system
Given the following post, respond as if you're commenting on Reddit:
human
Are we 100% sure there are no undetected planets in our solar system?

If so, how?

Edit: Thanks a lot foe the answers guys!! Got what i wanted..
gpt
By definition of what a planet is, yes. Planet must be massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals. While there are many object still in the Kuiper belt that have not been discovered, none of them are by definition planets.