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Space agency starts to unfold atlas of 1 billion stars in 3D

On its way to assembling the most detailed 3D map ever made of our Milky Way galaxy, European Space Agency’s Gaia probe has pinned down the precise position in the sky and the brightness of 1,142 million stars, astronomers working on the mission have said.

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Scientists hope that studying the stars will allow them to peer back in time, to when the galaxy was first forming.

To collect such data, Gaia will have to survey the same stars a couple of times, allowing the telescope to further analyze a star’s movement within its galaxy and relative to the Milky Way. This figure matches the count of total population of India.

At a press conference today in Madrid, Spain, ESA officials revealed examples of the work already undertaken by ESA’s Gaia satellite, as the first batch of data was released to the astronomical community.

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. So far, it has carried out many hundreds of billions of individual measurements, yielding 40 gigabytes of data every single day.

The agency says the “huge stellar census” will help resolve mysteries about the origin and evolution of the galaxy.

“With Gaia’s first data, it is now possible to measure the distances and motions of stars in about 400 clusters up to 4,800 light-years away”, said Antonella Vallenari, an astronomer at the Istituto Nazionale di Astrofisica.

ESA’s Gaia space observatory.

“Imagine taking pictures with Hubble, except of the full sky – that is effectively what you are seeing here,”said Anthony Brown, a researcher at Leiden University in the Netherlands and a member of Gaia’s data processing and analysis team”.

Scientists also expect Gaia to discover new planets and asteroids as well as distant supernovas and quasars, the hot and bright cores of galaxies.

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ESA admitted last month that the Gaia mission has faced a number of challenges since it launched in December 2013 including freezing optics, stray light on instruments and “micro-clanks”.

A display mock-up of Tiangong-2