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Philosophical Transactions A from the Royal Society has published an edition titled “The redefined kelvin: progress and prospects”. It was edited by Graham Machin, Senior NPL Fellow.
This special edition follows a Royal Society meeting last year which celebrated the 200th anniversary of Lord Kelvin’s birth. The event brought together leading scientists in thermometry to explore the progress and future of the kelvin, five years after its historic redefinition in May 2019.
Thermometry continues to evolve through quantum technologies, photonic innovations and new traceability methods. Far from static, temperature measurement is a dynamic frontier of modern metrology.
The content of the papers in the focus edition demonstrate that thermometry is a very active field of metrology with multiple avenues of research to pursue and many decisions to be made concerning its future in the years to come.
NPL is highly active in this area including:
the development of acoustic thermometry to give direct traceability to the kelvin definition
the use of high temperature fixed points to simplify traceability to the kelvin to above 3000 K
the development of photon-based practical primary thermometry methods for in-situ traceable temperature measurement.
Graham Machin, Senior NPL Fellow, said: “As this special edition of Phil Trans A demonstrates, the kelvin redefinition in May 2019 kickstarted a global research endeavour that is reshaping thermometry practice.”
The collection comprises 15 open-access papers. It delves into these and related topics and is available here: https://royalsocietypublishing.org/rsta/issue/384/2312
Find out more about NPL’s work in Kelvin Measurements
Find out more about Graham Machin
19 Jan 2026