Since the Kepler Space Telescope began its prowl for exoplanets in 2009, it has uncovered a strange pattern among these alien ...

Planet 9 sits at the edge of scientific imagination, promising either an epic expansion of the Solar System or a lesson in ...

Which way is ‘down’ has a different answer depending on where you are on Earth, in the solar system, in our galaxy and beyond ...

LONDON — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper's authors have ...

Astronomers have captured an exceptionally rare view of young planets in mid-transformation, revealing how bloated, giant worlds may shrink into the most common planets in the galaxy. Astronomers have ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be ...