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