Bulk Characteristics of Titan • Diameter: 5,150 km • Average Density: 1.88 g/cm3 • Surface Temperature: 97K • Surface Pressure: 1.5 bars • Theorized to have an interior liquid layer composed of ammonia and water ice Guide to Titan • Titan parallels early Earth ▫ Lakes, Atmosphere, Clouds, Rain, Volcanoes, Plate Tectonics. • Only other body in solar system known to harbor stable liquids on its surface. ▫ Weather cycle ▫ Good indications for life or at the very least, pre-earth conditions. Atmosphere • Only known moon with an atmosphere. • 1.45 Denser than Earth’s ▫ 1.19 times as massive. • Result of volcanism or microbial life. • Like a young planet Earth. ▫ Research simulated atmospheric conditions and were given the building blocks of life. Rain on Titan • Recorded evidence of methane rainstorms on Titan in 2010. • Occurred over equator, rather than at poles. • Replenishes methane lakes and river systems. • Skepticism on whether this is any indication of life. Methane Lakes • Thanks to Triple Point and rain, Methane Lakes exist on Titan’s surface • Only known terrestrial body other than Earth to have stable liquids on its surface. • Not difficult to land. Cryovolcano • Winter, S Hemisphere. • Sotra Facula is a cryovolcano ▫ Emits water with ammonium, or polyethylene, paraffin waxes, or asphalt. Possibly replenishes methane in atmosphere. • Located at 12degrees S / 39.8 degrees W • 235 km wide Habitability of Titan • Titan’s PHI is 0.64 • Solid Surface ▫ Evidence of tectonics • Atmosphere ▫ Nitrogen and Hydrocarbons ▫ Believed to be similar to Earth’s atmosphere before oxygen was introduced • Surface Liquid ▫ Titan’s 93K surface temperature is directly above the triple point for methane (90.68K) Triple Point Image Source: http://www.nmij.jp/english/library/units/temperature/triple-chart_en.gif • The temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in equilibrium. • Different changes in temp and pressure transform substance to ice, liquid, vapor. • EARTH’S SURFACE: temps and pressures similar to the triple pt of WATER. • TITAN’S SURFACE: temps and pressures similar to the triple pt of METHANE. Possibility for Methanogenic Life • 2005 – Chris McKay suggested that methane-based (rather than water-based) life on Titan could consume hydrogen, acetylene, and ethane – i.e. organisms called methanogens. • EARTH = O2 metabolism Image Source: http://www.engr.ku.edu/images/media/methanotrophs.jpg C6H12O6 (glucose) + O2 -> CO2 + H2O Methanogenic Life (continued) Titan’s organisms would: •Inhale H2 instead of O2 •React it with acetylene (or CO2) instead of glucose •Exhale methane instead of carbon dioxide •TITAN= H2 metabolism Water is widespread on Earth, therefore life is widespread on Earth because it uses water. Analogous to Earth = Liquid methane lakes are widespread on the surface of Titan. C2H2 (acetylene) + 3H2 -> 2CH4 Photo source: http://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/PIA10008_Seas_and_Lakes_on_Titan.jpg/300px-PIA10008_Seas_and_Lakes_on_Titan.jpg The Miller-Urey Experiment • The Experiment (1953): ▫ ▫ ▫ ▫ INORGANIC components ORGANIC components in conditions similar to pre-biotic Earth. Warm water + four gases [H2O, CH4, NH3, and H2] + electrical discharges Formed simple organic molecules, including amino acids and RNA nucleotides. Formed the idea that on pre-biotic Earth there existed an abundance of RNA life produced through chemical reactions. • In the search for extraterrestrial life? Helps to understand the conditions required for life to form. • Titan’s atmosphere lacks oxygen, but complex organic molecules are present. ▫ Could form biological materials in a pre-biotic habitat resembling that of early Earth. Photo source: http://www.chem.duke.edu/~jds/cruise_chem/Exobiology/Pmilurey.gif Titan as a Prebiotic Environment? • Possible host for microbial extraterrestrial life because of its pre-biotic-like environment rich in complex organic chemistry. • Possibly subsurface liquid ocean serving as a biotic environment. • Implications of a possible ammonia-water ocean inside Titan. Yellow = hazy surface of Titan Light gray = ice layer starting near the surface Blue = internal ocean Light gray = another layer of ice Dark gray = mixture of rock and ice in the interior Past Mission: Cassini-Huygens • NASA / ESA / ASI Spacecraft to study Saturn and its satellites. • Launched in 1997, reached system in 2004 • Cassini: first to enter Saturn’s orbit. ▫ To study structure and history of the rings and satellite surfaces. ▫ Studies Titan’s cloud, hazes, and regional surfaces. Huygens Probe • Reached Titan Jan 14th, 2005 • Sent data for 90 minutes after touchdown. • Designed to brake in atmosphere and parachute a robotic lab to the surface. • Sent signals to Cassini to relay back to Earth. Huygens Design • Heat shield and parachute. • 6 Types of Instrumentation to study: ▫ Physical and electrical props of atmosphere ▫ Radiation balance in Titan’s atmosphere ▫ Chemicals in Titan’s atmosphere ▫ Volatiles and decompose complex organic materials ▫ Physical properties at point of impact. Huygens Findings • Landed in “Titanian Mud” • Rounded pebbles imply possible fluid motion. • Dense cloud or thick haze ~ 18 – 20 km from surface. Two New Proposals: TSSM and TiME • Titan Saturn System Mission ▫ Consists of an orbiter and 2 probes. ▫ More features than Huygens. • Titan Mare Explorer ▫ Land in and travel around a methane lake. ▫ To sample and analyze organics for 3 – 6 months. ▫ New power source: Advanced Stirling Radioisotope Generator. Goals of TSSM & TiME • Explore Titan as a system. • Study Titan’s organic inventory and astrobiological potential • Constrain Titan’s origin and evolution models. • Recover information on Enceladus and Saturn’s magnetosphere. Mission: PLOT Landing on Titan • • • • Probe for Life and Organics on Titan Land in Lake Ontario Lacus Possibly explore nearby cryovolcano Look for Evidence of Life: CO2, acetylene, amino acids, enzymes, isotopic fingerprints ▫ Use Cassini to relay back data Advanced Stirling Radioisotope Generator Landing on Titan ▫ Powerful generator currently being developed by NASA. ▫ ▫ ▫ ▫ ≥14 year lifetime Mass ~ 20 kg Uses 0.8 kg plutonium-238 January 2015 Source: NASA Testing Testing • Mass Spectrometer • Composite Infrared Spectrometer ▫ Test for hotspots in lake • MOD III • Seismometer • Camera Image Source: NASA Mission Target- Ontario Lacus • Located at 72° S & 183°W • Composed of methane, ethane, and propane. • Volume: 7-50 km3 Ontario Lacus Tour of Ontario Lacus http://www.youtube.com/watch?v=kK4n5 l7bHSw Timeline Timeline 2017: Launch 2024: Land The goal is to land and test during winter in the Southern Hemisphere. 2017 2024 Cost Mission Cost ofof Mission • Proposed Cost: 1 billion ▫ Includes cost of designing and launching a new probe. ▫ Use of the orbiter from the Cassini mission will cut costs • Cassini-Huygens mission (launched 1997) cost NASA 3.2 billion! The Search for Life Bibliography … is expensive but IMPORTANT!