PICK a line and follow it with your eyes. You are looking at this page in the same pattern as the European Space Agency’s Gaia satellite looks at the sky. The neon colours in this image represent which direction Gaia was rotating as it scanned that part of the cosmos.
Launched in 2013, Gaia is dedicated to making the best 3D map of our galaxy we have ever had by tracking the precise distances and locations of more than a thousand million stars.
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In order to do so, it rotates slowly as it glides around its orbit, allowing its two telescopes to take in the entire sky. Places where the lines intersect indicate regions of the sky that Gaia has observed multiple times. By the mission’s end in 2019, this entire picture will be saturated with bright lines.
Gaia’s first data catalogue, with measurements of more than a billion stars, was released in 2016. Its second release, scheduled for 25 April, will contain information on the movements and distances of 1.3 billion stars, along with less-detailed data on 360 million more.
Astronomers hope to use this data to learn more about how our galaxy formed and evolved, and what exactly it is made of. It may even help us resolve hotly debated issues like how fast the universe is expanding.
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ESA/Gaia
This article appeared in print under the headline “Swirl and whirl”
