Is there a massive undiscovered planet on the outer reaches of the Solar System? The idea has been around since before the discovery of Pluto in the 1930s. Labelled as planet X, prominent astronomers ...

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...

We’re closer than ever before to knowing whether there is a ninth planet whooshing around the sun – and, alas, it’s not Pluto. Planet X, also called Planet Nine, is a hypothetical planetary body seven ...

NEW YORK (AP) — A new Tatooine-like planet outside the solar system may orbit two failed stars, scientists reported Wednesday. Located about 120 light years away, the exoplanet appears to take an ...

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