The most detailed 3D map of the Milky Way ever includes nearly 2 billion stars

You can’t just drive a Google Maps machine around the Milky Way to draw it. It is fortunate, therefore, that the new information gathered by the European Space Agency’s Gaia Observatory offers the most detailed map of the galaxy. The map includes nearly 2 billion stars and helps the agency trace the history of the Milky Way.

“The new Gaia data promises to be a treasure trove for astronomers,” Jos de Bruijne, deputy scientist of ESA’s Gaia project, said in a statement.

The new information not only brings the total number of stars mapped over seven years to nearly 2 billion, but includes “a detailed census of over 300,000 stars in our cosmic neighborhood,” meaning stars within 326 light years of the sun. That number of 300,000 is believed to be 92% of the stars in that area. They are 100 times more stars than the old data, which dates back to 1991.

The new data provides measurements of position, motion and brightness that are more exact “orders of magnitude” than the old information. In fact, the data is so accurate that it revealed that the sun’s path is not a straight line, but a slightly curved one.

“Gaia has been staring at the sky for the past seven years, mapping the positions and speeds of stars,” said Caroline Harper, head of space science at the British Space Agency. “Thanks to its telescopes, today we have in our possession the most detailed 3D atlas with billions of stars ever assembled.”

The new map helps astronomers make predictions by imagining the movements of 40,000 stars 1.6 million years into the future, the agency said.

This week’s release is the first of two parts, with the second scheduled for 2022. Gaia’s “stellar census” began in 2013.