GAIA SATELLITE CREATES RICHEST STAR MAP TO DATE
It’s time to remap the cosmos. ESA’s Gaia mission has produced the most detailed picture yet of the night sky, pinpointing the positions of nearly two billion stars.
Launched in December 2013, the Gaia space observatory is creating a three-dimensional map of the Milky Way. After an initial data release in 2016, this second phase covers the period from 25 July 2014 to 23 May 2016, and increases the number of surveyed stars from two million to almost 1.7 billion. It also ramps up the accuracy, with a maximum precision equivalent to someone on the Earth being able to spot a coin on the surface of the Moon.
As well as their positions, Gaia also measured the brightness and colour of most of the stars, the velocity across the sky of more than 1.3 billion of them, the surface temperatures of about 100 million and the effect of interstellar dust on 87 million. It also measured the positions of more than 14,000 asteroids in our Solar System and, much further afield, of half a million quasars – luminous galactic nuclei powered by supermassive black holes.
Astronomers are now eagerly sifting through all this new data. “The new Gaia data are so powerful that exciting results are just jumping at us,” said Antonella Vallenari, one of the lead scientists involved in the project. “It feels like we are inaugurating a new era of galactic archaeology.”
Of particular interest so far are measurements suggesting that fast-moving stars in the Milky Way’s outer ‘halo’ region consist of two separate stellar populations that were created through two different processes.
Further observations should shed more light on these stars, and help us piece together how our home galaxy came into being.
NASA’s Gaia space mission is giving us a much clearer picture of the Milky Way