Galaxies 4/29

http://www.nasa.gov/sites/default/files/thumbnails/image/image2stscihp1726bf4000x1750.png

A galaxy is a gravitational bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. There are many different types of galaxies. This includes Spiral Galaxies, Elliptical Galaxies, Peculiar Galaxies, and Irregular Galaxies. Spiral Galaxies are characterized as broad, flat, rotating disks of stars, gas, and dust. It has a central bulge of older, redder stars, sometimes with a long cylindrical or rectangular bar of stars and a huge extending halo of older stars. The spiral arms extend from the very center out to the visible edge of the galaxy. Elliptical Galaxies is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile. Some are nearly spherical, gigantic cotton balls of billions of stars. Others are more elongated, shaped like cigars or American footballs. They tend to have no overall structure and range in size dramatically. Elliptical Galaxies are characterized by a lack of gas and dust in them, they are populated with older stars. Peculiar Galaxies is a galaxy of unusual size, shape, or composition. They are not shapeless, but have a shape that is weird. Peculiar galaxies are essentially all due to collisions. Irregular Galaxies are galaxies that do not have a distinct regular shape, unlike a spiral galaxy or an elliptical galaxy. They are truly shapeless. These galaxies tend to be small, and chaotically shaped.

S&EP - SP1: Asking questions and defining problems

I formulate testable questions when I scanned through the document that my classmates and I were assigned to fill out. When observing this document, I discovered that I was supposed to watch a video about galaxies and then answer questions that correlated with the video. I established what is already known about different types of galaxies and galactic collisions when I answered the questions as I watched the video. This helped me efficiently answer the questions once I discovered the answers to them. I determine what questions have yet to be answered when I looked over the questions on the document and figured out which questions I haven't found the answer to yet. I defined constraints and specifications for a solution as I realized that some of the questions required a little more detail in the explanations that the video may have not included. So as a solution, I decided to do some extra research in order to thoroughly answer certain questions.