1-4 1st couple set to each other. Then 1st man casts off to 2nd place as 1st woman, starting slightly to her left, makes a petronella turn to end facing down in 1st place between 2nd couple who step up.
5-8 LIGO (or L-shape) set and link:-
' 2nd and 1st women with 2nd, 1st and 3rd men set taking hands in an L shape. 2nd man at the vertex faces in diagonally with arms at right angles.
' 2nd woman (with left hand free) dances diagonally across to 3rd man's place while the other four pull right shoulders back and cast clockwise to form a new L shape with 2nd man again at the vertex between 1st and 3rd women on the women's side and 1st and 3rd men across in 1st place.
9-12 Repeat the LIGO set and link figure from new places. This time 3rd woman dances diagonally across to 1st man's place as the other four cast clockwise. The corners are now diagonally opposite their starting places, 1st man is in 2nd place on the women's side and 1st woman is on the centre line in 3rd place.
13-16 1st couple dance clockwise around each other, passing right shoulder, starting by making a wide loop about half way round, moving into the centre. Then coming towards each other they birl (or turn tightly about one and a half times with the right hand) to end facing their 1st corner position (3rd corner person).
17-20 1st couple dance half a diagonal reel of four with 1st corners, starting by passing right shoulder. They then pass left shoulders with each other (a wave-like wiggle) to face 2nd corner position (4th corner person).
21-24 1st couple dance half a diagonal reel of four with 2nd corners, starting by passing right shoulder. They then pass right shoulders with each other to end in 2nd place on their own side.
25-32 All circle six hands round and back, ending in the order 2,1,3.
(Dance Crib compiled by the deviser, Murrough Landon, CC BY-SA August 2019)
Bars 5-12 represent the LIGO detector which has two 4 km long arms arranged in an L shape. Bars 13-16 show the circling and merging black holes. The wiggly reels are the resulting gravitational waves and the final circle is for the Nobel Prize medallions awarded by the Swedish Academy in recognition of this amazing scientific achievement.
(Dance Information by the deviser, Murrough Landon, CC BY-SA August 2019)
They were proposed by Henri Poincaré in 1905 and subsequently predicted in 1916 by Albert Einstein on the basis of his general theory of relativity. Gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation. Newton's law of universal gravitation, part of classical mechanics, does not provide for their existence, since that law is predicated on the assumption that physical interactions propagate instantaneously (at infinite speed) - showing one of the ways the methods of classical physics are unable to explain phenomena associated with relativity.
Gravitational-wave astronomy is a branch of observational astronomy that uses gravitational waves to collect observational data about sources of detectable gravitational waves such as binary star systems composed of white dwarfs, neutron stars, and black holes; and events such as supernovae, and the formation of the early universe shortly after the Big Bang.
On 11 February 2016, the LIGO and Virgo Scientific Collaboration announced they had made the first direct observation of gravitational waves. The observation was made five months earlier, on 14 September 2015, using the Advanced LIGO detectors. The gravitational waves originated from the merging of a binary black hole system. After the initial announcement the LIGO instruments detected two more confirmed, and one potential, gravitational wave events. In August 2017, the two LIGO instruments and the Virgo instrument observed a fourth gravitational wave from merging black holes, and a fifth gravitational wave from a binary neutron star merger. Several other gravitational wave detectors are planned or under construction.