Will Pluto Become a Planet Again? Plans to Promote the Former Ninth Planet.

Will Pluto Become a Planet Again? Plans to Promote the Former Ninth Planet.

Will Pluto Become a Planet Again? Plans to Promote the Former Ninth Planet.


For a planet we thought little enough of to demote, we sure seem to obsess over Pluto! After all, we travelled over four billion miles to visit him in 2015. Not to mention, he’s now the subject of shirts, books, documentaries and more. However, 2017 has struck up talk of, once again, making Pluto a true planet. So Astronimate asks, will Pluto become a planet again?

Why was Pluto demoted in the first place?

Astronomy’s governing body, the International Astronomical Union (IAU) essentially makes the rules, and calls the shots. As a result, they defined what “being a planet” means. Simply put, a real planet:

  • Orbits the Sun
  • Has a nearly-round (spherical) shape due to the power of its own gravity
  • Has “cleared the neighborhood” around its orbit

Unfortunately, Pluto only meets some criteria, missing out on #3. Despite living here for almost five billion years, little Pluto has not cleared its neighborhood. In other words, Pluto shares this part of our solar system with other gravitationally-dominant planets. As a result, any planet, like Pluto, not meeting all three requirements is considered a dwarf planet.

However, Pluto had a great run, being a true planet for 76 years! But, will Pluto become a planet again at some point? After all, requirements, names and everything else change over time.

Will Pluto become a planet again in 2017?

Suddenly, 2017 shows new hope and discussions around revamping the definition of a planet. In fact, a group of NASA scientists has restructured the criteria to become a genuine world. Actually, their new criteria are so much more lenient that even new bodies, including Earth’s Moon would be within the limits!

Even Alan Stern, point man on the New Horizons mission, agrees that we need a review. In fact, Stern has historically been a key adversary of Pluto’s demotion, telling Business Insider in 2015, the decision was “bullshit.”

Several key players, including Stern, argue that planetary definitions and requirements should not be made my general astronomers. Instead, dedicated planetary scientists are much more precisely qualified to make such calls. Primarily, this argument pertains to the CalTech astronomers’ definition that ultimately led to Pluto’s planetary demise.

So, what should the definition of a planet be?

Stern and others don’t simply want to reinstate Pluto for pure nostalgia. Ultimately, they desire an entirely new definition of a planet, which, by default would also regain Pluto. Then, what do they feel makes a more effective and modernized planetary definition? The proposed definition is as follows:

[pullquote align=”normal”]“A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameter.” [/pullquote]

So, what does that mean? Will Pluto become a planet again under this new definition? Simply put, yes. Pluto and several other new objects would officially become planets under this update.

Basically, here is the layman’s terms version of the above definition:

[pullquote align=”normal”]“A planet is smaller than a star, can’t generate nuclear power and has gravity strong enough to shape itself into a sphere, like Earth!”[/pullquote]

Currently, our planetary definition is criticized for being too narrow. However, several worry that newly proposed definitions, like the above are far too broad.

What comes next for Pluto?

Ok, with a newly proposed planetary definition, and powerhouse players like Alan Stern leading the charge, will Pluto become a planet again? If so, when will it become a planet again?

Ultimately, nothing will change in the immediate future. Certainly not 2017. And, while a new definition of what constitutes a planet will likely be accepted, it will take years. In fact, historically, large changes or decisions take quite some time to completely flow through the IAU.

So, will Pluto become a planet again? Highly likely, but not certain. For what it’s worth, we here at Astronimate vote YES on Pluto’s planetary status!

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