1

2

FELIX QUI POTUIT RERUMCOGNOCERE CAUSAS

3

PHYS 181

ASTRONOMYASTRONOMY

4

A FEW RECENT DEVELOPMENTS…

5

6

Abell 1835 IR 1916: Virgo Cluster: Red shift Factor 11

7

V838 Monocerotis

8

9

10

11

12

13

14

                                           

                                                             

15

16

Is There Anybody Out There?

An Exercise in the Method of ANALYSIS

17

ANALYSIS:The separation of an intellectual or material whole into its constituent parts for individual study.

dictionary.com

18

300 B.C. Speculation of Life Elsewhere

Physics – Biology – Chemistry – Sociology – Archeology Theology

Lack of information and poor understanding lead us to analysis…

19

FUNDAMENTAL QUESTIONS…

1. What is the likelihood that other Earth-like planets exist?

2. Given an Earth-like planet, what is the likelihood that life would arise there?

3. Given life, What is the likelihood that such life would develop intelligence?

4. Given intelligence, what is the likelihood that technology would be developed by such an intelligence?

5. Given technology, what is the likelihood that intelligent life would contact us or us them?

Grounded in Science – Mindful of Uncertainty

20

What is the likelihood that other Earth-like planets exist?

Life on Earth is the only life KNOWN to exist…

21

22

Approximately 400 billion stars…

23

50% Binary Stars...

Sorry, No Planets

Only 200 Billion Stars Left!

24

25

Other stars have planets…

How many are Earth-like?

26

High mass stars burn too fast…

Low mass stars burn too cold…

Only about 10% have the right mass.

27

28

UNCERTAINTY

Optimism

V.S.

Pessimism

29

Optimistic: All good stars have planets.

Pessimistic: Only 10% have planets.

30

31

Optimistic: All good solar systems have at least one Earth-like planet.

Pessimistic: Only 10% have Earth-like planets.

EARTH-LIKE?EARTH-LIKE?

32

Optimistic: 20 Billion Earth-Like Places

Pessimistic: 200 Million Earth-Like Places

33

Given an Earth-like planet, what is the likelihood that life would arise there?

Optimistic: Life is certain

Pessimistic: Only 10%

34

Optimistic: 20 Billion Planets with Life

Pessimistic: 20 Million Planets with Life

35

Given life, what is the likelihood that life would develop

intelligence?

36

BIOLOGICAL CONVERGENCE

37

Optimistic: Intelligence is a certainty

Pessimistic: 1 in a million

38

Optimistic: 20 Billion Planets with Intelligent Life

Pessimistic: 20 Planets with Intelligent Life

39

Given intelligence, what is the

likelihood that technology would

be developed by such an

intelligence?

Optimistic: All intelligent life develops the ability to send radio signals

Pessimistic: Only 10% develop technology

40

41

Optimistic: 20 Billion Planets with Intelligent, Technological Life

Pessimistic: 2 Planets with Intelligent, Technological Life

42

Given technology, what is the likelihood that intelligent life would contact us or us them?

Our estimate shows that we a reasonable suspicion that Intelligent, technological life to develop, or develop in the future, elsewhere in our galaxy.

43

IS THERE ANYBODY OUT THERE?IS THERE ANYBODY OUT THERE?

44

Berkley Online Infrastructure for Network Computing

45

IMPORTANT

• 400 Billion Stars in Our Galaxy• 50% of Them are Binary• Large Stars Burn Quickly• Our Moon Always Shows the

Same “Face”• Radio Signals are Common in our

Universe

46

NEXT TIME:

A UNIVERSE OF SCALE