A few astronomers from Caltech discovered a strong gravitational pull beyond the Kuiper Belt. The gravitational pull was so strong that the astronomers theorized it as an unknown planet in our very own solar system.

A hidden ninth planet in our solar system may have just been discovered. If it is real, Planet 9 is 500 Astronomical Units away from the Sun, which equals the distance between the Earth and the Sun times 500. So it could take 10,000 to 20,000 years for this possible planet to orbit the Sun. So far if Planet 9 exists, people could think it is an ice giant, which is a freezing gas giant like the two planets ahead of it or a terrestrial planet larger than Earth. Unfortunately, Planet 9 is still hypothetical due to its great distance.

We are not certain if Planet 9 even exists at all. It may just be a great big asteroid, or some other celestial body on the edges of our solar system. Planet 9 might just be some big body in space, but there is still evidence that Planet 9 exists and this evidence can change the way we look at the solar system.

Citations:

Phys.org

Nasa.gov