Searching for Habitable New Worlds and Life in the Universe Hosted by Night Sky Network.
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Transcript of Searching for Habitable New Worlds and Life in the Universe Hosted by Night Sky Network.
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?
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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. .. . ..
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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
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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. . .
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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)
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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