The female astronomer who discovered the pulsar – Bell

  Jocelyn Bell Burnell (JB Burnell, 1943-) was born in Belfast, Northern Ireland, on June 15, 1943. She has been interested in natural science knowledge since childhood and aspires to become a scientist. She has worked in universities and research institutions such as University of Southampton, Murad Space Science Laboratory, Royal Observatory of Edinburgh, etc. She has served as President of the Royal Society of Edinburgh (RSE), the first female President of the British Physical Society (IOP), Oxford University astrophysics visiting professor and other positions. In 2018, the Fundamental Physics Special Excellence Award was awarded to Bell for her contributions to the discovery of pulsars and her outstanding leadership in the scientific community over the years[1].
early school

  Bell’s parents attach great importance to their children’s education, and she has received a good education since she was a child. Bell’s father is an architect. When Bell was in secondary school, his father was doing construction work at the Armagh Planetatium in the UK (located in Armagh, County Armagh, Northern Ireland, not far from Belfast, where Bell lives). , she often followed her father to the observatory. Bell often chatted with the staff of the observatory, and under their influence, she began to develop a strong interest in astronomy [2]. At that time, very few girls would study natural sciences, so in the curriculum, boys and girls were also treated differently, with boys studying natural sciences and girls usually studying life skills such as cooking. But Bell found himself really interested in astronomy [3].
  Bell failed the UK 11+ exam at the age of 11 (equivalent to China’s primary school entrance exam. Because most of the students taking the exam are 11-year-olds, it is often called the “11-year-old exam” or “11+ exam”. The 11+ exam It will decide the children’s future training direction. Children who pass the 11+ exam will receive secondary education. Those who do not pass the 11+ exam will receive vocational and technical training). So he went to a boarding school in the north of England for two years. Bell met Henry Tillot, an interesting physics teacher at boarding school who sparked her interest in physics [4]. In the first science exam at the boarding school, Bell achieved good results in the first place [4]. But she got one question wrong on this exam, which was about the speed of light. She thought the speed of light 186,000 mph was too fast, so she changed 186,000 mph to 186,000 mph [4]. This exam made her start to think deeply about physics issues, and she became attached to physics since then.
  After graduating from high school, 18-year-old Bell studied physics at the University of Glasgow in Scotland. As the only girl in her class, when she entered the classroom, boys often booed [3]. Because almost no women would study physics at that time, Bell was always concerned and questioned by everyone.
  In 1965, Bell went to Cambridge University to study for a doctorate, her tutor was the famous radio astronomer Antony Hewish (1924-). Hewish was studying quasars at the time, and in order to observe more quasars, he planned to build a large radio telescope. The radio telescope project is an antenna array composed of 2,048 dipole antennas, and this large-scale project was built by scientists in Hewish’s team. Bell, who has just entered the University of Cambridge, has also joined the construction work. Because the construction work of the radio telescope is relatively difficult, some physical work needs to be done on the construction site, such as swinging a sledgehammer to drive a pile, twisting a wire with a wrench, etc. Therefore, Bell’s colleagues considered her unsuitable for this type of construction work [3]. But Bell did not back down because the construction work was hard, but actively engaged in it [3]. In 1967, the construction of the radio telescope was completed and put into use, becoming an important tool for the discovery of pulsars.
Discover pulsars

  Bell’s first research achievement was the discovery of pulsars, which became her most controversial and influential research result. However, the discovery of the pulsar was an accidental event, as their research at the time was aimed at finding more quasars than pulsars. Quasars were discovered by scientists in the 1960s. Quasars are radio galaxies with enormous energy and very far from Earth, but at the time it was not known which radio galaxies were quasars. Therefore, identifying more quasars became Hewish’s research goal.
  The University of Cambridge built advanced astronomical observation instruments under the leadership of M. Ryle, which provided a good technical foundation for the discovery of pulsars. In 1965, Hewish applied for a large sum of money from the Scientific Research Council for the construction of a radio telescope [5]. The telescope utilizes a technique known as interplanetary scintillation (IPS, a distinct fluctuation of radio-source radiation formed when radio waves pass through the solar wind in interstellar space), which efficiently selects quasars. The radio telescope uses 2048 dipole antennas to form an antenna array covering an area of ​​18,000 square meters, which also greatly improves the sensitivity of the radio telescope. Since the resolution of a radio telescope is inversely proportional to the wavelength, in order to obtain higher resolution, radio astronomers usually use shorter wavelengths to observe celestial matter [6]. Hewish designed the radio telescope to do the opposite. It can operate at relatively long wavelengths, is also sensitive to radio waves, and makes it easier to detect pulsed signals. In 1967, this radio telescope was built and put into operation.
  Before 1967 there was no concept of a “pulsar”, which was actually a spinning neutron star. Scientists predicted the existence of neutron stars in the 1930s, but no one has discovered neutron stars until the discovery of pulsars, which confirmed the correctness of the neutron star theory. The discovery of pulsars also indirectly verified Einstein’s general theory of relativity, laying the foundation for the subsequent exploration of gravitational waves, black holes, and dark matter.
  Bell’s job is primarily responsible for operating large telescopes and analyzing related data. She analyzes the vast amount of graph data the telescope produces every day, and she needs to identify planetary glints and disturbances through graphs, which is not an easy task. Because computers were not yet available for extensive analysis of the data, Bell needed to manually calculate large amounts of data and maintain a high level of vigilance in order to identify specific signals. Eight weeks into the study, she found that the recordings were a bit “shaky” and didn’t appear to be entirely flickering light sources or entirely human interference. At first she thought it was a point light source and checked carefully. At the same time, he contacted his mentor, Hewysh, who felt that the signal was artificial interference, and quickly organized a team to discuss, but no results were discussed [7].

  Since there was no concept of a pulsar at the time, this “unusual signal” was speculated to be a signal from human interference, a signal from a white dwarf, or even a signal from aliens. These speculations were quickly rejected one by one. Since they didn’t know it was a signal from a pulsar at first, they dubbed the signal they found “little green men” (LGM), jokingly calling it an alien signal. Then, Bell discovered the little green men No. 2, No. 3, and No. 4. As more signals were discovered, the speculation that the little green man was a signal sent by an alien intelligent creature to Earth was dismissed. If the signal is sent by alien intelligent life, it should observe the signal flickering at the same frequency in the same direction, but the four signal sources they found do not originate from the same direction, nor do they flicker at the same frequency. These signals can only be radiation from stars.

  They also began to try to use the theory of white dwarfs and neutron stars to explain the detected pulse signals. In February 1968, the Hewish team published the paper “Observation of a Rapidly Pulsing Radio Source” in the journal Nature, and in April, “Observation of a Rapidly Pulsing Radio Source”. In the paper, Hewish has not yet fully defined the pulse signal, and proposed to use the stable oscillation of white dwarf or neutron star to explain it [8], and also stated that the variation of the pulse cannot be attributed to interstellar dust [9]. Soon, however, the claim that the pulsar was a white dwarf was also ruled out.
  In May 1968, Thomas Gold published “Rotating Neutron Stars as Sources of Pulsed Radio Sources” in “Nature”, speculating that the newly discovered radio sources may be rotating neutron stars, because there were still many known stars at the time. No one has been found to have such a short and accurate period as the newly discovered radio source [10]. At this point, pulsars began to be thought of as rotating neutron stars. The discovery of pulsars has also opened up a new research field for astronomy. Scientists have carried out detailed studies on the evolution process, radiation mechanism, and basic structure of pulsars.
  In 1974, Hewish and Ryle shared the Nobel Prize in Physics. Hewish won for his discovery of pulsars, and Ryle won for his invention of the Synthetic Aperture Radio Telescope. Another major discovery about pulsars is a binary star system jointly discovered by American astronomers RA Hulse and JH Taylor. In 1993, Russell and Joseph shared the Nobel Prize in Physics for the discovery of binary star systems. Although some scientists dispute that Bell did not win the Nobel Prize in Physics, Bell himself was not bothered by it.
  Bell’s contribution to the discovery of pulsars has been recognized by many scientists and scientific institutions. Astronomers Hoyle (F. Hoyle) and Gold both believe that Bell has taken a crucial step in the discovery of pulsars, and that Bell’s observations effectively identify the pulse signal is a time-dependent change of position of the star. Hewish also said: If Bell did not pay attention to the special law of the signal source, it would miss the opportunity to find the pulse signal [2]. In 1973, Hewish and Bell received the Michelson Medal. This shows that scientists have recognized Bell’s contribution before the 1974 Nobel Prize in Physics was awarded. In 2011, Bell received the Gret Reber Medal, which is only awarded to the field of wireless astronomy, which fully affirmed Bell’s contributions to wireless astronomy.
Postdoctoral research and work

  After graduating from Ph.D. Bell, the research scope covers the fields of gamma rays, X-rays, infrared rays and so on. In addition to her research work, she also holds a number of teaching and administrative roles. In 1968 Bell married her husband, M. Burnell, a government official. Because Martin’s work often needs to change the working place, it is difficult for Bell to do research in a fixed place for a long time, and he also needs to change his research direction frequently to adapt to the new research environment. Every time she moved, she had to find a local job related to astronomy or physics. She worked part-time for 18 years and served as a teacher at the University of Southampton, University of London, and the James Clark Maxwell Telescope project on Mauna Kea. manager. It is a pity that the marriage between Bell and Martin finally broke down in 1993 for various reasons.

  In terms of scientific research, Bell mainly does data analysis and project management in universities and research institutions. From 1968 to 1978, Bell worked at the University of Southampton. During this period, she participated in the data analysis of the Alouette satellite, and after 1970 began to study gamma rays. From 1974 to 1982, Bell worked at the Murad Space Science Laboratory, focusing on X-rays, and participated in the data analysis of the Ariel satellite. In 1982 he was the project manager of the James Clark Maxwell Telescope project led by the Royal Observatory. The James Clark Maxwell Telescope Project was a joint British, Dutch, Canadian facility, and Bell’s research at the time involved the observation of most of the electromagnetic field spectrum, from radio waves to gamma rays [4]. Although Bell has a wide range of research fields and has worked in many institutions, Bell has not yet obtained a fixed professional title during this period. It was not until 1991 that Bell received his first tenure at the Open University.
  In terms of teaching, Bell mainly teaches introductory courses in physics and astronomy in colleges and universities. She has served as a teacher at the University of Southampton, The Open University, Princeton University, Oxford University, etc. When Bell took classes at universities such as the University of Southampton, he adopted a face-to-face classroom teaching model. The teaching method of the Open University is different from that of other colleges and universities, and it adopts the teaching mode of distance teaching. The teaching mode of distance teaching is not so strict with the teaching method and location of teachers. Bell can communicate with students through the Internet, letters, etc. The flexible teaching model of the Open University allows Bell more time to balance work and family, so Bell has been a part-time teacher at the Open University since 1973 [4].

  In terms of management, Bell presided over major conferences and organized fund construction in research organizations and institutions such as the International Astronomical Union (IAU), the British Physical Society (IOP) and the Royal Astronomical Society (RAS). The IAU holds a conference every three years, where scientists from various countries discuss important astronomical issues. Bell sometimes serves as the chair member of the Resolution Council, presiding over the IAU General Assembly and coordinating the various resolutions among the members of the General Assembly. Because of Bell’s outstanding scientific research and management skills, she served as the chairman of RAS in 2002 and the chairman of IOP from 2008 to 2010. This is the first time that IOP has a woman in this position. During his tenure at the IOP, Bell has been paying close attention to the current situation of female scientists in scientific research, and has also actively participated in projects to promote the development of gender equality in science. She has been involved in the implementation of Athena SWAN and Project Juno, both IOP projects to advance equality in science.
  Bell also contributed to the establishment of the Bell Burnell Graduate Fellowship, which stemmed from her 2018 Fundamental Physics Special Excellence Award. After receiving the £2.3m award, she actively discussed with the IOP how the funding could be used to help postgraduate students in need. In the end, Bell decided to hand the funds over to the IOP for management, establishing the Bell Burnell Graduate Fellowship. The establishment of this scholarship is mainly to promote the diversity of physicists in the UK and Ireland, to promote equality in physics education, and to help Ph.D. students with difficulties [1].

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