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 Summary • Titan is the size of a planet, and resembles the Earth, with a thick, 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?