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

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Physiosphere

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