In 2003, Palomar Observatory astronomers were in the midst of their search for planet-sized objects beyond Neptune when they imaged Eris – but because they’d limited their search based on the speed that objects were moving, and Eris was quite sedate, it went undetected. It wasn’t until they discovered the likewise pokey Sedna the following Continue reading "Jan. 5, 2005: Eris is discovered" The post Jan. 5, 2005: Eris is discovered appeared first on Astronomy Magazine .