ESA's Gaia on the Way to Map a Billion Stars

European Space Agency's Gaia observatory- was launched from Kourou, French Guiana at 06:12 local time (09:12 GMT), the agency said Thursday.

The 740m-euro ($1.02-billion)-mission Gaia is given the task of accurately mapping over a billion stars. The data obtained from the observatory will answer many questions about the evolution of our galaxy- The Milky Way.

"Gaia promises to build on the legacy of ESA's first star-mapping mission, Hipparcos, launched in 1989, to reveal the history of the galaxy in which we live," said Jean-Jacques Dordain, ESA's Director General.

The satellite is now en-route to an observing station some 1.5 million km. It will take about a month to complete the journey, BBC reported.

Gaia will observe each of the billion stars about 70 times during five years. It will measure the position, temperature and chemical composition of each star. The observatory will also scan the sky repeatedly to look for hidden planets and asteroids. After five years, the data collected by the multi-billion telescope is expected to be about 1 Petabyte or 1 million Gigabytes, which is about as much as 200 000 DVD's worth of data.

"Where Hipparcos catalogued 120 000 stars, Gaia will survey almost 10 000 times as many and at roughly 40 times higher precision," said Timo Prusti, ESA's Gaia project scientist, according to a news release."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."

Creating a 3D Map of the sky

The satellite has two telescopes focusing light on a huge, one billion-pixel camera detector, BBC reported. Gaia will use its super sensitive equipment to hunt for stars.

Gaia is expected to nail down the co-ordinates of the brightest stars in the galaxy to an error of about seven micro-arcseconds. "This angle is equivalent to the size of a euro coin on the Moon as seen from Earth," Prof Alvaro Gimenez, Esa's director of science told BBC.

By calculating the distance, speed and motion of millions of galaxies, the observatory will help scientists create a 3D map of our home-galaxy, The Associated Press reported.