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

Amir Siraj and team propose Planet Y, a possible unseen planet influencing Kuiper Belt object orbits. Vera C. Rubin ...

From lava worlds to gas giants, NASA says the variety of these worlds is staggering—and that signs of a further 8,000 distant ...

Our solar system is a smashing success. A new study suggests that from its earliest period—even before the last of its ...

The solar system is a grand cosmic stage where each planet and moon plays a unique role in a story billions of years in the making. From Mercury’s shrinking surface and Venus’s runaway greenhouse ...

We all need some space sometimes—but it's harder to find than you might think. How far into our universe do we have to go to ...

The rate of finding these distant worlds has recently increased, with astronomers scrambling to accommodate the data ...

Astronomers have discovered new evidence that suggests the possibility of an unknown planet in our solar system's farthest reaches. The study, published in the Monthly Notices of the Royal ...

Exoplanet hunters Christopher Watson and Annelies Mortier explain the long search for a 'twin Earth' capable of sustaining ...

A mysterious space object named 2023 KQ14, nicknamed “Ammonite,” challenges theories about the mysterious and possible Planet ...

The methane gas may constitute a rarefied atmosphere, or it may come from erupting plumes on Makemake’s surface.

3I/ATLAS, an interstellar object currently zipping through the solar system, is capturing the attention of astronomers, the ...