For a long time, children learning about space in school were taught that there were nine planets in our solar system. Then, ...

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Ever since Pluto was demoted from planet status, astronomers believe a real Planet Nine exists in the solar system ...

Planet Nine is a theory about a massive planet that could be located far beyond Neptune, as per the studies and reports ...

If there is some planet nine, or "Planet X" lurking out there, we have yet to find it. But there is some tentative evidence for it. As we have found more Pluto-like bodies known as Trans-Neptunian ...

Known as Planet Nine or Planet X, it is a hypothetical planet that has long been rumoured to exist in the outer solar system. Although "several claims to have found an extra planet have been made ...

Astronomers have been trying to find a new planet beyond the orbit of Neptune for several decades, but all to no avail. Its nickname is Planet Nine; supposing this planet exists, it could help explain ...

Aside from the solar system once again having nine planets—which it had before Pluto’s demotion in 2006—the discovery of a distant Earth-mass planet would have profound implications for ...