Active galaxies called blazars make up the largest class of objects detected by Fermi's Large Area Telescope (LAT). Massive black holes in the hearts of these galaxies fire particle jets in our direction. Fermi team member Elizabeth Hays narrates this quick tour of blazars, which includes LAT movies showing how rapidly their emissions can change. Learn more http://guide.slinky.me http://guide.slinky.me/Category:Education_and_Communications