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Astrobiology
- 2. Outline What is Astrobiology? Evolution & the Origin of Life on Earth What is Life? The Search for Life Interesting Topics
- 3. Fields of Study Geology Paleontology Microbiology Organic Chemistry Planetary Sciences Cosmochemistry Engineering Astronomy Evolutionary Biology Biochemistry Materials Science Oceanography Astrophysics Philosophy
- 4. History 1960: NASA Exobiology Program 1976: Viking missions to Mars 1995: Extrasolar planet orbiting a sun-like star 1996: Controversial Martian Meteorite Today: Exoplanets, Mars, Titan, and Europa Source: http://www.nasa.gov/50th/50th_magazine/astrobiology.html
- 5. Key Questions How does life originate? How does life evolve? What kind of environment is necessary for life to survive? What are the environmental limits or “extremes” under which life can survive? What might life look like on another world? Is there or has there been life elsewhere in our solar system? How can we observe and identify a habitable – or even inhabited – world? What is humanity’s future on Earth and beyond?
- 6. Outline What is Astrobiology? Evolution & the Origin of Life on Earth What is Life? The Search for Life Interesting Topics
- 7. Hierarchical View • Universe (one or many) Galaxies (~150 Billion Galaxies) Milky Way (~100 Billion Stars) Solar System (Sun, planets..) Earth Life Source: Margaret Race, NASA, 2010 Teachers Workshop
- 9. Early Conditions • Liquid water • Energy source • UV (sun), Electrical (lightning), chemical (hydrothermal vents) Source: theecolologist.tumblr.com
- 10. The Origin of Life Exogenesis / Panspermia Life came to earth from elsewhere in the universe Autotrophic Hydrothermal vents Heterotrophic ‘RNA-World’ Theory RNA self-replicating Miller-Urey Experiment Source: http://www.ib.bioninja.com.au/options/option-d-evolution-2/d1-origins-of-life-on-earth.html
- 11. Miller-Urey Experiment Source: http://lcdm.astro.illinois.edu/static/classes/astr330sp13/Lecture2 1.pdf Conclusion: AA’s can self assemble in similar conditions that existed on early earth
- 12. Evolutionary Explanations Fitness Chance 20 amino acids Past selective pressures I.e. appendix
- 13. Common chemical model? Fitness Weak A:T and strong C:G is optimal Chance Random & conserved Past selective pressure Adenine’s precursor used to be more abundant / favorable Adenine -weaker bond Amino-Adenine -stronger bond Source: http://www.sciencedirect.com/science/article/pii/S1367593104001358
- 14. Outline What is Astrobiology? Evolution & the Origin of Life on Earth What is Life? The Search for Life Interesting Topics
- 15. Parameters for Life Chemical base for creation of complex molecules Liquid Solvent Energy Source
- 17. Handle Information Metabolize resources in environment to construct parts Carry out self-replication Display some sort of evolution Necessary Characteristics of Early Life?
- 18. Alternative Life Forms Carbon based life Silicon? Germanium? Metal Oxides? Heteropoly acids Polyoxometalates Source: http://www.sciencedirect.com/science/article/pii/S1367593104001358
- 19. Polyoxometalates Source: Lee Cronin http://www.newscientist.com/article/dn20906-lifelike-cells-are-made-of-metal.html https://youtu.be/unNRCSj0igI?t=10m5s
- 20. Non-Water Solvents Hydrocarbons, ammonia (NH3), sulfuric acid, liquid N / H Why water? Wide liquid phase (T) High heat capacity (heat per degree) Large heat of vaporization ( L G) Amphoteric (Acid & Base) Density: S < L
- 21. Space conditions Temperature Heat Cold Vacuum Radiation Protons & cosmic rays Salinity Acidity
- 22. Extremophiles Acidophile (acidic, low pH) Alkaliphile (basic, high pH) Anaerobe (no oxygen) Endolith (inside rocks, in pores between mineral grains) Halophile (high concentrations of salt) Methanogen (H + CO2 CH4) Oligotroph (nutrient limited) Barophile (high pressure) Psychrophile (around -10ºC) Thermophile (around 40ºC ) Toxitolerant Xerophile (low H2O)
- 24. Giant Tube Worm
- 25. Loricifera Tiny 100 um – 1 mm Deep in the Mediterranean Sea Salt-saturated brine Oxygen & light free How?
- 26. Tardigrades (Water Bears) Vacuum of space High pressure of deep sea UV rays, cosmic radiation -458ºF – 300ºF
- 27. So what?
- 28. Outline What is Astrobiology? Evolution & the Origin of Life on Earth What is Life? The Search for Life Interesting Topics
- 29. Life Outside Our Solar System
- 30. Search Methods Exoplanets detected up to Sept 2014
- 35. Life in Our Solar System Source: http://www.bhatt.id.au/blogimg/planets-in-our-solar-system.jpg
- 38. Mars: H2O Gale Crater Salt Brines in a daily water cycle Recurring slope lineae Source: http://www.nature.com/nge o/journal/v8/n5/full/ngeo2 412.html Glacial features
- 39. Mars: Methane Methane degradation: ~300 years Source: http://www.nasa.gov/images/content/303598mai
- 40. Outline What is Astrobiology? Evolution & the Origin of Life on Earth What is Life? The Search for Life Interesting Topics
- 41. The Fermi Paradox: Where is everyone? Source: http://waitbutwhy.com/2014/05/fermi-paradox.html
- 42. We’re Rare
- 43. We’re Isolated
- 44. We’re Doomed
- 46. Chirality
- 49. Terraforming Mars Introduce greenhouse gases raised temperature vaporized CO2 in the south polar cap Melting ice increased atmospheric pressure suitable for trees
- 50. Putting it all together
- 51. Sample Topics Physics of light, gravity, matter, energy, magnetism, radioactivity, nuclear energy and relativity Evolution of life on Earth Biochemical machinery of all living organisms Uniqueness of the organisms on Earth inhabiting very extreme environments (extremophiles) Geology of volcanism, plate tectonics, atmosphere, and erosion as applied to all planets Chemical composition of space H-R diagram and its role in understanding the evolution of all stars Physics, chemistry and biology of space exploration and habitation Suitability of life on comets Origin of the Universe Origin of our solar system and the planetary systems Birth and death of stars and galaxies Does life require a dynamic environment?
- 52. One last thing…. Source: http://tierra.rediris.es/Geoethics_Planetary_Protection/geoethics_JMF_AGID.jpg
- 53. Policy & Ethics Ethical Concerns Colonization Monuments Terraforming Resource use Environmental Concerns Space junk Forward contamination Back contamination Regulatory Concerns Regulation (private vs. government vs. UN vs. world democracy) Tourism Sacred celestial bodies
- 54. Works Cited* https://depts.washington.edu/astr obio/drupal/content/what- astrobiology Dr. Margaret S Race, NASA Astrobiology Teachers workshop 2010 http://www.space.com/15498- europa-sdcmp.html http://www.ucl.ac.uk/~ucbpmbo/ something.html/Work_files/Case %20Presentation%203.pdf http://www.powershow.com/view /242d5- YmFhY/Astrobiology_an_Introduc tion_powerpoint_ppt_presentation https://en.wikipedia.org/wiki/Tar digrade https://en.wikipedia.org/wiki/Gia nt_tube_worm http://www.astronomynotes.com/ starprop/s3.htm http://www.hou.usra.edu/meeting s/abscicon2015/program/topics/ *: resources directly cited in presentation not included here
Editor's Notes
- Introduction
- What I want them to get out of talk explain their presentations think about topics for their presentations this is a broad overview and is certainly not exhaustive
- Goal: give you a broad overview of the topic & some areas of current research and controversy
- 1959 = first project 1976 – viking missions had 3 biology experiments to look for microbial life – some unexpected chemical activity but no clear evidence 1996 – alan hills 84001 metoerite, found in antartica, left mars 17 million years ago, earth for 13,000 And then one more bullet point for now
- How does life begin and evolve? Is there life beyond Earth and, if so, how can we detect it? What is the future of life on Earth and in the universe?
- Universe been around for 14billion years. Earth for 4.5 billion years. Humans as a genus, only a few million years old Homo sapiens, 200,000 years old If earth history was a year long video, humans would not appear until the last hours of Dec 31st. How did we start?
- Synthesize more complex organic compounds from simple building blocks
- i’m only giving a quick summary, but these are all really interesting topics which a lot of research is focusing on: panspermia – comets or meteorites Autrophic – means it can produce its own energy – simple organisms got energy source from pyrite on hydrothermal vents Heterotrophic – consumes other things (ie all the stuff floating in the prebiotic soup). Complex molecules formed in soup that could store information and do enzyme like activity
- Stanley miller and harold urey The experiment used water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2). The chemicals were all sealed inside a sterile 5-liter glass flask connected to a 500 ml flask half-full of liquid water. The liquid water in the smaller flask was heated to induce evaporation, and the water vapour was allowed to enter the larger flask. Continuous electrical sparks were fired between the electrodes to simulate lightning in the water vapour and gaseous mixture, and then the simulated atmosphere was cooled again so that the water condensed and trickled into a U-shaped trap at the bottom of the apparatus.
- To skip past 100’s of millions of years, get to where we are now. Much of astrobio about this process, so why is this important for studying space? Why does what happens here matter for other life? Ask them. Have all of you studied evolution? Raise you hand if so. Why ribose (for RNA) and deoxyribose (for DNA)? Is the DNA-RNA-Protein essential? Past selective pressures may no longer exist, or they may
- So what? Examining the reasons and path that life has taken on earth can offer clues into what earth may look like elsewhere
- Liquid solvent generally regarded as necesarry: Solute, temperature, polarity
- What do you t Energy,respond to enviroment, grow, reproduce, adapt, cells, levels of organication
- Carbon is much more abundant in the cosmos and is more versatile (t can bond with more different types of atoms) The Cronin group at Glasgow University reported self-assembly of tungsten polyoxometalates into cell-like spheres Heteropoly acid - class of acid made up of a particular combination of hydrogen and oxygen with certain metals and non-metals.
- By modifying their metal oxide content, he can give the spheres a hole as part of its structure and become a porous membrane, selectively allowing chemicals in and out of the sphere according to size. The purple thing is them creating a membrane inside the cell to mimic the nucleus/ now this is old, and wasn’t ultimately successful but it gives you an idea of the types of work you can do. So weve now looked at the chemical bassis for life.
- Subsurface liquid water is considered likely or possible on several of the outer moons: Enceladus (where geysers have been observed), Europa, Titan. To compare this to ammonia, it’s abundant, can donate/accept proton ( not as well as water) BUT weaker h-bonds so heat of vaporization less, its surface tension to be a third, and reducing its ability to isolate non-polar molecules through a hydrophobic effect Energy source - anything
- Chlorphyll degrade @ 75 C Organic molecules decompose @ 150 C Can reanimate organisms at -200 C, but hard for them to be active, partly because enzyme are so slow & ice crystals can rupture cells Radiation increased during solar flares
- Halophile – typically have high concentration of chemicals so that water from the internal cytoplasm doesn’t want to escape into the salty environment outside, or they accumulate more salt in the cell Psychrophiles have more flexible bonds so they don’t rupture, antifreeez proteins that lower the freezing points of other biomolecules Thermophiles have stronger bonds
- Temp, acidity, salinity Defines a region of possible life. Not a cuboid structure, it is dented in corners and extends at the bottom level What do you think this means? One conclusion: dealing with one extreme can hurt it’s ability to deal with another aspect
- Up to a mile deep near hydrothermal vents
- How can they survive without oxygen? Usually needed by mitochindria for aerobic respiration Use a different process involving hydrogenosomes
- Swedish university: 10 days in space Survived space vacuum, UV radiation, cosmic rays They can dessicate and then rehydrate when water is available again Also: heat (300 degrees F -, cold (almost to absolute zero), pressure Not technically extremophiles, because are not adapted to live in this conditions, and more will die longer they are out there.
- What I want to stress about this research into extremophiles is that there is no one form of life. When looking outwards, know types of conditions that life has adapted to on earth can offer clues as to what to look for. Additionally, we must consider forward contamination, there are overlaps between conditions on earth and in our solar system, notably Mars.
- Cannot be directly imaged – any ideas why not?
- A star with a planet has its own small orbit because of the gravity of a planet. Then you measure these variations regularly you can measure the gravitational impact & mass of a planet the displacement of the spectral lines due to the doppler effect towards you: blue shift – higher frequency & smaller wavelength away: red shift – lower frequency and bigger wavelength
- Planet crosses in front of parent star. Gets you the planet size, and later (with the radial velocity method as well) its density and mass. Hard because have to be perfectly positioned, gotten over this by massive scans of 100,000’s of stars.
- Green shades – habitable zone / goldilocks zone (within a stars habitable zone) Size of the circles – radius of planets (estimated from mass when not known directly) amount of energy reaching each square centimeter of a detector (eg., your eye, CCD, piece of the sphere) per unit time (gets smaller as you get farther away) . Related to the inverse square laq
- amount of energy reaching each square centimeter of a detector (eg., your eye, CCD, piece of the sphere) per unit time (gets smaller as you get farther away) . Related to the inverse square laq
- Passing Galileo spacecraft shows the little moon has a dense core and a rocky mantle. It appears that it has a liquid water ocean beneath the ice crust. Heat may be provided by the decaying elements in this core Chemical base for creation of complex molecules Liquid Solvent Energy Source
- Very cold, liquid hydrocarbon lakes, thick atmosphere with carbon rich compounds but mostly composed of nitrogen left: array in chile, shows the spacial maps of gaseous chemicalls: hydrogen isocyanide , cyano-acetylene east-west zone formation: saturns magnetic field, unknown atmospheric circulation patterns, or thermal effects Chemical base for creation of complex molecules Liquid Solvent Energy Source
- Brine streaks caused by seeping water Chemical base for creation of complex molecules Liquid Solvent Energy Source
- So what? Methane can be part of biological activity and this methane is both created and used up in a very rapid seasonal cycle Bit of controversy about the source
- Type I civilization: can use all the energy on their planet (we are .7) Type II civilization: can use all the energy on their host star Type III civilization: can harness all the power comparable to that of the milky way galaxy Filter: life to start, prokaryote eukaryote
- The universe has only recently calmed down enough, used to be gamma ray bursts that would kill everything Hasn’t been this much time for life to form
- What I think – we have only been listening for 50 years in the universe that is around for 14 billion years.
- This is a bit advanced, so I’m only going to touch on most of these subjects. Try to not get overwhelmed, instead just think of the big topics. Two types of objects – chiral and achiral (or not chiral)
- Chira (shoes)l vs achiral (baseball bat, pen) R & S enantiomers (or versions, of the same molecule)
- Racemic mixture In pharmcuedical industry, all drugs have to be either the R or S enantiomer, because they can have different properties So why is this important? b/c All amino acids in proteins are ‘left-handed’, while all sugars in DNA and RNA, and in the metabolic pathways, are ‘right-handed’ Typically, it was thought you cannot get a mix of R and S in what is called achiral conditions (baseball bat). An interesting debate,
- the chiral product precipitates from the solution I show this example to get you thinking about all the different disciplines that get involved here. Chemists, geologists, astronomers, engineers, all together in this field
- Stress: this is not likely, but an interesting topic Greenhouse effect – thermal radiation from a planet surface is absorbed & re-radiated back by atmospheric gasses, so average temp increases In this context, a runaway greenhouse gas trigger can cause the boil off of a planets oceans
- Broad range of topics When you choose what you want to present on, think about the range of things Start from earth and move outward origin of life, evolution, habitable planets,