Have you ever wondered how the vast, swirling cluster of stars known as the Milky Way came to be? According to a report from Phys.org, astronomers working with the Sloan Digital Sky Survey have created a stunning new map that charts the growth of our galaxy from the inside out.

The map was presented last week at the American Astronomical Society meeting in Kissimmee, FL, alongside a number of recent astronomical studies and breakthroughs. It was created by a team of researchers led by Melissa Ness of the Max Planck Institute for Astronomy in Heidelberg, Germany.

The chart drew upon the ages of over 70,000 stars to show the galaxy’s progression over time, and extends a distance of roughly 50,000 light-years, or roughly halfway across. The chart tells the story of how the Milky Way grew from humble beginnings into the massive spiral galaxy we know today.

According to Ness, “Close to the center of our galaxy, we see old stars that were formed when it was young and small. Farther out, we see young stars. We conclude that our galaxy grew up by growing out. To see this, we needed an age map spanning large distances, and that’s what this new discovery gives us.”

Scientists were able to map out the evolution of the galaxy thanks to a recent breakthrough in observing red giant stars. Co-author Marie Martig released a related study that laid out a method for determining the mass of a red giant star. Once the star’s mass is known, astronomers can tell its age by determining how far along its internal fusion clock has ticked.

Using spectra captured from the Apache Point Observatory Galaxy Evolution Experiment and light curves captured by NASA’s Kepler satellite, scientists were able to determine the relative ages of 70,000 stars scattered across the Milky Way. The resulting visual representation shows the oldest stars in the center, and the youngest stars zooming along the outer wisps of the galaxy’s spirals.

A press release from SDSS describing the method used to create the growth chart can be found here.