Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45NSCI 314LIFE IN THE COSMOS9 - SEARCHING FOR LIFE IN OUR SOLAR SYSTEM: THE INNER PLANETS Dr. Karen KolehmainenDepartment of Physics CSUSBhttp://physics.csusb.edu/~karen/EARTH’S MOONDIAMETER: 27% EARTH MASS: 1.2% EARTHDENSITY: 3.3 gm/cm³SUNLIGHT: 1 EARTHTEMP: 160 to 400 K (-110 to 130 oC or –170 to 260 oF)ATMOSPHERE: NONEWATER: NO LIQUID WATER, BUT PERMANENT ICE IN A FEW CRATERS NEAR THE POLES THAT NEVER GET SUNLIGHTSURFACE: ROCKY, HEAVILY CRATERED, SMOOTHER MARIA (FORMED VIA LAVA FLOODING BASINS AFTER LARGE IMPACTS), NO CURRENT GEOLOGICAL ACTIVITY (COOL SOLID INTERIOR)TIDAL FORCESTHINK ABOUT THE GRAVITATIONAL FORCE OF THE MOON PULLING ON THE EARTH.THE SIDE OF THE EARTH THAT IS CLOSEST TO THE MOON EXPERIENCES A STRONGER FORCE THAN DOES THE SIDE OF THE EARTH THAT IS FARTHEST FROM THE MOON.THE DIFFERENCE BETWEEN THE FORCES ON DIFFERENT SIDES OF THE EARTH CAUSES TIDES. (OCEANS CAN ALTER SHAPE MORE EASILY THAN ROCK.)EARTH ROTATES INSIDE TIDAL BULGES, PRODUCING TWO HIGH TIDES PER DAY.FRICTION BETWEEN WATER AND OCEAN BOTTOM IS SLOWING DOWN EARTH’S ROTATION.TIDAL FORCESEARTH ALSO EXERTS TIDAL FORCES ON THE MOON.THE MOON HAS NO OCEANS, BUT THE ROCK ITSELF IS DISTORTED INTO AN ELONGATED SHAPE.THE MOON WAS ORIGINALLY ROTATING FASTER, BUT AS IT ROTATED, THE SHAPE WAS CONTINUALLY DISTORTED TO KEEP THE BULGE POINTED TOWARED THE EARTH.THE RESULTING FRICTION SLOWED DOWN THE MOON’S ROTATION UNTIL IT NOW ROTATES ONLY ONCE PER ORBIT.SYNCHRONOUS ROTATION: THE MOON NOW KEEPS ONE SIDE FACING THE EARTH.THIS HAS ALSO HAPPENED WITH MOST MOONS OF OUTER PLANETS.MERCURY DIAMETER: 38% EARTH MASS: 5% EARTHDENSITY: 5.4 gm/cm³SUNLIGHT: 6.5 X EARTHTEMP: 100 to 700 K (-170 to 430 oC or –280 to 800 oF)ATMOSPHERE: NONEWATER: NONESURFACE: ROCKY, HEAVILY CRATERED, NO CURRENT GEOLOGICAL ACTIVITYLIFE ON EARTH’S MOON OR MERCURY?PROBABLY NOTPROBLEMS:–NO ATMOSPHERE (MOON AND MERCURY HAVE TOO LOW A MASS, THEIR GRAVITY CAN'T HOLD ONTO LIGHT GAS MOLECULES)•NO PROTECTION FROM UV BOMBARDMENT OR COSMIC RAYS•NO LIQUID WATER (OR ANY OTHER LIQUID THAT COULD SERVE AS A SOLVENT)•LARGE TEMPERATURE EXTREMES (ESPECIALLY ON MERCURY)VENUS DIAMETER: 95% EARTH MASS: 82% EARTHDENSITY: 5.3 gm/cm³SUNLIGHT: 2 X EARTHTEMP: 730 K (460 oC or 850 oF), NOT MUCH VARIATIONATMOSPHERE: 97% CO2 , 3% N2, 90 X EARTH PRESSURE, SULFURIC ACID CLOUDSWATER: NONESURFACE: ROCKY, CRATERED, RECENT LAVA FLOWS, UNCLEAR WHETHER ANY CURRENT GEOLOGICAL ACTIVITYGREENHOUSE EFFECTSUNLIGHT ABSORBED BY PLANET’S SURFACE ENERGY RE-RADIATED FROM GROUND AS INFRARED INFRARED RADIATION ABSORBED BY ATMOSPHERIC GREENHOUSE GASES: CO2 ,H2O, CH4, OTHERSATMOSPHERE WARMS, RADIATES EXCESS HEAT TO SPACE (AS BLACKBODY)EVENTUALLY EQUILIBRIUM IS REACHED SO THAT ENERGY ABSORBED = ENERGY RADIATED, AND TEMPERATURE STABILIZES- EARTH 40K (OR 72 oF) HOTTER- MARS 5K (OR 9 oF)HOTTER- VENUS 400K (OR 720 oF)HOTTERWHY ISN’T THE GREENHOUSE EFFECT MORE IMPORTANT ON EARTH?LIMESTONE ROCKS (CALCIUM CARBONATE OR CaCO3) FORMED IN OCEANS.MOST CO2 (170,000 x MORE THAN IN OUR ATMOSPHERE) IS DISSOLVED IN SEA WATER AND LOCKED UP IN LIMESTONE. IF IT WEREN’T, GREENHOUSE EFFECT WOULD BE MUCH MORE SEVERE.HUMAN INDUSTRIAL ACTIVITY IS ADDING GREENHOUSE GASES TO ATMOSPHERE, RESULTING IN GLOBAL WARMING.WHY IS THE GREENHOUSE EFFECT SO IMPORTANT ON VENUS?TEMPERATURE ON PRE-GREENHOUSE VENUS WOULD HAVE BEEN ~350 TO 400 K, TOO HOT FOR LIQUID WATERTHEREFORE ALL WATER ON VENUS EVAPORATEDH20 VAPOR IS A GREENHOUSE GAS AND INCREASED TEMPERATURE FURTHERMOST H20 VAPOR WAS PHOTODISSOCIATED, H ESCAPED TO SPACE, O COMBINED WITH OTHER ELEMENTSNO OCEANS  NO CARBONATE ROCKS TO ABSORB CO2, SO IT REMAINS IN ATMOSPHERELIFE ON VENUS?PROBABLY NOTPROBLEMS:–WAY TOO HOT DUE TO RUNAWAY GREENHOUSE EFFECT–NO LIQUID WATER (OR ANY OTHER LIQUID THAT COULD SERVE AS A SOLVENT)–ATMOSPHERIC PRESSURE VERY HIGH (ALTHOUGH NO HIGHER THAN AT SOME HYDROTHERMAL VENTS ON EARTH)MARSDIAMETER: 53% EARTHMASS: 11% EARTHDENSITY: 3.9 gm/cm³SUNLIGHT: 43% OF EARTHTEMP: 180 TO 280 K (-90 TO 7oC OR –135 TO 45oF)ATMOSPHERE: 95% CO2, 3% N2, 2% Ar, H2O & CO2 CLOUDS, <1% OF EARTH PRESSUREWATER: POLAR ICE CAPS, SUB-SURFACE PERMAFROST(?), LARGE AMOUNTS (?) OF LIQUID WATER ON SURFACE WHEN PLANET WAS YOUNGSURFACE: ROCKY, CRATERED, FORMER (BUT MAYBE NOT CURRENT?) GEOLOGICAL ACTIVITYJanuary 1997October 1996 March 1997EVIDENCE FOR WATER ON MARSIN THE DISTANT PAST:–DRY RIVER CHANNELS–ERODED FEATURES–PRESENCE OF CERTAIN TYPES OF ROCKS THAT PROBABLY FORMED IN WATER–SALTY OCEAN?MORE RECENTLY?–SOME DRAINAGE FEATURES LOOK YOUNG AND UNERODED.–PERHAPS THERE IS STILL SUB-SURFACE WATER, AND OCCASIONALLY A LANDSLIDE ON THE SIDE OF A CLIFF (OR SOME SIMILAR EVENT) FREES SOME WATER TO RUN OUT BRIEFLY ONTO THE SURFACE.18012060030024024030012018060060°30°0°-30°-60°180° 240° 300°0°60° 120° 180°840-4-8CHALLENGES THAT LIFE ON MARS WOULD FACELOW ATMOSPHERIC PRESSURENO LIQUID WATER ON SURFACE (ATMOSPHERE IS TOO THIN – WATER WOULD BOIL)COLDLARGE DAILY TEMPERATURE VARIATIONULTRAVIOLET BOMBARDMENT OF SURFACE (NO OZONE LAYER)VIKING LANDER EXPERIMENTS: TESTS FOR LIFECARBON ASSIMILATION: MARTIAN SOIL EXPOSED TO RADIOACTIVELY LABELED (14C) CO2 AND CO GAS, LOOK FOR 14C IN SOIL (PRESUMABLY WOULD HAVE GOTTEN THERE VIA METABOLIC PROCESSES IN ORGANISMS)•RESULTS: FOUND 14C IN SOIL, BUT…•HEAT-STERILIZED SOIL GAVE SAME RESULTS •CAN BE EXPLAINED NON-BIOLOGICAL CHEMICAL REACTIONSLABELED RELEASE: RADIOACTIVELY LABELED (14C) NUTRIENTS DRIPPED ON SOIL, LOOK FOR 14C IN GAS ABOVE (RELEASED VIA METABOLIC PROCESSES)•RESULTS: FOUND 14C LABELED GAS, BUT…•CAN BE EXPLAINED BY INTERACTION OF BROTH AND PEROXIDES (NON-ORGANIC CHEMICALS) IN SOIL, PRODUCING CO2VIKING LANDER EXPERIMENTS: TESTS FOR LIFEGAS EXCHANGE: ADD MARTIAN SOIL TO NUTRIENT BROTH; LOOK FOR O2, CO2, N2, H2, OR CH4 ADDED TO GAS ABOVE –RESULTS: O2 PRODUCED, BUT… –ALSO PRODUCED WHEN DONE IN DARKNESS–ALSO PRODUCED WHEN