The Milky Way is older than scientists originally thought

It turns out that the galaxy's thick disc began forming as early as 13 billion years ago. That's two billion years earlier than scientists had previously thought!

How old is our galaxy? Scientists have been asking this question for years. With the Gaia space telescope, scientists at the Max Planck Institute for Astronomy in Germany have finally managed to determine the exact age of the Milky Way. 

Previously, it was impossible to establish the age of the Milky Way. It was limited to assumptions with 60% accuracy so that the calculation could be more than a billion years off. Then, to end the debate and discussion forever, scientists combined data on the brightness and position of stars from Gaia with measurements of their chemical composition taken by the Chinese LAMOST telescope. So, this is how scientists have discovered that some parts of the Milky Way were fully formed as early as a billion years after the Big Bang!

As you know, the Milky Way consists of a halo and a disk. The halo is the spherical area around the disk, which divides into two 'layers', a thin and a thick one. Scientific research has also revealed that the formation of the Milky Way occurred in two phases. The first stars in the thick disk appeared in the first stage. It began less than a billion years after the Big Bang. At the same time, the inner part of the halo began to form, but most of it did not develop until 2 billion years later. The thin disk, which contains the most stars and our Sun, was not formed until the second phase of the Milky Way's development.