galaxies
DESCRIPTION
Galaxies. What Are Galaxies?. Greek galax = milk William Herschel, 1783: A disk with the Sun slightly off-center. What Are Galaxies?. 19th Century: “Spiral Nebulae” Nearby? Maybe Solar Systems in Formation? 1920: Galaxies are Stars 1920’s: Galaxies are like the Milky Way - PowerPoint PPT PresentationTRANSCRIPT
Galaxies
What Are Galaxies?• Greek galax = milk• William Herschel, 1783: A disk with the Sun
slightly off-center
What Are Galaxies?
• 19th Century: “Spiral Nebulae”• Nearby? Maybe Solar Systems in Formation?• 1920: Galaxies are Stars• 1920’s: Galaxies are like the Milky Way• Biggest single increase in our mental picture
of the Universe in human history
Where Are We in our Galaxy?
• The visible Milky Way suggests our galaxy is a flat disk
• Surrounding other galaxies is a spherical halo of Globular Star Clusters
Galaxies and Globular Clusters
The Milky Way’s Globular Clusters
The Milky Way As We See It
Anatomy of a Galaxy
Spiral Arms
In Microwaves, We Can See the Hub of the Galaxy
Mapping the Neighborhood
Mapping the Neighborhood
Mapping the
Galaxy: Not There
Yet
Mapping the
Galaxy: Not There
Yet
Hubble’s Classification of Galaxies
Elliptical Galaxy (M87)
S0/Sa Galaxy
Barred S0 Galaxy
SBb Galaxy
SBc Galaxy
Density Waves
Rotation of the Milky Way
Ring Galaxy
Ring Galaxy
The Local
Group
Downtown: The Virgo Cluster: 50 m.l.y
The Local
Super-cluster
The Coma Cluster
350 m.l.y.
Large-Scale Structure
of the Universe to 500 m.l.y.
Large-Scale Structure of the Universe