Do skydivers shoot upward when their parachute opens?
The closest many of us will get to jumping out of an airplane is watching it on TV or in a movie. The most familiar part of such scenes is the moment that the skydiver pulls a cord and is immediately yanked sharply upward as his chute opens.
A real skydiver will tell you that this doesn’t happen and is actually impossible. The jumper is falling toward the Earth and the parachute will slow his descent, but he is still falling. The reason he appears to ascend is an optical illusion.
Think about where the camera is located in such a scene – it’s being held by another skydiver who exited the plane at nearly the same moment. When skydiver #1 deploys his parachute, his rate of descent slows relative to skydiver #2 (holding the camera). Therefore, skydiver #1 is not shooting up higher into the sky – at that moment #2 is simply falling faster than #1.
A similar illusion is when your car is stopped or parked and a large truck begins moving forward next to you. Instead of seeing the truck moving forward, your brain may interpret this as your own car moving in reverse. This only happens with large vehicles because they block any visual cues that would tell you that you’re not actually moving. Your brain is similarly fooled by skydiving videos, since there are no visible reference objects in the open sky.