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

We still don't know for sure if there's a ninth planet in our solar system, but a new discovery could help to prove that ...

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

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

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

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.

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 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.

In October 2017, NASA released a statement saying that Planet Nine may be 20 times further from the Sun than Neptune is, going so far as to say "it is now harder to imagine our solar system ...

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.

But even if it doesn't spot Planet 9 directly, the Rubin Observatory might find some more minor planets, ones whose orbits might be affected by Planet 9. And that could provide additional evidence ...