Hypothetical Planet 9 accounts for the movement of several trans-Neptunian ... We know there isn’t a Mars-sized planet orbiting between Jupiter and Saturn nor a brown dwarf nemesis heading our way.

Planet 9 is 47K, but if it weren't for its core it would be 10K, meaning the majority of its thermal energy comes from inside the planet. Image source, E. Linder/C. Mordasini/University of Bern ...

Almost a decade after astronomers proposed the existence of Planet 9, an unseen extra planet in the distant reaches of the solar system, they still haven’t all agreed whether it’s real or not ...

Planet 9 may be closer and easier to find than thought—if it exists. A new study's "treasure map" suggests that a planet several times more massive than Earth could be hiding in our solar system ...

Our solar system used to have nine planets. Astronomer Mike Brown, also known as “the man who killed Pluto,” said he got hate mail from kids and obscene calls at 3 a.m. for years after his ...

"If Planet 9 is anomalous in some respect, there could be more interest in expediting such a mission." It is also possible that a private space exploration company, such as SpaceX, ...

The hunt for Planet 9 was part of a Zooniverse citizen science project, conducted in real-time, with the BBC’s Stargazing Live broadcast. The project was hosted at the Siding Spring Observatory ...

While Planet 9’s existence remains fully up in the air, more evidence could become available within a year or two, when a Chilean observatory that’s currently under construction opens, ...

If Planet 9 is real, this observatory has around a 70 to 80 percent chance of finding it, he estimates, adding that it's not a sure thing because there are so many uncertainties.

Some scientists are convinced that beyond Neptune, there's a planet they've yet to see. This so-called "Planet 9" is so far away, it would be a faint object. The stretch of sky researchers would ...

Good news: we're all not going to die (yet). Some "news" reports have suggested a ninth planet (Planet 9) lurking at the edge of our solar system will soon be responsible for mass extinctions ...