Medical Term:

weightlessness

Pronunciation: wāt′les-nĕs

Definition: The psychophysiologic effect of zero gravity, as experienced by someone falling freely in a vacuum (astronauts in a stable orbit). A temporary state of simulated weightlessness can be achieved during powered flight within the earth's atmosphere by traversing an inverted parabolic curve where gravitational pull and centrifugal force cancel each other out.

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