Renowned physicist Brian Greene visited "The Late Show" this week to discuss the recent discovery of gravitational waves. The "Elegant Universe" author and “all around smarty-pants” as Stephen Colbert refers to him, is known for his ability to break down complicated ideas into easy-to-understand concepts. Greene’s appearance on "The Late Show" was a shining example of this special ability — after all, gravitational waves are tricky to wrap your head around.

Greene defines gravitational waves as “a ripple in the fabric of space.” Gravitational waves were detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) on Sept. 14. LIGO made the official announcement earlier this month. The discovery is important because it allows scientists to study the universe in a whole new way, say Greene.

“Gravity can go into places in the universe that light cannot penetrate ... So, using these gravitational disturbances we may actually be able to study how black holes combine. We may be able to study even the Big Bang itself.”

Albert Einstein theorized the existence of gravitational waves in 1916 — 100 years before LIGO proved his theory. Greene explains Einstein’s theory and how gravitational waves interact with the universe, “His math shows that as a gravitational wave ripples by anything, it will stretch it and compress it.” Greene shows Colbert a video of an exaggerated simulation of the waves affecting Earth, saying that the waves would compress everything “by less than an atomic diameter.”

To explain how LIGO made the discovery, Greene uses a small model of the facility. The model is complete with laser beams that are sensitive enough to detect changes in wave activity. Greene explains how the LIGO facility’s lasers are shielded from all factors except gravity, allowing them to detect the gravitational waves that were created 1.3 billion years ago by two black holes colliding.

To show how lasers can pick up on disturbances in wave activity, he invites Colbert to join the experiment by altering the lasers with sound waves. Much to the delight of "The Late Show" audience, the laser patterns change as Colbert repeatedly yells “Science!” at the laser beam.

Physicist Brian Greene explains gravitational waves to Stephen Colbert
The physicist uses a model with lasers to explain the discovery.