"Planet X" might actually exist — and so might "Planet Y."
At least two planets larger than Earth likely lurk in the dark depths of space far beyond Pluto, just waiting to be discovered, a new analysis of the orbits of "extreme trans-Neptunian objects" (ETNOs) suggests.
Researchers studied 13 ETNOs — frigid bodies such as the dwarf planet Sedna that cruise around the sun at great distances in elliptical paths.
Comet Lovejoy, a bright celestial ball of dust and ice probably born in the Oort Cloud, is currently traveling across the skies of the Northern Hemisphere. While photographer Gerald Rhemann snagged a shot of Lovejoy on December 22 (from the Southern Hemisphere), casual observers in the top half of the world might be able to enjoy the show into February.
"Comets this bright [appear only] every few years, on average," says Matthew Knight, a research scientist who studies comets at Lowell Observatory in Flagstaff, Arizona. Indeed, some viewers with keen sight might be able to spy it with the naked eye from a location far from urban lights— think the Arizona desert or Michigan's Upper Peninsula.