MOONS will create an accurate 3D map of the centre of our galaxy. It captures infrared light from stars in that region — light that, unlike visible light, can pass through the dust shrouding the centre of the Milky Way. By decomposing it into its constituent colours it provides detailed information about the composition and velocity of these stars. It will also study distant galaxies whose light has been shifted to infrared wavelengths due to the expansion of the universe. 2/3