William Coblentz (1873-1962), US physicist and astronomer. Coblentz is best known for his work in infrared spectroscopy. He accepted a job at the National Bureau of Standards in 1905, remaining there for the rest of his career and heading the Radiometry Division for 40 years. Coblentz began studying elements and compounds before moving on to astrophysical research. His measurements of the absorption of infrared light by numerous substances lead to the ability to identify a molecule by this property. He also measured the infrared radiation from stars, planets and nebulae and measured the day and night time temperatures of Mars' surface.