Experimentum Crucis

Experimentum Crucis, meaning "crucial experiment," is a definitive test that confirms or refutes a scientific theory. Historically, it refers to Galileo’s 1610 telescope observations of moons around Jupiter, which provided strong evidence against the belief that Earth was the universe's center. This experiment was pivotal because it directly supported heliocentrism—Earth orbiting the Sun—by producing clear, observable data that challenged existing ideas. In general, an Experimentum Crucis is a carefully designed experiment capable of decisively settling a scientific debate.