There are also four other gravitational wave detectors that work on the
same principle:
GEO600 has an arm-length of 600m and is located in Ruthe, Germany (near
Hanover). It is operated by the Max Planck Institute for Gravitational
Physics in Hanover. The GEO collaboration consists of 250 members and is
part of the LIGO scientific collaboration.
LIGO is an abbreviation for “Laser Interferometer Gravitational Wave
Observatory”. The LIGO project has two interferometric detectors in the
United States, “Advanced LIGO”, each with arm lengths of 4 kilometres.
They are located in Hanford, Washington, and Livingston, Louisiana. A
third detector of the LIGO network has been under construction in India
in 2020.
Virgo is a European detector with an arm-length of 3 kilometres near
Pisa in Italy. The initial detector, Virgo, was upgraded to achieve 10
times higher sensitivity and started operation as Advanced Virgo in 2017.
KAGRA (Kamioka Gravitational Wave Detector) is an underground
gravitational wave detector in the Kamioka mine in Japan. It uses
cyrogenic technology, which means that the mirrors are cooled down to 20
Kelvin in order to reduce thermal noise. The detector has been in
operation since 2020.
https://www.einstein-online.info/en/spotlight/gw_detectors/
Brent
On 3/23/2025 12:05 PM, John Clark wrote:
*Correction: the two LIGO installations are in Louisiana and
Washington state. not Oregon as I originally said. *
*John K Clark See what's on my new list at Extropolis
<https://groups.google.com/g/extropolis>*
n0w
e3b
*
*
*
*
On Sun, Mar 23, 2025 at 2:47 PM John Clark <[email protected]> wrote:
On Sun, Mar 23, 2025 at 2:36 PM Alan Grayson
<[email protected]> wrote:
//
*>> LIGO is able to measure the distance between two
mirrors 2 1/2 miles apart to an accuracy of 1/10,000 the
width of a proton. And you need that sort of accuracy if
you want to detect gravitational waves. They achieve this
astounding level of precision by measuring the
interference effects between two laser beams. *
/> So they measure an interference pattern. How do they know
it's a gravitational wave? AG
/
*LIGO is L shaped with each leg being 2 1/2 miles long, theory
says gravitational waves should shrink the distance between one
leg at the same time it's expanding the distance in the other leg,
nothing else could do that. And to make sure they have two
identical facilities, one in Louisiana and the other in Oregon, if
it's a gravitational wave then the two detectors should measure
the same thing at almost the same time because gravitational waves
move at the speed of light, any slight delay between the two can
help them figure out the direction the gravitational wave is
coming from. *
*John K Clark See what's on my new list at Extropolis
<https://groups.google.com/g/extropolis>*
e3b
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