  Recently, an intriguing relationship (the "double copy") has been discovered
between theories like electromagnetism, and gravity. This potentially gives us
a new way to think about gravity, and there are also practical applications
involving the efficient calculation of gravitational observables, and also how
to simulate gravity using optical systems. In this tutorial, we will review
what is known about the double copy, and argue that now is the perfect time for
researchers in optics and / or condensed matter to become interested in this
fascinating correspondence.
