Approximately 4.5 billion years ago, a cold cloud of gas and dust buried deep in one of the Milky Way galaxy’s spiral arms started to collapse. From there, gravity worked its magic. The cloud began to ...

Editor's note: This article was updated March 25 at 11:40 a.m. ET to account for the recent discovery of new moons around Saturn and Jupiter. The total number of planetary moons and small-body ...

From meteorites that impact Earth, to a moon that orbits backwards, to an imposter lurking in the asteroid belt, a variety of strange, wandering worlds are rewriting what we know – and even how we ...