For example, I’m sitting on my front porch which overlooks the town. Miles away I can see streetlights, signs, etc. How does the source project light to my location, yet doesn’t illuminate my location?
Holy moly friends, thanks for the awards and stuff. I didn’t think this question would spark so much interest, lol. I am thoroughly grateful for all your replies.
In: Physics
It’s a question of numbers. In a pitch black room, your dark-adapted eye can almost detect single photons, little packets of light. The more photons that hit your eye at any moment, the brighter the source.
To make out an object, your eye needs to receive lots of photons all at the same time. That cross-town street light is blasting photons out into space in all directions and your eye is picking up the few photons that travel directly from the light to your eye. There simply aren’t enough of them that hit some object near you and then bounce into your eye, all at the same time.
A camera doesn’t care about time. You can leave the shutter open and it’ll collect photons all night *and remember them*. After a bit, it can collect enough photons to make out Andromeda, a galaxy that occupies more of the night sky than a full moon. Our eyes don’t remember photons over time so we can’t see Andromeda without using a telescope or camera.
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