The only non-marginal application for this is military, surely.

It sounds too coarse-grade in terms of its area to be anything other than disruptive socially and ecologically.

Sporting and cultural events? Not really (extending the hours of sunlight over a city does have marginal value for a major celebratory event I suppose, but there just aren't that many of these).

Farming? Don't plants need night too? Does harvesting need the sun anymore?

But being able to illuminate a war zone with spontaneous sunlight you can switch off at will, that is a weapon, not least because if you are the only one with the power, your opponents will have to act knowing they may not have the cover of night.

It's not as dangerous as allowing Elon Musk to launch so many more satellites that he ends up with de facto control over access to earth orbit, but it's pretty dangerous.

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ben_w 4 hours ago | parent | next [-]

> The only non-marginal application for this is military, surely.

I think so, but even then it's a heck of a lot of work to make it useful for that.

> Farming? Don't plants need night too? Does harvesting need the sun anymore?

Mostly limited by other things, hence why there's only limited farming in the Sahara, relatively little phytoplankton in the North Atlantic Gyre.

> But being able to illuminate a war zone with spontaneous sunlight you can switch off at will, that is a weapon, not least because if you are the only one with the power, your opponents will have to act knowing they may not have the cover of night.

Even then, nah. Militaries have had night vision for ages. We can make a wall-penetrating radar work as heartbeat/breathing sensor out of kit fairly close to (but not close enough to be a software patch from) a WiFi base station.

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dofm 3 hours ago | parent [-]

I guess it has policing applications, marginally. But most police forces just use helicopters and night vision, and ultimately rely on the disruptive sound of the helicopter to bring people out to look for whoever they are chasing; the noise of a helicopter makes people vigilant.

I just don't really get it.

	▲	cindyllm 2 hours ago \| parent [-]
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brookst 4 hours ago | parent | prev [-]

Illuminating a solar farm for 24 hour power generation?

	▲	ben_w 4 hours ago \| parent \| next [-]
		At the orbits they're talking about, at best 30 minutes before dawn and after sunset. Earth gets in the way, have to go much much higher to get 24 hour coverage, and if you can focus that well over that distance you've got the optics for a super-weapon. And as this is optical, won't go through clouds. This is why beamed power discussions often talk about converting to microwaves instead, though that comes with an even bigger spot size on the ground.
	▲	dofm 4 hours ago \| parent \| prev [-]
		Is it possible it can deliver anywhere near enough solar energy to make this economically viable? It's not going to be full daylight, is it?