ON WEDNESDAY, the Indian Space Research Organisation (ISRO) released an image from Chandrayaan-2 showing measurements from the Moon, carried out by the instrument Imaging Infrared Spectrometer (IIRS). Such studies make up a branch of physics called spectroscopy.
It is well known how visible light can disperse into rainbow colours after passing through a prism. The science of spectroscopy grew from there, and today it has extended to include the study of interaction between matter and electromagnetic radiation. IIRS is designed to measure light from the lunar surface in narrow spectral channels (bands). It has the ability to split and disperse reflected sunlight (and its emitted component) into these spectral bands.
From the reflected solar spectrum, scientists will look for signatures, including of minerals. This will help map the lunar surface composition, which in turn will help us understand the Moon’s origin and evolution in a geologic context.