1. Astrobiology: The Semester in Review
HNRS 353 – FALL 2016
with Dr. Harold Geller

2. A Universe of Life Searching for life everywhere
Planets, stars, galaxies, Big Bang
Conception of size and distance
Stars and the origins of chemicals
Formation of planets
Defining astrobiology – the science

3. iClicker Question
The nebular condensation model of the formation of the solar system suggests that __________ should condense closest to the Sun.
A Jovian planets
B metals and metal oxides
C sulfates
D ices of water, methane, and ammonia
E low density materials

4. The Science of Life in the Universe
Ancient cosmologies
Science as the way to know the universe
Copernicus, Galileo, Kepler, Newton
Pseudoscience and nonsense

5. The Nature of Life
What is it?
Cells
Metabolism
DNA
Extremophiles

6. iClicker Question Life on Earth is based on A silicon chemistry.
B helium chemistry.
C carbon chemistry.
D oxygen chemistry.
E nitrogen chemistry.

7. The chemical building blocks of life are found throughout space
All life on Earth, and presumably on other worlds, depends on organic (carbon-based) molecules
These molecules occur naturally throughout interstellar space
Organic molecules needed for life to originate were possibly brought to the young Earth by comets or asteroids, as well as being formed on Earth

8. The Geological History of the Earth
Geologic Timescale
Plate Tectonics
Solid Earth
Greenhouse Effect
Relative/Absolute Dating

9. iClicker Question The greenhouse gas effect occurs because
A carbon dioxide is transparent to visible light and opaque to infrared radiation.
B carbon dioxide is transparent to infrared radiation and opaque to ultraviolet radiation.
C ozone is transparent to ultraviolet radiation and opaque to infrared radiation.
D methane is transparent to infrared radiation and opaque to visible light.
E the sun emits more infrared radiation than ultraviolet radiation.

10. The Origin and Evolution of Life on Earth
Origin of Life
Prokaryotes
Eukaryotes
Oxygen in Air
Impacts & Extinctions
Human Evolution

11. iClicker Question
Which of the following companies or agencies has Prof. Geller NOT worked for in his employment history?
A – General Sciences Corporation
B – Science Applications Int’l Corporation
C – Research Data Systems Corporation
D – Federal Bureau of Investigations
E – Defense Systems Inc.

12. iClicker Question
Which of the following was NOT a title that Dr. Geller held in his life?
A – taxi driver
B – truck driver
C – priest
D – program manager
E – deputy director

13. Another likely source for organic molecules is chemical reactions in the Earth’s primitive atmosphere
Similar processes may occur on other worlds

14. Searching for Life in the Solar System
Environmental Needs
In the Solar System

15. Mars
Science Fiction
Search for Life
Martian Meteorites
Exploration

16. The Viking Lander spacecraft searched for microorganisms on the Martian surface, but found no conclusive sign of their presence

17. Two NASA rovers reached Mars in 2004 at locations that once had water

18. “Faces” on Mars

22. From Curiosity briefing at AGU in S. F
From Curiosity briefing at AGU in S.F., CA 12/3/12 [after much media hype that was a misunderstanding of statements made by NASA scientists]
"SAM results show that the Rocknest sand drift does NOT contain abundant organics”

23. Meteorites from Mars have been scrutinized for life-forms
An ancient Martian rock that came to Earth as a meteorite was examined for evidence that microorganisms once existed on Mars
This has not been corroborated

24. Life on Jovian Moons
Europa
Titan
Others

25. Europa and Mars best potential for life to have evolved
Besides Earth, only two worlds in our solar system—the planet Mars and Jupiter’s satellite Europa—may have had the right conditions for the origin of life
Mars once had liquid water on its surface, though it has none today
Life may have originated on Mars during the liquid water era
Europa appears to have extensive liquid water beneath its icy surface
Future missions may search for the presence of life

26. The Nature and Evolution of Habitability
Habitability Zone
Past, Present, Future

27. The Search for Habitable Worlds
Planet Formation
Extrasolar Planets (>1000)
Detection Methods
“Earth-like” Planets

28. Infrared telescopes in space began searching for Earthlike planets
A new generation of orbiting telescopes may be able to detect terrestrial planets around nearby stars
If such planets are found, their infrared spectra may reveal the presence or absence of life

29. The Search for Extraterrestrial Intelligence
SETI
Drake Equation

30. The Drake equation helps scientists estimate how many civilizations may inhabit our Galaxy

31. The Geller ETI Sex Equation?
Consider the number of ETI life forms with whom humans could successfully have sexual relations:
Where:
Sx = Number of ETI civilizations with whom humans could have sexual relations.
N = Number of civilizations in The Milky Way Galaxy with electromagnetic emissions.
fs = Fraction of ETIs with dextro sugar stereo-isomers.
faa = Fraction of ETIs with levo amino acid stereo-isomers.
fcod = Fraction of ETIs with same codon interpretation.
fchr = Fraction of ETIs with same chromosomal length.
fmem = Fraction of ETIs with same cell membrane structure to allow egg penetration.

32. iClicker Question The Drake equation allows us to estimate
A the number of intelligent civilizations in our galaxy.
B the number of stars in our galaxy.
C the number of people on the Earth.
D the lifespan of a civilization.
E the lifespan of a species.

33. Interstellar Travel How realistic? Relativity and time dilation
Engineering
Limited by c
Relativity and time dilation
Wormholes and hyperspace?

34. iClicker Question
What limitation(s) make it close to impossible to travel, round trip, between stars?
I. Fuel requirements
II. The tremendous distances between stars
III. The finite speed at which objects can travel
A I
B I and II
C III
D II and III
E I, II and III

35. The Fermi Paradox Where are the aliens? Galactic colonization
Resolving the paradox

36. Contact – Implications of the Search and Discovery
Can we make contact
Which kind 1st, 2nd, 3rd
Contact implications

37. Radio searches for alien civilizations are under way
No signs of intelligent life have yet been detected
searches are continuing and using increasingly sophisticated techniques
The so-called water hole is a range of radio frequencies in which there is little noise and little absorption by the Earth’s atmosphere
scientists suggest that this noise-free region would be well suited for interstellar communication

38. If an alien civilization were someday to find this message, which of the features on the plaque do you think would be easily understandable to them?

39. 20 Tips for Interpreting Scientific Claims
Differences and chance cause variation
No measurement is exact
Bias is rife
Bigger is usually better for sample size
Correlation does not imply causation
Regression to the mean can mislead
Extrapolating beyond the data is risky
Beware the base-rate fallacy
Controls are important
Randomization avoids bias
Seek replication, not pseudoreplication
Scientists are human
Significance is significant
Separate no effect from non-significance
Effect size matters
Study relevance limits generalizations
Feelings influence risk perception
Dependencies change the risks
Data can be dredged or cherry picked
Extreme measurements may mislead

41. Extraterrestrial Altruism
Astrosociology:
A multidisciplinary study combining astrobiology and sociology

42. Book Based Upon Spring 2014

43. Astrobiology in One Sentence
The universe is unimaginably large, and alive; you are not at the center of the universe; and, the way to know the universe is through science
Dr. Harold Geller
HAVE A GREAT WINTER BREAK