Julio Ángel Fernández Alves (born 5 April 1946)[1] is a Uruguayan astronomer and teacher, member of the department of astronomy at the Universidad de la República in Montevideo.

[11] Subsequent computer models by Martin Duncan, Tom Quinn and Scott Tremaine in Canada supported the view, and led eventually to the discovery of the Kuiper belt.

[12] David Jewitt, who discovered the belt, believes that Fernández deserves more credit than anyone else, including Gerard Kuiper, for predicting its existence.

As an alternative to the IAU's draft proposal, which had included Pluto, its moon Charon and Ceres among the planets, Fernández with his Uruguayan colleague Gonzalo Tancredi proposed a definition where they reserved the term "planet" only for those objects in the Solar System which had cleared their neighbourhoods of planetesimals, describing those objects which had not cleared their orbits yet retained a spherical shape as "planetoids.

"[15] The IAU's final definition incorporated much of Fernández and Tancredi's proposal, though the objects were christened "dwarf planets.