Julia M. Riley (née Hill, born 1947)[1] is a British astrophysicist who developed the Fanaroff–Riley classification.
Riley is a Fellow of Girton College associated with the Cavendish Astrophysics Group at University of Cambridge.
Riley lectures and supervises physics within the Natural Sciences Tripos at the University of Cambridge.
In 1974, along with Bernard Fanaroff, she wrote a paper[2] classifying radio galaxies into two types based on their morphology (shape).
[3] Fanaroff and Riley's classification became known as Fanaroff–Riley type I and II of radio galaxies (FRI and FRII).