Scales of the Universe
a distinguished speaker series
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”
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 20th Century Heritage:
A Galaxy is our (essential)
Home.
Ours is a Universe of
Galaxies.
...SC
ALE
‘Normal’ Galaxies
Dwarf Galaxies
• M ~ 1012 M8
•
•
•
• M ~ 107 M8
L ~ 3 x 1010 L8
R ~ 100,000 l-y
N~
1012
• M~
M8
L ~ 105 L8
•
R ~ 1000 l-y
• N ~ 105
Giant Galaxies
1013-14
•
But what do these numbers mean?
• L ~ 5 x 1011 L8
1 billion sec (109 sec)
•
R ~ 1 million l-y
1 trillion inches (1012 in)
•
N ~ 1015
1 quadrillion grains of sand (1015)
The Galactic Disk
Where most stars die and
recycle their ashes.
Where most
stars live out
their lives.
Where stars are born today
The Galactic Bulge
A surprising haven of massive
star formation (Galactic Bar?)
The highest
stellar density
in our Galaxy
Home of a super-massive
Black Hole at the Galactic
Center
The Galactic Halo
NGC6093
47 Tuc
Our Milky Way
(side view)
8
Really, NGC 891
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
Distribution
v = HD
Evolution
We see >10 billion yrs into
the past:
There were more galaxies!
They were closer together!!
Nearby Galaxies: ‘Normal’
Variable Stars
Remote Galaxies: Supernovae
Galaxies would have first grown from collapse, then merging.
We can see that long-past era today . . . and the
processes at work then are still going on . . .
Collisions/Mergers
. . . even in the Milky Way!
It may have looked something like this . . .
Dark Sky (14 billion yrs)
SMC (250,000 yrs)
Alpha Centauri (4.2 yrs)
47 Tuc (12000 yrs)
Milky Way (28,000 yrs)
Meteor (0.00001 sec)
Comet McNaught (15 min)
Earth (0.000001 sec away)