Titan
1 March 2016
Titan Facts
• 16-day orbit, 30-yr year
• Titan has a thick, Earth-like atmosphere:
N2, CH4, Ar, C2H6, C2H2, etc. The N2 came from ammonia
(Nitrogen, methane, argon, ethane, acetylene…)
Polar hood (seasonal); Clouds and hazes
• Titan’s methane cycle resembles Earth’s hydrologic (water) cycle
• Complex organic molecules are made in the atmosphere and
fall out as cloud droplets, form dunes on the surface
• All requirements for life are available: organics, energy, solvent
(water or methane)
Titan Summary
Titan [2003]
• Second-largest moon in SS
• Density ~1900 kg/m3
• thick atmosphere! Sublimation
Voyager 1981
• N2 (90%), methane, ethane
• ethane may condense
• clouds,
rain,oceans/lakes/ponds/erosion??
?
• Geology was unknown due to
thick atmosphere
Titan is differentiated:
Core, mantle of ice and
water, icy crust covered in
organics
Titan [2005]
• Thick Atmosphere
• N2 (90%),
methane, ethane
• methane clouds,
rain, lakes
• Geology
• Erosion!!!!!!!!!!
• Volcanism,
Tectonics
• A few impact
craters
Titan has a "hydrological
cycle" like Earth but with
methane instead of
Methane rain water!
Upper haze layers
Photochemical smog
Temps ~80-90K
= -300 F
Atmospheric pressure
at surface ~1.5 bars
Huygens
Landing
Site
Rounded cobbles
resemble Mars
Titan’s Lakes:
Of methane
mostly
(& ethane)
Few 100m deep
Red areas are
those that
changed
between images
a year apart
Blue appeared
2004-5
solid vs. liquid
False Color - Radar Reflectivity
Cassini Radar images
Lakes- high latitudes
Braided channels – floods?
440 km impact crater Minerva
Linear dunes near equator
440 km diameter
25 km
Impact Crater
Dune Field
Cryovolcanic Extrusion ?
Geology
• Cryovolcanism
• Impact cratering
• Dune field formation
Surface Chemistry and
interaction with the
atmosphere
Ices + Liquids +
Aerosol Precipitates
Titan: Life today; life’s origins
Life in the methane-ethane
lakes and seas of Titan:
--totally alien biology
--does not violate
physics
--strict test of
life’s cosmic
Base of
the liquid water
commonality
ocean:
life as we know it in
hydrothermal vents?
Impact craters:
Comet/asteroid impacts melt crust for hundreds to
thousands of years.
--organics evolve in water then freeze
--experiments in origin of life preserved
Saturn obliquity = 26.73°
FY14 –
awaiting update on this graphic
FY17
SOLSTICE
22
More hydrocarbons by 100 times than oil
and gas on Earth!
• In 2013 Cassini:
– Expanded the known seas on
Titan by a factor of three.
– Measured the depth of a
Titan sea.
• From 2014-2016 Cassini will:
– Measure depth of largest sea
– Look for waves not ever seen
– Watch seas boil in summer
Sun
23
These three images, created from Cassini Synthetic ApertureRadar (SAR) data, show the appearance and evolution
of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan.
The views, taken during three different Cassini flybys of Titan, show that this feature was not visible in earlier radar
images of the same region and its appearance changed between 2013 and 2014
.
Titan’s Toxic Cloud
Titan Toxic Cloud
Titan Mare Explorer (TIME)
• Was proposed to NASA, but not selected for
flight
• TiME is a relatively low-cost, outer-planet
mission designed to measure:
• organic constituents on Titan
• and would have performed the first nautical
exploration of an extraterrestrial sea,
• analyzed its nature and,
• possibly, observed its shoreline.
Summary
• Titan is the size of a planet, and resembles the
Earth, with a thick, organic-rich and complex
atmosphere
• Methane-ethane lakes resupply the methane
in the atmosphere, which is continuously
released from Titan’s interior by volcanoes
• Titan shows pre-biotic chemistry, like on Earth
before life arose
• Life using methane as a solvent or eating
acetylene are possible
Life on Titan?
• If not, it resembles Earth before life: plenty of
organics and chemical reactions: Can
organisms eat these?
• After giant impacts? ‘Titan Spring’
• Hot springs?
• At great depths: warm pond or deep-sea vent?
• Methane-based or acetylene eating life?