Post on 20-Jan-2015
description
Life Beyond Earth
Our Solar System
Our Solar System
Our Solar System
The Planets
Our Solar System
The Planets
Our Solar System
The Planets Moons
Our Solar System
The Planets Moons
Our Solar System
The Planets Moons
Dwarf Planets
Our Solar System
The Planets Moons
Dwarf Planets
Our Solar System
The Planets Moons
Dwarf Planets
Our Solar System
The Planets Moons
Dwarf Planets Asteroids and Comets
What do we need for life on Earth?
What do we need for life on Earth?
•The right chemical elementsOxygen Hydrogen Carbon IronSilicon NitrogenCalcium
What do we need for life on Earth?
•The right chemical elementsOxygen Hydrogen Carbon IronSilicon NitrogenCalcium
What do we need for life on Earth?
•The right chemical elements•Liquid water
What do we need for life on Earth?
•The right chemical elements•Liquid water •The right temperature range
0 - 100 Celsius
What do we need for life on Earth?
•The right chemical elements•Liquid water•The right temperature range•An atmosphere
shields planet traps heat
What do we need for life on Earth?
•The right chemical elements•Liquid water •The right temperature range•An atmosphere•Enough gravity
What do we need for life on Earth?
•The right chemical elements•Liquid water •The right temperature range•An atmosphere•Enough gravity•Volcanic activity
What do we need for life on Earth?
•The right chemical elements•Liquid water •The right temperature range•An atmosphere•Enough gravity•Volcanic activity
...The ‘Habitable’ Zone!
too close…
too far…
just right!
Now that we know what a planet needs for life...
Now that we know what a planet needs for life...
...what exactly are we looking for on other planets?
Micro-organisms!
Micro-organisms!•Dominate terrestrial life
•Existed on Earth for over 3.5 billion years
Micro-organisms!•Dominate terrestrial life
•Existed on Earth for over 3.5 billion years
Micro-organisms and extremophiles
Life exists at extremes of:–acidity / alkalinity–salt solution–pressure–temperature–1km below the surface–darkness
Antarctica
Underwaterheat vents
What about finding life in our solar system?
What about finding life in our solar system?
Mars
What about finding life in our solar system?
Mars Europa
What about finding life in our solar system?
Mars Europa Titan
Exploration of MarsFlyby (4 successes)
Exploration of MarsOrbiter (11 successes)
Exploration of MarsLander (4 successes)
Exploration of MarsRover (3 successes)
Exploration of MarsOpportunity’s Path
atmosphere of CO2
in habitable zoneT range -127 to 17oC
waterwater vapourin ice capsin cratersdry river beds
atmosphere of CO2
in habitable zoneT range -127 to 17oC
waterwater vapourin ice capsin cratersdry river beds
Methane on Mars
• Plumes of methane mean something has to be generating methane
• Source = subsurface -- geological or bacterial?
• http://www.nasa.gov/mission_pages/mars/news/marsmethane.html
ESA Exomars (2009)NASA Mars Science Laboratory (2010+)Sample return missions (~2014)
Human missions to Mars (~2040)
Europa
Europa
Could extremophiles live on Europa?
Drill through ice without contamination = HARD!
NASA Jupiter’s Icy Moons Orbiter 2011+
Titan
Titan• Thick methane
atmosphere with lots of Nitrogen.
• Only other nitrogen domiated atmosphere except Earth
• May be pre-biotic atmosphere, like early Earth.
• Lakes of methane--good organic solvent.
ExoplanetsPlanets around stars other than our Sun in our galaxy,
the Milky Way
ExoplanetsPlanets around stars other than our Sun in our galaxy,
the Milky Way ... about 500 so far!
Aug
ust 2
010
ExoplanetsPlanets around stars other than our Sun in our galaxy,
the Milky Way ... about 500 so far!
Aug
ust 2
010
detect by transit
detect by radial velocity
detect by imaging
Detection Methods:radial velocity
• Star moves because of planet’s gravity pull
• Measure motion of star along our line of sight to get period of orbit
Detection Methods:transit
• Planet moves in front of star during its orbit• Light from star is dimmed because planet is
in front of it
Detection Methods:direct imaging
• Take a picture of a planet around a star• Hard to do because planets are faint and
stars are bright
Hot Jupiters
• Most extrasolar planets we have found are “hot Jupiters”
• Most are 1 to 13 x Mass of Jupiter• Most are located 10 x closer to their star
than Earth• Most are around Sun-like stars (because
they are easily observed using radial velocity)
Hot Jupiters
• Most extrasolar planets we have found are “hot Jupiters”
• Most are 1 to 13 x Mass of Jupiter• Most are located 10 x closer to their star
than Earth
Hot Jupiters
• Most extrasolar planets we have found are “hot Jupiters”
• Most are 1 to 13 x Mass of Jupiter• Most are located 10 x closer to their star
than Earth• Most are around Sun-like stars (because
they are easily observed using radial velocity)
• Densities are very different
Earth-like Planets
• Kepler Telescope lets us look for Earth-mass planets in the habitable zone of other stars
• Also finds “super Earths” which are 1 to 10x mass of Earth but are not gas balls
• More common than Jupiter-mass planets but VERY new area of research
Earth-like Planets
• Are any of these planets actually like Earth?:– Air, water, rocks, life, etc?
• Could we visit one of these planets?– How? Why or why not?
• Could we communicate with one of these planets?– Have we tried already? How would we identify
communication from another planet?
Intelligent Alien Life
–Pioneer probes sent out of solar system
–Best chance of encountering extraterrestrial life
Intelligent Alien LifePlaque on Pioneer 10 probe
The End