I can still recall reading the Science section of Time Magazine, before they became a less glossy People periodical during the reign of the Luce's, when an article appeared describing PSR B1919+21, a pulsar type neutron star located in the constellation Vulpecula. Neutron stars are much too small and faint to view in any but the world's largest telescopes.
First detected in December 1967 by Jocelyn Bell (now Dame Jocelyn Bell Burnell) at Cambridge University, pulsars are a very dense ball of material that are created when a star runs out of fuel and collapses on itself. This pulsar was flickering repeatedly every 1.3 seconds and did not match the already-discovered quasar. Because they could not rule out that the signal was coming from an intelligent alien species due to the extremely precise regularity of its signal, the pulsar was named LGM-1. It wasn’t until Bell discovered a second pulsar elsewhere in the universe that the discovery was announced, as Cambridge’s researchers were afraid that possible alien life would create unnecessary publicity for them and chaos among the poorly educated masses.
Pulsars spin rapidly, while simultaneously radiating opposing beams of radio waves out into space. The setup is similar to a lighthouse that spins around one up-and-down axis and radiates two beams of light from a second axis. To ships on the water, the steady beams looks like a light pulsing on and off. The same is true for pulsars; if one of the beams happens to sweep across the Earth, it appears to astronomers as though the object is blinking or pulsating.
Bell Burnell was studying objects using a radio telescope she helped build at the Mullard Radio Astronomy Observatory, outside Cambridge, under the supervision of her advisor, Antony Hewish*, who designed the instrument. The telescope was intended to help study the radio cosmos using a technique called interplanetary scintillation**. Hewish intended to use this method on objects called quasars, or incredibly bright centers of massive galaxies, illuminated by material swirling around monster black holes. Quasars vary in brightness, and Hewish thought the interplanetary scintillation technique was appropriate for identifying those changes.
Bell Burnell was in charge of operating the telescope and analyzing the data, according to an article she wrote for
Cosmic Search Magazine in the 1970s. Using this technique, Bell Burnell spotted an object that appeared to be flickering every 1.3 seconds; this pattern repeated for days on end. The object didn't match the profile of a quasar. The signal conflicted with the generally chaotic nature of most cosmic phenomenon, the researchers would later explain. In addition, the light was of a very specific radio frequency, whereas most natural sources typically radiate across a wider range.
For those reasons, Bell Burnell, Hewish and some other members of the astronomy department had to acknowledge that they might have found an artificially created signal — something emitted by an intelligence species. Burnell even labeled the first pulsar LGM1, which stood for "little green men 1."
Jocelyn Bell Burnell finally received the much-deserved recognition for her work in 2018.
The Breakthrough Prize is the largest monetary science prize in the entire world. Funded by Silicon Valley giants like Sergey Brin and Mark Zuckerburg, Bell Burnell joins a high-profile group of past winners like Stephen Hawking. Edward Witten***, the chair of the prize’s selection committee, said in a statement. “Until that moment, no one had any real idea how neutron stars could be observed if indeed they existed. Suddenly it turned out that nature has provided an incredibly precise way to observe these objects, something that has led to many later advances.”
Jocelyn Bell Burnell already has big plans for her prize money. She told the
BBC, that she plans to donate all of her winnings to under-represented groups in order to help them with funding to become physics researchers.
“I don’t want or need the money myself and it seemed to me that this was perhaps the best use I could put to it,” she told the
BBC.
* Antony Hewish grew up in Newquay, on the Atlantic coast and there developed a love of the sea and boats. I was educated at King’s College, Taunton and went to the University of Cambridge in 1942. From 1943-46, he was engaged in war service at the Royal Aircraft Establishment, Farnborough and also at the Telecommunications Research Establishment, Malvern, and was involved with airborne radar-counter-measure devices and during this period he also worked with Martin Ryle.
Returning to Cambridge in 1946, Hewish graduated in 1948 and immediately joined Ryle’s research team at the Cavendish Laboratory. I obtained my Ph.D. in 1952, became a Research Fellow at Gonville and Caius College where he had been an undergraduate, and in 1961 Hewish transferred to Churchill College as Director of Studies in Physics where he was University Lecturer during 1961-69, Reader during 1969-71 and Professor of Radio Astronomy from 1971 until his retirement in 1989. Following Ryle’s illness in 1977 Hewish assumed leadership of the Cambridge radio astronomy group and was head of the Mullard Radio Astronomy Observatory from 1982-88.
Hewish's decision to begin research in radio astronomy was influenced both by his wartime experience with electronics and antennas and by one of his teachers, Jack Ratcliffe, who had given an excellent course on electromagnetic theory during the final undergraduate year and whom Hewish had also encountered at Malvern. Ratcliffe was head of radiophysics at the Cavendish Laboratory at that time.
Hewish's first research was concerned with propagation of radiation through inhomogeneous transparent media and this has remained a lifelong interest. The first two radio “stars” had just been discovered and Hewish realised that their scintillation, or “twinkling”, could be used to probe conditions in the ionosphere and he developed the theory of diffraction by phase-modulating screens and set up radio interferometers to exploit the ideas. Thus Hewish was able to make pioneering measurements of the height and physical scale of plasma clouds in the ionosphere and also to estimate wind speeds in this region. Following our Cambridge discovery of interplanetary scintillation in 1964 Hewish developed similar methods to make the first ground-based measurements of the solar wind and these were later adopted in the USA, Japan and India for long term observations. Hewish also showed how interplanetary scintillation could be used to obtain very high angular resolution in radio astronomy, equivalent to an interferometer with a baseline of 1000 km – something which had not then been achieved in this field. It was to exploit this technique on a large sample of radio galaxies that I conceived the idea of a giant phased-array antenna for a major sky survey. This required instrumental capabilities quite different from those of any existing radio telescope, namely very high sensitivity at long wavelengths, and a multi-beam capability for repeated whole-sky surveys on a day to day basis.
Hewish obtained funds to construct the antenna in 1965 and it was completed in 1967. The sky survey to detect all scintillating sources down to the sensitivity threshold began in July. By a stroke of good fortune the observational requirements were precisely those needed to detect pulsars.
Jocelyn Bell joined the project as a graduate student in 1965, helping as a member of the construction team and then analysing the paper charts of the sky survey. She was quick to spot the week to week variability of one scintillating source which I thought might be a radio flare star, but our more detailed observations subsequently revealed the pulsed nature of the signal.
Surprisingly, the phased array is still a useful research instrument. It has been doubled in area and considerably improved over the years and one of my present interests is the way our daily observations of scintillation over the whole sky can be used to map large-scale disturbances in the solar wind. At present this is the only means of seeing the shape of interplanetary weather patterns so the observations made a useful addition to in-situ measurements from spacecraft such as Ulysses, now (1992) on its way to Jupiter.
Hewish believes scientists have a duty to share the excitement and pleasure of their work with the general public, and he enjoys the challenge of presenting difficult ideas in an understandable way.
** interplanetary scintillation refers to random fluctuations in the intensity of radio waves of celestial origin, on the timescale of a few seconds. It is analogous to the twinkling one sees looking at stars in the sky at night, but in the radio part of the electromagnetic spectrum rather than in the visible light.
*** Edward Witten's father, Louis Witten, was a theoretical physicist specializing in gravitation and general relativity.
Witten studied at Brandeis University, in Massachusetts, and received his B.A. in 1971. From there he went to Princeton, in New Jersey, receiving his M.A. in 1974 and his Ph.D. in 1976.
After completing his doctorate, Witten went to Harvard where he was postdoctoral fellow during session 1976-77 and then a Junior Fellow from 1977 to 1980. In September 1980 Witten was appointed professor of Physics at Princeton. He was awarded a MacArthur Fellowship in 1982 and remained as professor of Physics at Princeton until 1987 when he was appointed as a Professor in the School of Natural Sciences at the Institute for Advanced Study****, where .
Basically Witten is a mathematical physicist and he has a wealth of important publications which are properly in physics. However, as
Atiyah writes in:-
Speaking at the
American Mathematical Society Centennial Symposium in 1988, Witten explained the relation between geometry and theoretical physics:-
In his study of these areas of theoretical physics, Witten has achieved a level of mathematics which has led him to be awarded the highest honour that a mathematician can receive, namely a
Fields Medal. He received the medal at the International Congress of Mathematicians which was held in Kyoto, Japan in 1990. The Proceedings of the Congress contains two articles describing Witten's mathematical work which led to the award. The main tribute is the article by
Atiyah, but
Atiyah could not be in Kyoto to deliver the address so the address at the Congress was delivered by
Faddeev who quotes freely from
Atiyah.
The first major contribution which led to Witten's Fields Medal was his simpler proof of the positive mass conjecture which had led to a Fields Medal for
Yau in 1982. Gawedzki and Soulé describe this work by Witten, which appeared in 1981, in:-
One of Witten's subsequent works was a paper which
Atiyah singles out for special mention in [
3], namely
Supersymmetry and Morsetheory which appeared in the
Journal of differential geometry in 1984.
Atiyah writes that this paper is:-
Since this highly influential paper, the ideas in it have become of central importance in the study of differential geometry. Further new ideas of fundamental importance were introduced by Witten and described in:-
The authors sum up Witten's contributions to mathematics:-
**** Physicist Albert Einstein (1879-1955) was one of the Institute For Advanced Study's first Faculty members, serving from 1933 until his death in 1955, and he played a significant part in its early development. Einstein came to the United States to take up his appointment at the Institute at the invitation of Abraham Flexner, the Institute's founding Director.
See:
https://www.space.com/38916-pulsar-discovery-little-green-men.html
See:
https://allthatsinteresting.com/jocelyn-bell-burnell
See:
https://mathshistory.st-andrews.ac.uk/Biographies/Witten/
See:
https://www.ias.edu/about/mission-history
One must enjoy and be able, I think, to assemble varied trains of thought from the arcane bits of knowledge tossed to us from many sources and then to be able to assemble them in a coherent picture. Most important, however, is our ability to assemble these puzzle pieces into a coherent whole and then to explain this picture and its parts to all those who may inquire.
Hartmann352