The Cosmic Life I met in Baltimore
J. Hwang (KNU)“A Memorial Day Mini-Workshop on Life in the Universe” SNU 2009.06.06
Based on talks presented in STScI Spring Symposium 2009: “The Search for Life in the Universe” May 4-7 (2009). http://www.stsci.edu/institute/conference/spring2009
Life in the UniverseContingency (chance):
“Man at last knows that he is alone in the unfeeling immensity of the universe, out of which he emerged only by chance.”
Jacques Monod (1910-1976)Chance and Necessity (1971)
“We are glorious accidents of an unpredictable process with no drive to complexity, not the expected results of evolutionary principles that yearn to produce a creature capable of understanding the mode of its own necessary construction”
Stephen Jay Gould (1941-2002)Full House (1996)
Stephen Jay Gould
Life in the UniverseNatural outcome (law):
“The universe is pregnant with life…Life is a cosmic imperative!Life is almost bound to arise… wherever physical conditions are similar (to Earth).”
Christian de Duve (1917-)Vital Dust (1995)
“In it are an infinity of worlds of the same kind as our own.”Giordano Bruno (1548-1600)
On the Infinite Universe and Worlds (1584)
Giordiano Bruno
Biological Universe
•Geometrical Universe: ~17th century•Mathematical Universe: ~19th century
Celestial mechanicsPositional astronomy
•Physical Universe: 20th centurySpectroscopy
•Biological Universe?: 21st centuryMultidisciplinary!
Big Questions
• What is life?
• How did life originate?
• What is the course of life?
• What is the future of life on Earth and in the Universe?
• Are we alone in the Universe?
• Who are we?
Final Goal of Astrobiology
• “Reveal the origin, evolution, and distribution of life throughout the Universe in the context of cosmic evolution. And thereby to build the foundations for the construction and testing of meaningful axioms to support a theory of life.”
Horneck and Rettberg (ed.)
Complete course in astrobiology (2007)
Is there intelligent life elsewhere?
Five paths toward an answer:
1.Study the origin of life
2.Study extremophiles
3.Search for life in the Solar System
4.Study of extrasolar planets
5.Shortcut: SETI
Mario Livio
What are the relevant data?• Many suitable stars• Many planetary systems• Organics in ISM and Outer Solar System• Miller-Urey synthesis of amino acids• RNA world shows an intermediate step• Early appearance of life on Earth• Unity and common ancestor of life on Earth• Continuity of life on Earth over 3.5 Gyr• Life in extreme environments on Earth• Liquid water on other worlds• Rocks from Mars
Chris McKay
Signatures of Life• Extrasolar planets
– Atmospheric constituents– Vegetation’s red edge
• Solar System– In-situ experiments– Trace gas detection
E.g. methane on Mars• Homochirality
All known living organisms use only left-handed L-amino acids in proteins; right-handed D-sugars in nucleic acids.
William SparksChris McKay
Life as we don’t know it
Steve Benner
oo o
o
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H C NHOC C
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Paleogenetics
A path to the simplest first life
C C C N
Eucarya
interstellar organics
Life as a universal
HOC
NH2H
backwardsin time tosimplerlife
forwards from chemistry
Archaea Bacteria
infer ancestral life forms; resurrect for laboratory study
PrebioticChemistry
Synthetic biologyBaross, Benner et al. (2007) Natl. Res. Councl.Limits toLife
Ricardo et al. (2004) Science 303, 196
Benner et al. (2007) Adv. Enzymol. Mol. Biol. Protein Evol. 75, 1-132
Benner (2004) Acc. Chem. Res. 37, 784-797
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RH
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H HN N
N NO
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N NN NO
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H H
H
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N NN NN
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Construct life in the lab
Search cosmos
discover alien life
independent genesis?
H 1He 0.1O 8.3 . 10-4
C 4.0 . 10-4
N 1.0 . 10-4
Ne 0.8 . 10-4
Si 4.3 . 10-5
Mg 4.2 . 10-5
S 1.7 . 10-5
Fe 4.3 . 10-5
Na 2.1 . 10-6
P 3.0 . 10-7
Cosmochemistry
Pascale Ehrenfreund
OCNSP
History of Life on Earth• Beginning of our universe: 13.7Gyrs ago• Formation of the solar system: 4.6Gyrs ago
- Chemical evolution• Origin of life: 3.8 Gyrs ago
- Biological evolution, genetic takeover• Oxygen crisis: ~ 2 Gyrs ago• Multicellular life: 600 Myrs ago• Cultural evolution: ~ 100,000 yrs ago
- Intelligent life: 1960’s (Chris McKay)• Future:
- Directed evolution?- Robotic (AI) takeover? - Posthuman era?- Collapse? With
in this c
entury?
Solar System Timeline
~0.05 Gyr: Earth completed
0.7 Gyr: end heavy bombardment; life
2 Gyr: oxygen catastrophe
4.5 Gyr: NOW
~10 Gyr: Sun-like star becomes red giant
'life like us'
Jane Greaves, Impact
Future Life on Earth?
History of Life in the Universe
~0.05 Gyr: Earth completed
0.7 Gyr: end heavy bombardment; life
2 Gyr: oxygen catastrophe
4.5 Gyr: NOW
~10 Gyr: Sun-like star becomes red giant
'life like us'
Future Life on Earth?
13.7Gyrs ago
4.6Gyrs ago
present
~11Gyrs ago
Big bang
Our galaxyOur solar system
Geologic time
Warm (?)
Rise of atmospheric O2
First shelly fossils (Cambrian explosion)Snowball Earth ice ages
Warm
Ice age
Origin of life
(Ice age)
James Kasting, Atmosphere
Pascale EhrenfreundDes Marais (Science, 2000)
Oxygen crises
Janet Siefert, LUCA
Now
LUCA
Janet Siefert, LUCA
Five KingdomsThree levels of life: vegetative life (plants), sensitive life (animals), conscious life (man).
Aristotle, De Anima
Five Kingdoms:
Janet Siefert, LUCA
Three Domains
16S rRNA
Carl Richard Woese (1928-)
Doolittle, SciAmer
Janet Siefert, LUCA
“Never underestimate the complex, improbable beauty and creative potential of evolution.”
Horizontal Gene Transfer
“Another sample would be nice… really nice.”
On Earth the defining ecological requirement for life is liquid water. Operationally the search for life elsewhere in our solar system and beyond is first a search for liquid water.
Chris McKay
Follow the Water
Other worlds with liquids
Mars Europa TitanEnceladus
Past water CO2 and N2Cold preservationOrganics?
Ocean under iceSurface organics?
H2O jetOrganicsN2EnergyLiquid water?
Liquid CH4OrganicsEnergyActive cyclesLife?
Chris McKay
Increasing chance of life not related to Earth life
Rare Titan
Chris McKay
Scientists have discovered liquid (H2O) on another planet! however;• it is extremely corrosive to organics & inorganics• solution concentrations will be so high as to be toxic• high temperatures imply life reproduce on timescale of days• solid phase floats; rendering the polar & winter regions
uninhabitable and creating a climate feedback instability• its photolysis product, O2, poisons the atmosphere. • …proving the suitability of our Titan environment of liquid CH4
at normal temperatures and the intelligence of its design.
If we find organic material on Mars, Europa, Enceladus, or Titan how can we tell if it was ever alive?
If its like us then easy, less interestingIf its alien then hard, but interesting
“Nothing would be more tragic in the American exploration of space than to encounter alien life and fail to recognize it.”
COEL report 2007
Chris McKay, Sara Seager
Abiotic distributions are smoothBiotic distributions are spiked
McKay 2004 PLoS Biol 2(9)1260-12623
alien
Chris McKay
Squyres, Mars
Map of Mars showing H2O
P
Luann Becker, Mars
Michael Kelley, Mars
Strong Release of Methane on Mars in Northern Summer 2003M.J.Mumma, G.L.Villanueva, R.E.Novak, T.Hewagama, B.P.Bonev, M.A.DiSanti, A.M.Mandell, M.D.Smith. Science Jan. 15, 2009
• Methane varies with location, source strength rivals terrestrial gas seepso A strong peaks are seen over Terra Sabae,
Nili Fossae, and Syrtis Major (SE quadrant) o The source strength > 0.6 kg/sec
• Methane and water are sometimes correlated, but not always so
• Lifetime of methane is <4 yearso Methane lifetime from photo-chemical
destruction is ~350 yearso Need new model for its destruction, perhaps
oxidants on airborne dust
The big question: Is methane produced biologically or geologically? Either way, Mars must be active today
R1 &R0 methane lines are detected and mixing ratios vary from <3ppbv – 60ppbv
Michael Kelley, Mars
Michael Mumma, Mars
Features created by life Features created by nonbiological processes
"Biosignatures :" features created ONLY by life
Features created ONLY by nonbiological processes
Ambiguous features
Recognizing Extraterrestrial Biosignatures
Michael Kelley, Mars Mars Meteorite ALH84001
Viking Landers experiments
Ambiguous cases
"Observation Year" vs "Number" (329개)
1 1 0 0 2 1 1 161
10 8
2419
27
17 19
33 33
57 59
9
0
10
20
30
40
50
60
70
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Year
Number
Extra-solar Planets
Dongwan Kim 김동완
김동완
김동완
Hot Jupiter Gas Giant
김동완
Solar system bias
김동완
Habitable Zone
김동완
Moore’s law exponent: t1988=20yr/log2320=2.4yrt1992=16yr/log2318=1.9yr
COROT
KEPLER
김동완
Solar System at 10pc
39
17.5 mag,10 million
25 mag,10 billion
Lisa Kaltenegger
Biomarkers on Exo-Earth“Good planets are hard to find.”
Ronald N. Bracewell (1921-2007)
Lisa Kaltenegger
Telescope size matters
HST 2.4-m JWST 6.5-m ATLAST 8-m ATLAST 16-m
1.5 m 2.4 m 4 m 10 m
Ref.: (upper) M. Postman et al., ATLAST study; (lower) W. Cash et al., NWO study.Wesley Traub
Advanced Technology Large-Aperture Space Telescope
1. Earth-like planets around Sun-like stars 2. Organics (any) on Mars 3. O3 or O2 detected on any x-planet 4. Samples from Enceladus5. Reconstructed-deconstructed life in the lab6. Retirement 7. Landing on Europa8. Revisit Titan
C. McKay is waiting for:
Chris McKay
Any Detectable Technology Will Be Older Than We Are
TimeTech
nolo
gy UsTechnological Revolution
TimeTech
nolo
gy Disaster
If technology is short-lived,then
we will not find them
If technology is long-lived,then
we will find them here
Unless technology is long-lived, SETI will not succeed. “The probability of success is difficult to estimate;but if we never search, the chance of success is zero.”
Cocconi and Morrison (1959)
SETI
Jill Tarter
Great silence problem:“Where are they?”
Enrico Fermi (1901-1954)
One possible answer (out of more than 50):“The Great Filter”
Robin Hanson (1998)
Civilizations are destined to collapse prematurely. Is the filter in our past or in our future?
“It would be good news if we find Mars to be completely sterile. Dead rocks and lifeless sands would lift my spirits.”
Nick Bostrom (2008)
Fermi Paradox
Paul Davis
Jeffrey Bada, Origins of Life
Search for Life in the Universe
“SETI is a search for ourselves –who we are and where we fit into the universe”
Frank Drake
We shall not cease from explorationAnd the end of all our exploringWill be to arrive where we startedAnd know the place for the first time.
T. S. Eliot (Four Quartets, No 4, 1942)
