What are Gravitational Waves?

Simply put, gravitational waves are a ripple in the fabric of space and time.  That sounds simple, but it implies knowledge of astrophysics, gravitational theory, and Einstein’s work.  PHDComics, as they usually do, designed a simple comic for us lay people to understand – at least in principle – what gravitational waves are, how they were detected, and why they are so important.

Gravitational Waves Explained

Source:  PHDComics.com
Created by Umberto Cannella, Daniel Whiteson and Jorge Cham
with special thanks to Aidan Brooks, Flip Tanedo and LIGO.

Since the initial detection of gravitational waves in September of 2015 (followed by the announcement in February 2016), LIGO has already detected another signal from two black holes in their final orbits and their coalescence into a single black hole.   One can certainly imagine that LIGO will continue to detect more.

As the comic implies, gravitational waves give astronomers another way to observe the universe. For example, waves from the Big Bang would tell us a little more about how the universe formed. Gravitational waves form when black holes collide,  and even when supernovae explode, and massive neutron stars wobble. So detecting these waves would give us a new insight into the cosmic events that produced them.  Gravitational waves could also help physicists understand the fundamental laws of the universe, since they are a crucial part of Einstein’s general theory of relativity. Finally, studying gravitational waves could also lead to a more accurate model of our universe and bring us one step closer to the famed theory of everything.