Largest Age Map Yet Created for Our Milky Way Galaxy
Scientists have created the largest age map yet of the Milky Way Galaxy, revealing just how our galaxy grew up. The new map, released by the Sloan Digital Sky Survey (SDSS) may just tell us a bit more about the history of our galaxy.
In this latest effort, the researchers examined the ages of more than 70,000 stars in order to create the new map. It charts an extent that stretches halfway across our galaxy to 50,000 light-years away.
"Close to the center of our Galaxy, we see old stars that were formed when it was young and small," said Melissa Ness, one of the researchers, in a news release. "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."
The researchers used red giants to help map the galaxy. These bright stars are in the final stages of their lives and can be observed out to large distances from our sun into the very inner and outer reaches of the Milky Way.
The researchers first started with spectra taken from one of the SDSS's component surveys, called the Apache Point Observatory Galaxy Evolution Experiment, and combined it with light curves from the Kepler satellite to help measure the ages of the stars.
"In the galaxy we know best-our own-we can clearly read the story of how galaxies form in the universe with large amounts of cold dark matter," said Ness. "Because we can see so many individual stars in the Milky Way, we can chart its growth in unprecedented detail. This unprecedented, enormous map really is one for the ages."
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