Gaia's first sky map. Image: ESA/Gaia/DPAC

Europe Has Added 1.1 Billion Stars to Its Milky Way Map

European Space Agency releases first data from Gaia star mapping mission.

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Sep 14 2016, 1:20pm

Gaia's first sky map. Image: ESA/Gaia/DPAC

The European Space Agency (ESA) has released the first batch of data from its Gaia star mapping project—a mission that is currently on track to chart one billion stars in the Milky Way.

The space telescope launched in 2013 and its first data dump contains the precise celestial position and brightness of a mammoth 1,142 million stars. The release also contains the distances and movements for more than two million stars so far.

ESA's director of science Alvaro Giménez told a press conference held at the European Space Astronomy Centre in Spain on Wednesday morning that the data release features around 490 billion astrometric, 118 billion photometric, and 10 billion spectroscopic measurements.

"[The] Final survey will contain [around] 250,000 Solar System Objects, 1,000,000 galaxies, and 500,000 quasars," said Giménez.

Read More: The Gaia Satellite Will Map One Billion of the Milky Way's Stars

Those numbers are almost unimaginable, but ESA has used the data so far to form an "all-sky" view of the stars in our galaxy and neighbouring galaxies, based on Gaia's observations from July 2014 to September 2015.

An annotated version of Gaia's sky map. Image: ESA/Gaia/DPAC

The incredibly detailed map shows the density of stars seen by the Gaia satellite in each segment of the sky. However, as ESA explained, one billion stars is only one percent of our total galactic stellar population.

Only measuring 10 metres in diameter with its solar array deployed, the Gaia satellite uses two identical astro telescopes, blue and red photometers, and a radial velocity spectrometer, in conjunction with a one billion-pixel digital camera, to observe the one billion stars about 70 times each over the five-year mission. That's an average of 40 million observations a day. The objective is to create the most accurate 3D map yet of our galaxy, a map that will help scientists understand more about the origin and evolution of the Milky Way.

Artist's impression of Gaia mapping space. Image: ESA/ATG medialab; background: ESO/S. Brunier

Wednesday's data release is the first of four planned before the mission's finale in 2022.The trove of data has been opened to the public in the hope of any professional or budding astronomers being able to help extrapolate and analyse the information.

"Gaia is at the forefront of astrometry, charting the sky at precisions that have never been achieved before," said Giménez. "Today's release gives us a first impression of the extraordinary data that await us and that will revolutionise our understanding of how stars are distributed and move across our Galaxy."

Along with stars, the mission is expected to find hundreds of thousands of asteroids and comets within our own Solar System, seven thousand planets beyond our Solar System, and 20 thousand supernovae.

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