Our Galaxy the Milky Method is made up of 100 billion stars. To really perceive its evolution we have to know precisely the place we stand on this mass of regularly transferring and altering celestial objects. To do that, astrometry, the science of measuring the place, distance and motion of stars round us, is nearly to take a large leap ahead with the launch of ESA’s new house telescope, Gaia. Gaia will make it doable to measure a billion stars of our Milky Method.
