The true size of the Milky Way has been determined

To conduct the census, the team used data from the Apache Point Observatory Galactic Evolution Experiment, which counted about 250,000 red giants, which are usually hidden by interstellar dust. This allowed the scientists to pinpoint the positions of red giants and get a better idea of ​​their distribution, especially in the bulge region around the galaxy’s center.

The solar system is on the outskirts of the galaxy, making it difficult to accurately determine the structure of the Milky Way. Previous estimates were based on the number of stars in different parts of the galaxy and assumptions about the structure of other galaxies.

In the new paper, the researchers found that the density of red giants levels off near the midpoint between the galaxy’s edges and the bulge, rather than increasing exponentially as previously thought. This suggests that the bulge is not as dense as previously thought.

In addition, the scientists found that the galaxy’s effective radius, within which half of all light is emitted, is about twice as large as previously thought. This finding suggests that the galaxy’s stars are more evenly distributed than previously thought, which could mean fewer stars overall. If so, the Milky Way galaxy may have less mass than previously thought and contain more dark matter than previous estimates predicted.