Searching for Habitable New Searching for Habitable New WorldsWorlds

andand

Life in the UniverseLife in the Universe

Hosted by

Night Sky Network

Universal Universal LawsLaws of Biology ? of Biology ?

Lawrence Hall of Science

Liquid WaterLiquid Water

DNADNA

IntelligenceIntelligence

Is there life Is there life elsewhere in ourelsewhere in ourSolar System?Solar System?

The Only Known Site of BiologyThe Only Known Site of BiologyIn the Universe.In the Universe.

MarsMars

Liquid WaterLiquid WaterImpossibleImpossible

Pressure Pressure = 0.01 of Earth= 0.01 of Earth

. . . too low for. . . too low forLiquid water.Liquid water.

Jupiter and Two Moons

IoIo EuropaEuropa

Surface of Jupiter’s Moon: :

EuropaEuropa

Fractures inFractures in Floating IceFloating Ice

IcebergsIcebergs

Jupiter’s MoonJupiter’s Moon: EuropaEuropa

Sub-CrustSub-CrustOceanOcean ....

Life in the Ocean?

..

Hydrogen-Carboncompounds likely:

Amino acids

First New Ocean

Since Balboa

Now Exiting our Solar System to …Now Exiting our Solar System to …

The Milky Way Galaxy. .. . ..

. .. . . .. .

..

. . ..

. . ..

..

Meanwhile, we are hunting for abodesBeyond our Solar System

The Discovery of Other

Collaborators: Paul Butler, Debra Fischer, Steve Vogt Chris Tinney, Greg Laughlin, Hugh Jones

Andrew Cumming, Greg Henry,

Jack Lissauer Jason Wright, Brad Carter, Eugenio Rivera, Chris McCarthy, John Johnson

www.exoplanets.org

Planet DetectionPlanet Detection

Wobble of Star:Wobble of Star:

Gravitational pullGravitational pullby the planetby the planet

VVPLPL2 2 == G MG MStarStar / r / r VVPL PL ~ 10 ~ 10 km/skm/s

VVStarStar = = VVPLPL VVSTARSTAR ~ 10 ~ 10 m/sm/s

xx (M(MPLPL /M /MJUPJUP))

Momentum:Momentum:

WobbleWobbleVelocityVelocity

MMPLPL

MMSTARSTAR

Energy Equipartition:Energy Equipartition:

( )

12 years12 years . . . Jupiter . . . Jupiter

(Met

ers/

sec)

(Met

ers/

sec)

Need Telescope . . .

World’s most World’s most Successful Planet Successful Planet

SearchSearch

1997 – Present1997 – Present

Survey: 1300 Nearby Stars

Keck 1

Echelle Spectrometer

CCD

Echelle

Grating

Collimator

StarlightStarlight

From TelescopeFrom Telescope

High Resolution ``Echelle”High Resolution ``Echelle”

SpectrometerSpectrometer

Spectrum of Star:Spectrum of Star:

Doppler EffectDoppler Effect

Doppler Precision:Doppler Precision:v / c ~ 10v / c ~ 10-9-9

~ 10~ 10-9-94096 Pixels

16 Cygni 16 Cygni BBMass = 1.7 M

JUP (Min)

Orbit PeriodOrbit Period

2.2 yr2.2 yr

Not SinusoidalNot Sinusoidal

VelocitVelocit

yy

WobbleWobble

Orbit of Planet around 16 Cygni

16 Cygni: Planet & Moon

Life on Gas Giant Planets ?Life on Gas Giant Planets ?

FloatersFloaters

Earth-Like MoonEarth-Like Moon

Mass = 0.62 MMass = 0.62 MJUPJUP

70 Days70 Days

Upsilon AndromedaeUpsilon Andromedae::Velocity ResidualsVelocity Residuals

0.6 M0.6 MJUPJUP

2 M2 MJUPJUP

4 M4 MJupJup

Upsilon Andromedae:Upsilon Andromedae:

Triple Planet SystemTriple Planet SystemPlanets havePlanets haveNo NamesNo Names

..

..

..

..

.

..

..

..

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Upsilon AndromedaeUpsilon Andromedae

Per = 1.94 dPer = 1.94 d

M = 7.5 MM = 7.5 MEarthEarth

Gliese 876 dGliese 876 d

Lowest Mass Exoplanet :Lowest Mass Exoplanet : 7.5 Earth-Masses7.5 Earth-Masses

1.94 Days1.94 Days 5 m/s

Three Planets Orbiting Gliese 876

7 1/2 Earth-masses

Ring in Between:Ring in Between:

LukewarmLukewarm

Hot:Hot:370 C370 C

Cold:Cold:-100 C-100 C

7.5 Earth-Mass Planet 7.5 Earth-Mass Planet Orbiting Gliese 876Orbiting Gliese 876

Tides:Tides:

One Planet Side One Planet Side

always Faces Staralways Faces Star

Milky Way GalaxyMilky Way Galaxy

200 billion stars200 billion stars

~10% of all Stars ~10% of all Stars

have have detecteddetected planets. planets.

Detected so far:• Jupiter-mass• Saturn-mass• Neptune-mass

~ Earth-Mass ?~ Earth-Mass ?

More Low-MassMore Low-MassPlanetsPlanets

Planet MassPlanet Mass

Only Known Abode of Life

But are theyBut are theyHabitable ?Habitable ?

Must EnvironmentsEnvironmentsBe “Just Right”For Life ?

Conclusion: Many Earth-Conclusion: Many Earth-massmass Planets Planets

Yellowstone National Park :Yellowstone National Park :

Suitable for Life ?Suitable for Life ?

• Boiling GeysersBoiling Geysers• Freezing winterFreezing winter• Sulfuric acid.Sulfuric acid.

One of the Least Hospitable Places on Earth:

YellowstoneYellowstone

Pinwheel GeyserPinwheel Geyser

BacteriaBacteriaThriveThrive

Near Boiling:Near Boiling:T ~ 80 CT ~ 80 C

Water: AcidicWater: Acidic

as battery acidas battery acid

Each colorEach colora differenta differentspecies ofspecies ofbacteriumbacterium

Life at High TemperatureLife at High Temperatureand High Acidityand High Acidity

Temp = 65 CTemp = 65 C pH = 2 pH = 2

YellowstoneYellowstone

Yellowstone

Churning CauldronChurning Cauldron

Boiling TempBoiling Temp

Yellowstone

Churning CauldronChurning Cauldron

Boiling Temp,Boiling Temp,pH = 2pH = 2

Bacteria &Bacteria &Algae Algae Thrive Thrive

AlgaeAlgae

pH = 2pH = 2

CorrosionCorrosion

Cyanidium CalderiumCyanidium CalderiumLife atLife at

Extreme TempExtreme Temp&&

Extreme AcidityExtreme Acidity

Lives only atLives only atT > 60 CT > 60 C

Extremophiles Show that LifeExtremophiles Show that Life

• Tolerates heat or cold

• Takes food from a variety of sources

• Thrives in acidic or alkaline environments

• Copes with Intense Solar Radiation - - or none!Copes with Intense Solar Radiation - - or none!

Liquid Water LifeLiquid Water Life

Primitive Life:Primitive Life: Common in the Universe Common in the Universe

Is our Milky Way GalaxyIs our Milky Way Galaxy Teeming with Intelligent Life ?Teeming with Intelligent Life ?

• Galaxy is Galaxy is 10 Billion Years Old10 Billion Years Old - - - Twice the Age of Earth- - - Twice the Age of Earth

• 50% of Stars are50% of Stars are as Old as the Sun & Earth as Old as the Sun & Earth

Many stars & planets older Many stars & planets older by billions of years!by billions of years!

How Many Civilizations ?How Many Civilizations ?

Is our Milky Way TeemingIs our Milky Way Teemingwith Intelligent Life ?with Intelligent Life ?

• 20 Billion 20 Billion Planetary Systems:Planetary Systems: 1/2 are older than Earth1/2 are older than Earth

• What fraction have What fraction have Intelligent Life? Intelligent Life? • PessimistPessimist: 1 in a Million: 1 in a Million

There must be Thousands of Civilizations There must be Thousands of Civilizations In the Milky Way Galaxy. . .In the Milky Way Galaxy. . .

. .

.

.

.

.

.

..

.

.

..

.

Where is Everybody?Where is Everybody?Why Didn’t They Come Here?Why Didn’t They Come Here?

• Moon: Moon: No Alien Spacecraft, Crash Debris, ObeliskNo Alien Spacecraft, Crash Debris, Obelisk• Mars: Same StoryMars: Same Story• Earth: Earth: Lovely Planet for 4 Billion Years . . .Lovely Planet for 4 Billion Years . . .

Yet, no Alien Settlement.Yet, no Alien Settlement.

• 100’s of Telescopes: No Alien Ships spotted100’s of Telescopes: No Alien Ships spotted• Night Sky: No Exotic Rocket ExhaustNight Sky: No Exotic Rocket Exhaust• No Robotic Probes Visit Solar SystemNo Robotic Probes Visit Solar System

• SETI: No Radio Signals in 40 years.SETI: No Radio Signals in 40 years.

Where Where IsIs Everybody? Everybody?• Hypothesis: - Thousands of Civilizations in GalaxyThousands of Civilizations in Galaxy - Head Start of Billions of years.- Head Start of Billions of years. They should be Near!They should be Near!

• Migration Throughout Galaxy: Easy with robotic spacecraft=================================================

• Observation: No Aliens Detected, and no Traces.

• Conclusion: Hypothesis possibly flawed.Hypothesis possibly flawed.

( Ants eventually find your Kitchen)( Ants eventually find your Kitchen)

.

• •

•

•

•

•

•

•

•

•

•

How Long doTechnological

Civilizations Last?

Expect: 1000Expect: 1000 CivilizationsCivilizations in 5 Billion Yearsin 5 Billion Years

For Multiple Civilizations Today, For Multiple Civilizations Today, Lifetimes Must Overlap:Lifetimes Must Overlap:

Lifetime > 5 Million yrLifetime > 5 Million yr

Recipe for Recipe for Exobiology:Exobiology:

PlanetsPlanets ChemicalsChemicals WaterWater Energy - - -Energy - - - Stars, Tidal, GeothermalStars, Tidal, Geothermal

Life:Life:Probably Probably Common Common in the in the Universe.Universe.

Primitive Life, at leastPrimitive Life, at least

February 5, 1996

SETISETIATA: Proposed Radio Telescope ArrayATA: Proposed Radio Telescope Array

Life in our Milky Way Galaxy:Life in our Milky Way Galaxy:

Primitive Life: CommonIntelligence: Rare ?

IntelligenceIntelligence

Semi-Intelligent Life formsSemi-Intelligent Life forms

....

www.exoplanets.org