How do car headlights look so bright from far away but only really illuminate a small area?
In: Technology
When you are looking a light directly, photons are flying out with some energy directly into your eyes – lots of photons means it appears bright.
If you are looking at the things it is illuminating, the photons need to travel out from the light, hit the road/tree/deer in front of you, and then bounce back into your eye.
Most surfaces (other than mirrors or smooth surfaces) absorb a portion of the incoming light and reflect the remainder back diffusely (scatter) in all directions. This results in much less photons making it back off the bounce directly to your eyes, thus much these things appear darker.
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