Gaia telescope's 'book of the heavens' takes shape
The Gaia observatory has released a second swathe of data as it assembles the most precise map of the sky. The European Space Agency telescope has now plotted the position and brightness of nearly 1.7 billion stars. It also has information on the distance, motion and colour of 1.3 billion of these objects. Gaia's "book of the heavens" will not be complete until the 2020s, but when it is the map will underpin astronomy for decades to come. It will be the reference frame used to plan all observations by other telescopes. It will also be integral to the operation of all spacecraft, which navigate by tracking stars. But beyond that, Gaia promises a raft of new discoveries about the properties and structure of our Milky Way Galaxy, its history and evolution into the future. It will enable scien...