Science & TechnologyGreek → English
Photometry
/foʊˈtɒmɪtri/noun
The measurement of the brightness of light, especially of stars.
The Greek roots
φῶς
phôs
light
μέτρον
métron
measure
Literally: “light measuring”
The story of the word
Lambert published Photometria in 1760 and showed how far you could get with no instrument but an eye judging when two surfaces looked equally bright. The technique carried astronomy past mere position: comparing brightness over time is how variable stars were sorted out, and how transiting planets are found now, from a dip of a fraction of one percent. Photographic plates and then silicon replaced the eye, and the word stayed.
- How it travelled
- Ancient Greek → Modern Latin → English
- First recorded
- 18th century
Same family
photographphotonsymmetrygeometry
In a sentence
Their photometry of the cluster took four clear nights.
Amateur photometry is good enough to confirm many exoplanet candidates.