The Hangar

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Tanner Swett

00:17

Say, a question occurred to me just the other day. Why do airliners, flying high, appear white from underneath?

At first, the answer seems obvious: it's because they're white.

But here's the thing.

During a clear day, the sky is pretty bright. It's much brighter than, say, the ground.

And that's why low-flying aircraft look dark. They're not brightly lit like the sky.

But apparently airliners are somehow exempt from this effect?

ymb1

01:24

@TannerSwett: someone will probably come up with a cleverer explanation, but here's a hint: what is the sky? it's not just above the plane, but also below -- the higher you fly, the darker the sky gets (not talking U-2 here, but say FL390 on a 777), this already tells you light scattering is happening more underneath, and hence the reflection.

low flying on the other hand, is not subjected to enough scattering from below due to the proximity to the ground

and the relative dullness of terra firma

here's a FL 370 example :

via (airliners.net/photo/Cathay-Pacific-Airways/Boeing-777-367-ER/…) -- the upper bands get darker and darker

you don't see this gradual darkening on ground

discounting sunrise/sets

but the U-2 (which is still flying in the sky) provides a nice contrast as well:

more extreme, but the fading to darkness is the same

14 hours later…

Sanchises

16:00

That's actually a really good explanation @ymb1. I never explicitly addressed this in my mind, I just took it for granted that airplanes that are close look dark.

2 hours later…