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It looks like CES wasn't the only big thing happening this early in the year. The 209th meeting of the Astronomical Society of America also occurred last week, and one of the big presentations of the meeting was an assertion about one of our neighboring galaxies. According to the findings, it seems as if the Andromeda galaxy is five times larger than people thought.
Without getting too scientific, first imagine that a galaxy is made up of three parts, as our source notes: "a flattened disk, a bright central bulge of densely packed stars, and an extended spherical halo where stars are more sparsely distributed." The stars in the halo are supposed to be the first stars that form in the galaxy, and current theories of galaxy formation state that the halo stars should have less heavy metal content on them compared to the stars closer to the galaxy's center.
Now, our galaxy and the Andromeda galaxy are supposed to have similar rates of galaxy formation. This should mean that the halo stars of Andromeda ought to have a similar amount of heavy metal content. Researchers who've previously seen Andromeda's halo stars, however, noted that they're 10 times richer in metals than our own halo stars. In astronomical terms, that's a pretty big discrepancy.
What members of the study team found were some new stars farther away from Andromeda's center. These new red giant stars weren't seen before, and may explain why the halo stars were so metal rich: because they weren't the actual edge of the Andromeda galaxy and, therefore, not actual halo stars. As the picture above shows, this means that an even larger portion of our night sky may actually be part of another galaxy.
Better still, it gives us an even better reason to look up at the night sky.
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