Ask Ethan: Is antigravity even possible?
Humans, when we consider space travel, recognize the need for gravity. Without our planet, is artificial or antigravity even possible?
by Ethan Siegel
Here in our Universe, under general relativity, everything that has mass or energy seems to both cause and also to respond to the curvature of spacetime, rendering gravity an always attractive force. And yet, when we think about science fiction, from Star Trek to Battlestar to 2001, artificial gravity and even antigravity are ideas that have permeated our culture in film, literature, television, and more. Is this even something that’s physically possible? Or do the rules of general relativity absolutely forbid something like this from becoming reality? Physics investigates.
For as long as we’ve been thinking about journeying to other star systems and the planets and worlds that orbit them, we’ve been compelled to consider just how to keep human beings intact during any journey that would bridge the interstellar distances. While short trips through the zero-gravity environment of space might be feasible for humans, over longer time periods, human bodies suffer from all sorts of maladies: space blindness, bone density loss, muscle atrophy, and much more. While instantaneous teleportation or faster-than-light travel, either through a wormhole or via warp drive, might be satisfactory solutions for science fiction, when it comes to reality, we need a superior plan.