The precise locations of more than a billion stars have been revealed in the largest and most accurate star map ever made.
And nearly half of them are new to astronomers, having never been recorded before.
"In the future we will realise that this was a big day for our understanding of the universe," says Paolo Tanga of the Côte d'Azur Observatory.
"When people will talk about the formation of our solar system, its environment and the nearby stars, our understanding will come thanks to Gaia."
The bright objects in the lower right of the image are the Large and Small Magellanic Clouds - dwarf galaxies which orbit the Milky Way.
Annotated version of the Gaia map - click for a larger version (ESA)
Andromeda, about twice the size as our galaxy, can be seen in the lower left - as can its own satellite galaxy, Triangulum.
The European Space Agency's Gaia satellite, launched 2013, sits 1.5 million kilometres away from the planet in a spot where gravity is balanced between the sun and Earth, keeping it in place. It looks at around 70 million objects and sends back 40GB of data every day.
Astronomers say it has already forever changed their understanding of the Milky Way.
"It's a 1000 times expansion of what we can see today in the stars," says Dr Tanga. "It's a completely different sky."
But still one, even with this map, that remains largely unknown - the billion-star map still only represents about 1 percent of all the stars in the Milky Way.
The next step is for Gaia to produce a "six-dimensional" map of the galaxy.
"Gaia is not only going to provide the position of the stars in the sky, but also the motion."
This will help astronomers better understand how the galaxy formed.