1. "Planet X" as a hypothetical planet beyond Neptune:
* Historically: This was the term used to describe a potential large planet in our solar system, beyond Neptune, that was theorized to explain some gravitational anomalies observed in the orbits of Uranus and Neptune. This idea was popular in the late 19th and early 20th centuries.
* Current status: This hypothetical planet has not been found, and the gravitational anomalies that initially fueled its search are now explained by the combined gravitational influence of known objects in the Kuiper Belt.
2. "Planet X" as a name for a particular object:
* Current status: There is no official astronomical object named "Planet X." Any object discovered beyond Neptune, if it meets the criteria for "planet," will be given a proper name by the International Astronomical Union (IAU).
3. "Planet Nine" as a recent hypothetical planet:
* Evidence: Some astronomers believe there might be a large planet, much farther out than Neptune, based on the clustering of orbits of some trans-Neptunian objects.
* Current status: This hypothetical planet, often referred to as "Planet Nine," is still under debate. While some evidence suggests its existence, it has not been directly observed yet.
In summary:
* "Planet X" as a hypothetical planet beyond Neptune has been largely debunked.
* "Planet Nine" is a recent hypothesis, and its existence is still under investigation.
* There is no officially named "Planet X" in astronomy.
It's crucial to be aware of these different meanings when encountering the term "Planet X."
