Introduction

Gravitational waves, ripples in the fabric of space-time, first predicted by Einstein more than a century ago. Most gravitational waves and astronomers' catalogs have come from pairs of colliding middleweight black holes. But these giant collisions make correspondingly huge gravitational waves - so big their wavelengths are larger than our entire solar system. That enormity makes them enormously hard to detect; crest to trough a single such wave could take more than a decade to pass through our solar system,. So how can we see them? The best solution astronomers have stumbled upon is to effectively build a galaxy-sized detector looking for the waves tell-tale tweaks to the spins of dead stars called pulsars scattered