September 23, 2017 all-day
Sept 23, 1846. Neptune is 2.796 billion miles from the sun (about 30 times as far from the sun as Earth). Eighth planet from the sun, Neptune takes 164.8 years to revolve around the sun. Diameter is about 31,000 miles compared to Earth at 7,927 miles. Discovered by German astronomer Johann Galle.