The Gaia mission continues to unlock the galaxy’s secrets | MarketingwithAnoy

It’s probably there 200 billion stars in the Milky Way, stretched across space in a disk shaped like a ninja’s throwing star. It is so large that when you travel at the speed of light, it will still take you 100,000 years to cross it. But if you could find the ideal point in space to stare at these stars around the clock for, say, eight years, track their motions and study their brightness with very accurate astronomy tools, you would have created a pretty good moving, living map of the galaxy.

Since 2013, the European Space Agency Gaia probe has done just that. The mission’s latest result, Data Release 3, released two weeks ago, maps 1.8 billion stars in and around our galaxy – covering about 1 or 2 percent of all star objects in the Milky Way. It is the most comprehensive star map humanity has ever made, and scientists are already using it to unlock new secrets about our galactic neighborhood.

“Like a study of stars in our galaxy, it blows all other studies out of the water,” it says Conny Aertsa star astrophysicist at the Katholieke Universiteit Leuven and a member of the Gaia consortium.

The Gaia mission was launched in 2013, but its history goes much deeper. Its predecessor, the Hipparcos Mission, was launched in 1989 to measure stellar positions, distances and motions with unprecedented precision – a field called “astrometry”, which the mission pioneered in space. Precision astrometry of the entire sky is difficult on Earth; Before Hipparcos was launched, there were fewer than 9,000 accurate “parallax” measurements of stars. (Parallax means that as the Earth moves, nearby stars appear to move in the sky, just as a lamppost appears to move relative to the background hills as you cross the street. The magnitude of the displacement indicates how far away objects are.) Hipparcos increased the number of these measurements to 120,000 at the end of the 1993 mission.

“But we knew we could do better, even while Hipparcos was working,” he says Anthony Brown, an astronomer at the University of Leiden and leader of Gaia’s data processing team. Gaia, a nearly $ 1 billion mission, was approved in 2000 as an upgrade with two much larger 1.5-meter telescopes and 106 charge-coupled devices or CCDs, sensitive photon detectors. (This instrumentation is relatively similar to the Hubble Space Telescope in that respect.) But unlike Hubble, which carries a series of heavy instruments designed to train its gaze on small areas of space, Gaia’s mission is expansive: Monitor the entire sky and collect huge amounts of data.

“Our problem with understanding the Milky Way galaxy is that we are in it,” he says Timo Prusti, a star astronomer for ESA and project researcher on the Gaia mission. “Say you want to know what shape a forest has. If you are thrown into that forest, you will see lots of trees, but no shape because you are inside the forest itself.”

In 2014, Gaia arrived at the second Lagrange point, an ideal, quiet perch from which one could stare at the galaxy. Then the craft, shaped a bit like a top hat with a shiny shade, began to look.

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