Albert Einstein famously predicted the existence of gravitational waves in 1916 based on his theory of relativity, and since then many not steeped in theoretical physics have struggled to understand even the basics of his theory. Watch as physicists Nergis Mavalvala, Janna Levin, and Lisa Randall team up to explain the concept of gravitational waves for a lay audience:

Although Einstein’s calculations told him that gravitational waves must exist in theory, he had no way of actually proving his own calculations were correct. Scientists have doggedly tried to find proof ever since, without success — that is, until LIGO. Standing for the Laser Interferometer Gravitational-Wave Observatory, LIGO allowed scientists to collect the proof that had eluded them for nearly a century.

These aren’t gravitational fluctuations from our cosmic neighborhood, though. When two black holes 30 times more massive than our own collide millions of lightyears away, the change that LIGO measures on Earth is smaller than the width of proton.

History has relatively few examples of decades-long projects ending in success, and LIGO stands out as an instance where over 50 years of research, funding battles, and technological limitations resulted in an unequivocal triumph.

Not only were physicists fighting for funding and resources, but they were also tirelessly working out any and all wrinkles in the theoretical calculations. The ability of scientists today to breathlessly interpret the highly complex data sets that LIGO produces rests in no small part on scientists who laid the theoretical groundwork decades before.