Most detailed 3D map ever of Milky Way includes nearly 2 billion stars

The new data it offers provides measurements that are "orders of magnitude" more exact than prior information, scientists say.

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CNET editor Gael Fashingbauer Cooper, a journalist and pop-culture junkie, is co-author of "Whatever Happened to Pudding Pops? The Lost Toys, Tastes and Trends of the '70s and '80s," as well as "The Totally Sweet '90s." She's been a journalist since 1989, working at Mpls.St.Paul Magazine, Twin Cities Sidewalk, the Minneapolis Star Tribune, and NBC News Digital. She's Gen X in birthdate, word and deed. If Marathon candy bars ever come back, she'll be first in line.
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Gael Cooper
2 min read

The map measures stars closer to the edge of the Milky Way than ever before.


You can't just drive a Google Maps car around the Milky Way to diagram it. It's fortunate, then, that new information gathered by the European Space Agency's Gaia observatory offers the most detailed map yet of the galaxy. The map includes almost 2 billion stars and it helps the agency trace the Milky Way's history.

"The new Gaia data promise to be a treasure trove for astronomers," Jos de Bruijne, ESA's Gaia deputy project scientist, said in a statement.

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

The new data provides location, motion and brightness measurements that are "orders of magnitude" more exact than the old information. In fact, the data is so precise it's revealed that the sun's path isn't a straight line, but slightly curved.

"Gaia has been staring at the heavens for the past seven years, mapping the positions and velocities of stars," said Caroline Harper, head of space science at the UK Space Agency. "Thanks to its telescopes, we have in our possession today the most detailed billion-star 3D atlas ever assembled."

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

This week's release is the first of two parts, with the second expected in 2022. Gaia's "stellar census" began in 2013.

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