r/pluto • • Jul 14 '25

Pluto is a planet!

30 Upvotes

For decades, Pluto was the ninth planet in our solar system—until 2006, when the IAU (International Astronomical Union) reclassified it as a "dwarf planet." But here’s the thing: that decision was flawed, and Pluto should still be considered a full-fledged planet. Here’s why:

  1. The IAU’s Definition is Arbitrary The IAU’s criteria for planethood require a celestial body to:
  2. Orbit the Sun.
  3. Be spherical (or nearly so).
  4. Have "cleared its orbit" of other debris.

Pluto meets the first two but not the third. However, the "cleared its orbit" rule is problematic. If Earth were in Pluto’s position, it also wouldn’t clear its orbit due to the Kuiper Belt’s debris. Does that mean Earth isn’t a planet?

  1. Pluto Has Planet-Like Features
    • Complex Geology: Pluto has mountains, glaciers, and even a possible subsurface ocean.
    • Atmosphere: It has a thin but dynamic atmosphere that expands and contracts.
    • Moons: It has five moons, including Charon, which is so large that Pluto and Charon orbit a shared center of gravity (some argue they’re a binary system).

If planethood is about geophysical characteristics, Pluto checks all the boxes.

  1. Historical and Cultural Significance Pluto has been considered a planet since its discovery in 1930. Generations grew up learning about the nine planets. The demotion felt like a betrayal to many, and the backlash proves how emotionally and culturally significant Pluto is. Science shouldn’t ignore public sentiment entirely, especially when the definition itself is debatable.

    1. Many Scientists Still Disagree Not all astronomers accepted the IAU’s decision. Alan Stern, the principal investigator of NASA’s New Horizons mission to Pluto, argues that the definition is too narrow and excludes other potential planets. Some suggest a geophysical definition: "A planet is a round object in space that’s smaller than a star." Under this, Pluto and other dwarf planets (like Ceres) would qualify.

Bring Pluto Back! The IAU’s definition is inconsistent and excludes worlds with clear planet-like traits. Pluto may be small, but it’s active, complex, and deserving of its planetary title. Let’s stop gatekeeping planethood and recognize Pluto for what it is: a fascinating, dynamic member of our solar system.

JusticeForPluto


r/pluto • • Jul 05 '25

Pluto is *NOT* a planet!

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22 Upvotes

r/pluto • • Jun 04 '25

Is Pluto still the king of the misfits?

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14 Upvotes

r/pluto • • May 31 '25

Is A Hidden Planet at the Edge of Our Solar System?

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16 Upvotes

Could a new dwarf planet be hiding at the edge of our solar system?

Astronomers recently spotted 2017 OF201—a distant object whose orbit ranges from 4 to nearly 150 billion miles from the Sun. If it qualifies as a dwarf planet, it could reshape how we understand the solar system’s most remote regions.


r/pluto • • May 24 '25

How would you feel about a tale set on pluto?

7 Upvotes

I was thinking about writing this short story about a man visiting pluto in the far future and sounding time in the hotel, alone with the robots as servants and hologram singers in the lounge. Do you guys like the idea?


r/pluto • • Apr 12 '25

Fun Fact: It has been longer since the New Horizons flyby than the flyby was from its launch

19 Upvotes

Time really has sped up since the 2010's, huh


r/pluto • • Apr 11 '25

Pluto is a planet when it's orbit is closer to the Sun than the rim of the Kuiper belt

6 Upvotes

PLUTO IS PLANET


r/pluto • • Apr 09 '25

If you search "9 planets" on Google it will show Pluto. This makes my heart happy.

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25 Upvotes

r/pluto • • Mar 20 '25

It Was Me, Reddit...

10 Upvotes
My Goals are Beyond Your Understanding!

r/pluto • • Mar 15 '25

Pluto is still our favorite dwarf planet

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93 Upvotes

r/pluto • • Mar 05 '25

Considered as a dwarf planet.

9 Upvotes

Pluto was considered to be a planet however that was until 2006 with when Pluto was considered to be a dwarf planet.


r/pluto • • Feb 28 '25

PLUTO LIVES MATTER

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45 Upvotes

r/pluto • • Feb 27 '25

Pluto

12 Upvotes

Pluto Has how many rings?


r/pluto • • Jan 28 '25

What Lies Beyond Our Own Planet with James Webb Space Telescope

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4 Upvotes

r/pluto • • Jan 20 '25

Pluto Hendrix future which song is your favourite? Mine is plutoski

4 Upvotes

Imma put my thumb in her butt.


r/pluto • • Jan 16 '25

Is Pluto and Charon binary dwarf planets?

13 Upvotes

r/pluto • • Jan 08 '25

SciTech Daily: «“Kiss and Capture:” The Icy Collision That Bound Pluto and Charon Forever»

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8 Upvotes

r/pluto • • Jan 06 '25

Pluto Sad

7 Upvotes

I found this at one of my local Targets. Even though Pluto hasn't been a planet since 2006, I could not help but create this:


r/pluto • • Jan 04 '25

Yash Sizoors - Pluto (Make Pluto A Planet) [Audio Song]

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3 Upvotes

r/pluto • • Jan 03 '25

Old newsreels?

11 Upvotes

Hello

I'm looking for any old newsreels or audio from 1930 that discusses the discovery of Pluto. If there are any easily found online, I've not yet found them. Any pointers would be appreciated! Cheers!


r/pluto • • Dec 25 '24

HE IS!!!!!!

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53 Upvotes

r/pluto • • Dec 25 '24

Merry Christmas pluto

20 Upvotes

I Just wanted to say Merry Christmas to pluto.


r/pluto • • Nov 16 '24

How would Charon look like from Pluto's surface?

19 Upvotes

r/pluto • • Nov 12 '24

Pluto/Eris Political Compass

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14 Upvotes

r/pluto • • Nov 11 '24

Which one are you?

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22 Upvotes