Scientists said they have found evidence of a giant planet far out in our solar system.

In a statement, the California Institute of Technology – Caltech said this planet travels a strange "highly elongated in the distant solar system."

The discovery was made by two researchers at Caltech: Konstantin Batygin and Mike Brown. They used mathematical modeling and computer to find the planet.

So far, there have not been any direct observations of the planet.

"My hit the floor," said astronomer Mike Brown, the moment he realized there might be a ninth planet.

The scientists said it would take this planet 10,000 to 20,000 years just to make one full orbit around the sun. The new planet, called "Planet Nine" has a mass about
times the size of Earth.

If they are right, the newly found planet would be the ninth planet in our solar system. Pluto had been called the ninth planet until , when it was renamed a "dwarf planet."

Actual confirmation of a ninth planet would be very big news.

"This would be a real ninth planet," Brown said in the statement. "There have only been two true planets discovered since ancient times, and this would be a third. It's a pretty substantial of our solar system that's still out there to be found, which is pretty exciting."

It is believed that the planet orbits, or travels, around the sun from a great distance. The planet Neptune's average distance to the sun is about kilometers. But "Planet Nine," could be 20 times farther away from the sun than that.

While they did not get a picture of "Planet Nine" yet, the scientists say they are using the biggest—and best -- telescopes on Earth to try to find "Planet Nine."

They are also working on their computer simulations. They want to find out more about "Planet Nine's" orbit, and its impact on the part of our solar system.

Brown and Batygin reported their findings in the Astronomical Journal. They say that this new planet is so large that there should be no doubt that it is a planet, once they confirm it.

Robert Massey is with the Royal Astronomical Society in London. He told AFP that planets have been predicted before, and then were not .

But, he said the work of these researchers is definitely worth following up.

"It would be a really exciting thing to find. At the moment it's simply a prediction."

I'm Anne Ball.