A dwarf galaxy is “a small galaxy composed of several billion stars – a smaller number than the 200 to 400 billion stars in our own Milky Way” (Wikipedia). On February 23, 2014, it was reported that two galaxies that once orbited the Andromeda Galaxy were merging. The collision created a stream of stars in one of Andromeda's dwarf galaxies, Andromeda II. The researchers then observed the flow of stars, separating them into categories and trying to analyze which ones might be members of Andromeda II versus which might be "foreground dwarf stars in the Milky Way halo." (Amorisco et al, 2014, p 4). Since the star stream is located over an area of ​​Andromeda II that has limited luminosity, the researchers found 14 "high-probability contaminants" in a region of the stream with "stars that [were] significantly more likely to belong to the population of Andromeda II. » (Amorisco et al, 2014, p. 4). By measuring the characteristics of the stream, the researchers were able to conclude that it presented "remnants of a merger between two dwarf galaxies... illustrating the scale-free nature of galaxy formation, down to the lowest galactic mass scales" ( Amorisco et al., 2014, p. 1).As we discussed in the lecture, galaxies are constantly colliding with each other and these collisions shape the structure and evolution of galaxies. “Andromeda II provides direct evidence of the importance of mergers, even for the smallest and faintest galaxies” (Amorisco et al, 2014, p. 3). As we discover more evidence of galactic collisions, cosmologists and astronomers will be able to determine the effect they have on the Universe. The merger of galaxies allows them to grow: small galaxies are merged to create ...... middle of paper ...... is observed between the satellites of Andromeda and the Milky Way and has been proposed to be due to differences in the formation and/or evolution of dwarves” (Martin et al, 2006, p. 1989). This suggests that collisions can have other impacts on the universe depending on their frequency and the speed at which they collide. The evolution of new dwarf galaxies proves that the universe is shaped by colliding galaxies and that galaxies create large balls/star clusters when they collide. Dwarf galaxies, over time, will merge with larger galaxies and this cycle will contribute to the growth of the universe. Throughout this course we have learned about the expansion of the universe and it seems that the universe will never stop expanding. . There is so much to discover even though our ideas evolve.