Pluto is a dwarf planet in the Kuiper Belt whose 2006 reclassification by the International Astronomical Union sparked a large online protest movement.

Where did Pluto come from?

The meme started with the IAU's August 24, 2006 vote that placed Pluto in a new dwarf planet category alongside Eris.

What does Pluto mean?

'To pluto' was named 2006 Word of the Year by the American Dialect Society, defined as 'to demote or devalue someone or something'.

How do you use Pluto?

People use 'plutoed' as a verb for unfair downgrades, and Urban Dictionary defines Pluto as 'a loner reject planet that the solar system kicked out'.

Is Pluto still popular?

The Pluto-as-planet debate is a classic recurring online argument, and the 2015 New Horizons flyby produced a major surge in attention when the mission team spoke publicly about feeling 'devastated' by the demotion.

Pluto

2006eventclassic

Published August 5, 2026

Pluto is the dwarf planet whose 2006 demotion from full planetary status sparked a lasting online fandom, protest sites, and the verb 'plutoed.' The 2015 New Horizons flyby revived it as an internet-wide sympathy meme when close-up photos revealed a heart-shaped, dog-face-like surface.

word of the year memes slang memes protest memes late 2000s memes fandom discourse memes

Overview

Pluto is a small icy body in the Kuiper Belt that was reclassified as a dwarf planet in 2006, a decision that sparked an unusually loud online reaction2. Widespread description of the move as a demotion led to online petitions and a new coined verb, 'to pluto,' which the American Dialect Society named 2006 Word of the Year with the definition 'to demote or devalue someone or something'1.

The Pluto meme picked up a second wave in July 2015 when the New Horizons probe returned the first close-up photos of the dwarf planet, showing a reddish surface with a heart-shaped region that many said looked like the Disney cartoon dog Pluto, spawning Photoshop edits and sympathy captions on Twitter, Tumblr, and Reddit3.

Gallery

Origin & Background

Platform

Usenet, blogs (initial) / Reddit and Tumblr (2015 viral spread)

Date

2006

On August 24, 2006, the International Astronomical Union formalized a definition of 'planet' that excluded Pluto and placed it in a new 'dwarf planet' category alongside Eris2. The trigger was Caltech astronomer Mike Brown's discovery of Eris, a body slightly more massive than Pluto, which pushed the IAU to either add many new planets or draw a tighter line2. In January 2007, the American Dialect Society chose 'plutoed' as its 2006 Word of the Year, beating 'climate canary' in a runoff vote and defining the verb as 'to demote or devalue someone or something'1.

How It Spread

Pushback started fast. Fan groups like the Society for the Preservation of Pluto as a Planet ran offline petitions, Usenet discussion in alt.planets.pluto stayed active for years, and New Horizons chief scientist Alan Stern publicly called the IAU decision 'sloppy' while pushing for reinstatement3.

The July 2015 New Horizons flyby produced a major surge in Pluto attention online. Software engineer Gail Oxton, who joined the mission in 2002, said the team was 'devastated' when Pluto got demoted and that 'it still stings a little'2. Roughly 400,000 people tweeted about the dwarf planet on July 13, when the first close-up image arrived, and NASA's follow-up photos two days later showed ice mountains and informally named regions like Cthulhu on Pluto and Mordor on the moon Charon3.

How to Use This Meme

The meme is typically used two ways: as the verb 'plutoed,' meaning to demote or devalue someone or something1, and as sympathy content around the 2015 New Horizons flyby, often paired with mock arguments for restoring planet status2.