Sep 28 John R. Spencer (Southwest Research Institute) “Taking the Measure of the Solar System” Oct 05 Carl Heiles (Berkeley) “Our Local Microcosmos” Oct 19 Mario Mateo (Michigan) “Galaxies: Where Space Becomes Time” Nov 02 Niel Brandt (Penn State) “A Rich and Evolving Tapestry of Cosmic Structure” Nov 16 Michael S. Turner (Chicago) Mohler Prize Lecture “Quarks to the Cosmos: Connecting the Smallest and Largest Scales” Scales of the Universe a distinguished speaker series 7:30 PM, 1800 Dow Chemistry Buliding Telescope observing / planetarium show following

NGC 3310

NGC 1300

NGC 5866

M 104

M 83

NGC 3370

NGC 2787

Center of M 51

Galaxies: Where Space Becomes Time The 20 th Century Heritage: A Galaxy is our (essential) Home. Ours is a Universe of Galaxies.... S C A L E

Dwarf Galaxies M ~ 10 7 M   L ~ 10 5 L  R ~ 1000 l-y N ~ 10 5 Dwarf Galaxies M ~ 10 7 M   L ~ 10 5 L  R ~ 1000 l-y N ~ 10 5 ‘Normal’ Galaxies M ~ M   L ~ 3 x L  R ~ 100,000 l-y N ~ ‘Normal’ Galaxies M ~ M   L ~ 3 x L  R ~ 100,000 l-y N ~ Giant Galaxies M ~ M   L ~ 5 x L  R ~ 1 million l-y N ~ Giant Galaxies M ~ M   L ~ 5 x L  R ~ 1 million l-y N ~ But what do these numbers mean? 1 billion sec (10 9 sec) 1 trillion inches (10 12 in) 1 quadrillion grains of sand (10 15 )

The Galactic Disk Where stars are born today Where most stars live out their lives. Where most stars die and recycle their ashes.

The Galactic Bulge The highest stellar density in our Galaxy A surprising haven of massive star formation (Galactic Bar?) Home of a super-massive Black Hole at the Galactic Center

The Galactic Halo NGC Tuc

Our Milky Way (side view) Really, NGC 891 

Oldest Humans (60k) Neanderthals disappearing (45k) Humans cross Bering Strait to NA (17k) Egyptian Civilization develops (8k) Present day The Progression of Time in a Galaxy Photo

But Galaxies like the Milky Way are just individual players on the stage of the Universe... How big is the stage? Distances Nearby Galaxies: ‘Normal’ Variable Stars Remote Galaxies: Supernovae Distribution Evolution v = HD We see >10 billion yrs into the past: There were more galaxies! They were closer together!!

Galaxies would have first grown from collapse, then merging. We can see that long-past era today... Collisions/Mergers... even in the Milky Way! and the processes at work then are still going on...

It may have looked something like this...

Earth ( sec away) Meteor ( sec) Comet McNaught (15 min) Alpha Centauri (4.2 yrs) Milky Way (28,000 yrs) 47 Tuc (12000 yrs) SMC (250,000 yrs) Dark Sky (14 billion yrs)