Planet Nine, undiscovered planet at the edge of the solar system, might be the reason why the Sun tilts.

This planet is estimated to be the size of Neptune and takes 10,000 to 20,000 years to revolve around the sun. It orbits around the sun in an elongated orbit that can be found beyond Pluto, NASA reported.

Researcher Elizabeth Bailey explained that the undiscovered planet might be the reason why the Sun appears tilted. She said that this planet is massive that the solar system is forced to compensate by slowly twisting out the alignment.

Bailey stressed that all the planets in the solar system are located in a flat plane. They are separated couple degrees from each other, Science Daily reported.

Mike Brown, one of the researchers, admits that the six-degree tilt of the sun still remains a mystery. He explained that no compelling explanation has been given regarding this matter.

The researchers believed that they have found an explanation for the sun's tilted appearance. They believe that the reason is Planet Nine which is 10 times bigger than Earth and 20 times farther from the Sun.

Their calculations of the planet that the undiscovered planet is 30 degrees off from other planet's orbital plane. This may cause a slight shifting on the Sun and Kuiper Belt, a region of the solar system beyond Neptune.

Researcher Konstantin Batygin explained that this amazed them because Planet Nine tends to solve the solar system's mystery.

He stressed that the planet explains the tilt that was a mystery to astronomers. He said that astronomers have always been baffled by a spinning cloud that collapses into a disk.

The researchers said the angular position of the planet is giving an outsize impact to the solar system. However, the researchers believe that Planet Nine's angular momentum contributes to the smooth spin of our solar system.

The researchers are now currently looking for Planet Nine that was hypothesized this January.