Mercury, Venus... Oh, forget it!

Full 'Planet' Rising  (Photo by Jessie Eastland)

Elementary science quizzes just got a whole lot harder.  Students can no longer rely upon catchy acronyms when reciting planetary names.

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. 

Resources

https://thespacereporter.com/2017/03/solar-system-100-planets-new-criteria/ 

Copyright March 20, 2017 by Linda Van Slyke   All Rights Reserved