page_title: Synchrotron radiation
section_title: History of detection
hierarchical_section_title: Synchrotron radiation / Synchrotron radiation in astronomy / History of detection
caption_attribution_description: English: This is a mosaic image, one of the largest ever taken by NASA's Hubble Space Telescope of the Crab Nebula, a six-light-year-wide expanding remnant of a star's supernova explosion. Japanese and Chinese astronomers recorded this violent event nearly 1,000 years ago in 1054, as did, almost certainly, Native Americans. The orange filaments are the tattered remains of the star and consist mostly of hydrogen. The rapidly spinning neutron star embedded in the center of the nebula is the dynamo powering the nebula's eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The neutron star, like a lighthouse, ejects twin beams of radiation that appear to pulse 30 times a second due to the neutron star's rotation. A neutron star is the crushed ultra-dense core of the exploded star. The Crab Nebula derived its name from its appearance in a drawing made by Irish astronomer Lord Rosse in 1844, using a 36-inch telescope. When viewed by Hubble, as well as by large ground-based telescopes such as the European Southern Observatory's Very Large Telescope, the Crab Nebula takes on a more detailed appearance that yields clues into the spectacular demise of a star, 6,500 light-years away. The newly composed image was assembled from 24 individual Wide Field and Planetary Camera 2 exposures taken in October 1999, January 2000, and December 2000. The colors in the image indicate the different elements that were expelled during the explosion. Blue in the filaments in the outer part of the nebula represents neutral oxygen, green is singly-ionized sulfur, and red indicates doubly-ionized oxygen. Français&#160;: Cette image, une des plus grandes de la Nébuleuse du Crabe jamais prises par le télescope spatial Hubble de la NASA, est en réalité une mosaïque de plusieurs clichés. La nébuleuse s'étend sur une distance de six années-lumière et est composée des restes de l'explosion d'une supernova. Les astronomes chinois et japonais ont observé cette violente explosion il y a environ un millénaire, en 1054, comme l'ont certainement également fait les indiens d'Amérique. Les filaments oranges sont les restes en lambeaux de l'étoile et se composent principalement d'hydrogène. L'étoile à neutrons qui tourne rapidement sur elle-même, intégrée dans le centre de la nébuleuse, est la dynamo alimentant l'intérieur de la nébuleuse de l'étrange lueur bleuâtre. La lumière bleue provient des électrons tourbillonnant presque à la vitesse de la lumière autour de lignes du champ magnétique de l'étoile à neutrons. L'étoile à neutrons, comme un phare, émet des faisceaux de rayonnements jumeaux qui semblent battre 30 fois par seconde en raison de la rotation de l'étoile à neutrons. Une étoile à neutrons est le noyau écrasé ultra-dense de l'étoile qui a explosé. L'image est formée de l'assemblage de 24 prises individuelles de la Wide Field and Planetary Camera 2 datant d'octobre 1999, janvier 2000 et décembre 2000. Les couleurs de l'image indiquent les différents éléments qui ont été expulsé lors de l'explosion. Le bleu dans les filaments de la partie extérieure de la nébuleuse représente l'oxygène neutre, le vert est le souffre ionisé I, et le rouge indique l'oxygène ionisé II. العربية: هذه الصورة المركبة, هي واحدة من أكبر الصور على الإطلاق التي التقطها تلسكوب هبل لسديم السرطان, وهو بقايا مستعر أعظم تمتد على مساحة قطرها 6 سنوات ضوئية. قام الفلكيون القدماء العرب والصينيون بتسجيل هذا الحدث قبل 1,000 عام في سنة 1054م, كما فعل ذلك البحارة الأمريكيون (بالرغم من أنه ليس من المؤكد تماماً أن ما سجلوه هو هذا). الخيوط البرتقالية الظاهرة في الصورة هي أشلاء وشظايا متبقّية من النجم الذي انفجر (وكوّن السديم) وهي تتركب بشكل رئيسي من الهيدروجين. النجم النيوتروني سريع "الدوران المحوري" المتواري في وسط السديم يَعمل كمولد طاقة يُسبب البريق المُزرقّ الغريب المُشع من وسط السديم. وهذا الضوء الأزرق قادم من إلكترونات تدور بما يُقارب سرعة الضوء حول الحقل المغناطيسي للنجم النيوتروني. النجم النيوتروني, مثل المنارة, يُطلق شعاعين من الضوء في اتجاهين مختلفين يَجعلناه يبدو كأنه ينبض 30 مرة في الثانية نتيجة لدورانه المحوري السريع (النجوم النيوترونية تُتم بضعة دورات حول نفسها في الثانية على الأقل). والنجم النيوتروني هو نواة مسحوقة شديدة الكثافة لنجم انفجر. هذه الصورة المركبة رُكّبت من 24 صورة بعضها التطقت في تشرين الأول (أكتوبر) 1999, وكانون الثاني (يناير) 2000, وكانون الأول (ديسمبر) 2000. الألوان في الصورة تدل على عناصر مختلفة قذفت أثناء الانفجار. اللون الأزرق في الشعيرات في الجزء الخارجي من السديم هو لأكسجين طبيعي, والأخضر لكبريت متأين فردياً, والأحمر لأكسجين متأين.
context_page_description: Synchrotron radiation is the electromagnetic radiation emitted when charged particles are accelerated radially, e.g., when they are subject to an acceleration perpendicular to their velocity. It is produced, for example, in synchrotrons using bending magnets, undulators and/or wigglers. If the particle is non-relativistic, then the emission is called cyclotron emission. If, on the other hand, the particles are relativistic, sometimes referred to as ultrarelativistic, the emission is called synchrotron emission. Synchrotron radiation may be achieved artificially in synchrotrons or storage rings, or naturally by fast electrons moving through magnetic fields. The radiation produced in this way has a characteristic polarization and the frequencies generated can range over the entire electromagnetic spectrum which is also called continuum radiation.
  In astrophysics, synchrotron emission occur, for instance, due to ultra-relativistic motion of a source around a black hole. When the source performs a circular geodesic around the black hole, the synchrotron radiation occur for orbits close to the photosphere where the motion is in ultra-relativistic regime.
context_section_description: It was first detected in a jet emitted by Messier 87 in 1956 by Geoffrey R. Burbidge, who saw it as confirmation of a prediction by Iosif S. Shklovsky in 1953, but it had been predicted earlier by Hannes Alfvén and Nicolai Herlofson in 1950.
  Solar flares accelerate particles that emit in this way, as suggested by R. Giovanelli in 1948 and described critically by J.H. Piddington in 1952.
  T. K. Breus noted that questions of priority on the history of astrophysical synchrotron radiation are complicated, writing:
  In particular, the Russian physicist V.L. Ginzburg broke his relationships with I.S. Shklovsky and did not speak with him for 18 years. In the West, Thomas Gold and Sir Fred Hoyle were in dispute with H. Alfven and N. Herlofson, while K.O. Kiepenheuer and G. Hutchinson were ignored by them.
  Supermassive black holes have been suggested for producing synchrotron radiation, by ejection of jets produced by gravitationally accelerating ions through the super contorted 'tubular' polar areas of magnetic fields. Such jets, the nearest being in Messier 87, have been confirmed by the Hubble telescope as apparently superluminal, travelling at 6 × c (six times the speed of light) from our planetary frame. This phenomenon is caused because the jets are travelling very near the speed of light and at a very small angle towards the observer. Because at every point of their path the high-velocity jets are emitting light, the light they emit does not approach the observer much more quickly than the jet itself. Light emitted over hundreds of years of travel thus arrives at the observer over a much smaller time period (ten or twenty years) giving the illusion of faster than light travel. There is no violation of special relativity.
caption: Crab Nebula. The bluish glow from the central region of the nebula is due to synchrotron radiation.
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