Gaia gathers knowledge concerning the composition of far-off stars utilizing a way referred to as spectroscopy, with its instrument referred to as the Radial Velocity Spectrometer (by way of ESA). Spectroscopy works by breaking down mild into completely different wavelengths, just like the rainbow of colours you see when mild passes by a prism. By breaking down mild on this method, sensors on the spacecraft can detect which wavelengths of sunshine are absent. These correspond to sure components, which soak up mild at explicit wavelengths. Because of this, you’ll be able to inform what a distant star consists of by trying on the mild it offers off (by way of Gaia).

That is what has allowed Gaia to create a colored-coded representation of the celebs within the Milky Manner, displaying what proportion of heavy components every star incorporates. This data — which astronomers name a star’s metallicity — is beneficial to know as a result of youthful stars are likely to have larger metallicity. That is as a result of older stars are made up of less complicated components like hydrogen and helium, and so they create heavier components by nuclear fusion. When these stars die, they launch these heavier components which then turn into newer, youthful stars.

So by taking a look at which areas have stars with larger or decrease metallicity, researchers can see how our galaxy has developed by time. “Subsequently, a star’s chemical composition is a bit like its DNA, giving us essential details about its origin,” ESA writes. “With Gaia, we see that some stars in our galaxy are made from primordial materials, whereas others like our Solar are made from matter enriched by earlier generations of stars. Stars nearer to the middle and aircraft of our galaxy are richer in metals than stars at bigger distances.”