 The Gaia mission is a space telescope that's run by the European Space Agency. It was launched to space back in 2013, and its goal is to help us better understand our galaxy, the Milky Way. This is an artist's impression of what our galaxy looks like. It's a spiral galaxy, which means it's flat and it's round, and our sun is just one of over 100 billion stars that make up the Milky Way. Each of those stars have their own individual motions, but most of them are orbiting the Milky Way's center. The sun, for example, is located about two-thirds of the way out from the center, and it takes about 250 million years to go around once. Since its launch, Gaia's mission has been to track the positions, velocities, and measure the colors for as many stars as possible. And just recently, the ESA announced a second data release, a catalog of information on 1.7 billion stars. Yes, that's billion with a B. With such an incredible amount of data, astronomers will be able to look for a number of interesting things. For example, with three-dimensional motions of so many stars, we'll be able to turn the clock backwards and see how the Milky Way has changed over time. And the color information allows scientists to easily distinguish between different kinds of stars, like red giants or white dwarfs. As an added bonus, while watching the sky for the last few years, Gaia has gathered data on 14,000 known asteroids, allowing a more high-precision calculation of their orbits. The Gaia data set is a big deal because it allows us to study the bulk properties of the galaxy in a way never before done. The potential for incredible discovery is very high, as astronomers will be studying this data for the next few years.