Development & Alumni Relations Office 


Dr William Buchanan Somerville, BSc, PhD (died 22 January 2021, aged 84)


Obituary submitted by Bill’s wife, Jackie.


Bill Somerville obtained a double first in Physics and Mathematics from Queen’s University Belfast. As a postgraduate student in the Department of Applied Mathematics at Queen’s, his postgraduate project was carried out under the supervision of Professor David Bates and his PhD thesis was entitled “Some Three-Particle Systems in Quantum Mechanics”. The degree of PhD was awarded to Bill by Queen’s in 1961. 


He moved to University College London (UCL) in 1960 to take up a Research Fellowship in Physics and, apart from a Research Fellowship in Astronomy at Princeton University in the USA, 1962-1963, UCL became his academic home until and after his retirement.


In the years following his PhD he wrote some papers addressing questions that arose in current debates in astronomy: how does starlight emerge through the outer layers of cool stars? In these regions, molecular hydrogen and electrons are present. These electrons can stick to the molecules forming a negative ion. Astronomers asked: could this ion absorb some of the starlight emerging from cool stars? Bill showed that these negative molecular ions would indeed affect the spectrum of starlight from cool stars, and he used the powerful methods he had developed in his thesis work to show that this could be a significant effect.


After this, his interests were turning gradually toward astronomy. While at Princeton, he wrote with others a study of molecular hydrogen in astronomy. The molecule had not at that time been discovered in space, but Bill’s article was helpful to those astronomers who were trying to understand how the molecule would be formed and destroyed in interstellar space. In fact, the presence of the molecule in interstellar space was established a year or two after Bill’s paper was published.  


Eventually, by the late 1970s, Bill had made the complete transition from being a theoretician with an interest in problems arising in astronomy to becoming an observational astronomer. He used a wide range of astronomical telescopes, located around the globe (he enjoyed travelling) and also in space (the famous Hubble Space Telescope) to investigate the properties of the gas and dust in interstellar space. This interstellar material is important in astronomy because it is the reservoir of matter from which new stars are formed. Bill was interested in many of the unsolved problems arising from the study of the material in interstellar space, many of which still remain unsolved today. He designed a number of observing projects to try and provide the answers.


In addition to his contributions to scientific research, Bill was an indispensable member of the department at UCL for his work as a teacher of physics and astronomy. There are a number of professional astronomers who owe their start to Bill’s encouragement to study astronomy. His commitment to teaching and to the needs of his students was widely recognised. He was particularly committed to the UCL Certificate of Higher Education in Astronomy, a 2-year part-time evening course open to everyone interested in learning about astronomy, with practical work at the UCL Observatory, and had an excellent rapport with students on the course, and its graduates.


Bill had a quiet Christian faith which was reflected in his commitment to the congregation at Bloomsbury Baptist Church, London where he offered his time and energy to serve in various undertakings of the church.


Bill made great contributions during his life and will be greatly missed. He had a fine mind and gentle but firm personality.


He is survived by Jackie, his wife of twenty-four years.


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