Answer: Eris

Just because a planet is tiny doesn’t mean it can’t cause a ruckus. In 2005, the dwarf planet Eris was discovered by a Palomar Observatory-based team led by astronomer Mike Brown and its discovery touched off a debate that extended well beyond the realms of scientific meetings and papers.

NASA initially described Eris as the tenth planet in our solar system as it orbits the sun and is 27 percent larger than Pluto. After Eris’ discovery, however, a veritable flood of discoveries of other trans-Neptunian objects called into question whether or not Pluto and its newly discovered neighbors out in the far reaches of our solar system should even be considered planets.

The International Astronomical Union revised their definition of what constitutes a planet, created a new class for planets like Pluto, dwarf planets, and in the process raised the ire of the general public who had been taught since the 1930s that Pluto was one of the nine main planets in our solar system.

Given how much of an uproar Eris caused by triggering the demotion of Pluto, it’s extremely appropriate that it is named after the goddess Eris, the personification of chaos, strife, and discord.