Researchers use the Subaru Telescope in Hawaii to find a small object on the outer edge of the Solar System. Nicknamed ...

A newly discovered dwarf planet called 'Ammonite' (2023 KQ14) has been spotted in the outer solar system, and it could be ...

"It is possible that a planet once existed in the solar system but was later ejected, causing the unusual orbits we see today ...

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the ...

Planet Nine should appear stationary over the course of a single day but show detectable movement over months.

What we know about the search for ‘Planet Nine’ in our solar system - The idea of a massive undiscovered planet has been around since before the discovery of Pluto in the 1930s ...

Planet Nine's composition is probably "most like Neptune," due to its distance from the sun, Brown said. "That would put its diameter at something like two times the width of Earth," he added.

If their calculations serve them correctly, Planet Nine would have a mass that is about 1.5 to 3 times that of Earth, at 500 times the distance between our home and the sun. Caltech researchers in ...

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.

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.