www.nineplanets.org
Lattimer, AST 248, Lecture 21 p.1/17
Titan
Only moon with substantial atmosphere,
1.5 times Earths
Saturns largest satellite and second largest
in Solar System
Atmosphere a result of relatively cold
temperature and high gravity
Major g

Homework and other written assignments
Homework and other written assignments should be neat, organized, and easy to read, and
the work should demonstrate a mastery of the material. While producing clear written assignments are essential for this class, g

Homework Set 4
Chapter 5 Exercises 3, 4, 10, 12, 17, 18, 19, 20, 51
Due on paper in class on October 13.
5 points each for a total of 45 points.
AST 248

Homework Set 3
AST 248
Chapter 3 Exercises 1, 8, 14, 17, 20, 21, 25, 36, 40
Chapter 4 Exercises 38, 54
Due on paper in class on September 29.
All but problems 3.36, and 4.38 are 5 points each. 3.36 and 4.38 are 2 points each for a total
of 49 points.

Homework Set 5
Chapter 6 Exercises 1, 3, 7, 11, 15, 16, 19, 25, 48
Due on paper in class on October 20.
10 points for 48, the rest 5 points each for a total of 50 points.
AST 248

Determining Earth's Interior Structure
Seismic (Body) Waves
P waves Compressional or longitudinal (analogous to sound waves in air), can travel through fluid, solid and gaseous materials. P means primary, because they travel faster and arrive sooner. S

Star Formation
Dense cores of molecular clouds collapse into hot
plasma which eventually triggers nuclear reactions.
Release of gravitational energy both heats the
material and produces infrared radiation.
Conservation of angular momentum requires spin

Homework Set 1
Chapter 1, exercises 3, 12, 18, 19
Chapter 3, exercises 4, 34, 61, 62
Due in class on September 13.
5 points each for a total of 40 points.
AST 248

Homework Set 2
Chapter 2 Exercises 1, 2, 3, 12, 17, 20, 38, 50, 53
Due on paper in class on September 20.
5 points each for a total of 45 points.
AST 248

Homework Set 10
AST 248
Chapter 12 Exercises 1* , 12, 13, 27, 28, 29, 32
Chapter 13 Exercises 2, 9, 21, 37
Due on paper in class on December 5.
5 points each for a total of 55 points.
*
Note: Just answer the rst part What is the value of the Drake equatio

Homework Set 2
AST 248
Chapter 2 Exercises 1, 2, 3, 12, 20, 38, 52, 56
Due on paper in class on September 17.
5 points each for a total of 40 points.
2.1) The three characteristics of Greek thought that helped pave the way for modern science
are
1. A trad

Homework Set 8
AST 248
Chapter 10 Exercises 12, 16, 20, 22, 24, 29, 30, 32
Due on paper in class on November 14.
5 points each for a total of 40 points.
12) The Sun gradually brightens over time because as it fuses hydrogen into helium, the number of inde

Homework Set 5
AST 248
Chapter 6 Exercises 1, 3, 7, 18, 19, 23, 24, 27, 45
Due on paper in class on October 17.
10 points for 45, the rest 5 points each for a total of 50 points.
6.1) The three lines of evidence that point to an early origin of life on Ea

Homework Set 6
AST 248
Chapter 8 Exercises 3, 4, 6, 10, 32, 33
Chapter 9 Exercises 27, 33
Due on paper in class on October 31.
5 points each for a total of 40 points.
8.3) Liquid water is unstable on the surface of Mars for two reasons. First, it is so co

Homework Set 3
AST 248
Chapter 3 Exercises 1, 4, 8, 14, 24, 26, 34, 40
Due on paper in class on September 24.
5 points each for a total of 40 points.
3.1) Quoting the book:
1. The universe is vast and old. Its vastness implies an enormous number of worlds

Homework Set 4
AST 248
Chapter 4 Exercises 38, 51
Chapter 5 Exercises 3, 10, 12, 17, 19, 50
Due on paper in class on October 10.
5 points each for a total of 40 points.
4.38) Earth has far less atmospheric carbon dioxide than Venus because
(c) Earths carb

CHAPTER 10 (the nature and evolution of habitability)
Habitable zone: the region around a star in which planets could potentially have surface
temperatures at which liquid water could exist.
o Inner boundary set by threshold for runaway greenhouse effect

Galaxies
Galaxies are self-gravitating systems containing billions
The observed universe has billions of galaxies.
We live in a Galaxy known as the Milky Way.
Galaxies dont exist randomly in space, but tend to cluster.
S. Harris
of stars and having di

The Sun: Example of Radiation Laws
= 4 1033 erg/s
L
Use Wiens Law to nd the surface temperature of the Sun:
T = 0.29 cm/max 6000 K
Invert the blackbody luminosity formula to derive the solar radius:
Yellow color means that the peak wavelength of the Suns

Unity of Life
All lifeforms on Earth have a common system. Examples:
universal usage of DNA to store genetic information
the ribosome technique of protein synthesis
proteins serve as enzymes and catalysts
the same 20 amino acids are always used, and only

Determining Earth's Interior Structure
Seismic (Body) Waves
P waves Compressional or longitudinal (analogous to sound waves in air), can travel through fluid, solid and gaseous materials. P means primary, because they travel faster and arrive sooner. S

Star Formation
Dense cores of molecular clouds collapse into hot
plasma which eventually triggers nuclear reactions.
Release of gravitational energy both heats the
material and produces infrared radiation.
Conservation of angular momentum requires spin

Galaxies
Galaxies are self-gravitating systems containing billions
The observed universe has billions of galaxies.
We live in a Galaxy known as the Milky Way.
Galaxies dont exist randomly in space, but tend to cluster.
S. Harris
of stars and having di

The Sun: Example of Radiation Laws
= 4 1033 erg/s
L
Use Wiens Law to nd the surface temperature of the Sun:
T = 0.29 cm/max 6000 K
Invert the blackbody luminosity formula to derive the solar radius:
Yellow color means that the peak wavelength of the Suns

AST 248
The Search for Life in the Universe
James Lattimer
lattimer@astro.sunysb.edu
Department of Physics & Astronomy
449 ESS Bldg.
Stony Brook University
Lattimer, AST 248, Lecture 1 p.1/8
Course Components
Ofce Hours: 2:30 3:30 Tu, W, Th, ESS 449
Exams

Communication by Radio
Advantages:
Speed: velocity of light exceeds physical transportation speeds
Cost is small compared to space voyages or probes
Commonly used bands in the radio spectrum.
What determines the choice of communication frequency?
1. Econo

Chemical Evolution Theory of Lifes Origins
1. the synthesis and accumulation of small organic molecules, or monomers, such as
amino acids and nucleotides.
Production of glycine (an amino acid)
energy
3 HCN + 2 H2 O C2 H5 O2 N + CN2 H2 .
Production of ade