The disk shaped like a ninja's throwing star is made of 200 billion stars. It takes 100,000 years to travel at the speed of light. If you could find the ideal point in space to stare at these stars around the clock for eight years, you would have created a map of the universe.

The European Space Agency's probe has been doing that for the last few years. Data Release 3, which came out two weeks ago, maps 1.8 billion stars in and around our galaxy, covering about 1 or 2% of all stellar objects. Scientists are using the most comprehensive star map humankind has ever made to uncover new secrets about our neighborhood.

Conny Aerts is a stellar astrophysicist at Katholieke Universiteit Leuven and member of the Gaia consortium.

There is much more to the history of the Gaia mission. The Hipparcos mission was launched in 1989 to measure the position, distances, and motions of stars with unprecedented precision. Hipparcos has made it easier to measure the stars in the sky. As Earth moves, nearby stars appear to shift in the sky as you cross the street. The amount of shift is used to show how far away objects are. By the end of the mission, Hipparcos had increased the number of measurements to over 100,000.

Anthony Brown is an astronomer at the University of Leiden and the lead of the data processing team. In 2000 the mission was upgraded to include two larger telescopes and 106 charge-coupled devices. The instruments are similar to the Hubble Space Telescope. Unlike Hubble, which is used to train its gaze on tiny areas of space, Gaia is used to survey the entire sky and collect huge amounts of data.

The problem with understanding the universe is that we are in it. Do you want to know the shape of the forest? If you are dropped into the forest, you will see a lot of trees, but no shape.

The second Lagrange point is an ideal perch from which to look at the universe. The craft, which is shaped like a top hat with a shiny brim, began to look.