Brent, My intended meaning for "reversal" is that attraction would become repulsion. You're quite right that (as Josh Burton just reminded me) in Einstein's theory of gravity, the sign of the mass of a body doesn't affect the dynamics. I was conceiving of the joke in a Newtonian framework. All comments are welcome, but I'm especially interested in ones that, like Cris Moore's, expand on the scenario in a goofy but scientific way (e.g., invoking the theory to explain how the Moon lost its atmosphere). Jim On Sunday, January 12, 2014, meekerdb wrote:
On 1/11/2014 7:37 PM, James Propp wrote:
Has anyone ever proposed in the Annals of Improbable Research or a similar venue that, in addition to undergoing periodic reversals of its magnetic field, Earth is also subject to occasional short-lasting reversals of its gravitational field?
Since gravity is always attractive, would reversal make any difference.
Brent
Such a phenomenon would handily explain selective extinction of megafauna: a mouse could survive an upward fall for five seconds followed by a downward fall for five seconds followed by an extreme deceleration, but a mastodon would not fare as well. :-)
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