Wednesday, May 23, 2018

Question About Human Vision and Missiles

Consider, say, a missile, 5 meters long and 1 meter in diameter. After it's launched, at what speeds could it be tracked by the human eye? What's the upper limit on that speed? Viz., when does the missile become effectively invisible?

(I know the diameter might not be realistic. I just wanted to make it an easy number.)

This is tangentially related to an article I'm working on.

Note added 5/27: I think my query was somewhat ambiguous, because the ability for the eye to track something depends on how far away it is. (Not too far, but not too close.) You can assume any distance you want.... For that matter, make any assumptions you want about size of the object being viewed.... What if the starship Enterprise (or Voyager) dipped into a planet's atmosphere? When could you see it and when would it be moving too fast to catch?


4 comments:

Layzej said...

I wouldn't have thought that was possible. The eye can track a meteor going so fast it burns up: This one was 1 meters in diameter: https://www.youtube.com/watch?v=BNkORbGOb4o

David Appell said...

But is the eye tracking the meteor itself, or remnants of it (the relatively large cloud and its trail)?

David Appell said...

I think my query was somewhat ambiguous, because the ability for the eye to track something depends on how far away it is. (Not too far, but not too close.) You can assume any distance you want....

Layzej said...

These folks seem to have some good answers:

https://www.reddit.com/r/askscience/comments/7hqq6y/how_fast_of_an_object_can_the_human_eye_track_or/

The eye moves about 400° per second. At the surface of your eyeball, that's about 0.1mph. The further away something is, the bigger the distance that 400° covers.

...the human eye can see about 50 Hz then you could say that people can only see things that persist in their vision for longer than 20ms.