Can you see a plane at 30,000 feet?

Long story short, I'd just like to be sure to prove a point. someone was discussing UFO sightings, they said it was 30,000 feet up, not a plane. now, i know planes fly at this altitude so it was probably a plane, but then someone said, ":O you can see that far up?" i did read once that your eyes... show more Long story short, I'd just like to be sure to prove a point. someone was discussing UFO sightings, they said it was 30,000 feet up, not a plane. now, i know planes fly at this altitude so it was probably a plane, but then someone said, ":O you can see that far up?"

i did read once that your eyes dont really have a limit, ex. you can see stars, it just depends on how many photons reach your retina. so essentially, im asking if enough phontons reach your eye to see a plane that high (in optimal conditions).
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