WASHINGTON (Reuters) - Dwarf planet Eris, similar in size to its better-known cosmic cousin Pluto, has remained an enigma since being discovered in 2005 lurking in the solar system's far reaches.

New models show Eris is behaving less like a solid, rocky world and more like "soft cheese." When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.

The first flight of Eris, the first Australian-designed and built rocket, set to launch no earlier than March 15. When you purchase through links on our site, we may earn an affiliate commission. Here ...

The methane gas may constitute a rarefied atmosphere, or it may come from erupting plumes on Makemake’s surface.

Siraj’s Planet Y search started about a year ago when he was trying to find out whether the shape of the Kuiper Belt is flat. “The planets of the solar system have slight tilts up and down, but ...