As in the case of many spiral galaxies spread across the universe, the Milky Way features two structures in the shape of a thinner and a thicker disk. The thicker one contains approximately 20% of the stars found within the Milky Way and is deemed to be the older one, based on the traits of the stars present within.
A team of 38 experts used data collected during the Kepler mission to evaluate the force of starquakes present in the disk. With the help of the results, the researchers determined that the thick disk has an age of approximately 10 billion years.
To reach the new results, the scientists used a method called asteroseismology by measuring the oscillations generated by starquakes, a phenomenon similar to the earthquakes found on Earth. Data identified with the technique allowed the researchers to run galactic-archaeology, tracing the origins of the Milky Way to the formation, which took place over 13 billion years ago.
A new method allows researchers to determine the age of the Milky Way
A starquake releases powerful waves inside the star, leading to powerful vibrations. Researchers can analyze the vibrations to learn more about the intrinsic properties of a star, including the age. The process can be compared to the one of trying to identify an original instrument by listening to the sound it makes when played.
At this point, it is essential to mention the fact that what astronomers detect are not proper sounds. The movements which take place within a star can be traced by measuring any changes related to the brightness.
In the past, astronomers observed that some observations recorded during the Kepler mission were not on par with models of the Milky Way’s structure, as the models anticipated a more significant number of low-mass stars. It is now known that the discrepancies were caused by inaccuracies related to the galactic models. More information can be found in a study that was published in a scientific journal.