Nigel Weiss
Authority on the processes behind sunspots and solar flares
NIGEL WEISS, who has died aged 83, was Professor of Mathematical Astrophysics at the University of Cambridge and distinguished for his work on magneto-convective eddies in the Sun through which magnetic fields rise from the solar interior to the solar surface and beyond – processes which lie behind the development of sunspots and solar flares.
In early work in 1966 he discovered the process of “flux expulsion” by which a conducting fluid undergoing rotation acts to expel the magnetic flux from the region of motion, a process now known to occur in the photosphere – the visible surface – of the Sun and similar stars.
Nigel Oscar Weiss was born in Johannesburg on December 16 1936. His father, Oscar, from a Jewish-hungarian family, was a geophysicist. His mother, Molly (née Kisch) was active in anti-apartheid circles in South Africa in the 1960s.
Nigel was educated at Hilton College, Natal, then at Rugby School and Clare College, Cambridge, where he read Natural Sciences and stayed on to take a PHD in 1961 on Variable Hydromagnetic Motions.
After a spell at Culham Laboratory in Oxfordshire, where he developed the mathematical techniques he used for his later flux expulsion work, he returned to Cambridge in 1965 as a lecturer in the Department of Applied Mathematics and Theoretical Physics, and as a fellow of Clare College. He became Professor of Mathematical Astrophysics in 1987 and an emeritus professor in 2004.
Weiss published extensively in the field of mathematical astrophysics, and wrote two important textbooks, Sunspots and Starspots (with John Thomas, 2008) and Magnetoconvection (with Mike Proctor, 2014).
He was elected a Fellow of the Royal Society in 1992 and from 2000 to 2002 served as president of the Royal Astronomical Society, whose Gold Medal he was awarded in 2007.
That year, however, he was infuriated by an article in the Toronto-based National Post which maintained that he had claimed that global warming could be accounted for by fluctuations in solar activity.
In 1999 Weiss had observed that there was mounting evidence that the earth’s climate responds to changing patterns of solar activity.
In 2006 in an interview with New Scientist he pointed out that while the late 20th century had been “a period of abnormally high solar activity”, such periods do not last long – “perhaps 50 to 100 years. Then you get a crash. It’s a boom-bust system, and I would expect a crash soon.”
The National Post article, which branded him a climate-change “denier”, led him to be vilified by environmental campaigners and scientists unfamiliar with his work.
But Weiss was nothing of the sort. Describing the claims as a “slanderous fabrication”, he pointed out that he had long believed that the warming is caused by greenhouse gases produced by human activity, and that “any temperature changes caused by variations in solar activity are small compared to the global warming that we are already experiencing, and very small compared to what will happen if we continue to burn fossil fuel at the present rate.”
Weiss subsequently took legal action against the newspaper, which published a full retraction and apology.
A man of many interests, including 20th-century opera and art, Weiss travelled widely, and in later life served as a member of the National Gallery scientific consultative group.
In 1968 he married Judy Martin, an expert on Anglo-norman literature, with whom he established an educational trust in Cape Town to provide school and university bursaries for young South Africans from the townships.
She survives him with their two daughters and a son.