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Extra-terrestrial life:
Is there anybody out there?
Dr Martin Hendry
University of Glasgow
Reach
for the
Stars
Is there Anybody Out There?
Life in the Solar System?
Extra-Solar Planets
Searching for Life
Life in the Solar System
Runaway Greenhouse Effect
Formation of the Moon:
Impact from Mars-sized
planetesimal during first
aeon.
Impact energy = 1 million million megatons
5 billion cubic miles of the crust sprayed
into space
Atmosphere ejected into space
Ring of ejecta coalesces into Moon
Is there life on Mars?…
Is there life on Mars?…
Mars 2004:
 Mars Express ( + Beagle 2)
 Spirit + Opportunity
Jan 23rd 2004:
Mars Express
Orbiter detects
water ice at the
South Pole of Mars.
Jan 23rd 2004:
Mars Express
Orbiter detects
water ice at the
South Pole of Mars.
Jan 23rd 2004:
Mars Express
Orbiter detects
water ice at the
South Pole of Mars.
H2O
CO2
Visible light
Water on Mars
Images suggest flowing water
on Mars in the past
Mars
Earth
2mm
The moons of
Jupiter
Isaac Newton:
1642 – 1727 AD
The Principia: 1684 - 1686
The tidal pull of the Moon on the Earth
Galileo’s Moons
Inside Europa
Could there be life?…..
EXTRA-SOLAR PLANETS
The stars are VERY far away. The
nearest star (after the Sun) is about
40 million million km from the Earth.
It takes light more than 4 years to
travel this distance..
If the distance from the Earth to the Sun
were the width of this screen, the nearest
star would be in Paris !!!!
Wobbling stars: the key to finding
extra-solar planets
Planets are too faint to see directly
but
Planets and stars orbit their
common centre of mass
- so stars wobble
The Sun’s “wobble”, due to Jupiter, seen from 30 light
years away = width of a 5p piece in Baghdad
The Electromagnetic
Spectrum
Doppler Shift
Star
Laboratory
The origin of spectral lines
Absorption
ee-
Emission
ee-
Star
Laboratory
51 Peg – the first new planet
What have we learned about exoplanets?
Highly active, and rapidly changing, field
Aug 2000: 29 exoplanets
What have we learned about exoplanets?
Highly active, and rapidly changing, field
Aug 2000: 29 exoplanets
2004: ~120 exoplanets
What have we learned about exoplanets?
Highly active, and rapidly changing, field
Aug 2000: 29 exoplanets
Up-to-date summary at
http://www.exoplanets.org
Now finding planets at larger
orbital semimajor axis
2004: ~120 exoplanets
Looking to the Future
1.
The Doppler wobble technique will not be sensitive enough to
detect Earth-type planets (i.e. Earth mass at 1 A.U.), but will
continue to detect more massive planets
Looking to the Future
1.
The Doppler wobble technique will not be sensitive enough to
detect Earth-type planets (i.e. Earth mass at 1 A.U.), but will
continue to detect more massive planets
2.
The ‘position wobble’ (astrometric) technique will detect
Earth-type planets – Space Interferometry Mission in 2009
(already done with HST in Dec 2002 for a 2 x Jupiter-mass planet)
Looking to the Future
1.
The Doppler wobble technique will not be sensitive enough to
detect Earth-type planets (i.e. Earth mass at 1 A.U.), but will
continue to detect more massive planets
2.
The ‘position wobble’ (astrometric) technique will detect
Earth-type planets – Space Interferometry Mission in 2009
(already done with HST in Dec 2002 for a 2 x Jupiter-mass planet)
3.
The Kepler mission (launch 2007?) will detect transits of
Earth-type planets, by observing the brightness dip of stars
(already done in 2000 with Keck for a 0.5 x Jupiter-mass planet)
Looking to the Future
1.
The Doppler wobble technique will not be sensitive enough to
detect Earth-type planets (i.e. Earth mass at 1 A.U.), but will
continue to detect more massive planets
2.
The ‘position wobble’ (astrometric) technique will detect
Earth-type planets – Space Interferometry Mission in 2009
(already done with HST in Dec 2002 for a 2 x Jupiter-mass planet)
3.
The Kepler mission (launch 2007?) will detect transits of
Earth-type planets, by observing the brightness dip of stars
(already done in 2000 with Keck for a 0.5 x Jupiter-mass planet)
There was a (rare) transit of Mercury on May 7th 2003,
and a (very rare) transit of Venus on June 8th 2004
Looking to the Future
4.
NASA: Terrestrial Planet Finder
ESA: Darwin
}
~ 2015 launch
These missions plan to use nulling interferometry to ‘blot out’
the light of the parent star, revealing Earth-mass planets
Looking to the Future
4.
ESP
NASA: Terrestrial Planet Finder
ESA: Darwin
}
~ 2015 launch
These missions plan to use nulling interferometry to ‘blot out’
the light of the parent star, revealing Earth-mass planets
Follow-up spectroscopy will search for signatures of life:Spectral lines of oxygen, water
carbon dioxide in atmosphere
Simulated ‘Earth’ from 30 light years
What will TPF look for?….
Earth from 30 lyrs
Is there anybody out there?….
….if there isn’t, it seems
a terrible waste of space !!!!