PSR B1919 21
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PSR B1919+21 is a
pulsar A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be obse ...
with a period of 1.3373 seconds and a pulse width of 0.04 seconds. Discovered by
Jocelyn Bell Burnell Dame Susan Jocelyn Bell Burnell (; Bell; born 15 July 1943) is a Northern Irish physicist who, as a doctoral student, discovered the first radio pulsars in 1967. This discovery later earned the Nobel Prize in Physics in 1974, but she was not ...
on 28 November 1967, it is the first discovered radio pulsar. The power and regularity of the signals were briefly thought to resemble an extraterrestrial
beacon A beacon is an intentionally conspicuous device designed to attract attention to a specific location. A common example is the lighthouse, which draws attention to a fixed point that can be used to navigate around obstacles or into port. More mode ...
, leading the source to be nicknamed LGM, later LGM-1 (for " little green men"). The original designation of this pulsar was CP 1919, which stands for Cambridge Pulsar at RA . It is also known as PSR J1921+2153 and is located in the
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...
of
Vulpecula Vulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the Summer Triangle (an ...
.


Discovery

In 1967, a radio signal was detected using the Interplanetary Scintillation Array of the
Mullard Radio Astronomy Observatory The Mullard Radio Astronomy Observatory (MRAO) is located near Cambridge, UK and is home to a number of the largest and most advanced aperture synthesis radio telescopes in the world, including the One-Mile Telescope, 5-km Ryle Telescope, and ...
in
Cambridge Cambridge ( ) is a List of cities in the United Kingdom, city and non-metropolitan district in the county of Cambridgeshire, England. It is the county town of Cambridgeshire and is located on the River Cam, north of London. As of the 2021 Unit ...
, UK, by Jocelyn Bell Burnell. The signal had a -second period (not in 1967, but in 1991) and 0.04-second pulsewidth. It originated at celestial coordinates
right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the equinox (celestial coordinates), March equinox to the (hour circle of the) point in questio ...
, +21°
declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or ...
. It was detected by individual observation of miles of graphical data traces. Due to its almost perfect regularity, it was at first assumed to be spurious
noise Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrat ...
, but this hypothesis was promptly discarded. The discoverers jokingly named it ''little green men 1'' (''LGM-1''), considering that it may have originated from an extraterrestrial civilization, but Bell Burnell soon ruled out extraterrestrial life as a source after discovering a similar signal from another part of the sky. The original signal turned out to be radio emissions from the pulsar CP 1919, and was the first one recognized as such. Bell Burnell noted that other scientists could have discovered pulsars before her, but their observations were either ignored or disregarded. Researchers
Thomas Gold Thomas Gold (May 22, 1920 – June 22, 2004) was an Austrian-born astrophysicist, who also held British and American citizenship. He was a professor of astronomy at Cornell University, a member of the U.S. National Academy of Sciences, and a Fe ...
and
Fred Hoyle Sir Fred Hoyle (24 June 1915 – 20 August 2001) was an English astronomer who formulated the theory of stellar nucleosynthesis and was one of the authors of the influential B2FH paper, B2FH paper. He also held controversial stances on oth ...
identified this astronomical object as a rapidly rotating
neutron star A neutron star is the gravitationally collapsed Stellar core, core of a massive supergiant star. It results from the supernova explosion of a stellar evolution#Massive star, massive star—combined with gravitational collapse—that compresses ...
immediately upon their announcement. Before the nature of the signal was determined, the researchers, Bell Burnell and her PhD supervisor
Antony Hewish Antony Hewish (11 May 1924 – 13 September 2021) was a British radio astronomer who won the Nobel Prize for Physics in 1974 (together with fellow radio-astronomer Martin Ryle) for his role in the discovery of pulsars. He was also awarded the ...
, considered the possibility of extraterrestrial life:
We did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problem – if one thinks one may have detected life elsewhere in the universe how does one announce the results responsibly? Who does one tell first?


Nobel Prize controversy

When Antony Hewish and Martin Ryle received the
Nobel Prize The Nobel Prizes ( ; ; ) are awards administered by the Nobel Foundation and granted in accordance with the principle of "for the greatest benefit to humankind". The prizes were first awarded in 1901, marking the fifth anniversary of Alfred N ...
in physics in 1974 for their work in
radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...
and pulsars,
Fred Hoyle Sir Fred Hoyle (24 June 1915 – 20 August 2001) was an English astronomer who formulated the theory of stellar nucleosynthesis and was one of the authors of the influential B2FH paper, B2FH paper. He also held controversial stances on oth ...
, Hewish's fellow astronomer, argued that Jocelyn Bell Burnell should have been a co-recipient of the prize. In 2018, Bell won the $3-Million Breakthrough Prize in Fundamental Physics for her work.


Cultural references

The English
post-punk Post-punk (originally called new musick) is a broad genre of music that emerged in late 1977 in the wake of punk rock. Post-punk musicians departed from punk's fundamental elements and raw simplicity, instead adopting a broader, more experiment ...
band
Joy Division Joy Division were an English Rock music, rock band formed in Salford in 1976. The group consisted of vocalist, guitarist and lyricist Ian Curtis, guitarist and keyboardist Bernard Sumner, bassist Peter Hook and drummer Stephen Morris (musici ...
used an image of CP 1919's radio pulses on the cover of their 1979 debut album, ''
Unknown Pleasures ''Unknown Pleasures'' is the debut studio album by the English rock band Joy Division. It was released on 15 June 1979 through Factory Records. The album was recorded and mixed over three successive weekends at Stockport's Strawberry Studios i ...
''. German-born British composer
Max Richter Max Richter (; ; born 22 March 1966) is a German-born British composer and pianist. He works within postminimalist and contemporary classical styles. Richter is classically trained, having graduated in composition from the University of Edinbu ...
wrote a piece inspired by the discovery of CP1919 titled ''Journey (CP1919)''. The English
indie rock Indie rock is a Music subgenre, subgenre of rock music that originated in the United Kingdom, United States and New Zealand in the early to mid-1980s. Although the term was originally used to describe rock music released through independent reco ...
band
Arctic Monkeys Arctic Monkeys are an English Rock music, rock band formed in Sheffield in 2002. They comprise lead singer Alex Turner, drummer Matt Helders, guitarist Jamie Cook and bassist Nick O'Malley. The co-founder and original bassist Andy Nicholson ...
used a sound based on the pulses in their music video for " Four Out of Five." from 0:05-1:16


See also

*
Variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...


References


Further reading

* * *


External links

* * {{DEFAULTSORT:PSR B1919+21 Rotation-powered pulsars Vulpecula Astronomical objects discovered in 1967 LGM-1