Gaia Finally Launched, on Its Way to Map One Billion Stars

December 27, 2013

ESA's Gaia space observer liftoff.

ESA's Gaia space observer liftoff. Credit: ESA–S. Corvaja, 2013

After a troublesome pre-launch period, Gaia space telescope is finally on its way to Earth's orbit. Gaia is European Space Agency's (ESA) spacecraft set out to observe one billion stars in order to create a 3D map of our galaxy as well as to give insight into our galaxy's past and future.

After a postponed launch caused by parts replacement, Gaia space observer has been launched on December 19 from French Guiana and is well on its way to L2 Lagrangian point, 1.5 million kilometers from Earth. When it reaches its destination, its systems and instruments will be activated at which point its five year mission will begin.

Gaia's main mission is mapping one billion stars in Milky Way Galaxy, measuring their brightness, temperature and chemical composition. Also, as Gaia orbits the Sun, it will be in position to measure their distance as described in this picture:

The closer the star, the more it "moves" between two measurements. We can calculate its distance because we know the Sun-Earth distance and can measure parallax angle by how much the star changes its apparent position during six months.

Because of the length of Gaia's mission, not only will these measurements be repeated year after year to yield more accurate results, it will also be possible to observe long-term, real movements of stars across the sky during the five year period. This will enable us to know more about both our galaxy's past as well as the future by providing enough data to recreate stars' past movement and their current trajectory.

"Along with tens of thousands of other celestial and planetary objects, this vast treasure trove will give us a new view of our cosmic neighbourhood and its history, allowing us to explore the fundamental properties of our Solar System and the Milky Way, and our place in the wider Universe," says Timo Prusti, ESA’s Gaia project scientist.

Speaking of data collected, after five years worth of taking pictures, there will be more than 1 Petabyte data stored for us to analyze in years to come.

Additional tasks of Gaia space observer are discovery of asteroids in our system, planets around other stars by detecting wobbles in the positions of some stars caused by their planet's gravitational pull. Furthermore, it will observe dying stars and supernovae when they finally reach their end.

"After years of hard work and determination of everyone involved in the mission, we are delighted to see our Gaia discovery machine on the road to L2, where we will continue the noble European tradition of star charting to decipher the history of the Milky Way," says Giuseppe Sarri, ESA’s Gaia project manager.

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