The Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration (LSC) has recently discovered gravitational waves from a pair of neutron star-black hole (NS-BH) mergers. Utilizing the most sensitive scientific instruments ever constructed, LSC was able to detect the reverberations from the two celestial entities. This discovery has shed light on the notions surrounding NS-BH hybrid collision, previously undiscovered due to focus primarily on collisions between black holes or neutron stars.
Black Hole Explained
A black hole is an area in space where gravity pulls so strongly that even light cannot escape. This intense gravity is due to matter being compressed into a very small space. When two black holes orbit each other and consequently merge, they generate gravitational waves – an avenue of physics yet to be thoroughly explored.
The Structure and Evolution of Neutron Stars
Neutron stars represent the final evolutionary stage of high-mass stars. When the core of such a star has entirely burned to iron, energy production ceases and the core collapses rapidly, squeezing electrons and protons together to form neutrons and neutrinos. One result is a neutron star – a star supported by neutron degeneracy pressure – that can become a pulsar if its magnetic field aligns with its spin axis.
Gravitational Waves: Details and Impact
Gravitational waves are invisible ripples in space formed when a star explodes in a supernova; two large stars orbit each other; two black holes merge; or a NS-BH merger occurs. Traveling at light speed, these gravitational waves distort anything in their path, causing it to stretch in one direction and compress in the other.
Origins and Discovery of Gravitational Waves
Albert Einstein proposed the existence of gravitational waves more than a century ago, as part of his General Theory of Relativity. But the actual detection of a gravitational wave wasn’t accomplished until LIGO did so in 2015.
Techniques for Gravitational Wave Detection
When two large, compact bodies orbit each other and eventually merge due to the energy loss as gravitational waves, these waves are detected by LIGO, despite being hidden deep within a significant amount of background noise.
The Importance of Gravitational Wave Discovery
Unlike black holes, neutron stars have a surface. They are approximately 1.4-2 times the mass of the sun, while black holes are vastly more massive. Uncovering these mergers can reveal interesting effects that can be detected and analyzed. It also helps us understand the behavior of matter at extreme densities and the formation of binaries and their abundance.
About LIGO Scientific Collaboration (LSC)
Established in 1997, the LSC consists of over 1000 scientists from more than 100 institutions and 18 countries. The group is dedicated to discovering and comprehending gravitational waves, exploring the fundamental physics of gravity, and making gravitational wave science an effective tool for astronomical discovery.
LIGO Observatories Across the Globe
LSC conducts scientific research at the LIGO Observatories located in Hanford, Washington; Livingston, Louisiana; and the GEO600 detector in Hannover, Germany. Other prominent observatories include VIRGO located near Pisa in Italy, KAGRA in Kamioka, Gifu, Japan, and the upcoming LIGO-India project, which is set to be built in the Hingoli District of Maharashtra by 2024.
The LIGO observatories serve as crucial instruments in the exploration of gravitational waves and the widening of our understanding of the universe. By studying these waves, scientists hope to gain insights into cosmic events and phenomena, further propelling our knowledge about space and celestial bodies.