Galaxies: Building Blocks of the Universe This montage highlights the main galaxy types in Edwin Hubble’s 1926 tuning-fork classification: • Ellipticals — smooth, featureless systems dominated by old stars • Spirals — rotating disks with winding arms and active star formation • Lenticulars (S0) — transitional galaxies bridging ellipticals and spirals • Irregulars — chaotic structures rich in star-forming regions These forms reveal billions of years of cosmic evolution shaped by gravity, mergers,