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How Many Arms Does the Milky Way Galaxy Have?

-- Janail | January 1, 2024

Question:

Does the Milky Way Galaxy have two arms or four? I did some research about the change but some sources say it has four again.

-- Janail

Answer:

The most recent analysis of the structure of our Milky Way galaxy, derived from the Spitzer Space Telescope, indicates that it has two main spiral arms. As noted in the Spitzer Space Telescope image referenced above, the Milky Way’s two major arms (Scutum-Centaurus and Perseus) can be seen attached to the ends of the Milky Way’s central bar. The two now-demoted minor arms (Norma and Sagittarius) are less distinct and located between the major arms.

-- Jeff Mangum

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