For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.

Giant planets are not rare per se — after all, we have four in our own solar system. Such large worlds are, however, rarely ...

Plus, an in-depth look at how the West Texas city of Seminole reacted when a measles outbreak tore through the region.

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 ...

Discovery of 2017OF201, a large trans-Neptune Object, challenges previous beliefs about the Kuiper Belt and hints at the ...