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Behold a Billion Stars in This Stunning New Map of the Milky Way

Generated from Gaia satellite data, this stellar new map is the most complete chart of our galaxy to date

Produced by the European Space Agency’s Gaia satellite, this three-dimensional view of the Milky Way Galaxy is the first of its kind. (ESA)
smithsonian.com

If you think reading a two-dimensional road map is tough, the latest map of our galaxy may send you running. The European Space Agency just released a three-dimensional map of the Milky Way galaxy that charts the location of over a billion celestial objects.

The billion-star catalog precisely details the location and brightness of 1.142 billion stars in the Milky Way, and is the most complete map of the galaxy ever created. For stargazers, it is an unrivaled accomplishment.

The new 3D map reflects the first 14 months of data collected by ESA’s Gaia satellite. Launched on December 19, 2013, Gaia orbits the Sun-Earth second Lagrange point (L2), which lies beyond the moon’s orbit, approximately one million miles from Earth. The map is the mission’s first publically available data, which was collected through September of 2015.

“Today’s release gives us a first impression of the extraordinary data that await us and that will revolutionize our understanding of how stars are distributed and move across our Galaxy,” Alvaro Giménez, ESA’s director, announced in a statement.

As impressive as the 3D catalog is, it is only the first step in Gaia’s five-year-long mission. As Maddie Stone writes for Gizmodo, the satellite wasn’t constructed to just chart the locations of stars, but was designed to track their movement through the celestial landscape.

Over the course of its mission, Gaia will observe each of its billion-plus targets about 70 times. And the resulting series of observations will allow astronomers to track the changes in brightness and position of the stars over several years—critical information to understand the properties and history of the Milky Way. Gaia’s data could even help scientists calculate how fast the universe has expanded since the Big Bang.

Gaia’s data collection is driven by a billion-pixel camera, which provides astrophysical information for each star with enough precision to quantify the early formation, and subsequent dynamical, chemical and star formation evolution of the Milky Way Galaxy.

The galactic catalog represents a major improvement over the Hipparcos Catalogue, which was the definitive astronomical reference guide until now. Launched in 1989, Hipparcos documented just over 100,000 stars, and charted another 2 million with less certainty.

The data released from Gaia's first scan is not uniformly complete, though the fresh data is already illuminating the cosmos. The first map is only based on a small portion of the sky, but as described by ESA, it is already possible to measure the distances and motions of stars in clusters up to 4,800 light-years away. The Large and Small Magellanic Clouds, two dwarf galaxies in one portion of the sky that was repeatedly scanned during the first months of observations, are visible as two bright spots in the lower right portion of the map.

The European Space Agency believes that Gaia’s first data dump shows that it is on track to achieve its ultimate goal of charting the positions, distances, and motions of one billion stars—nearly one percent of the stars in the Milky Way.

Anthony Brown, chair of the Gaia data processing team, explains the significance in the ESA press release: “Gaia’s present and future data will revolutionise all areas of astronomy, allowing us to investigate our place in the Universe, from our local neighborhood, the Solar System, to Galactic and even grander, cosmological scales.”

About Aaron Sidder

Aaron Sidder is an ecologist and a freelance science writer based in Denver, CO. He is a former AAAS Mass Media Fellow whose work has appeared National Geographic and Eos.

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