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 45Slide 46Slide 47NSCI 314LIFE IN THE COSMOS10 - SEARCHING FOR LIFE IN OUR SOLAR SYSTEM: MARS AND THE OUTER PLANETSDr. Karen KolehmainenDepartment of Physics CSUSBhttp://physics.csusb.edu/~karen/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(?), NO LIQUID WATER ON SURFACE NOW BUT IT WAS THERE LONG AGOSURFACE: ROCKY, CRATERED, FORMER (BUT MAYBE NOT CURRENT?) GEOLOGICAL ACTIVITYJanuary 1997October 1996 March 1997EVIDENCE FOR WATER ON MARSIN THE DISTANT PAST (SEVERAL BILLION YEARS AGO):–DRY RIVER CHANNELS–ERODED FEATURES–CERTAIN TYPES OF ROCKS THAT COULD ONLY HAVE FORMED IN THE PRESENCE OF WATER–SALTY OCEAN?MORE RECENTLY (WITHIN THE LAST FEW MILLION YEARS?)–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VERY 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)MARS VIKING LANDER EXPERIMENTS: TESTS FOR LIFECARBON ASSIMILATION: MARTIAN SOIL WAS SCOOPED UP AND EXPOSED TO RADIOACTIVELY LABELED (WITH 14C) CO2 AND CO GAS. THEN THE SOIL WAS ANALYZED TO LOOK FOR 14C. IF THERE WERE MARTIAN ORGANISMS THAT ABSORB CO2 OR CO LIVING IN THE SOIL, THE 14C COULD HAVE GOTTEN INTO THE SOIL VIA METABOLIC PROCESSES IN THE MARTIAN ORGANISMS.•RESULTS: FOUND 14C IN SOIL, BUT…•HEAT-STERILIZED SOIL GAVE SAME RESULTS. •CAN BE EXPLAINED NON-BIOLOGICAL CHEMICAL REACTIONS.MARS VIKING LANDER EXPERIMENTS: TESTS FOR LIFELABELED RELEASE: RADIOACTIVELY LABELED (WITH 14C) NUTRIENTS WERE DRIPPED ONTO SCOOPED-UP MARTIAN SOIL. THEN THE GAS ABOVE THE SOIL WAS EXAMINED FOR THE PRESENCE OF 14C. IF THERE WERE MARTIAN ORGANISMS LIVING IN THE SOIL, THEY MIGHT HAVE ABSORBED THE NUTRIENTS AND THEN RELEASED GASES CONTAINING THE 14C.•RESULTS: FOUND 14C LABELED GAS, BUT…•CAN BE EXPLAINED BY INTERACTION OF BROTH AND PEROXIDES (NON-ORGANIC CHEMICALS) IN SOIL, PRODUCING CO2MARS VIKING LANDER EXPERIMENTS: TESTS FOR LIFEGAS EXCHANGE: MARTIAN SOIL WAS SCOOPED UP AND ADDED TO A NUTRIENT BROTH. THEN THE GAS ABOVE THE SOIL WAS ANALYZED FOR THE PRESENCE OF O2, CO2, N2, H2, OR CH4IF THE SOIL CONTAINED MARTIAN ORGANISMS, THEIR METABOLIC PROCESSES MAY HAVE RELEASED ONE OR MORE OF THESE GASES.–RESULTS: O2 PRODUCED, BUT… –ALSO PRODUCED WHEN DONE IN DARKNESS–ALSO PRODUCED WHEN SOIL WAS HEAT-STERILIZED–ALSO PRODUCED WHEN WATER REPLACED BROTH –CAN RESULT FROM CHEMICAL (NOT BIOLOGICAL) INTERACTION WITH WATER IN BROTHVIKING LANDER EXPERIMENTS: TESTS FOR LIFEGAS CHROMATOGRAPH - MASS SPECTROMETER MEASUREMENTS: SCOOPED-UP MARTIAN SOIL WAS BAKED UNTIL VOLATILES (EASILY VAPORIZED MATERIALS) OUTGAS. THE RESULTING GAS WAS ANALYZED, LOOKING FOR ORGANIC MOLECULES.RESULTS: NONE FOUNDBOTTOM LINE RESULTS OF ALL EXPERIMENTS: RESULTS TANTALIZING, BUT INCONCLUSIVEMARTIAN METEORITE ALH84001ONE OF 19 KNOWN METEORITES OF MARTIAN ORIGINMARTIAN ORIGIN DETERMINED BY –COMPOSITION: VOLCANIC ROCK–ISOTOPIC ABUNDANCES–TRAPPED BUBBLES OF GAS CONSISTENT WITH KNOWN COMPOSITION OF MARTIAN ATMOSPHEREHOW DID IT GET HERE?–BLASTED OFF MARS IN AN IMPACT 16 MILLION YEARS AGO–ORBITED THE SUN FOR NEARLY 16 MILLION YEARS–COLLIDED WITH EARTH 13,000 YEARS AGO–FOUND IN ANTARCTICA IN 1984CONTENTS OF ALH84001CARBONATE GLOBULES –INDICATE PAST PRESENCE OF LIQUID WATER–HAVE A LAYERED STRUCTURE THAT LIVING ORGANISMS CAN PRODUCE–BUT THERE ARE NON-BIOLOGICAL WAYS OF PRODUCING THIS LAYERING AS WELLMAGNETITE CRYSTALS –SIMILAR TO THOSE PRODUCED BY SOME TERRESTRIAL BACTERIA–BUT MAY HAVE A NON-BIOLOGICAL ORIGINCONTENTS OF ALH84001POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) –ORGANIC MATERIALS USUALLY PRODUCED BY DECAY OF ORGANISMS ON EARTH–BUT COULD BE PRODUCED IN NON-BIOLOGICAL WAYS, OR BE A RESULT OF CONTAMINATION AFTER LANDING IN ANTARCTICATINY (100 NM) ROD-SHAPED STRUCTURES–RESEMBLE FOSSIL ANAEROBIC EARTH BACTERIA–BUT MUCH SMALLER –PROBABLY TOO SMALL TO BE REAL FOSSILS–COULD BE NON-BIOLOGICAL STRUCTURES OF THE SAME SHAPESOME TERRESTRIAL BACTERIA –PROOF OF CONTAMINATIONPROSPECTS FOR LIFE ON MARSNO KNOWN EARTH LIFE FORM (NOT EVEN EXTREMOPHILES) COULD SURVIVE ON THE SURFACE OF MARS.SOME TERRESTRIAL EXTREMOPHILES MIGHT BE ABLE TO SURVIVE UNDERGROUND ON MARS.IT’S DIFFICULT TO IMAGINE HOW LIFE COULD ARISE UNDER CURRENT MARTIAN CONDITIONS.BUT 3.5 BILLION YEARS AGO, THERE WAS A THICKER ATMOSPHERE AND LIQUID WATER.COULD LIFE HAVE EVOLVED ON MARS THEN?IF SO, MARS MAY HAVE SEEDED EARTH WITH LIFE ???PROSPECTS FOR LIFE ON MARSCOULD LIFE HAVE EVOLVED 3.5 BILLION YEARS AGO (OR EARLIER), AND SINCE EVOLVED TO ADAPT TO HARSH CONDITIONS?IF SO, IT MAY STILL SURVIVE–UNDERGROUND (WATER, UV PROTECTION)–AT THE EDGE OF POLAR CAPSWE NEED TO GO THERE AND CHECK!SUMMARYTHERE IS DEFINITELY NO COMPLEX LIFE ON MARS.SIMPLE LIFE MAY HAVE EVOLVED LONG AGO ON MARS, AND THEN IT EITHER BECAME EXTINCT OR ADAPTED TO SURVIVE UNDERGROUND AND/OR IN SPECIALIZED LOCATIONS.WHAT WENT WRONG?–MARS IS TOO SMALL, GRAVITY IS TOO WEAK, COULDN’T HOLD ONTO MUCH OF AN ATMOSPHERE. –ATMOSPHERIC LOSS HELPED BY IMPACTS AND/OR SOLAR WIND.–ONCE ATMOSPHERE WAS MOSTLY LOST, LIQUID WATER COULDN’T EXIST ON SURFACE.JUPITERDIAMETER: 11 X EARTHMASS: 318 X EARTH = MORE THAN REST OF SOLAR SYSTEM (EXCLUDING THE SUN) COMBINEDDENSITY: 1.3 gm/cm³SUNLIGHT: 4% OF EARTHTEMP: 125 K (–150oC OR –235oF) AT CLOUD TOPS, BUT WARMER DEEP IN ATMOSPHEREATMOSPHERE: 86% H, 14% He, TRACES of CH4, NH3,H2O, HIGH WINDS & STORMSSURFACE: NONE VISIBLE, (ONLY ATMOSPHERE IS VISIBLE), THERE IS