Get Ready For The 100 Planet Solar System

Posted March 20, 2017

Kirby Runyon from Johns Hopkins University, along with six colleagues from five institutions will present a proposed new definition of "planet", and a justification for that definition at the upcoming Lunar and Planetary Science conference which is being held this week in Texas. Now, a group of scientists says Pluto should definitely be added back to the planet list - oh, and that there are over 100 other objects in our solar system that should also be called planets.

This comes more than a decade after the International Astronomical Union changed the definition of a planet, according to Tech Times.

Astronomers want to reclassify Pluto as a planet again, according to the blog Universe Today.

Still, Pluto "as everything going on its surface that you associate with a planet". Pluto's diameter is under three-quarters that of the moon and almost a fifth of Earth. He said that Pluto is basically being a planet, Phys.org reported. All the authors are science team members on the New Horizons mission to Pluto, operated for NASA by the John Hopkins University Applied Physics Laboratory.

The team argued that a planet should be defined by a celestial body's intrinsic qualities and not on external factors such as its orbit or the objects surrounding it.

In 2006, the IAU officially defined a planet as "a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit". It does away with the IAU's requirement that a planet and its moons move alone in their own orbit, not with a bunch of asteroids as well. The proposed new geophysical definition omits stars, black holes, asteroids and meteorites, but includes much of everything else in our solar system. It would expand the number of planets from eight to about 110. The increase would make understanding the solar system more hard - but ultimate more rewarding, the astronomers said.

The team's definition doesn't require approval from a central governing body for scientists to start using it - in fact, it's already been adopted by Planet Science Research Discoveries, an educational website founded by scientists at the University of Hawaii. As the very word "planet" seems to carry a "psychological weight", he reasons that more planets could encourage that public interest.

"I want the public to fall in love with planetary exploration as I have", Runyon said. Most planetary scientists are also generally trained as geoscientists more than astrologists, so a geophysical definition might suit them better than the old classification.