On Dec. 23, 1672, Italian astronomer Giovanni Cassini found Rhea, Saturns second-largest moon. Rhea is likewise the only moon discovered to have an oxygen environment. Rhea was the second moon that Cassini found.
On Dec. 23, 1672, Italian astronomer Giovanni Cassini found Rhea, Saturns second-largest moon. Rhea is likewise the only moon discovered to have an oxygen atmosphere. Rhea was the 2nd moon that Cassini discovered.