Scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) launched an 18-month initiative on May 24 to identify the farthest-ever observed collisions between black holes and neutron stars.
As per Nature's report, the upgraded detectors at LIGO have significantly increased sensitivity, enabling the measurement of gravitational waves produced by the merging of black holes in galaxies situated over 5 billion light-years away from Earth. Michael Landry, the head of LIGO Hanford Observatory, expressed great enthusiasm about this development.
Understanding Black Holes and Gravitational Waves
Black holes are incredibly dense objects in space-time with gravitational forces so intense that even light cannot escape. Similar to how planets orbit stars and stars move around other stars, black holes can orbit each other. According to Live Science, this orbital motion generates ripples, known as gravitational waves, which carry energy and angular momentum away from the black holes.
As a result, the black holes spiral closer together until they eventually collide, creating one of the most energetic events in the universe. In 2015, the LIGO made history by detecting the first-ever gravitational waves from two black holes with masses approximately 30 times that of the Sun, colliding at a distance of over 1 billion light-years from Earth, with their collision occurring at nearly half the speed of light.
LIGO detects gravitational waves by monitoring the minute movements of mirrors suspended in long tunnels. The mirrors must remain incredibly still, with displacements smaller than the size of a proton. Laser beams bouncing off the mirrors enable the measurement of these tiny displacements.
LIGO architects Kip Thorne, Rainer Weiss, and Barry C. Barish received the Nobel Prize in Physics in 2017 for the first gravitational wave detection after overcoming several decades of technological challenges. Since then, LIGO and Virgo have observed 90 gravitational wave events originating from the collisions of black holes or neutron stars, compact remnants of massive stars resulting from supernovae.
The global pursuit of gravitational waves will be expanded as the campaign progresses. LIGO's facilities in Hanford, Washington, and Livingston, Louisiana, will be joined by the Virgo detector in Italy and the Kamioka Gravitational Wave Detector (KAGRA) in Japan.
READ ALSO : Black Holes Crashing Into Each Other Generate Gravitational Waves, Distorting Space-Time
What's New In the Upgraded LIGO?
Team member Chad Hanna wrote in an article in The Conversation that the addition of a 300-meter optical cavity and the utilization of quantum squeezing techniques allow for a reduction in detector noise using the quantum properties of light. These improvements, coupled with upgraded software algorithms, enable LIGO to detect much weaker gravitational waves than before.
The team has set a sensitivity goal for different facilities. Universe Today reports that LIGO aims to detect binary neutron star mergers at distances of 160-190 megaparsecs (Mpc), while Virgo targets a sensitivity of 80-115 Mpc. KAGRA, which utilizes unique but challenging detection technology, is expected to achieve a sensitivity greater than 1 Mpc.
These sensitivity goals represent the distances at which the facilities can detect colliding neutron stars, serving as a measure of their overall sensitivity to all gravitational waves.
In the months ahead, the LIGO, Virgo, and KAGRA facilities anticipate multiple "multi-messenger" observations. These observations involve combining gravitational wave data with other types of astronomical information, pushing the boundaries of modern astrophysics and providing deeper insights into cosmic phenomena.
RELATED ARTICLE: LIGO Detected Gravitational Waves That Intrigues The Nature Of Black Holes & Dark Matter For The Third Time
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