LIGO’s detection of gravitational waves from merging black holes was a landmark achievement in fundamental physics and a triumph of measurement technology. LIGO is a pair of giant interferometers in the US that use lasers to monitor the changes in separation of large mirrors hanging 4 km apart. Einstein predicted that these waves are unimaginably small, and the very strong gravitational wave that passed through the Earth in September 2015 squeezed and stretched the 4 km long detector by around a billionth of the size of the molecules making up the mirror's surface.
For the last two decades scientists and engineers around the globe have been working to design an even larger interferometer to make measurements of lower frequency gravitational waves produced by much more massive sources. This Laser Interferometer Space Antenna, or LISA, will be a space mission that will shoot laser beams between three spacecraft separated by millions of kilometres in orbit around the sun.
This talk will give an overview of the basics of gravitational wave interferometry and discuss the challenges of building a gravitational wave detector in space.
Bruce Marsh