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 47Slide 48NSCI 314LIFE IN THE COSMOS12 - WHERE TO SEARCH FOR LIFE:(A) IN OUR SOLAR SYSTEM – MOONS OF OUTER PLANETS (CONTINUED), AND OUTSIDE OUR SOLAR SYSTEM – (B) EXOTIC LIFE AND (C) SUITABLE STARS AND PLANETSDr. Karen KolehmainenDepartment of Physics, CSUSBhttp://physics.csusb.edu/~karen/HABITABLE ZONES AROUND OTHER STARSFOR BRIGHTER STARS:–HABITABLE ZONE IS FARTHER FROM STAR AND LARGER IN EXTENT (E.G., 5 TO 20 AU FOR AN A-TYPE MAIN SEQUENCE STAR)FOR FAINTER STARS:–HABITABLE ZONE IS CLOSER TO STAR AND SMALLER IN EXTENT (E.G., 0.02 TO 0.06 AU FOR AN M-TYPE MAIN SEQUENCE STAR)–HABITABLE ZONE MAY BE SO SMALL THAT IT IS UNLIKELY THAT ANY PLANETS ARE FOUND WITHIN IT–IF PLANET IS TOO CLOSE TO STAR, OTHER POSSIBLE PROBLEMS INCLUDE:•SOLAR FLARES •PLANET’S ROTATION MAY BE TIDALLY LOCKED (MIGHT BE OK IF ATMOSPHERE CAN SPREAD HEAT AROUND ENOUGH)MOONS OF SATURNMOST ARE SMALL BODIES CONSISTING OF A MIXTURE OF ICE AND ROCK, WITH NO ATMOSPHERES. TITAN IS AN EXCEPTION: A LARGER ICE/ROCK BODY WITH A THICK ATMOSPHERE.ENCELADUSSMALL TO MEDIUM-SIZED MOON OF SATURNMIXTURE OF ICE AND ROCKFEW IMPACT CRATERS, NO ATMOSPHERETIDAL FORCES FROM SATURN CAUSE INTERNAL WARMINGHAS ICE VOLCANOES–SOME REGIONS NEAR THE SOUTH POLE ARE WARMER THAN THE REST OF THE SURFACE–CRACKS IN ICY CRUST, MATERIAL CAN SPEW UP FROM BELOW–FOUNTAINS OF ICE PARTICLES AND WATER VAPOR–SOME ORGANIC MOLECULES FOUNDIAPETUSMEDIUM-SIZED MOON OF SATURNHEAVILY CRATERED, NO ATMOSPHERELEADING HEMISPHERE IS DARK, TRAILING HEMISPHERE IS LIGHTDARK MATERIAL IS ORGANIC MAY BE COLLECTED FROM SPACE AS IAPETUS MOVES IN ITS ORBITMORE MOONS OF SATURNMIMAS – HAS BIG IMPACT CRATER, IMPACT MUST HAVE ALMOST BROKEN MIMAS APARTDIONE OR RHEA?ICE/ROCK COMPOSITIONNO ATMOSPHERENOT GOOD CANDIDATES FOR LIFEMOONS OF URANUSMOST INTERESTING ONE IS MIRANDAICE/ROCK COMPOSITIONNO ATMOSPHERENOT A GOOD CANDIDATE FOR LIFEHAS MIXTURE OF DIFFERENT TYPES OF TERRAIN – OLDER CRATERED TERRAIN AND YOUNGER TERRAIN WITH GROOVESMAY HAVE BEEN BROKEN APART BY LARGE IMPACT AND REASSEMBLEDTRITONLARGEST MOON OF NEPTUNERETROGRADE ORBIT - PROBABLY CAPTURED KUIPER BELT OBJECTINTERIOR OF ICE AND ROCKFEW IMPACT CRATERSSURFACE CONTAINS NITROGEN ICE AND METHANE ICEACTIVE SURFACE (ICE MAY COVER LAKES OR OCEAN OF NITROGEN, METHANE, AMMONIA, AND/OR WATER?)LIQUID GEYSERS OR ICE VOLCANOES OCCASIONALLY ERUPTVERY THIN NITROGEN ATMOSPHEREPROBABLY WAY TOO COLD FOR LIFETHIS COMPLETES OUR “TOUR” OF OUR SOLAR SYSTEM.WHAT ABOUT LOOKING FOR LIFE BEYOND OUR SOLAR SYSTEM?WE EXPECT OTHER SOLAR SYSTEMS TO CONTAIN THE SAME TYPES OF OBJECTS AS OUR SOLAR SYSTEM:–A STAR (MAYBE A DOUBLE OR MULTIPLE STAR)–PLANETS–MOONS–SMALLER OBJECTS:•DWARF PLANETS•COMETS •ASTEROIDSADVANTAGES OF PLANETS AND LARGE MOONS FOR LIFECONDUCIVE TO CHEMISTRY (ATOMS COMBINING AND RECOMBINING TO FORM MOLECULES)PROVIDE A RELATIVELY STABLE AND PROTECTED ENVIRONMENT (AT LEAST IN MANY CASES)SMALL VARIATIONS IN ENVIRONMENTVARIETY OF INTERFACES BETWEEN LAND, OCEANS, AND ATMOSPHERELIFE IN LOCATIONS OTHER THAN PLANETS OR LARGE MOONS?SMALL MOONS, ASTEROIDS, ETC.–NO ATMOSPHERE - THEREFORE NO LIQUIDS, EXTREME TEMPERATURE VARIATIONS, AND NO PROTECTION AGAINST ULTRAVIOLET RADIATIONSTARS–TOO HOT FOR COMPLEX MOLECULES TO FORMNEBULAE (CLOUDS IN THE INTERSTELLAR MEDIUM)–LOW TEMPERATURE AND DENSITY  CHEMICAL REACTIONS PROCEED VERY SLOWLY  HARD TO IMAGINE COMPLEX MOLECULES FORMINGNEUTRON STARS??LIFE ELSEWHERE COULD HAVE:Very similar proteins and DNA sequences to us (if so, a common origin is likely)Same amino acids and genetic bases as us, but combined into different proteins and DNA sequences (common origin?)Amino acids and genetic bases, but not the same 20 amino acids and 4 or 5 bases as usDifferent monomers, (not amino acids and genetic bases), but still carbon-based polymers of some sortDifferent chemistry (silicon-based?)No chemistry at all! (exotic matter, or interactions other than electromagnetic)CHEMISTRY INVOLVES COMBINING ATOMS TO MAKE MOLECULES (INCLUDING MOLECULES BEING BROKEN APART INTO ATOMS, THEN ATOMS REARRANGING AND COMBINING INTO NEW MOLECULES)BASIS OF ALL LIFE ON EARTHBASIS OF ALL CARBON-BASED LIFEBASIS OF SILICON-BASED LIFE (IF POSSIBLE)HAPPENS BECAUSE OF ELECTROMAGNETIC FORCESFUNDAMENTAL FORCESMANY FORCES ARE ELECTROMAGNETIC FORCES.–ELECTRICAL FORCES HOLD ATOMS TOGETHER (ATTRACTION BETWEEN POSITIVELY CHARGED NUCLEUS AND NEGATIVELY CHARGED ELECTRONS).–ELECTRICAL FORCES HOLD ATOMS TOGETHER TO FORM MOLECULES. (ELECTRONS ARE TRANSFERRED OR SHARED BETWEEN ATOMS.)–“CONTACT” FORCES ARE ELECTRICAL WHEN EXAMINED ON A MICROSCOPIC LEVEL.–ELECTRICITY AND MAGNETISM ARE CLOSELY RELATED - MAGNETISM IS CAUSED BY MOVING ELECTRIC CHARGES.GRAVITY IS A FUNDAMENTALLY DIFFERENT KIND OF FORCEHOW MANY KINDS OF “FUNDAMENTAL” FORCES ARE THERE? WE THINK THERE ARE ONLY FOUR TYPES OF FUNDAMENTAL FORCES.FUNDAMENTAL FORCES(IN ORDER FROM STRONGEST TO WEAKEST)NAME RANGE COUPLES TOSTRONG SHORT “COLOR”ELECTROMAGNETIC LONG ELECTRIC CHARGEWEAK SHORT “FLAVOR”GRAVITY LONG MASSNOTES: (1) “SHORT RANGE” MEANS THAT THE PARTICLES MUST BE WITHIN 10-15 m (0.000000000000001 m) OF EACH OTHER TO FEEL THE FORCE. “LONG RANGE” MEANS THAT THE PARTICLES WILL FEEL THE FORCE EVEN IF THEY ARE VERY FAR APART (ALTHOUGH THE FORCE WILL BE WEAKER IF THE PARTICLES ARE FARTHER APART). (2) “COUPLES TO” MEANS THAT THIS IS THE PROPERTY THE PARTICLES MUST HAVE IN ORDER TO FEEL THE FORCE OR EXERT THE FORCE ON OTHER PARTICLES.FUNDAMENTAL FORCES(IN ORDER FROM STRONGEST TO WEAKEST)NAME EFFECTSSTRONG HOLDS NUCLEI OF ATOMS TOGETHER, CAUSES CERTAIN TYPES OF REACTIONS BETWEEN PARTICLESELECTROMAGNETIC HOLDS ATOMS AND MOLECULES TOGETHER, CAUSES CERTAIN TYPES OF REACTIONS BETWEEN PARTICLESWEAK CAUSES BETA DECAY (TYPE OF RADIOACTIVE DECAY)) AND CERTAIN TYPES OF REACTIONS BETWEEN PARTICLESGRAVITY HOLDS PLANETS, STARS, AND GALAXIES TOGETHERHOW ARE THE FUNDAMENTAL FORCES RELATED