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by llsf 948 days ago
Yes, but what about the same place, sitting on the tarmac in hot latitude airport (Singapore, Doha, Las Vegas, etc.) ? It is a bit puzzling to know that heat from lights could damage windows of an airplane.
3 comments

Cribbing off [another comment](https://news.ycombinator.com/item?id=38222198), there's as much as 72kW of lighting being focused on a few square meters of the plane's skin. Direct sunlight at noon at the equator is roughly 1kW/m²; the artificial lighting here is well over an order of magnitude brighter than the sun.
the sun is very very hot and bright, but it is also very far away.
Inverse square law should apply to the lights too. The lights may be bright and very hot but each meter away from them would mean a significant drop in the transmitted energy.
Inverse square applies to spherically projected energy. It was directed in this case.
No
Care to elaborate?

Focusing a light, while still leaving the falloff ""spherical"", makes it so the center of the sphere is not at the light source, it's a virtual point significantly behind it. With a narrow beam, being 1 meter from the light and 10 meters from the light might only be 2x different in brightness, or even less.

And for lights with significant width, you drift away from spherical falloff the closer you are and the wider they are. As you get quite close, and the light fills a lot of your field of view, you approach the situation of an infinite wall of light and that has linear falloff.

These lights are huge and wide and can have tight beam angles.

Oh, I accidentally undersold it, infinite wall of light has no falloff.

Infinite line of light has linear falloff.

Stage lights can reach 90c.
Why don't they bake the actors then?
SPF 200. Also the heat will dissipate over distance. At a rock concert where the ambient temperature is 32c due to being packed with humans, the heat can’t dissipate at well and so you get 60c on stage. Melt cables. Input jacks. Doc Martin soles.

You’ll often see those giant fans blowing all over the stage. It’s not just for big hair stances, it’s to keep humans alive.

On sets, less humans, more space, so the lights heat will dissipate pretty well after 5-10 feet. However I suspect that a simulator that is simulating the sun using a physical lamp would be using higher power lights to mimic the suns bloom. Even keeping it within operating normals it will get hot.