Gravitational Waves Found Inside Spectrum Postcard

Gravitational waves were recently discovered, confirming Einstein's prediction of gravitational waves from over 100 years ago. Einstein noted that the fabric of space-time can become curved by anything massive in the Universe, such as cataclysmic events such as black holes merging or stars exploding, and that events would cause a curvature of space-time and propagate as waves. Let your wry scientific side shine with this postcard featuring "The Gravitational Wave Spectrum" along with the geek humour saying "Gravitational Waves Found Inside". No need to be a physicist or astrophysicist to enjoy!