View source for Astronomy:PSR B1919+21

{{short description|Pulsar in the constellation Vulpecula}}
{{Starbox begin
 | name=PSR B1919+21
}}
{{Starbox image
| image =  [[File:Chart Showing Radio Signal of First Identified Pulsar.jpg|250px]]
| caption = Chart on which Jocelyn Bell Burnell first recognised evidence of PSR B1919+21, exhibited at Cambridge University Library
| credit = <!--credit for image if the image's use requires them (optional)-->
}}
{{Starbox observe
 | epoch=[[Astronomy:J2000|J2000]] ([[Astronomy:International Celestial Reference System|ICRS]])
 | constell=[[Astronomy:Vulpecula|Vulpecula]]
 | ra={{RA|19|21|44.815}}<ref name=Hobbs>{{cite journal|doi=10.1111/j.1365-2966.2004.08157.x|title=Long-term timing observations of 374 pulsars|journal=Monthly Notices of the Royal Astronomical Society|volume=353|issue=4|pages=1311|year=2004|last1=Hobbs|first1=G.|last2=Lyne|first2=A. G.|last3=Kramer|first3=M.|last4=Martin|first4=C. E.|last5=Jordan|first5=C.|bibcode = 2004MNRAS.353.1311H |doi-access=free}}</ref>
 | dec={{DEC|+21|53|02.25}}<ref name=Hobbs />
}}
{{Starbox character
 | type=Pulsar
}}
{{Starbox astrometry
 | dist_ly = {{val|1000|+2600|-700}}
}}
{{Starbox detail
 | mass = ~1.4
 | radius = ~1.4 × 10<sup>−5</sup>
 | luminosity = 0.006<ref name=atnf />
 | temperature=
 | rotation=1.3373 s<ref name=Arzoumanian1994 />
 | age_myr = 16<ref name="atnf" />
}}
{{Starbox catalog
 | names= PSR&nbsp;[[Astronomy:J2000.0|J]]1921+2153, [[Astronomy:Pulsar|PSR]]&nbsp;1921+2153, PSR&nbsp;B1919+21, PSR&nbsp;[[Astronomy:Equatorial coordinate system|1919+21]], WSTB&nbsp;12W15, [[Organization:University of Cambridge|CP]]&nbsp;1919[[Declination|+21]], CP&nbsp;[[Right ascension|1919]], {{nobr|LGM-1}}
}}
{{Starbox reference
 | Simbad=PSR+B1919%2B21
}}
{{Starbox end}}

'''PSR&nbsp;B1919+21''' is a [[Astronomy:Pulsar|pulsar]] with a period of 1.3373 seconds<ref name=Arzoumanian1994 /> and a pulse width of 0.04 seconds. Discovered by Jocelyn Bell Burnell on 28 November 1967, it is the first discovered radio pulsar.<ref name=edn /> The power and regularity of the signals were briefly thought to resemble an extraterrestrial [[Astronomy:Beacon|beacon]], leading the source to be nicknamed '''LGM''', later '''LGM-1''' (for "[[Social:Little green men|little green men]]").<ref name="aps.org">{{cite web|url=https://www.aps.org/publications/apsnews/200602/history.cfm|title=This Month in Physics History: February 1968: Discovery of pulsars announced.|website=www.aps.org}}</ref>

The original designation of this pulsar was '''CP&nbsp;1919''', which stands for Cambridge Pulsar at [[Right ascension|RA]] {{RA|19|19}}.<ref>{{cite book|url=https://books.google.com/books?id=1w5f5Po4XV8C&pg=PA325|title=An Introduction to Astrophysics|last=Basu|first=Baidyanath|isbn=978-81-203-1121-3|page=325|date=2003-02-01}}</ref> It is also known as '''PSR&nbsp;J1921+2153''' and is located in the [[Astronomy:Constellation|constellation]] of [[Astronomy:Vulpecula|Vulpecula]].

== Discovery ==
In 1967, a radio signal was detected using the [[Astronomy:Interplanetary Scintillation Array|Interplanetary Scintillation Array]] of the [[Astronomy:Mullard Radio Astronomy Observatory|Mullard Radio Astronomy Observatory]] in Cambridge, UK, by Jocelyn Bell Burnell. The signal had a {{val|1.337302088331}}-second [[Physics:Frequency|period]] (not in 1967, but in 1991) and 0.04-second [[Pulse-width modulation|pulsewidth]].<ref name=Arzoumanian1994 /> It originated at celestial coordinates {{RA|19|19}} [[Right ascension|right ascension]], +21° [[Declination|declination]]. 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, 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.<ref name="aps.org" />

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 [[Biography:Thomas Gold|Thomas Gold]] and [[Biography:Fred Hoyle|Fred Hoyle]] identified this astronomical object as a rapidly rotating [[Astronomy:Neutron star|neutron star]] immediately upon their announcement.{{cn|date=November 2019}}

Before the nature of the signal was determined, the researchers, Bell Burnell and her PhD supervisor [[Biography:Antony Hewish|Antony Hewish]], considered the possibility of extraterrestrial life:<ref>{{cite news |url= http://www.bigear.org/vol1no1/burnell.htm |title= Little Green Men, White Dwarfs or Pulsars? |first= S. Jocelyn Bell |last= Burnell |orig-year= 1977 |magazine= Cosmic Search Magazine |date= 2004-09-21 |access-date= 2013-07-28}} (after-dinner speech given at the Eighth Texas Symposium on Relativistic Astrophysics; first published in {{cite journal |journal= Annals of the New York Academy of Sciences |volume= 302 |pages= 685–9 |date= 1977 |title=Petit Four |doi=10.1111/j.1749-6632.1977.tb37085.x|last1= Bell Burnell |first1= S. Jocelyn |bibcode= 1977NYASA.302..685B |s2cid= 222086632 }})</ref>
<blockquote>
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?
</blockquote>

== Nobel Prize controversy ==
When Antony Hewish and [[Biography:Martin Ryle|Martin Ryle]] received the Nobel Prize in physics in 1974 for their work in [[Astronomy:Radio astronomy|radio astronomy]] and pulsars, [[Biography:Fred Hoyle|Fred Hoyle]], Hewish's fellow astronomer, argued that Jocelyn Bell Burnell should have been a co-recipient of the prize.<ref>{{cite news|url=https://www.nytimes.com/2003/10/20/opinion/no-nobel-prize-for-whining.html|title=No Nobel Prize for whining|last=Judson|first=Horace Freeland|date=2003-10-20|newspaper={{wipe|The New York Times}}}}</ref>

In 2018, Bell won the $3-Million Breakthrough Prize in Fundamental Physics for her work.<ref>{{Cite web|last=Billings|first=Lee|title=Pulsar Discoverer Jocelyn Bell Burnell Wins $3-Million Breakthrough Prize|url=https://www.scientificamerican.com/article/pulsar-discoverer-jocelyn-bell-burnell-wins-3-million-breakthrough-prize1/|access-date=2021-08-03|website=Scientific American|language=en}}</ref>

== Cultural references ==
The English post-punk band Joy Division used an image of CP&nbsp;1919's radio pulses on the cover of their 1979 debut album, ''Unknown Pleasures''.<ref>{{cite web|url=http://adamcap.com/2011/05/19/history-of-joy-division-unknown-pleasures-album-art/|title=The History of Joy Division's "Unknown Pleasures" Album Art|last=Capriola|first=Adam|publisher=Adamcap.com|date=2011-05-19|access-date=2013-06-28}}</ref><ref>{{cite web|url = http://www.joydiv.org/up.htm|title=''Unknown Pleasures''|date=June 1979|publisher=Joy Division|access-date=2008-07-05}}</ref><ref>{{cite web|url=http://blogs.scientificamerican.com/sa-visual/pop-culture-pulsar-origin-story-of-joy-division-8217-s-unknown-pleasures-album-cover-video/|title=Pop Culture Pulsar: Origin Story of Joy Division's Unknown Pleasures Album Cover|last=Christiansen|first=Jen|publisher=Scientific American|date=2015-02-18|access-date=2015-10-04}}</ref>

German-born British composer Max Richter wrote a piece inspired by the discovery of CP1919 titled ''Journey (CP1919)''.<ref>{{cite web|url=https://www.maxrichtermusic.com/2019/05/16/journey-cp1919-performed-by-aurora-orchestra/|title=Journey (CP1919) Performed by Aurora Orchestra|date=2019-05-16|access-date=2019-05-20}}</ref>

The English indie rock band Arctic Monkeys used a sound based on the pulses in their music video for "Four Out of Five."<ref>{{cite web | url=https://www.youtube.com/watch?v=71Es-8FfATo | title=Arctic Monkeys - Four Out Of Five (Official Video)| website=[[Company:YouTube|YouTube]]}} from 0:16-0:45 and 2:57-3:13.</ref><ref>{{cite web | url=https://www.youtube.com/watch?v=ryg077wBvsM | title=The Great Silence by LEMMiNO| website=[[Company:YouTube|YouTube]]}} from 0:05-1:16</ref>

== See also ==
*[[Astronomy:Variable star|Variable star]]

== References ==
{{reflist|refs=
<ref name=Arzoumanian1994>{{Cite journal|last1=Arzoumanian|first1=Z.|last2=Nice|first2=D. J.|last3=Taylor|first3=J. H.|last4=Thorsett|first4=S. E.|year=1994|title=Timing behavior of 96 radio pulsars|journal=Astrophysical Journal|volume=422|issue=2|pages=671|doi=10.1086/173760|bibcode=1994ApJ...422..671A|doi-access=free}}</ref>
<ref name=atnf>{{Cite web|title=The ATNF Pulsar Catalogue |url=http://www.atnf.csiro.au/research/pulsar/psrcat/| access-date=2010-02-11}}</ref>
<ref name=edn>{{Cite web|title=Pulsar is 1st observed, November 28, 1967 | publisher=EDN Network | url=http://www.edn.com/electronics-blogs/edn-moments/4402048/Pulsar-is-1st-observed--November-28--1967 | access-date=2013-12-20}}</ref>
}}

== Further reading ==
* {{cite journal|last1=Hewish|first1=A.|author-link1=Antony Hewish|first2= S. J.|last2=Bell|author-link2=Jocelyn Bell Burnell|first3=J. D. H.|last3=Pilkington|first4=P. F.|last4=Scott|first5=R. A.|last5=Collins|title=Observation of a Rapidly Pulsating Radio Source|journal=Nature|volume=217|issue=5130|pages=709–713|date=24 February 1968|doi=10.1038/217709a0|bibcode=1968Natur.217..709H
|s2cid=4277613}}
* {{cite web|url=http://www.k3pgp.org/pulsar.htm|title=K3PGP Experimenter's Corner – Pulsars (List of pulsars for amateur radio astronomers)|publisher=K3PGP.org|access-date=2008-02-25|archive-url=https://web.archive.org/web/20120210181519/http://www.k3pgp.org/pulsar.htm|archive-date=2012-02-10|url-status=dead}}
* {{cite web|url=http://www.astro.cornell.edu/~shami/psrvlb/|title=Pulsar Astrometry with the VLBA (Study of Pulsar Parallax, PSR B1919+21 is one of the pulsars studied)|publisher=[[Organization:Cornell University|Cornell University]]|date=2004-01-21}}

== External links ==
* {{cite web|url=http://www.jb.man.ac.uk/~pulsar/Education/Tutorial/tut/node1.html#SECTION00010000000000000000|title=A Tutorial on Radio Pulsars: The discovery of pulsars|last=Bell|first=Jon|date=1996-12-19|access-date=2013-06-28|archive-url=https://web.archive.org/web/20120903153414/http://www.jb.man.ac.uk/~pulsar/Education/Tutorial/tut/node1.html#SECTION00010000000000000000|archive-date=2012-09-03|url-status=dead}}
* {{cite web|url=http://www.atnf.csiro.au/research/pulsar/audio/CP1919.wav|title=Recording of the first-discovered pulsar CP1919 (PSR B1919+21) made at the Parkes radio telescope in April 2012|last1=Manchester|first1=R. N.|last2=Hobbs|first2=G.|last3=Khoo|first3=J.|publisher=CSIRO Astronomy & Space Science: Pulsar Group|access-date=2013-06-30|archive-url=https://web.archive.org/web/20160310155315/http://www.atnf.csiro.au/research/pulsar/audio/CP1919.wav|archive-date=2016-03-10|url-status=dead}}

{{Neutron star}}
{{Extraterrestrial life}}
{{Stars of Vulpecula}}
{{DEFAULTSORT:PSR B1919+21}}
[[Category:Rotation-powered pulsars]]
[[Category:Vulpecula]]
[[Category:Search for extraterrestrial intelligence|LGM-1]]

{{Sourceattribution|PSR B1919+21}}