2+ mon, 4+ week ago  (205+ words) Today in the history of astronomy, a new dwarf planet leads to Pluto's demotion. - Eris was initially imaged in 2003 by Palomar Observatory astronomers but remained undetected until 2005 due to early search parameters that excluded slower-moving objects. - The existence of Eris,…...

3+ mon, 1+ week ago  (180+ words) Today in the history of astronomy, Giovanni Cassini spots the second of the four moons of Saturn he'll discover. - Between 1671 and 1684, Giovanni Cassini identified four moons of Saturn'Iapetus, Rhea, Tethys, and Dione'collectively designating them "Sidera Lodoicea." - Rhea, discovered on December…...