Transcript Day-9
Astronomy 3040 Astrobiology Spring_2016 Day-9 Project http://www.ulalaunch.com/docs/product_sheet/Delt aIVPayloadPlannersGuide2007.pdf This is the Delta-IV payload guide overview. 20MB. Planetary quarantine program. Course Announcements • • Colloquium on Friday, Feb. 19. @2:30pm B310 Dr. David James, Cerro-Tololo InterAmerican Obs. • Open Clusters, Stellar Evolution and Calibrating the Ages of Stars: Blanco 1 • Galactic open clusters are laboratories, provided by nature, for us to study stellar evolution. Using 1m-, 4m- and 8m-class telescopes, I will show how spectroscopic and photometric observations of solar-type stars in open clusters allow us to establish a stellar chronometer, and create an age-ranking system for an ensemble of nearby, well-studied clusters. With the aid of new observations of Blanco 1, an high-Galactic latitude, Pleiades-age cluster, I will show how deriving stellar age must be based upon very high quality observational data and a diverse range of stellar models. ASTR-3040: Astrobiology The Nature of Life on Earth Chapter 5 Day 10 Homework Due Thur. Feb. 10 Chapter 5: 4, 6, 14, 20, 25, 27, 33, 37, 42, 47, 48, 49, 51 Environmental Reqriments Atmosphere Liquid water Temperature Pressure Radiation But, that's for Earth-like life. What about other forms of life? Earth Life Use 25 of 92 elements O, C, H, N – 96% of mass of living organisms 3, 4, 6, 1 – abundance in Universe 2% mass of solar system, < 0.1% in old SSs Temperature in protostellar nebula. Energy density from Sun Liquid water at Earth's distance Stays liquid over large temperature range Facilitates chemical reactions Earth Life Water: Liquid over wide and higher temperature range Solid water floats Charge separation of water molecule Environmental Rqrmnts for Habitability Source of molecules for building living cells Source of energy for metabolism Liquid medium for transporting molecules SS Tour Mercury and Moon No atmosphere No tectonic or volcanic activity No volatiles * Lunar polar ice? No magnetic field Temperatures SS Tour Venus and Mars Venus – similar in size to Earth Temperature and Pressure (95F w/o greenhouse) 880F in reality, 90 atm pressure Atmospheric composition – CO2 (96%) volcanism Mars – smaller, but Earth-like landscape Probably had liquid water (3 Gyr) More in next chapter Jovian Planets Moons Large moons Europa, Ganymede, Callisto, and Titan Lots of ices Small moons Phobos, Deimos – too small KBOs – too cold S/C Exploration Flyby Orbiter Lander/Probe Sample Return Astrobiology Missions Only those to Mars have been specifically designed to look for evidence of life. However, several s/c -flown and planned- look for evidence of water, organic molecules... Mars has a major exploration program First sample return scheduled in about 10 yrs Molecular Components Carbohydrates – energy sources Sugars and starches Lipids – energy stores, barriers Fats Nucleic Acids – DNA and RNA Molecular Components Proteins – structure & chemistry Structural materials Enzymes – catalysts for reactions Amino Acids (20 used in most life forms) Left-handed in biological entities. Defining Life What is Life? We have to know what we're looking for. 6 Key properties shared by most or all living organisms on Earth. Order – structure arrangement – necessary condition Reproduction – viruses and prions Growth & Development – heredity Energy Utilization - Response to the Environment Evolutionary Adaptation Role of Evolution Most biologists regard evolutionary adaptation as the most important of the six. Ancient idea - “change with time” Mechanism of evolution Darwin – The Origin of the Species - 1859 Based on two undeniable facts and inescapable concl. Overproduction and competition for survival. Individual variation ==> Unequal reproductive success. “Natural Selection” Evidence for Evolution 1st voyage of the HMS Beagle to Galapagos 13 finch species Closely resemble each other, but found nowhere else. Giant armadillo fossiles in Brazil and smaller living armadillos. Evidence in “Artificial Selection” - animal breeding Viruses evolve even faster. Molecular Basis of Evolution DNA – changes to the genome with time. mutations So, What is Life? Something that can reproduce and evolve through natural selection. Artificial Life?