After launching to space in 2013, the European Space Agency’s Gaia telescope has been spinning in full circles every six hours, mapping all the stars it can see in every direction. Scientists have released a new catalog that includes the latest data from the mission, including measurements of the chemical compositions, temperatures and masses of nearly two billion stars in our Milky Way. These data show typical star trends: Large stars tend to be young and hot. The older massive stars won’t be around for very long so they will be gone by now. We find smaller stars with lower masses at all ages. They are cooler and more reddish.
Gaia’s observations allow astronomers to piece together the history of our galaxy and see how it compares to other galaxies. Timo Prusti is Gaia’s project scientists. “We are inside the Milky Way.” “It’s like a forest. You see many trees, but you don’t know what the forest looks because you are inside. Gaia is a tool that measures all trees to determine what it looks like