The Search for Extra-Terrestrial
unIntelligence
Jonathan Tennyson
Department of Physics and Astronomy
University College London
"The two most common things in the universe are hydrogen and stupidity."
Is there anybody out there?
At least 100 thousand million (1011 or 1012) stars in the milky way
At least 100 thousand million (1011 or 1012) galaxies in the universe
Sagittarius Star Cloud / Hubble Space Telescope
How to find aliens
1. Hope that they visit us
2. Listen for their signals
3. Look for them
Search for
extraterrestrial
intelligence
(SETI)
The Arecebo
telescope
SETI: >500,000,000 screensaver downloads
and counting ……What has been found?
Nothing
Extra solar planets
Kepler (the mission)
Earth-size planet transiting Sun-type star ~
0.01 %
Kepler (NASA)
launch 2009
More than 1200 planetary
candidates discovered by
Kepler!
Exoplanets are common…
10
Jupiter—Sun: 15 m/s
Present sensitivity: 1 m/s
Earth—Sun: 0.09 m/s
Characterizing extrasolar planets
You are here!
Habitable zone for different stars
“Goldilocks zone”
Earth and moon from
the Galileo spacecraft
Can one detect
the signature of
life on Earth?
NASA’s Galileo Satellite
Launch 1989
Arrived at Jupiter 1995
“Flatulent ruminoids”
Segan et al, Nature (1995)
100 million+
years ago –
Plenty of
methane
emissions?
Multicell-
1
0.1
Human
s
Invertebrates
Oxygen
0.01
Eukaryotes
0.001
Prokaryotes
Oxygen!!!
0.0001
Methane ?
0.00001
4.5
4
3.5
3
2.5
Time (Gy)
2
1.5
1
0.5
0
Rye and Holland, 1998
How far is it to the nearest star?
A long way!
“ We will never know how to study by any
means the chemical composition (of stars), or
their mineralogical structure ”
Auguste Comte (1835)
Fraunhofer’s map of the solar spectrum
High resolution optical spectrum of the Sun
Jumping between energy levels
in an atom or molecule
Energy
Level 3
photon
photon
Level 2
Level 1
Absorption
Emission
Methane in the Earth’s atmosphere
Before
photosynthesis
After
photosynthesis
A pale blue dot, at 6 billion km away…
() C. Sagan
Direct observation of star GQ Lupi
and its planet GQ Lupi b
Direct observation
109 photons in the VIS -> Coronagraph
106 photons in the IR -> Nulling interferometry
Transit of Venus
June 8th 2004.
Next
June 5th 2012.
Radial velocity / Occultation
HD 209458b
Period = 3.524738 days
Mass = 0.69 ±0.05 MJupiter
Radius = 1.35 ±0.04 RJupiter
Density = 0.35 ±0.05 g/cm3
NASA’s Spitzer space telescope
Primary transit + IR + Spitzer
Beaulieu et al., 2007
Knutson et al., 2007
Water line list: BT2
Barber et al., 2006
Water, T-P at the terminator
Tinetti et al., Nature, 444, 169 (2007)
Pont et al., 2007
Swain et al., 2007
Knutson et al., 2007
Methane, plus
Confirmation of
water and hazes!
Beaulieu et al., 2007
So far discovered:
Water
H 2O
Methane
CH4
Carbon dioxide
CO2
Carbon monoxide CO
Hydrogen cyanide HCN
On HD189733b
with more to come
HD1897733b too hot for life
Giovanna Tinetti, UCL
Transit hunters
Transits of objects down to
Earth-size
COROT (CNES/ESA)
launch Dec. 2006 (mission extended)
25 transiting planets found
including 1 super-earth
Kepler (NASA)
launch 6 March 2009. 3.5 year mission:
22 confirmed planets so far + >1200 candidates
The New World Observer
NWO is a large-class Exoplanet mission that employs two
spacecrafts: a “starshade” to suppress starlight before it enters
the telescope and a conventional telescope to detect and
characterize exo-planets.
Cash, Nature, 2006
Exoplanet Characterisation Observatory
V-groove side
sunshield
Telescope Baffle
1.5m silicon
carbide mirror
Detectors
Service Module
GaAs
Solar
Cells
Exoplanet Characterisation Observatory
• 1.2 to 1.5m dedicated telescope
• L2 halo orbit, direction anti-Sun
• Broadband spectral coverage from VIS to IR ( 0.4 to 16 µm )
• Maximum spectral resolution R=300
• 5 year mission
PI Giovanna Tinetti (UCL)
launch 2022?
A year in the life of
July 10 Talk WCGS Science Conference
July 10 European Space Agency (ESA) formal call for M3 missions
Oct 10 European Research Council (ERC) awards me 2.5 MEuros for
ExoMol: Molecular line lists for exoplanet & other atmospheres
Nov 10 59 Expressions interest to ESA
Dec 10 43 Formal bids to ESA
Jan 11 13 bids selected (including EChO)
Feb 11 8 bids selected (including EChO)
March 11 4 bids selected for further study:
EChO, LOFT, MarcoPolo-R, STEQUEST
May 11
ExoMol project starts
June 11 UK Space Agency + PPARC select EChO as top priority
Future timelines (approximate)
2011-13
2014
2015-19
2019-21
2022
Specification and testing
“Down selection”
Instrument and satellite build
Assembly and testing
Launch ?
Linelists completed or
under construction @ UCL by
H3+ Liesl Neale (H2D+ Taha Sochi)
H2O Bob Barber (HDO Boris Voronin)
13CN/ H13CN) Greg Harris
HCN/HNC
(
H
The ExoMol project
+
HeH Elodie Engel
NH3 Bob Barber and Sergei Yurchenko (Dresden)
HCCH Andrea Urru
C3 Santina La Delfa and Taha Sochi