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In memoriam F. G. Houtermans
IN MEMORIAM
On 1 M a r c h 1966, F r i e d r i c h G e o r g H o u t e r ma ns, P r o f e s s o r of P h y s i c s at the U n i v e r s i t y of B e r n e , died at the age of 63. He was one of the p i o n e e r s of n u c l e a r e a r t h s c i e n c e and by his work and through his i n s p i r a t i o n and fine p o w e r s of p e r s u a s i o n he has g r e a t l y c o n tr i b u te d to the d e v e l o p m e n t of this new field, e s p e c i a l l y on the E u r o p e a n continent. H o u t e r m a n s was b o r n on 22 J a n u a r y 1903 in Dantzig. He g r e w up in Vienna and his i n t e l l e c tual f l ex i b i l i t y and wit, c u l t u r e and c o s m o p o l i t a n attitude b o r e the m a r k of that old city. He studied p h y s i c s at G~ttingen U n i v e r s i t y and w r o t e his d o c t o r ' s t h e s i s on the r e s o n a n c e f l u o r e s c e n c e of m e r c u r y u n d er J a m e s F r a n c k . Since at that t i m e G0ttingen was one of the g r e a t c e n t r e s of p h y s i c s , H o u t e r m a n s could and did p a r t i c i p a t e a c t i v e l y in the group of young m e n who r e v o l u tionized the foundations of this discipline. A f t e r his t h e s i s in a t o m i c p h y s i c s , he t u r n e d to the e m e r g i n g field of n u c l e a r p h y s i c s and with
F . G. H O U T E R M A N S
G e o r g e Gamow published the f i r s t c a l c u l a t i o n on the r a d i i of heavy nuclei. In t h e i r f a m o u s p a p e r ~Zur F r a g e d e r Aufb a u m 0 g l i c h k e i t e n d e r K e r n e in S t e r n e n ~, R. d'E. Atkinson and F . G . H o u t e r m a n s f o r m u l a t e d the t h e o r y of t h e r m o n u c l e a r r e a c t i o n s , thus p r o viding a m i l e s t o n e in our u n d e r s t a n d i n g of the e n e r g y s o u r c e of s t a r s . The b a s i c concept of that p a p e r has found application in the t h e o r y of m a n made t h e r m o n u c l e a r r e a c t i o n s , as well as in the m o s t advanced t h e o r i e s of e l e m e n t s y n t h e s i s in s t a r s . H o u t e r m a n s h e r e d e m o n s t r a t e d f o r the f i r s t t i m e his s p e c i f i c talent of b r i n g i n g t o g e t h e r d i f f e r e n t b r a n c h e s of s c i e n c e and, in p a r t i c u l a r , of applying the new c o n c e p t s and methods of a t o m i c and n u c l e a r p h y s i c s to o t h e r d i s c i p l i n e s . D u r i n g the 1930's and e a r l y 1940's, H o u t e r m a n s w o r k e d in v a r i o u s B r i t i s h , R u s s i a n and G e r m a n l a b o r a t o r i e s and in spite of t i m e s full of h a r d s h i p f o r h i m he made s o m e v e r y i m p o r tant c o n t r i b u t i o n s to n u c l e a r , neutron and r e a c -
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F.G. HOUTERMANS
t o r p h y s i c s . A f t e r the w a r , he went back to Gt~ttingen w h e r e his i n t e r e s t in the e a r t h s c i e n c e s was a r o u s e d by N i e r ' s e a r l y work on lead isot op e v a r i a t i o n s in nature. S i m u l t a n e o u s l y and independently of A. H o l m e s , he e s t i m a t e d the age of the c r u s t of the e a r t h f r o m t h e s e data. In this work, H o u t e r m a n s c o n c e i v e d the a - H - p l o t which has s i n c e p r o v i d e d the b a s i s f o r the i n t e r p r e t a tion of lead isotopic abundance v a r i a t i o n s and a n o m a l i e s . A l r e a d y at that t i m e , he saw that m e t e o r i t i c lead would be the key to a m o r e p r o found u n d e r s t a n d i n g of the t e r r e s t r i a l lead i s o tope v a r i a t i o n s . As in the i n s t a n c e of the a - f i - d i a g r a m , H o u t e r m a n s always a t t e m p t e d to f o r m u l a t e s c i e n t i f i c laws and r e l a t i o n s h i p s in a f o r m easy to p e r c e i v e , avoiding f o r m a l i s m . S i m i l a r l y , he had a knack f o r c o n c e i v i n g e x p e r i m e n t a l i d e a s which w e r e s t a r t l i n g in t h e i r s i m p l i c i t y . His d i s c o v e r y of the l e a d - 2 1 0 age d e t e r m i n a t i o n method is an example. In 1952 he c a m e to the U n i v e r s i t y of B e r n e as D i r e c t o r of the P h y s i k a l i s c h e s Institut. Now, at last, he could r e a l l y develop the type of s c i e n c e which had f a s c i n a t e d him for a n u m b e r of y e a r s , the application of the m e t h o d s and laws of n u c l e a r p h y s i c s to f u n d a m e n ta l p r o b l e m s of the e a r t h s c i e n c e s , to the o r i g i n of the s o l a r
system and to cosmology in general. He created a research centre of nuclear earth science and contributed many ideas and added new methods to this field. By his unconventional way of leading the institute and by his dedication, he promoted an intellectual atmosphere which inspired his students and colleagues alike. His power of persuasion has convinced scientists of many different fields of the possibilities which have been opened by applying nuclear methods to their disciplines. F.G. Houtermans had an open and creative mind for really interesting problems in general, regardless whether they were of scientific, educational or human nature. We shall remember him for his stimulating spirit, his unique and completely unconventional personality, his absolute devotion to science and the constant stream of ideas, sometimes resulting in heated discussions. He was a great storyteller and very often he chose to explain a scientific principle in the form of a parable, and as long as his friends and students are around, these stories and parables will be remembered.
J. Geiss H. Oeschger
On 1 M a r c h 1966, F r i e d r i c h G e o r g H o u t e r ma ns, P r o f e s s o r of P h y s i c s at the U n i v e r s i t y of B e r n e , died at the age of 63. He was one of the p i o n e e r s of n u c l e a r e a r t h s c i e n c e and by his work and through his i n s p i r a t i o n and fine p o w e r s of p e r s u a s i o n he has g r e a t l y c o n tr i b u te d to the d e v e l o p m e n t of this new field, e s p e c i a l l y on the E u r o p e a n continent. H o u t e r m a n s was b o r n on 22 J a n u a r y 1903 in Dantzig. He g r e w up in Vienna and his i n t e l l e c tual f l ex i b i l i t y and wit, c u l t u r e and c o s m o p o l i t a n attitude b o r e the m a r k of that old city. He studied p h y s i c s at G~ttingen U n i v e r s i t y and w r o t e his d o c t o r ' s t h e s i s on the r e s o n a n c e f l u o r e s c e n c e of m e r c u r y u n d er J a m e s F r a n c k . Since at that t i m e G0ttingen was one of the g r e a t c e n t r e s of p h y s i c s , H o u t e r m a n s could and did p a r t i c i p a t e a c t i v e l y in the group of young m e n who r e v o l u tionized the foundations of this discipline. A f t e r his t h e s i s in a t o m i c p h y s i c s , he t u r n e d to the e m e r g i n g field of n u c l e a r p h y s i c s and with
F . G. H O U T E R M A N S
G e o r g e Gamow published the f i r s t c a l c u l a t i o n on the r a d i i of heavy nuclei. In t h e i r f a m o u s p a p e r ~Zur F r a g e d e r Aufb a u m 0 g l i c h k e i t e n d e r K e r n e in S t e r n e n ~, R. d'E. Atkinson and F . G . H o u t e r m a n s f o r m u l a t e d the t h e o r y of t h e r m o n u c l e a r r e a c t i o n s , thus p r o viding a m i l e s t o n e in our u n d e r s t a n d i n g of the e n e r g y s o u r c e of s t a r s . The b a s i c concept of that p a p e r has found application in the t h e o r y of m a n made t h e r m o n u c l e a r r e a c t i o n s , as well as in the m o s t advanced t h e o r i e s of e l e m e n t s y n t h e s i s in s t a r s . H o u t e r m a n s h e r e d e m o n s t r a t e d f o r the f i r s t t i m e his s p e c i f i c talent of b r i n g i n g t o g e t h e r d i f f e r e n t b r a n c h e s of s c i e n c e and, in p a r t i c u l a r , of applying the new c o n c e p t s and methods of a t o m i c and n u c l e a r p h y s i c s to o t h e r d i s c i p l i n e s . D u r i n g the 1930's and e a r l y 1940's, H o u t e r m a n s w o r k e d in v a r i o u s B r i t i s h , R u s s i a n and G e r m a n l a b o r a t o r i e s and in spite of t i m e s full of h a r d s h i p f o r h i m he made s o m e v e r y i m p o r tant c o n t r i b u t i o n s to n u c l e a r , neutron and r e a c -
138
F.G. HOUTERMANS
t o r p h y s i c s . A f t e r the w a r , he went back to Gt~ttingen w h e r e his i n t e r e s t in the e a r t h s c i e n c e s was a r o u s e d by N i e r ' s e a r l y work on lead isot op e v a r i a t i o n s in nature. S i m u l t a n e o u s l y and independently of A. H o l m e s , he e s t i m a t e d the age of the c r u s t of the e a r t h f r o m t h e s e data. In this work, H o u t e r m a n s c o n c e i v e d the a - H - p l o t which has s i n c e p r o v i d e d the b a s i s f o r the i n t e r p r e t a tion of lead isotopic abundance v a r i a t i o n s and a n o m a l i e s . A l r e a d y at that t i m e , he saw that m e t e o r i t i c lead would be the key to a m o r e p r o found u n d e r s t a n d i n g of the t e r r e s t r i a l lead i s o tope v a r i a t i o n s . As in the i n s t a n c e of the a - f i - d i a g r a m , H o u t e r m a n s always a t t e m p t e d to f o r m u l a t e s c i e n t i f i c laws and r e l a t i o n s h i p s in a f o r m easy to p e r c e i v e , avoiding f o r m a l i s m . S i m i l a r l y , he had a knack f o r c o n c e i v i n g e x p e r i m e n t a l i d e a s which w e r e s t a r t l i n g in t h e i r s i m p l i c i t y . His d i s c o v e r y of the l e a d - 2 1 0 age d e t e r m i n a t i o n method is an example. In 1952 he c a m e to the U n i v e r s i t y of B e r n e as D i r e c t o r of the P h y s i k a l i s c h e s Institut. Now, at last, he could r e a l l y develop the type of s c i e n c e which had f a s c i n a t e d him for a n u m b e r of y e a r s , the application of the m e t h o d s and laws of n u c l e a r p h y s i c s to f u n d a m e n ta l p r o b l e m s of the e a r t h s c i e n c e s , to the o r i g i n of the s o l a r
system and to cosmology in general. He created a research centre of nuclear earth science and contributed many ideas and added new methods to this field. By his unconventional way of leading the institute and by his dedication, he promoted an intellectual atmosphere which inspired his students and colleagues alike. His power of persuasion has convinced scientists of many different fields of the possibilities which have been opened by applying nuclear methods to their disciplines. F.G. Houtermans had an open and creative mind for really interesting problems in general, regardless whether they were of scientific, educational or human nature. We shall remember him for his stimulating spirit, his unique and completely unconventional personality, his absolute devotion to science and the constant stream of ideas, sometimes resulting in heated discussions. He was a great storyteller and very often he chose to explain a scientific principle in the form of a parable, and as long as his friends and students are around, these stories and parables will be remembered.
J. Geiss H. Oeschger