ASTR-3040: Astrobiology Day 11 The Nature of Life on Earth Chapter 5.
ASTROBIOLOGY IS THE STUDY OF LIFE ACROSS THE UNIVERSE. PARTICULARLY: 1.The Origins of Life 2.The...
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Transcript of ASTROBIOLOGY IS THE STUDY OF LIFE ACROSS THE UNIVERSE. PARTICULARLY: 1.The Origins of Life 2.The...
ASTROBIOLOGY IS THE STUDY OF LIFE ACROSSTHE UNIVERSE.
PARTICULARLY:1. The Origins of Life2. The Distribution of Life3. The Destiny of Life
ASTROBIOLOGY
IDENTIFICATION OF LIFE
THE TRADITIONAL CHARACTERISTICSOF LIFE INCLUDE
RespirationDigestionEliminationReproductionMotilitySensation
MAJOR LIFE CATEGORIES ON EARTH
Anaerobic AerobicAerobic
ESSENTIALS OF COMMON LIFE ON EARTH
Anaerobic
Aerobic
EXTREMOPHILES
Water>70%
AciditypH 4-8
SubstrateViscosity (cP=1)
Atmosphericsc 7-35 lbs/in^2
O2 = c 20%CO2 = 3ppm
Toxic-tolerantMetals
Non-Metals
Temperature0-100 C max
15-60 C optimal
Environmental range of common life on earth…
Range for >80% of earth lifeRange for >80% of earth life
ExtremophilesFamiliar
XenophilesUnfamiliar
TransitionalNear-Life or
Life-Like
ECOSYSTEMS
Fringe for <20% of earth lifeFringe for <20% of earth life
THE GOLDILOCKS THEORY0
The occurrence of life at a given place in the universe is a statistical probability.It can be expressed in terms of “Drake’s Equation”
The Drake equation states that:
N=R* x fp x ne x fl x fi x fc x L
where:
N is the number of civilizations in our galaxy with which we might expect to be able to communicateat any given time, andR* is the rate of star formation in our galaxy fp is the fraction of those stars which have planets ne is average number of planets which can potentially support life per star that has planets fl is the fraction of the above which actually go on to develop life fi is the fraction of the above which actually go on to develop intelligent life fc is the fraction of the above which are willing and able to communicate L is the expected lifetime of such a civilization
THE RATE OF STAR FORMATION (R*)
0 5 10 152.5
Origin of Milky Way
Galaxy
Sol
1
2
N …Detecting life may require searching planets whichhad life in the past (1,2),
or will develop life in the future (3).
Detecting life may require searching planets whichhad life in the past (1,2),
or will develop life in the future (3).
Life may be nascent and ‘yet-to-form’, or deceased, ‘long-since-gone’
20
B I L L I O N Y E A R S
THE GOLDILOCKS THEORY1
Too Hot Too Cold Just Right
G
O
M
Given Drake’s Equation, we hope to find common life in Habitable Zonescomparable to Earth’s common life forms.
273K 373KLiquidH2O
THE GOLDILOCKS THEORY2
Too Hot Too Cold Just Right
G
OGiant Stars
MDwarf Stars
We also look for Habitable Zones compatible with Earth’s Extremophiles
273K 373KLiquidH2O
Moons ofJupiter &Saturn
Gas Giant Planets can create
geologic interior gravitational tides
which heat the moons thru ocean
venting.
THE GOLDILOCKS THEORY3
Too Hot Too Cold Just Right
G
OGiant Stars
MDwarf Stars
273K 373KLiquidH2O
In addition, anomalies can create Habitats outside recognizable habitable zones.
Terrforming
LIFE’s PROGRESSION ON EARTH
ArcheanEoarchean Era (3800 mya)
ProkaryotesAchaeansAnaerobic bacteria
Paleoarchean (3600 mya)Aerobic bacteria
MesoarcheanStomatolites
NeoarcheanProterozoic
Proto-Proterozoic (1800 mya)Complex single-celled
lifeNeo-Proterozoic (630 mya)
Multiple celled organisms
sustain an oxygenatedatmosphere …
PhanerozoicPaleozoic (412 mya)
Life moves to land (terra firma)
H2 bonds w/ gasesfrom volcanoes;
the atmosphere ispredominantly
greenhouse gasesNH3, CH4 & H2O
w/ others
Life starts terraforming earth;
adding O2 & N2
The atmosphere is predominantly
N2, O2 and H2O w/ CO2
NH3 (Ammonia)
CH4 (Methane) O2
CO2
N2
Achaean Life Begins
Aerobic Life Begins
The AtmosphereIs in Continuous
Transition
Nitrogen Cycle
OxygenCycle
THE ATMOSPHERELife on Earth is in symbiosis with the atmosphere …
LIFE & ITS ECOSYSTEMS1
AutotrophsFood Producers
HeterotrophsFood Consumers
SaprotrophsFood Decomposers
Biogenic Elements Biogenic Elements
Continuous Sourceof Energy
Continuous Sourceof Energy
UV Wave ProtectionUV Wave Protection
Gaia hypothesis suggests life can be detected on a planetary scaleBy tell tale signs, biomarkers or other indicators.
Markers of Life include•Waste gases such asMethane gas orother organic materials;•Waste alcohol;•Regenerated gases,e.g. O2•Seasonal color changes
QUESTIONS1
How did life begin?Is it planetary on-site,or Panspermic?
Physiosphere
Biosphere
Noosphere
ReplicationOrganic CompoundsMolecules
Microbial CellsMetabolic ActivityBiochemical Reactions
Sentient Thought & AwarenessInstinctive BehaviorPhoto-Chemical Response
ElementsHydrogen AtomsNuclear ParticlesDark MatterSingularity
The Evolutionary Process
The essentialElements of life, The Biogenics The Energy The UV Protectionhave been found on Planets in our Solar System, planetary discs beyond our solar system, and in galactic compositions, beyond the Milk Way…
QUESTIONS2
Common life formsFound on earth …
Common life formsFound on earth …
Given evolutionary potential for extremophiles, how is lifedistributed across the Universe?
Given evolutionary potential for extremophiles, how is lifedistributed across the Universe?
? Bacteria
Eukaryotes Achaeans
Is evolution necessarilyparallel for life everywhere?
QUESTIONS3
What is the fate of life in the universe?
Biosphere
Noosphere
ReplicationOrganic CompoundsMolecules
Microbial CellsMetabolic ActivityBiochemical Reactions
Sentient Thought & AwarenessInstinctive BehaviorPhoto-Chemical Response
ElementsHydrogen AtomsNuclear ParticlesDark MatterSingularityThe Evolutionary Process
???????
Physiosphere
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