Is there really a planet X?
“Planet x” is the name given to any theoretical planet that may be hypothesized to exist beyond the orbit of Neptune. The original “Planet X” was theorized to exist because of apparent discrepancies in the orbit of Neptune, suggesting that another object’s gravity was pulling on it. After an extensive search, Pluto (briefly called “Planet X”) was discovered, though its gravity was thought to be too little to affect Neptune. It was later realized that the discrepancies in Neptune’s orbit did not actually exist, and were caused by observor error (inaccurate measurements.) It is now considered highly unlikely that any large planet exists beyond Neptune. However, it is likely that many hundreds of Pluto-sized objects exist. Only one object (Eris) that is bigger than Pluto has been discovered beyond Neptune. Eris was also nicknamed “Planet X” for a brief time before it and Pluto were given “dwarf planet” status. The other hypothetical “Planet X” also known as “Nibiru” is actually physically
