Gaia, the surveyor stars - France Info

European Gaia satellite is gone to join its distant orbit, more than a million kilometers from Earth. Gaia is a fundamental mission, expected by astronomers for over 20 years …

The Gaia satellite will survey the Milky Way, our galaxy. Photo ESA / S.Brunier

It is a huge task , unpublished, the European Gaia telescope will tackle, during five years on its distant orbit, a million and a half miles Earth … survey the entire sky, locate, identify and analyze one by one billion stars in the Milky Way galaxy. Measured with astonishing accuracy, distance, their movement in the Milky Way, their brilliance. A key, the most prodigious stellar catalog ever made, and most importantly, for the first time in the history of astronomy, a new vision of our galaxy, which is literally 3D view.

The GAIA Mission is an unprecedented scientific and technological rupture. We know almost everything on the inner machinery of the stars on the evolution of our galaxy. The search field of Gaia is infinite, almost. A billion stars, so. But not only. This space telescope probably detect a multitude of planets revolving around them. How? 10000? 20000? 30000? Kissing, with its giant virtual compass and the entire Galaxy, Gaia finally say, perhaps, what this mysterious dark matter, invisible and undetectable, and yet, bathes the entire Milky Way. And Gaia is measured by Albert Einstein. His dizzying precision enable it by following the light path of the stars in the Galaxy, to verify that the famous theory of general relativity, which governs the architecture of the universe, is true, or whether it should be exceeded by a new paradigm.

To complete this portrait majesty of the Galaxy , Gaia will deploy an unprecedented technological arsenal, too. A camera than a billion pixels, accurate enough to observe a hair on the head of a Parisian from the city of Rome! The continuous rotation of the satellite itself and its rotation around the sun during the year will allow Gaia to scan the sky in great circles successive offset relative to each other. In 4 months, Gaia will thus observed the entire sky before starting a new cycle. During its mission of 5 years, the telescope will operate approximately 100 observations per object. These multiple measurements allow a dynamic view of the stars observed, especially their movement in the Galaxy.

Gaia will transmit to Earth more than 100 GB of data daily. Processing and storage of such a large amount of information is a real challenge for computer scientists.
They are anxiously awaiting the results of the basic astronomical mission. These are probably two or three generations of astronomers who study the new image of the sky revealed by Gaia. Unprecedented image of the Milky Way, especially because, as we are immersed in the disk, it is impossible for us to have an overall picture. We see, for the first time, the spiral structure of the Milky Way, which wraps around the mysterious black hole.

And yet … If this figure we seems staggering 1 billion stars that represents only 1% of the actual content of the Galaxy. This sample there enough astronomers to tell the story of our vast star ship, or will he take their survey of the cosmos, for, one by one, observe its 200 billion stars?