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

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 ...

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 ...

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 ...

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

On October 6 1995, at a scientific meeting in Florence, Italy, two Swiss astronomers made an announcement that would transform our understanding of the universe beyond our solar system. Michel Mayor ...

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

"It was just a matter of time before we found them." ...

Interstellar comet 3I/ATLAS — just the third such object ever confirmed to have entered our solar system — flew past Mars ...

A study led by Howard Chen looks to explain what NASA space telescopes are missing in the search for life beyond Earth.

Comets SWAN and Lemmon will both swing by Earth and appear bright in the sky near the end of October. Here’s how to see them.

Harvard professor Avi Loeb claims 3I/ATLAS could be an alien spacecraft. Arizona State University professor Steven Desch is ...