24 September

1906: On 24 September 1906, Pol Swings was born.

Swings was a Belgian astrophysicist who made spectroscopic studies to identify the elements and structure of stars and comets. He discovered the first interstellar molecule, the CH radical in 1937.

In comet atmospheres he studied the 'Swings bands' - carbon emission lines. He also identified a 'Swings effect' - a fluorescence which is partly due to solar radiation.

Swings also made spectroscopic studies of interstellar space and investigated stellar rotation, as well as nebulae, novae and variable stars.