This article was originally published at The Conversation. The publication contributed the article to Space.com's Expert Voices: Op-Ed & Insights. The size of the solar system is defined by the volume ...

Astronomers have discovered fresh evidence suggesting the possible existence of an unseen planet in the far reaches of our solar system.

NPR's Ari Shapiro talks with astronomer David Jewitt about what we can learn from the third interstellar object to have entered our solar system, a comet-like object known as 3I/ATLAS. A remarkable ...

Gareth Dorrian does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...