Stephen Barr offers a brief intro at First Things.

An extremely important effect in physics called the “diffraction” of light was discovered by Fr. Francesco Grimaldi in the seventeenth century (something no physics textbook that I have ever seen bothers to mention, so that few scientists are aware of it). One of the top biologists in the world in the eighteenth century was Fr. Lazzaro Spallanzani. Among his many accomplishments was to disprove the theory of “spontaneous generation.” (Pasteur later made use of Spallanzani’s work in doing his own famous experiments disproving spontaneous generation.)

Fr. Marin Mersenne is considered the “father of acoustics.” Many of the basic facts about wave motion and sound that are taught in freshman physics courses were discovered by Mersenne (though, again, textbooks never mention this). The first “binary star” was discovered by Fr. Giovanni Riccioli. One of the founders of modern astrophysics was Fr. Angelo Secchi. Priests also figure prominently in the history of mathematics, including Nicholas Oresme, fourteenth-century bishop of Lisieux, who was the first to graph mathematical functions and who discovered how to combine exponents (he also had important ideas in physics); Girolamo Saccheri, a forerunner of non-Euclidean geometry; Francesco Cavalieri, who made important contributions to the foundation of integral calculus; and Bernhard Bolzano, one of the people who helped put calculus and the theory of real numbers on a more rigorous basis.