 Moving out to the Milky Way, we have an update on Gaia, the spacecraft that's recording information on over a billion stars. In 2016, Gaia produced the most detailed 3D map ever made of our Milky Way galaxy. It has pinned down the brightness and precise position on the sky of 1 billion 142 million stars. This past year's data release also includes the distance and motion across the sky of more than 2 million stars. This map shows the density of stars observed by Gaia in each portion of the sky. Brighter regions indicate denser concentrations of stars, while darker regions correspond to patches of the sky where fewer stars are observed. The dark lines are artifacts of the collection process. They will disappear once more data has been collected. The image clearly shows the structure of our galaxy with its core, disc, and halo. Darker regions across the galactic plane correspond to dense clouds of interstellar gas and dust that absorb starlight along the line of sight. As Gaia rotates and captures the light from stars around us, it also sees orbiting and local group galaxies. Several are visible in this image. You may remember from our How Far Away Is It segment on globular clusters that they are the backbone of our galaxy. A significant number of them are visible here. You can see them spread throughout the central part of the halo. Open clusters are also visible. Note how they tend to occupy volumes closer to the galactic plane and are further out from the core than the globular clusters.