Gravitational Wave Detection

Gravitational waves are very difficult to detect

• Gravitational waves were originally predicted over 100 years ago as part of Einstein’s Theory of General Relativity.
• Building detectors sensitive enough to detect gravitational waves took over 40 years of design and enhancement. This is because gravitational waves only create a small distortion in space time that needs to be measures to the precision of 10,000 times smaller than a proton.
• Gravitational waves detectors need to be very large. LIGO (Laser Interferometer Gravitational wave Observatory) uses two detectors (both in the US), with each detector equipped with 4 km long interferometers. An additional detector called VIRGO is in Italy.

Scientists are steadily making Gravitational Wave detections

• As of July 2018, five black hole-black hole detections and one neutron star – neutron star detection have been confirmed
• The first detection of a black hole merger was made on 14 September 2015 at the LIGO observatories. Both observatories detected the gravitational wave signal.
• The first detection of a neutron star merger was make on 17 August 2017. This detection was made in both gravitational waves and in the electromagnetic spectrum as neutron stars do emit light.
• The neutron star merger resulted in a large release of electromagnetic energy called a kilonova and introduced a new field of astronomy now called multi-messenger astronomy.