Hacker News

> The temperature at the focal point may reach 3,500 °C

I thought this was interesting because it doesn’t really seem like an applicable top level claim, surely this is referring to a specific furnace, not all solar furnaces?

Then this got me thinking if there is some universal upper bound constraint to these temperatures. E.g. if I recall a telescope can’t make a source object brighter than it actually is, and this just seems like a thermal telescope, so I wonder if that principle applies here or not.

007: Die Another Day has it as a main plot point.

You can't focus sunlight at the satellite distances. And this is a fundamental problem, the focal distance varies for each wavelength so your focus point will be smeared. You need monochromatic light for that (a laser).

If sattelites can reflect enough light to make an impact on e.g. global warming, they can also reflect enough to circumvent it. Point them back at the sun or into space and in theory it redirects the same amount of energy away from the earth as it would pointing towards it.

That said, I'm (armchair) confident it'll be good for moonlight-level illumination on a local area at best. They'll need to scale up to thousands / tens of thousands to make any measurable impact - which is their objective by the looks of it, but it'll take a while yet. If this one creates enough backlash, a fleet won't make it. Assuming they get the money and customers to justify a fleet in the first place.

Though I have to ask the value of illuminating large tracts of mostly uninhabited land. Lighting areas where no humans are around to want the light seems like a proposition that’s mostly useful for further disturbing nocturnal wildlife.

What might be more useful is to illuminate just the areas where a human currently needs to see well. It would hypothetically be both more useful - you can concentrate more light in just the areas you need it - and less expensive.

What would be particularly cool about this hypothetical technology is that it could work equally well under foliage and indoors.

Mars… needs something rather bigger. I don't know what the most cost-effective solution would be, but Mars gets about half the per-area sunlight as Earth so it would need a reflector about the size of Mars to get the same overall insolation.

My guess is it's probably easier to make a bunch of greenhouses on the surface? But the scale is so huge that which is best will be affected by technology invented after you start.

> The problem is, global warming doesn't affect daylight.

In my book, that would have been a "Fortunately," entry.

I think what you're missing is that they could all be focused in one spot, not spread over the city. If curved reflective buildings can melt siding, and mirror solar plants can melt salt, I'm pretty sure a city's worth of sun focused on, say, a college campus, could start a massive fire

I think people overestimate the relative strength of the sun.

Then again, assuming there's no dispersion or loss, 50.000 times the sun focused on a 60ft patch will likely have some impact. But that's complete fiction.

Such as? Military in the next 100 years will be drone / remote based, they have IR / night vision and soon to be fully automated. Sunlight can be handy for humans but for decades now the only ones that would benefit from it would be foot soldiers, and they're like the last resort (for western forces anyway).

Daylight helps you just as much as your enemy. We've got plenty of cutting edge night vision and thermal imaging devices for humans and radar on vehicles. The Army's 160th helicopter regiment can fly nap of the earth on a moonless night. Satellite-based Synthetic Aperture Radar can pickup human sized objects during a pass and can switch to sub-centimeter resolution in finer modes. If anything, the military prefers fighting at night because of the advantage it holds.

Yes, think about how this can be weaponized. Illuminate an area? Or, focus that energy on a single point and you've got sun powered space lasers?

Here's a ninety thousand lumen floodlight: https://www.kaufland.de/product/500729350/?search_value=stad...

And a satellite isn't going to provide "hours" of extra light unless it's a very much higher orbit than current proposals. At 600 km altitude, you're talking 20-30 minutes even with an unbounded number of satellites (and 10-15 minutes when you've only got a few satellites). Same reason as sunset itself happens: Earth just gets in the way.

But they'd be competing with the old fashioned stadium lights. I don't think they would be cheaper somehow.

Opposed to holding the event during the earth's orientation towards the sun, aka daytime? Someone should tell the gala and event organizers about this idea of daytime.

How huge is it on a continuous basis? Ii's low earth orbit, so only available for a few hours after sunset, AND requires a new satellite in position every 15 min. So for two hours extra illumination you need to support a couple DOZEN satellites, costs of build, launch, control, and maintenance. Even with 100% bookings —every night— it is dubious finances. Seems much more like a scheme to generate a money flow from meme-investors they can siphon off into their pockets then oops, it fails.

If this is somehow an actual problem, it is far more solvable with tethered blimps or drones, battery pack in a container on a truck, a spool of wire, and light banks as big as you want. AND that isn't subject to clouds (but would be subject to high winds, which would also be more likely to cancel/postpone the event than clouds).

Meanwhile, they go beyond the already massive disturbance of existing terrestrial lighting and overwhelmingly screw up the biologically critical light signals used by every plant, insect, animal, and human in the zone, and do it at multi-kilometer scale.

Edit: Even if the revenue potential is actually huge, it is no justification. For any intelligent person, the actual sponsorship message will be "Tonight's lighting brought to you by [Insert_Company_From_Which_I_Will_Never_Buy_Anything_Again]

This level of stupidity is beyond evil — the kind of lunacy to make a good argument that humans should not exist.

Frankly I don't see this happening before the year of the Depend Adult Undergarment

Rescue operations, etc...

I saw a presentation by one of the founders where he talked about several use cases where the benefit is just phenomenal.

They don't fool me for a second, however. The end goal of this is to build a weapon that can fry people/places on demand (but only the bad guys, of course).

You jest but if one sattelite can be used to focus light onto the earth, it can also be used to focus it away from it, evening it out.

it'll be great for the GDP, too!

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.

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.

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?

MAAS

nothing beats free

Ah yes, the best part of human intimacy: the smells!

Was it ... Musk?

2014 was the inflection point. 2013 brought us the term unicorn for companies, and was just long enough after the iphone that we were starting to make sense of it. That's when Elon Musk became a household name thanks to Tesla and SpaceX. Then there was Palantir. Google bought Deepmind in 2014. Google Facebook Amazon and Apple showed founders that software startups could transform the world, and the world leapt at the chance.

Do you have anything to say about the project itself or do you only care about your perception of ai slop?

I think this company intentionally ignored discussing how battery storage has made solar energy a much more effective and viable solution.