Earl Carl Slipher (/ˈslaɪfər/; March 25, 1883 – August 7, 1964) was an American astronomer and politician.
He was the brother of astronomer Vesto Slipher.
Slipher was born in Mulberry, Indiana.
He first joined Lowell Observatory in 1908 and became a noted planetary astronomer, concentrating on Mars.
He served a two terms in the Arizona State Senate during the 8th and 10th Arizona State Legislatures, holding the seat from Coconino County.