the universe's cruelest joke: gravity is still pulling, you're just falling with it.
means the sensation of weightlessness that happens when you and everything around you fall at the same rate, so there's nothing to push back and make you feel heavy.
from the phrase caught on in the 1950s space race era, but the physics is pure einstein: his 1907 'happiest thought' realized a person in freefall feels no gravity at all, because gravity and acceleration are indistinguishable.
iss astronauts — live in continuous freefall 400km above earth since 1998
nasa vomit comet — parabolic flights give researchers 20-25 second weightless windows
apollo 8 — 1968 crew were first humans to fully experience it
zero gravity corporation — sells civilian parabolic flights since 2004