About LIGO

• LIGO stands for “Laser Interferometer Gravitational-wave Observatory“, the world’s largest gravitational wave observatory.
• It is the world’s largest gravitational wave observatory.
• LIGO exploits the physical properties of light and of space itself to detect and understand the origins of gravitational waves (GW).
• LIGO consists of two widely-separated interferometers within the United States—one in Hanford, Washington and the other in Livingston, Louisiana—operated in unison to detect gravitational waves.
• LIGO is not like any other optical or radio telescope as it does not see electromagnetic radiation (e.g., visible light, radio waves, microwaves) since gravitational waves are not part of the electromagnetic spectrum.
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• Each LIGO detector consists of two arms, each 4km long, comprising 1.2m-wide steel vacuum tubes arranged in an “L” shape, and covered by a concrete shelter that protects the tubes from the environment.
• LIGO’s interferometers can amplify the smallest conceivable vibrations enough that they are detectable and measurable.
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• LIGO made its first detection of gravitational waves (in 2015), generated by a pair of colliding black holes some 1.3 billion light years away.

What is VIRGO?

• Virgo is a gravitational-wave interferometer designed, built and operated by a collaboration made up of 20 laboratories in 6 countries.
• It consists of two 3-kilometre-long arms, which house the various machinery required to form a laser interferometer.
• It is located in Santo Stefano a Macerata, near the city of Pisa, Italy.
• Virgo and the LIGO Scientific Community work together in many areas and have a specific agreement on the exchange of data.

Why in News?

The LIGO Scientific and VIRGO Collaborations (LSC) have detected an unusual compact object whose mass falls in between that of a typical black hole and a neutron star.

More in the news

• When the most massive stars die, they collapse under their own gravity and leave behind black holes; when stars that are a bit less massive than this die, they explode and leave behind dense, dead remnants of stars called neutron stars.
• For decades, astronomers have been puzzled by a gap in mass that lies between neutron stars and black holes: the heaviest known neutron star is no more than 2.5 times the mass of our sun, or 2.5 solar masses, and the lightest known black hole is about 5 solar masses.
• With the above observations, scientists have announced the discovery of an object of 2.6 solar masses, placing it firmly in the mass gap.