IAU demotes Jupiter, Saturn, Uranus, Neptune from planetary status

December 9, 2012

Due to a shocking new rule defining what is and what isn’t a planet, the International Astronomical Union voted overwhelmingly to strip Jupiter, Saturn, Uranus and Neptune of their planetary statuses.

gas giants

Goodbye, “Gas-oids”

Besides orbiting the sun, being spherical or near spherical and “clearing out the neighborhood around its orbit”, the IAU has added this fourth definition of what constitutes a planet:

Must be terrestrial.

Mercury, Venus, Earth and Mars would qualify since all have solid surfaces where spacecraft can land and where people could walk (they, of course, would need space suits to walk on the planets outside of earth).

Jupiter, Saturn, Uranus and Neptune, however, do not qualify.

Underneath their thick cloud covers, both Jupiter and Saturn are believed to be oceans of liquid hydrogen, atop another ocean of metallic liquid hydrogen and then a rocky core. And under the cloudy covers of both Uranus and Neptune are believed to be first an ocean of liquid hydrogen and liquid helium and then, second, an ocean of water and ammonia and, third, a rocky core.

“Even if future spacecraft could be built to withstand the intense atmospheric pressure of the four gas giants, they would still not be able to land on any of the four planets, since each–save for their rocky cores–is an ocean of either hydrogen or both hydrogen and helium,” said the IAU in a statement. “Therefore, because the only thing suitable for the gas giants would be a spacecraft that could convert into a sea-worthy ship or into a submarine, none of the gas giants are terrestrial and, therefore, are not planets.”

Instead, the IAU suggests the four be called “gas-oids” to distinguish them from true planets.

Another note is that since both Jupiter and Neptune “share” their orbit around the sun with “Trojan Asteroids”, technically they do not clear their own paths and, therefore, each is no more a planet that Pluto is.

Or, was.

trojan asteroids

The Trojan Asteroids are the thick pink splotches in Jupiter’s orbit and are the light-blue cluster in Neptune’s orbit, center left on the image.

Nobody on Jupiter, Saturn, Uranus or Neptune could be reached for comment.

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