Get deep on the space technology behind the ESU’s effort to map our neighborhood.
From the outside, galaxies appear as a mass of stars orbiting a dense center. But inside, they are more complex, with some groups of stars moving at different speeds or directions, in part because they originated from separate galaxies that collided billions of years ago. To untangle these disparate components of the Milky Way, the European Space Agency plans to launch Gaia in October. The two-ton craft will map a billion of our galaxy’s more than 100 billion stars, collecting data on all three dimensions of each star’s position as well as its speed, direction, color, and brightness. Knowing where stars are located and headed will help astronomers determine where they came from. And that could shed light on how our galaxy formed and evolved.