more of these mirrors.”

Reflect Orbital did not reply to requests for comment for this story.

Not a new concept

The idea of a space mirror isn’t a new one, which was first proposed in the 1920s. On Feb. 4, 1993, Russia deployed Znamya 2, a space mirror 25 metres in diameter that ended up producing a five-kilometre bright spot. A few days later, it burned up over Canada.

The U.S. and the European Space Agency have also made such proposals, though none so far have come to fruition. Some say it’s because it’s not feasible.

So why is it still so appealing?

“With the proliferation of objects in orbit, there is a mentality that if you are able to do one thing from area, you must do one thing from area,” Boley said. “And I feel that’s driving a part of this concept.”

He explained that in order for the mirrors to work, the satellites would have to be on a polar orbit — which is like a ring moving from the south to north poles. That would take the satellites right over Canada.

“There’s this different concern of like shining mild once you merely don’t need it there … so as a result of we’ve this sun-synchronous design, then we will probably be having these satellites simply sweeping throughout Canada as twilight sweeps throughout Canada,” he said. “And so Canada must be very vocal about that.”

Consequences

Reflect Orbital has estimated the light produced by its mirrors would extend several kilometres across.

There’s concern over how that could impact not only people who don’t want the light, but also wildlife.

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John Barentine, founding father of Dark Sky Consulting, stated there’s so much that is unknown about Reflect Orbital’s technical particulars. However, he added, info the corporate has disclosed suggests it’ll have unintended penalties.

“These objects will appear like very bright stars in the sky moving slowly as seen from potentially hundreds of miles or kilometres away from the spot on the ground where the light appears,” he stated.

“It’s happening at a time when the world is dark. The expectation of [animal] biology is that the conditions will be dark around them. I worry a bit that if you are, say, a migratory bird — who we now know are navigating by the stars at some level — that this could be very disorienting.”

Then there are implications for observatories, each skilled and newbie.

“Reflect Orbital says we’re definitely not going to light up your observatories, but if I have bright objects that look like stars moving through the sky far from where the beam is reaching the ground, if it’s anywhere close to an observatory, that’s still a problem,” Barentine stated.

Brown, of Monash University, can be involved about unintended radio interference from the satellites. Recently it was found that SpaceX’s Starlink satellites are creating noise at radio observatories.

But there’s extra that distresses him.

“I’m also more concerned, oddly enough, I’d say from a sort of almost an aesthetic point of view. That I sort of like the sky being sort of this shared wilderness,” he stated.

“If you go somewhere where it’s nice and dark and look at the night sky and have these constant reminders of technology, I think that’s a bit of a loss.”