|Full 'Planet' Rising (Photo by Jessie Eastland)|
The “Big Nine” may soon welcome 100-plus relatives. The definition of “planet” seems to be expanding way faster than the universe itself. It used to be that a planet had to “orbit around the sun,” as well as clear “the neighborhood around its orbit.” Pluto was then demoted to dwarf status because its neighborhood was a bit too crowded.
Soon, “planet” could simply mean “a sub-stellar mass body that has never undergone nuclear fusion.” This body should “possess enough gravitational pull to maintain a spherical shape.” Our own moon would meet that new criteria, along with 100 other solar-system “pals.” Pluto, as well as its moon Europa, would be in that revised mix.
Copyright March 20, 2017 by Linda Van Slyke All Rights Reserved