Get Ready For The 100 Planet Solar System

Toby Manning
March 20, 2017

Kirby Runyon of Johns Hopkins University headed a six-man team of authors from five different scientific bodies in preparing their own version of how planets should be classified. A group of scientists is now poised to restore Pluto's lost planetary status, with a presentation this week at a scientific conference in Texas.

Astronomers want to reclassify Pluto as a planet again, according to the blog Universe Today. Pluto was smallest of the nine planets and its diameter being under three-quarters of the moon and approximately a fifth of the Earth.

Well researchers have asked for a definition for Pluto that tells the intrinsic qualities of the body itself, other than the external factors like its orbit or objects around 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".

Consequently Runyon and colleagues want to define a planet as "a sub-stellar mass body that has never undergone nuclear fusion" and that has enough gravitational heft to maintain a roughly round shape. The part that required a planet and its satellites move alone though their orbit- did not include Pluto.

Otherwise Pluto does fit the IAU definition - it orbits the sun and it is massive enough that the forces of gravity have made it round. That used to be one of the most popular mnemonic devices for remembering the order of the planets in our solar system - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.

If the team's version of planetary definition is indeed widely adopted - and to be clear, that's a long shot at best - it would greatly expand the number of planets in our solar system from the current eight to around 110.

The new definition is more helpful to planetary scientists and is more useful than the IAU's astronomical definition.

Astronomy studies claim that current definitions of what constitutes a planet are technically flawed as they only say that planets orbiting stars "count". Majority are closely affiliated with geology and other geosciences, thus making the new geophysical definition more useful than the IAU's astronomical definition, they said.

Other reports by VgToday

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