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Astronomy 141
Life in the Universe
Prof. Scott Gaudi

Lecture 1: Overview and Goals

(Note since I will be not be giving this lecture, the actual content may differ from what is presented on this page.)

Answering Unanswerable Questions

Break question up into components.
Make observations to answer component questions.
Verify with additional observations.
Construct lines of inquiry to allow progress in difficult areas.

Concept of large numbers: very improbable events or combinations are likely with many realizations.
Concept of selection biases.

How many extraterrestrial civilizations are there that we may come in contact with?

What is required for life?
Where can life exist?
What is required for communication?
What is required for intelligence?
How long does it take for life to develop?
How long do intelligent civilizations last?

The Drake Equation

Rate of star formation in the Galaxy.
Fraction of stars that form planets.
Fraction of planets that are Earth-like.
Fraction of Earth-like planets that develop life.
Fraction of such planets that develop intelligent life.
Fraction of such civilizations that are willing and able to communicate.
Period of time that the civilization can and does communicate.

Overview: What are we trying to do here?

Learn about the scientific progress toward answering that fundamental human question: Are we alone?

We will do this by trying to answer simpler questions:

What is life?
What is the nature of life on Earth?
How did life originate on Earth?
Is there life in the solar system?
Are there other solar systems?
Is there life on the planets of those systems?
How can we detect those systems and life on them?
Will we ever contact other sentient beings?
What is the long-term future of life on Earth?
What is the long-term future of life in the Universe?

Overview: Outline

Unit 1: Introduction to Science and Astronomy
Unit 2: Life on Earth
Unit 3: Life in the Solar System
Unit 4: Life in the Universe
Unit 5: Death in the Universe

Why Study Astrobiology? (Now)

Unique time in human history?
--Scientific method
--Copernican world view
Basis of knowledge
--Understand of Evolution of Life Earth
--Planets may be common
--Life may be common

The Sciences of Astrobiology

[Math and Physics]
Chemistry and Biology
Geology, Paleontology; Earth and Planetary Science
Astronomy, Astrophysics
(Philosophy, Computer Science, Sociology, Ethics, Religion)

Math and Physics

Provide the basic framework in which we describe nature.

Chemistry and Biology

Chemical principles of life
Definition of life and the diversity of life on Earth
Structure and nature of biology

Earth and Planetary Science

History and evolution of the Earth
Origin and evolution of life
Environmental conditions on the Earth and other planets

Astronomy and Astrophysics

Size, age, and scale of the Universe
Origin and evolution of chemistry
Frequency and properties of other worlds
Long-term future of the Universe


Computer Science

See A Note about Graphics to learn why the graphics shown in the lectures are generally not reproduced with these notes.

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