An artist's impression of the occultation of 2002 XV93. (NAOJ/Ko Arimatsu) In the wild unknown, out beyond the orbit of Neptune, astronomers have found a tiny world that defies our understanding of skies.

The discovery could reshape scientists’ understanding of the outer solar system.

A brief stellar eclipse suggests the tiny 2002 XV93 has a thin atmosphere — a first for any solar system body farther from the sun than Pluto.

A nearby Earth-sized planet offers a rare chance to study how atmospheres survive or disappear on rocky worlds.

New research suggests that many planets previously considered promising for life may, in fact, be far less hospitable. A distant planet might sit in the perfect orbit for life, with temperatures just right for liquid water.

Alfredo has a PhD in Astrophysics and a Master's in Quantum Fields and Fundamental Forces from Imperial College London. Alfredo has a PhD in Astrophysics and a Master's in Quantum Fields and Fundamental Forces from Imperial College London.View full profile ...

A 500-kilometre-wide object in a similar orbit to Pluto challenges our assumptions about small bodies in the outer solar system