# Introduction to LIGO & Gravitational Waves

## "Ripples on Space-time"

Gravitational waves are created by moving masses, much as electromagnetic waves are created by moving charges. But because gravity is the weakest of the four fundamental forces (the others being the electromagnetic, weak nuclear, and strong nuclear), gravitational waves are exceedingly small. For physicists, a strong gravitational wave will produce displacements on the order of 10

^{-18}meters - this is 1000 times smaller than the diameter of a proton. Waves of this strength will be produced by very massive systems undergoing large accelerations, like two orbiting black holes that are about to merge into one. Since systems like these are rare, these sources will be light-years away. Therefore, the search for gravitational waves is seeking the minute effects of some of the most energetic astrophysical systems from the depths of the universe.

# Contents

IntroductionNewton, Einstein and Gravitational Waves

→ "Ripples on Space-time"

Sources of Gravitational Waves:

Continuous

Inspiral

Burst

Stochastic

Detecting Gravitational Waves

Using Multiple Detectors

An Interferometer

LIGO's Interferometer

Advanced LIGO flyer

The Potential of Gravitational Waves