The European Space Agency’s billion-star surveyor, Gaia was launched into space on Thursday December 19, 2013, where it will embark on its mission to create a highly accurate 3D map of our galaxy. (See pp. 285, 290.)
By repeatedly observing a billion stars, with its billion-pixel video camera, the Gaia mission will allow astronomers to determine the origin and evolution of our galaxy whilst also testing gravity, mapping our inner Solar System, and uncovering tens of thousands of previously unseen objects, including asteroids in our Solar System, planets around nearby stars, and supernovae in other galaxies.
Gaia will map the stars from an orbit around the Sun, near a location some 1.5 million km beyond Earth’s orbit known as the L2 Lagrangian point. The spacecraft will spin slowly, sweeping its two telescopes across the entire sky and focusing their light simultaneously onto a single digital camera, the largest ever flown in space. The ‘eye’ of Gaia’s camera has the most sensitive set of light detectors ever assembled for a space mission.
Once Gaia starts routine operations, in late Spring 2014, astronomers will have the challenge of dealing with a flood of data. Even after being compressed by software, the data produced by the five-year mission will fill over 30,000 CD-ROMs!
The first Gaia science is expected to be discoveries of new sources – supernovae, extreme variable stars, and blazars.