Here's why:
* Many comets are undiscovered: Astronomers are constantly discovering new comets, and there are many more out there that haven't been spotted yet.
* Comets have different orbits: Some comets have very short orbital periods (a few years), while others take thousands or even millions of years to complete a single orbit around the Sun.
* Visibility: Not every comet is visible to the naked eye, and many are only detected by telescopes.
However, we can say:
* Recent bright comets: The last bright comet visible to the naked eye was Comet NEOWISE in 2020.
* Constant activity: There are always comets passing through our solar system, though not all are visible.
So, rather than asking about the "last comet", it's more accurate to ask about the last comet that was visible to the naked eye or the last comet that was discovered.
