Astronomy 101Astronomy 101GalaxiesGalaxies
Galaxy Concept
1755 Immanuel Kant
Vast collections of stars outside the Milky Way
William Parsons- (Lord Rosse) 72” scope in 1850’sSpiral structure in in Hershel’s Nebulae
1920 Shapley-Curtis Debate
CurtisSpiral Nebulae were Island Universes
ShapleySpiral Nebulae were close objects in our galaxy
Hubble 1924
Found Cepheid Variables in M-31
Could Determine Distances
Spiral M81 in Ursa MajorSpiral M81 in Ursa Major
Closest spiral is M-31Closest spiral is M-31
Barred Spirals Barred Spirals
Milky Way is Barred SpiralAPOD April 23, 2015
Elliptical M32 by Greg HigginsElliptical M32 by Greg Higgins
Irregular- Colliding GalaxiesIrregular- Colliding GalaxiesWhat about the stars?What about the stars?
Milky Way and Andromeda
Collision in 6 billion years
Peculiar M82 by J &R McCullough
Hubble’s Tuning Fork SchemeHubble’s Tuning Fork Scheme
Active Galaxies
Brighter than ordinary galaxies
10% of all galaxies
Talk for another time….
Hubble Ultra Deep Field Video