Planet X

English

Proper noun

Planet X

1. (astronomy) A hypothetical planet in our solar system. (Generally considered the next planet beyond the currently known outermost planet.)
2. (astronomy, obsolete) A theoretical planet that gravitationally perturbs the orbit of Neptune. (This was incorrectly applied to Pluto. Later it became another planet further out to account for the missing mass that Pluto did not provide.)
3. (astronomy, obsolete) A theoretical planet that gravitationally perturbs the orbit of Uranus. (This became Neptune.)
4. (astronomy, obsolete) A hypothetical tenth planet, beyond Pluto (Pluto was demoted to minor planet status as a dwarf planet, so there are only eight planets. It had been applied to Eris for a short while.)

Translations

hypothetical planet

• Chinese:

  Cantonese: X行星 (iks¹ hang⁴ sing¹, iks¹ haang⁴ sing¹)

  Mandarin: X行星 (X xíngxīng)

• Dutch: planeet X f
• Finnish: planeetta X
• French: planète X f
• German: Transpluto m, Planet X m
• Italian: pianeta X m
• (deprecated template usage) {{trans-mid}}
• Japanese: 惑星Ｘ (wakusei X)
• Maltese: pjaneta X
• Portuguese: Planeta X m
• Russian: Плане́та Х f (Planéta X), Плане́та Икс f (Planéta Iks)
• Slovene: planet X m
• Spanish: planeta X m
• Swedish: planeten X c
• Vietnamese: hành tinh X

See also

• Nibiru
• Tiamat

Anagrams

• explant