13: Galaxies Last updated Nov 20, 2024 Save as PDF 12.15: Gamma-Ray Bursts (GRBs) 13.1: Module Introduction Page ID64063 Lumen LearningLumen Learning ( \newcommand{\kernel}{\mathrm{null}\,}\) 13.1: Module Introduction13.2: What do you think?13.3: Galaxies13.4: The History of Studying Galaxies13.5: Hubble’s Major Contributions13.6: Hubble’s Law13.7: Classification of Galaxies13.8: Elliptical Galaxies13.9: Spiral Galaxies13.10: Irregular Galaxies13.11: Active Galaxies13.12: Quasar-stellar Objects13.13: Blazars- Quasar-like Object13.14: Galaxies, Distance, and Age13.15: The Ages of Galaxies and What that Reveals13.16: Galactic Groups13.17: Dark Matter13.18: WIMPs and String Theory13.19: Gravitational Lensing