Galaxy Evolution

Astronomers believe the new discovery of a so-called "fossil galaxy" by the Magellan telescope can give us a glimpse into our universe at a younger stage and provide insight into the evolution of galaxies. This tiny galaxy which circles the Milky Way may be like a fossil, a preserved evidence of what the universe was like shortly after creation. The stars found in this galaxy, known as Segue 1, notably is comprised of fewer heavy elements than any other galaxy discovered thus far. Astronomers believe that this suggests that the galaxy stopped evolving 13 billion years ago. Since Seague 1 potentially is an example of what galaxies were like at the beginning of the universe, this could also help astronomers to find out about how galaxies evolved from their original state.

Seague 1 is incredibly tiny, having only a few hundred un-evolved stars. The stars are comprised mostly of hydrogen and helium thus making Segue 1 "the least chemically evolved galaxy ever known." The lack of heavier elements and metals in Segue 1 has led some to suggest that these stars are the "direct descendant" of the first stars ever blown up in the universe. Since this galaxy is so old, there is some confusion as to why it's so small. The question of why this galaxy evolved (or failed to) in the way it did is causing astronomers to ask questions about the evolution of this galaxy and early galaxies in general. Some assume that the epoch of reionization might have stunted star growth. Segue 1 can possibly indicate not only what halts galaxy formation, but also what starts formation as well. What this also suggests is that Segue 1 could have been larger and then devolved. Also, some astronomers think it it likely that other smaller galaxies like this could exist, which could potentially provide an even deeper glimpse into the evolution of the universe.  

      

http://www.sci-news.com/astronomy/science-segue1-first-galaxies-universe-01842.html

http://www.scientificamerican.com/article/fossil-galaxy-segue1/

http://www.newser.com/story/184938/tiny-fossil-galaxy-could-hold-clues-to-early-universe.html