Gaia mapping the galaxy. 1.142 billion stars, all with their locations pinpointed. In general, is the Milky Way large or small in comparison to other galaxies? With more than 100 billion galaxies in observable universe (last number I heard) I feel rather insignificant when I estimate each star system to contain at least 5 planets each with who knows how many moons.
How does this map benefit astronomers? Will it need constant updating due to movement?