The most incomprehensible thing about the Universe is that it is

The most incomprehensible thing about the
Universe is that it is comprehensible. (Albert
Einstein)
Living on the Earth may be expensive, but it
includes an annual free trip around the Sun.
(Anonymous)
Physics is not a religion. It it were, we’d have a
much easier time raising money. (Leon Lederman)
January 6, 11
AY13
Astro 13 Galaxies & Cosmology
LECTURE 2 Thur 6 Jan 2011 P. Madau
• 15m II Finish Scale of the Universe
• 5m III Cosmic Calendar
• 15m IV Great Moments in the Universe
• 5m V Great Moments in Human History
•
•
•
•
10m Break
15m VI Great Moments in Ancient Cosmology
15m VII Great Moments in Pre-Modern Cosmology
15m VIII Great Moments in Modern Cosmology
January 6, 11
AY13
The Astronomical Distance Scale
cm
10+18
OBJECT
Light-year
ONE LIGHT YEAR
1
10+19 Nearest Stars
10
10+20 Thickness of Milky Way
100
10+21 Nearest Globular Clusters
1000 (1K)
10+22 Sun to Milky Way center
10K
10+23 Sun to Large Magellic Cloud
100K
10+24 Sun to Andromeda Galaxy
1000K (1M)
10+25 Virgo Supercluster of Galaxies
10M
10+26 Rich Clusters of Galaxies
100M
10+27 Supercluster of Clusters
1000M (1G)
10+28 Visible Universe
10 G
10+29 ?? Unobserved Universe
100 G
January 6, 11
AY13
Microwave Map of Sky
Temperature
Fluctuation Map
WMAP Team
Angular Power Spectrum (Caldwell et al 2003)
+SN &
+HST
==>
January 6, 11
AY13
From NASA WMAP Homepage
Nearby
Galaxies
(250 Million Ly )
January 6, 11
AY13
January 6, 11
AY13
Abell 2218 Cluster - 2 Billion Light Years Away
January 6, 11
AY13
January 6, 11
AY13
MOON vs Hubble Ultra Deep
Field -- 1 Ms Exposure
HUDF
January 6, 11
AY13
January 6, 11
AY13
Blowup of Tiny Part of HUDF
January 6, 11
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January 6, 11
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January 6, 11
AY13
January 6, 11
AY13
Massive Black Holes in Quasars
(1 Billion Suns)
Sun - Earth = 1 AU
1.5x1013cm = 500 light-s
Sun - Pluto = 40 AU
6x1014cm= 5.5 light-Hours
January 6, 11
AY13
Great Moments in Modern Cosmology
DATE NAME
CONTRIBUTION
1916
A. Einstein
General Relativity
1929
E. Hubble
Expanding Universe
1948
R. Alpher,
Predict Cosmic Radiation
G. Gamow
from Big Bang
1948
H.Bondi,
Bondi,
1948
H.
T. Gold Propose
ProposedSteady
Steady State
F. Hoyle
State Theory
T. Gold,
Theory
F.Penzias
Hoyle
1965
A.
Discovered Cosmic Radiation
1965 R.
A.Wilson
Penzias,
Discover
supporting Cosmic
Big Bang model
R.
Wilson
Radiation Universe
supporting Big
1981
A. Guth
etc
Inflationary
Bang
2000
SN teams
“Concordance Model” of Univ:
1981
A. Guth etc.
Inflationary Universe
2009
WMAP team
Flat, open, age=13.7Gyr, 4%
1992
G. Smoot
etc Fluctuations
in Cosmic
Baryons, 73%
Dark Energy,
23% Dark Matter
January 6, 11
AY13
Cosmic Calendar
January 6, 11
AY13
Great Moments in the Universe
After Big
Bang
0
Before
Today
~20 By
Redshift
10-43 sec
“
10+32
Planck
10-6 sec
“
10+13
Hadronic
1 sec
“
10+10
1 min
“
10+9
10,000 y
“
10+4
300,000 y
“
10+3
~1-2 By
~20
3 By
15.4 By
4.6By
0.4
17 By
3 By
0.2
200My
0.01
January 6, 11
Event
Singularity Big Bang
18-19
By
17 By
19.8 By
Epoch
6
Particle Creation
Proton-Anti-Proton
Annihilation
Leptonic
Electon-Positron
Annihilation
Radiation Helium & Deuterium
Creation
Matter
Matter Energy
Dominates
Decoupling Transparent U.
Structure Galaxy Birth?
Formation
“
Quasar Birth?
“
Earth is Born
Life Begins
Mesozoic
AY13
First Mammals
Great Moments in Human History
Years Ago
70 M
20 M
5 M
2 M
600,000
360,000
40,000
~20,000
13,000
6,700
5,500
3,500BC
January 6, 11
Event
Pre-Primates Evolve
Apes Separate from Monkeys
Apeman “ Chimps
Homo Erectus Homo Sapiens
Use of Fire
Complex Language
Agriculture Invented
Ceramic Pottery
Babylonian Calendar
Writing Developed
AY13
Great Moments in Ancient Cosmology
DATE
NAME
2,500 BC
Stonehenge
2,200 BC
-------
1,500 BC
--------
500 BC
Pythagoras
370 BC
Plato
360 BC
Eudoxus
330 BC
Aristotle
280 BC
Aristarchus
140 AD
Ptolemy
January 6, 11
CONTRIBUTION
Built
Astronomy in Egypt, Babylonia,
India, China
Sundial in Egypt
Spherical, Rotating Earth
Revolving a Central Fire
Stationary Earth, Planets in
Circular Orbits
33 Concentric spheres around a
Still Earth
55 Concentric spheres;
immutable Heaven
Heliocentric system !!
Geocentric system; good
epicycle theory
AY13
Great Moments in Pre-Modern Cosmology
DATE
NAME
600-1500 Very Dark
AD
BC
Ages
1543 AD Nicholas
Copernicus
1572
Tycho Brahe
~1600
~1600
1666
~1750
~1800
January 6, 11
CONTRIBUTION
Negative
Heliocentric model revived
Sees Nova --> Aristotle
wrong
Johan. Kepler Laws of planetary orbits
Galileo Galilei Uses telescope: sees moons
of Jupiter, sunspots, phases
of Venus
Isaac Newton Universal law of gravity
I. K a n t ,
First concepts of Milky
H. J. Lambert, Ways and Galaxies
T. Wright
W. Herschel Observes nebulae; Uranus
discovery confirms Newton
AY13
Nicolaus Copernicus devised the first
comprehensive heliocentric model
• Heliocentric (Sun-centered)
theory simplifies the
explanation of planetary
motions
• In a heliocentric system,
the Earth is one of the
planets orbiting the Sun
January 6, 11
AY13
Stars
Saturn
Jupiter
Mars
EARTH
Venus
Mercury
SUN
January 6, 11
AY13
Heliocentric
Model of
Copernicus
A planet undergoes retrograde
motion as seen from Earth when the
Earth and the planet pass each other
January 6, 11
AY13
January 6, 11
AY13
January 6, 11
AY13
Tycho Brahe’s astronomical observations
disproved ancient ideas about the heavens
January 6, 11
AY13
Johannes Kepler proposed elliptical paths
for the planets about the Sun
• Tycho Brahe’s
data enabled
Kepler to deduce
his famous laws of
planetary motion:
January 6, 11
AY13
Galileo’s discoveries with a telescope
strongly supported a heliocentric model
• The invention of the
telescope led Galileo
to new discoveries that
supported a
heliocentric model
• These included his
observations of the
phases of Venus and
of the motions of four
moons around Jupiter
January 6, 11
AY13
•
•
•
One of Galileo’s most important discoveries with the telescope was that
Venus exhibits phases like those of the Moon
Galileo also noticed that the apparent size of Venus as seen through his
telescope was related to the planet’s phase
Venus appears small at gibbous phase and largest at crescent phase
January 6, 11
AY13
Phases of Venus
are related to
the planet’s
angular distance
from the Sun
January 6, 11
AY13
Geocentric - Epicyclic Models do
not explain Galileo’s Venus data
• To explain why Venus is
close to the Sun,
Ptolemy’s epicycle
model never allowed
Venus to be on the
opposite side of the Sun
from the Earth. Thus
Venus could never show
the phases and sizes
seen by Galileo.
January 6, 11
AY13
• In 1610 Galileo
discovered four
moons, now called
the Galilean
satellites, orbiting
Jupiter. This
established that not
everything revolved
around only Earth.
January 6, 11
AY13