The stars in our night sky belong to the Milky Way galaxy. When we see a picture of a galaxy on TV or in a magazine, it is often a galaxy similar to how the Milky Way might instead appear from the outside: possessing beautiful spiral structure, with an easily visible conglomeration of stars, gas, and dust. Despite the impressions given by these typical depictions, the vast majority of the galaxies in the universe are puny dwarf
galaxies much smaller and dimmer than the Milky Way. In fact, ~20 dwarf galaxies possessing only one millionth the number of stars in the Milky Way have recently been discovered. These discoveries have made astronomers question the very meaning of the word "galaxy". This talk will highlight some basic history of astronomers' understanding of galaxies, how computer simulations can help us understand galaxies, and how invisible galaxies are now guiding our understanding of what makes a galaxy, a galaxy.
This presentation was given as part of the Fall, 2013 UNL Astronomy Education Workshop.
UNL Astronomy