The glittering expanse of the Universe might have become a little easier to comprehend. The European Space Agency (ESA) has released a 3D map of over a billion (precisely 1.142 billion) stars in the Milky Way galaxy, thanks to scans of the sky from its satellite Gaia, taken over 1,000 days.
The map is a technological marvel. The annotated map details “globular clusters” and “open clusters”, which are groups of stars that are bound together by gravity. The bright areas on the map highlight dense clusters of stars. The bright disc that runs through the centre of the map is where the majority of the Milky Way’s stars lie; the darker patches are where Gaia didn’t pick up as many, because of clouds of inter-stellar gas and dust that absorb starlight. According to the ESA, the expanse measures “1,00,000 light-years across and about 1,000 light-years thick”.
Gaia’s work isn’t over. It’s on a five-year mission to survey the stars in the Milky Way and its galactic neighbours. The ESA explains that “transforming the raw information into useful and reliable stellar positions to a level of accuracy never possible before is an extremely complex procedure”. The process has been carried out by a pan-European collaboration of about 450 scientists and software engineers. The ultimate goal is to build the most precise 3D map of the positions, distances, and motions of a billion stars—that’s just one per cent of the Milky Way’s stellar content.