Helge Stjernholm Kragh (born February 13, 1944) is a Danish historian of science who focuses on the development of 19th century physics, chemistry, and astronomy.
His published work includes biographies of  Paul Dirac, Julius Thomsen and Ludvig Lorenz, and The Oxford Handbook of the History of Modern Cosmology (2019) which he co-edited with Malcolm Longair. 
Kragh studied physics and chemistry at the
University of Copenhagen, graduating with a degree in 1970. He earned his Ph.D. in physics in 1981 at the University of Roskilde. He received a second doctorate, in philosophy, from the University of Aarhus in 2007. 
Kragh was an associate professor of history of science at
Cornell University from 1987 to 1989, a professor at the University of Oslo from 1995 to 1997, and a professor at Aarhus University in Denmark from 1997 to 2015. 
As of 2015 he retired, becoming emeritus professor at the
Niels Bohr Institute at the University of Copenhagen.
He is also a professor emeritus at the Centre for Science Studies of  Aarhus University. 
Kragh's areas of study are the
history of physics from the mid-19th century onward, the history of astronomy, the history of cosmology and the history of chemistry. He is known for his work on the history of the periodic system, early quantum atomic models, speculative cosmology and the northern lights. 
Honors and awards
Julius Thomsen: A Life in Chemistry and Beyond (2016) 
Ludvig Lorenz: A Nineteenth-Century Theoretical Physicist (2018) 
The Weight of the Vacuum (2014) 
Masters of the Universe (2015) 
Varying Gravity: Dirac's Legacy in Cosmology and Geophysics (2016) 
. Cambridge University Press 1990, 2005, Dirac - a scientific biography ISBN 0521017564
Quantum Generations: A History of Physics in the Twentieth Century. Princeton University Press, 1999
An introduction to the historiography of Science. Cambridge University Press, 1987
Matter and Spirit in the Universe - scientific and religious preludes to modern cosmology. 2004
Conceptions of Cosmos - From Myths to the Accelerating Universe: A History of Cosmology. Oxford University Press, 2006
Cosmology and Controversy - the historical development of two theories of the universe. Princeton University Press, 1999
The Moon that wasn't - the saga of Venus' spurious satellite. Birkhäuser, 2008
Den Sære Historie om Venus' Måne og Andre Naturvidenskabelige Fortællinger (The Strange History of Venus' Moon and Other Scientific Tales). Lindhardt og Ringhof, 2020, ISBN 9788711984000 
Entropy Creation - religious contexts of thermodynamics and cosmology. Ashgate, London 2008 with David Knight, eds.:
The Making of the Chemist: The Social History of Chemistry in Europe, 1789-1914. Cambridge University Press, 1998 with Peter C. Kjargaard & Henry Nielsen:
Science in Denmark - A Thousand-Year History. Aarhus University Press, 2009 with Malcolm Longair, eds.:
. Oxford University Press, 2019 The Oxford Handbook of the History of Modern Cosmology List of Kragh's publication at Aarhus University
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"Roy G. Neville Prize in Bibliography or Biography". Science History Institute . Retrieved 2018.
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"Abraham Pais Prize for History of Physics: Recipient Helge Kragh Niels Bohr Institute, University of Copenhagen". APS Physics . Retrieved 2020.
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"Academic staff". Centre for Science Studies Department of Mathematics Aarhus University . Retrieved 2020.
"Roy G. Neville Prize awarded to Helge Kragh". Niels Bohr Archive. September 14, 2019 . Retrieved 2020.
"Professor Emeritus Helge Kragh receives the prestigeous [sic] Abraham Pais Prize for History of Physics 2019". Niels Bohr Institute. May 29, 2019 . Retrieved 2020.
"Website of the ESHS" . Retrieved 2016.
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Rocha, Gustavo Rodrigues; Kragh, Helge (June 28, 2017). "Interview: Helge Kragh". Transversal: International Journal for the Historiography of Science (2): 233. doi: 10.24117/2526-2270.2017.i2.20 . Retrieved 2020.
"Helge Kragh". International Academy of the History of Science . Retrieved 2016.
"Members". Videnskabernes Selskab (The Royal Danish Academy of Sciences and Letters . Retrieved 2016.
^ Kragh, H.,
"Venus has no moon, yet this moon was discovered in the 1700s", ScienceNordic, June 3, 2020.