Gaia mission has obtained new details about two billion stars

A large portion of the Milky Way is about to become much less mysterious today as scientists release the most detailed data that has ever been obtained for more than two billion stars. The European Space Agency’s Gaia space observatory has measured stellar positions, colors, brightness, and movement,  including the first optical measurement of the acceleration of the solar system. 

Gaia was launched in 2013 to orbit around the so-called Lagrange 2 (L2) point, located 1.5 million kilometers behind the Earth in the direction away from the Sun. At L2, the gravitational forces between the Earth and the Sun are balanced, which keeps the spacecraft stable. Here, Gaia also has unobstructed views of the sky.

The primary goal of Gaia is to continuously scan the sky, allowing for astronomers to measure changes in the positions of stars over time. Calculating these tiny shifts makes it possible to calculate the distance between the stars. 

Two previous data releases from Gaia revealed the positions of 1.6 billion stars. The latest release will push this total up to just under 2 billion stars, and their positions are significantly more clear this time around.

Gaia also monitors how fast stars are moving toward or away from the Sun, assesses their chemical composition, and tracks their brightness and position. 

In addition, the spacecraft collects data on the two largest companion galaxies to the Milky Way, the Small and Large Magellanic Clouds. 

“Gaia is measuring the distances of hundreds of millions of objects that are many thousands of light years away, at an accuracy equivalent to measuring the thickness of hair at a distance of more than 2,000 kilometers. These data are one of the backbones of astrophysics, allowing us to forensically analyze our stellar neighborhood, and tackle crucial questions about the origin and future of our Galaxy.”

The data, as well as early scientific discoveries, will be presented today at a special briefing hosted by the Royal Astronomical Society.

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By Chrissy Sexton, Earth.com Staff Writer