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3-D map of Milky Way shows 1.7 bn stars
Context
450 scientists from 20 countries were involved in the project to catalogue solar system objects
What has happened?
Europe’s Gaia satellite has produced a 3-D map of more than a billion stars in the Milky Way galaxy — complete with their distance from Earth, colour, and motion through space
GAIA
- Launched in 2013, Gaia started operating the following year, gathering data on 1,00,000 stars per minute — some 500 million measurements per day
- Its first map was published in September 2016, based on a year’s worth of observations of about 1.15 billion stars.
- An update, launched at the ILA international air and space show in Berlin, adds stars and provides more data on each one, from measurements taken over 22 months in 2014-2016.
Web of space rocks
Gaia also revealed the orbits of some 14,000 “solar system objects” — mapped as an intricate web of space rocks shooting around the sun. “It represents the most accurate survey ever of asteroids in the solar system
What now?
The full data will be published in a series of scientific papers in a special issue of the journal Astronomy & Astrophysics , laying the foundation for decades of further study



