Wednesday was the day astronomers said goodbye to the old Milky Way they had known and loved and hello to a new view of our home galaxy.
A European Space Agency mission called Gaia just released a long-awaited treasure trove of data: precise measurements of 1.7 billion stars.
It's unprecedented for scientists to know the exact brightness, distances, motions and colors of more than a billion stars. The information will yield the best three-dimensional map of our galaxy ever.
"This is a very big deal. I've been working on trying to understand the Milky Way and the formation of the Milky Way for a large fraction of my scientific career, and the amount of information this is revealing in some sense is thousands or even hundreds of thousands of times larger than any amount of information we've had previously," said David Hogg, an astrophysicist at New York University and the Flatiron Institute. "We're really talking about an immense change to our knowledge about the Milky Way."
The Gaia spacecraft launched in 2013 and is orbiting our sun, about a million miles away from Earth. Although it has surveyed a huge number of stars, Gaia is charting only about 1 percent of what is out there. The Milky Way contains around 100 billion stars