This false-color radio image of half of AndromedaΓÇÖs ΓÇ£ringΓÇ¥ shows the distribution of hydrogen in the galaxy. The image was created with a special process. Like all disk galaxies, Andromeda rotates; the rotation makes some parts, including associated hydrogen atoms, appear as though they are moving toward us while others seem to be moving away. Astronomers select speed rangesΓÇö16 to 26 kilometers per second, for instanceΓÇöthen map out areas that appear to be moving at this rate. Although it is convenient for radio astronomers to process data in this way, it is difficult for others to understand these ΓÇ£velocity maps.ΓÇ¥
In fact, there is no ring in Andromeda. Because we see
