After two years of development, the Laser Interferometer Gravitational-Wave Observatory (LIGO) is almost ready for its next operation, scheduled to begin in March 2023.
During this fourth operation (O4), LIGO – which includes two machines, one in Washington and one in Louisiana – will be connected to two other gravitational waves: the Virgo interferometer, Italy, and the Kamioka Gravitational Wave Detector (KAGRA), Japan.
The gravitational waves in space are caused by highly violent cosmic events, such as the formation of neutron stars, black holes, or a combination of both. Einstein’s theory of relativity first foretold this situation.
Although the events that unlock these donkeys during space travel are compelling, the gravitational waves are significantly reduced – unconscious, in fact, so much so that Einstein predicted that we would not find them directly. We finally saw them, however, with the direct discovery of the gravitational waves that occurred in September 2015. Now, the new LIGO development enhances its sensitivity, allowing it to detect smaller signals than before and resulting in more events than it could have been.
With this upcoming application, LIGO scientists aim to make the device sensitive enough to detect gravitational waves from a total of 522 to 620 million light-years across the Earth from light. Major and violent incidents, such as collisions and black holes, should be seen in LIGO at even greater distances. (The first direct detection of gravitational waves was observed by two large black holes covering 1.3 billion light-years from Earth.)
Since then, researchers have discovered a myriad of gravitational waves. Virgo and LIGO received ripples launched by a combination of binary neutron stars in 2017, which helped identify this catastrophic cosmic event. KAGRA joined the LIGO-Virgo network in 2020, and in January 2020, the three observatories spotted gravitational waves in the black hole and a neutron star. This is the first type of mix identified, serving as an exciting promise for things to come together.
LIGO was completed on March 3, 2020, and was closed for development. The staff of the three centers is working closely together to launch O4 together following the effects of COVID-19, which has delayed the start of the fourth game from December 2021.
A month before O4 launches, the machines will conduct engineering work to test real-time development and systems that allow LIGO, Virgo, and KAGRA to work in unison. However, even in that engineering era, gravity waves can bring some exciting science, and LIGO’s first historic discovery of gravitational waves came during such a period of testing.