In depth | Hypothetical Planet X – NASA Solar System Exploration


Caltech researchers have found mathematical evidence suggesting that there may be a “planet X” deep in the solar system. This hypothetical planet the size of Neptune orbits our Sun in a very elongated orbit well beyond Pluto. The object, which the researchers dubbed “Planet Nine”, could have a mass about 10 times that of Earth and orbit about 20 times farther from the Sun on average than Neptune. It can take between 10,000 and 20,000 Earth years to make a complete orbit around the Sun.

The announcement does not mean that there is a new planet in our solar system. The existence of this distant world is only theoretical at this stage and no direct observation of the object nicknamed “Planet 9” has been made. A planet’s mathematical prediction could explain the unique orbits of some smaller objects in the Kuiper Belt, a remote region of icy debris that extends well beyond Neptune’s orbit. Astronomers are now looking for the predicted planet.

In depth

In January 2015, Caltech astronomers Konstantin Batygin and Mike Brown announced new research that provides evidence of a giant planet plotting an unusual elongated orbit in the outer solar system. The prediction is based on detailed mathematical modeling and computer simulations, not on direct observation.

This large object could explain the unique orbits of at least five smaller objects discovered in the distant Kuiper Belt.

“The possibility of a new planet is certainly exciting for me as a planetologist and for all of us,” said Jim Green, director of NASA’s planetary science division. “However, this is not the detection or discovery of a new planet. It is too early to say for sure that there is a so-called planet X. What we are seeing is an early prediction based on modeling from limited observations. This is the start of a process that could lead to an exciting result. “

Scientists at Caltech believe that Planet X may have a mass about 10 times that of Earth and be similar in size to Uranus or Neptune. The predicted orbit is about 20 times farther from our Sun on average than Neptune (which orbits the Sun at an average distance of 2.8 billion miles). It would take this new planet between 10,000 and 20,000 years to make a single complete orbit around the Sun (where Neptune completes one orbit about every 165 years).

When was it discovered?

Planet X has yet to be discovered and there is debate in the scientific community as to whether it exists. The prediction in the Jan. 20 issue of the Astronomical Journal is based on mathematical modeling.

What’s her name?

Batygin and Brown have nicknamed their predicted object “Planet Nine”, but the actual naming rights for an object rest with the person who actually discovers it. The name used in previous hunts for the long-suspected, undiscovered giant object beyond Neptune is “Planet X”.

If the predicted world is found, the name must be approved by the International Astronomical Union. The planets are traditionally named for the mythological Roman gods.

Why do they think it’s there?

Astronomers who study the Kuiper Belt have noticed that some of the dwarf planets and other small icy objects tend to follow orbits that cluster together. By analyzing these orbits, the Caltech team predicted the possibility that a large, previously unknown planet is lurking well beyond Pluto.

They believe that the gravity of this potential planet could explain the unusual orbits of these Kuiper objects.

And after?

Astronomers, including Batygin and Brown, will begin using the world’s most powerful telescopes to search for the object in its intended orbit. Any object this far from the Sun will be very faint and difficult to detect, but astronomers believe it should be possible to see it using existing telescopes.

“I would love to find it,” says Brown. “But I’d also be perfectly happy if someone else found it. That’s why we’re publishing this article. We hope other people will take inspiration from it and start looking.”

“Whenever we have an interesting idea like this, we always apply Carl Sagan’s Rules for Critical Thinking, which include independent confirmation of facts, seeking alternative explanations, and encouraging scientific debate,” Green said. “If Planet X is there, we’ll find it together. Or we’ll figure out another explanation for the data we’ve received so far.

“Now let’s go explore. “


Fesenmaier, Kimm, “Caltech researchers uncover evidence of a real ninth planet, “press release, last modification on January 20, 2015

Konstantin Batygin and Michael E. Brown, “Evidence of a distant giant planet in the solar system, “The Astronomical Journal

Green, James, “A new planet in our solar system? NASA takes a look“, video statement, last modified January 20, 2015

Arline J. Mercier