Administrivia. Administrivia

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Charles Wilkerson
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1 Administrivia Money for Philadelphia - $30.00!!!! by tonight Pick up and pay for T-shirt Pi day!!! Penny wars over tomorrow After spring break, softball practice!!! Bring your mitt if have one Read Sarah Elaine s s 1 Administrivia Project stuff Tie into space policy! Next milestone is rough/1 st draft Thursday 4 April Both electronic and hard copy 2 1

2 Astrobiology A Science in Search of its Second Data Point Or A Cautionary Tale 3 Outline What it is (and what it is not!) Search for life on Mars Then Now Future Search for life elsewhere in the Solar System 4 2

5 billion years ago 700 million years (0.7 billion years) after that evidence for prokaryotic life 1.

3 Astrobiology What? What is it? Is it the search for extraterrestrial intelligence (ET)? Why or why not? 5 Astrobiology Based upon on our one data point - Earth Earth forms 4.5 billion years ago 700 million years (0.7 billion years) after that evidence for prokaryotic life 1.5 billion years later (2.2 billion years after Earth forms) evidence for eukaryotic life Intelligent life < 10 million years ago 6 3

Astrobiology In other words Life forms same time Earth forms But ½ of that time is spent at the prokaryotic only stage (simple one celled life) 7 Astrobiology Currently (as

4 Astrobiology In other words Life forms same time Earth forms But ½ of that time is spent at the prokaryotic only stage (simple one celled life) 7 Astrobiology Currently (as of 10:00 am) 861 known planets in orbit around other stars Many multiple planetary systems If one of these planets had life on it what kind of life would you expect to find? 8 4

5 N = R s f p n e f L f i f c L The Drake Equation N = Number of civilizations that we could contact R S = Solar type star formation rate per year f p = Fraction of Stars that have planets n e = Number of Earth-Like planets per star f L = Fraction of planets on which life occurs f i = Fraction which become technologically advanced f c = Fraction willing and able to communicate L = Lifetime of technologically advanced civilization 9 The Drake Equation We know the value of only two of these variables R s about 10 per year f p ½ About half of all stars are binary (two stars orbiting each other) so assume that all of the other stars have planets The rest??? n e based upon our on solar system 3 f L based upon our on solar system f i based upon our on solar system 1 f c based upon our on solar system 1 L based upon our on solar system 100 years 10 5

The Drake Equation And the answer is 500

6 The Drake Equation And the answer is 500 (maybe) Change the numbers so only looking for life n e based upon our on solar system 3 f L based upon our on solar system L based upon our on solar system 3.8 billion years And the answer is 19,000,000,

7 Astrobiology What? Astrobiology is the scientific study of the: Origin Evolution Distribution Future of life in the universe The study of astrobiology brings together scientists from many different areas such as: Microbiology Ecology Chemistry Geology Paleontology Astronomy 13 Astrobiology Why? Intellectual curiosity? Just nice to know with no practical benefits? Spiritual curiosity? Are we alone in the universe? Spin-offs? 14 7

8 Search for Life NASA has had one (1) search for life on another planet (a second data point) It occurred before you were born (sigh) Mars Viking Mission Twin orbiters & landers Launched in 1975, arrived in 1976 All four spacecraft were successful 15 Mars Fact Sheet Gravity 1/3 of Earth Day 24.6 hours Surface pressure 1/100 of Earth 95% CO 2, 2.7% N 2, 1.6% Ar, O % Average temperature range -20 to -60ºC Full range -140ºC to 20ºC Polar caps of frozen H 2 O and CO 2 Cold and dry now but liquid H 2 O was present in the past 16 8

9 Weight about 600 kg, science payload 91 kg, 2.2 m wide, 1 m high, 70 W of power

10 Mars Viking Mission Biology Search Four experiments focused on biology, or evidence for life: Gas Chromatograph/Mass Spectrometer (GCMS) Gas exchange (GEX) Pyrolytic release (PR) Labeled release (LR) Use the robot arm to scoop up Martian soil and dump it into the spacecraft where the four experiments could use it 19 Mars Viking Mission Biology Search Gas Chromatograph/Mass Spectrometer (GCMS) Could detect molecules with carbon in them, chemists call all molecules with carbon in them organic molecules If I took you (or any living thing on the Earth) apart molecule by molecule would I find a lot of carbon containing molecules BUT not all carbon containing molecules come from life Really two experiments Gas chromatograph Mass Spectrometer 20 10

11 Mars Viking Mission Biology Search Gas exchange (GEX), Pyrolytic release (PR), & Labeled release (LR) Looking for microscopic plants or animals Variation upon a theme Add water and food to Martian Soil Sample Look for CO 2 and O 2 being given off 21 MARS Viking Mission Biology Search Gas exchange (GEX) A sample was sealed and purged by He Then a mixture of He, Kr, and CO 2 was introduced as an initial incubation atmosphere. Nutrient solution added Sample incubated. At certain intervals, samples of the atmosphere were removed and analyzed by a gas chromatograph with a thermal conductivity detector. Measured the production and/or uptake of CO 2, N 2, CH 4, H 2, and O 2 during incubation of a soil sample

12 MARS Viking Mission Biology Search Pyrolytic release (PR) A sample was incubated for several days in the presence of radioactive CO 2 or CO (containing 14 C). Some samples with simulated sunlight and some without. Each sample was heated to 120 C to remove unreacted CO 2 and CO. The soil was pyrolized at 650 C and any organic products were collected in an organic vapor trap (OVT). Finally, the trap was heated to combust the organic material to CO 2 and any evolved radioactive gas was measured. Sought to detect the photosynthetic or chemical fixation of CO 2 or CO 23 MARS Viking Mission Biology Search Labeled release (LR) 14 C-labeled nutrient medium added to sample Sample incubated at approximately 10º C Evolution of radiolabeled gas was monitored by a beta detector in a chamber connected to the test cell Measured the production of CO 2, CO, or CH 4 during incubation of a soil sample

13 Then they had a problem Is it Alive? Or Is it Chemistry? 25 At great budgetary expense SDU has procured 8 Martian soil samples Two are sterile Two have interesting chemistry Two have life Two have both life and interesting chemistry You have the following supplies to determine which is which: Warm water Warm nutrient solution (Water + C 12 H 22 O 11 ) Only observations of gas (or not) being given off But no digging in the dirt! (same as original experiment) Your intelligence Other groups samples Why use water? 26 13

14 Step 1 Come up with a procedure Come up with criteria that will enable you to decide is it alive or not? Step 2 Do your experiment Communicate your observations Step 3 Decide is your sample sterile, contains life, or has interesting chemistry Decide if you want to revise your life vs. chemistry criteria in step 1 27 Split into your project groups, get a worksheet and a soil sample and have at it. SAMPLES ARE HETEROGENOUS! 28 14

15 Results 1 Gas Chromatograph/Mass Spectrometer (GCMS) Zip, Zilch, Nada (Maybe) Did detect H 2 O Not sensitive enough? 29 Results 2 Gas exchange (GEX) After addition of nutrient and incubation saw O 2 being given off O 2 definitely coming from soil Biology? Chemistry? Presence of peroxides, H 2 O 2, on Martian soil? 30 15

16 Results 3 Pyrolytic release (PR) Seven of the nine pyrolytic-release tests executed on Mars gave positive results. The amount of radioactive carbon dioxide obtained by the experiment was small enough to furnish organic matter for between 100 and 1000 bacterial cells. So small...that it could not have been detected by the gas chromatograph-mass spectrometer 31 Results 4 Labeled release (LR) Like the gas-exchange experiment, this experiment added a small amount of nutrient to the soil sample. It also produced a large amount of gas after that injection. Shortly after the addition of the nutrient, the radiation counts rose sharply, leveling off at about 10,000 counts per minute. Careful examination of the radiation curve showed No evidence of any doubling of cells No growth appeared to be taking place But curve did not seem to behave would have expected it to for chemical reactions 32 16

17 33 Why look under a rock? 34 17

18 Results Summary Informed Opinion is that Viking discovered interesting chemistry on the surface of Mars Dr. Gilbert V. Levin, principal investigator for the Labeled release experiment argues that Viking did discover life on Mars 35 Results Summary Would it matter if NASA said yes, we have found life on Mars, but it is bacterial? What if the bacteria: Was DNA based life? Was NOT DNA based life? NASA gave up looking for life on Mars and focused on looking for water 36 18

19 Events Since Then Martian meteorite ALH84001 Extremophiles: Bacteria than can live under extreme conditions Discovery of Methane (CH 4 ) in the atmosphere of Mars Evidence for recent H 2 O on the surface of Mars Current Mars Missions 37 Martian meteorite ALH84001 The original igneous rock solidified within Mars about 100 million years after the formation of the planet. Between 3.6 and 4 billion years ago the rock was fractured, presumably by meteorite impacts. Water then permeated the cracks, depositing carbonate minerals 16 million years ago, a large meteorite struck Mars, dislodging a large chunk of this rock and ejecting it into space. 13,000 years ago, the meteorite landed in Antarctica 38 19

20 Martian meteorite ALH84001 Three indications of life all discovered within the meteorite close to each other Abundant polycyclic aromatic hydrocarbons (PAHs) Carbonate mineral "globules" Presence of tiny "ovoids" 39 Martian meteorite ALH84001 PAHs are a type of molecule with carbon in them Mixture of PAHs found on ALH84001 suggestive of a biological origin Carbonate mineral "globules" Some have cores containing manganese and rings of iron carbonate and iron sulfides, along with magnetite and pyrrhotite. These minerals bear strong resemblance to mineral alterations caused by primitive bacteria on Earth

21 Martian meteorite ALH84001 Presence of tiny "ovoids May actually be fossil remnants of tiny (20 to 100 nanometer) bacteria But if so, they are 100 times smaller than any bacteria microfossils found on Earth Virus Bacteria Animal cell 70 nanometers 1 micrometer = 1000 nanometers 25 micrometers

0 These bacteria grow in caves Saltiest 30% salt By

22 Digging in the Ice (on Earth) 43 Extremophiles Coldest -15 C Crypotendoliths (Antarctica) Most acidic ph 0.0 These bacteria grow in caves Saltiest 30% salt By comparison seawater and human blood are about 3.5% salt

23 Extremophiles Longest in space 6 years Bacillus subtilis Lived in an orbiting NASA satellite that exposed test organisms to the extreme conditions of outer space Are we Martians then? 45 Recent Water on Mars? 46 23

24 Mars Missions Notable failures: Mars Climate Orbiter burned up in atmosphere in 1998 because of unit conversion error Mars Polar Lander less than a month later failed most likely due to software\hardware problems Mars Global Surveyor lasted a long time , death due to software error Mars Odssey orbiter current Mars Exploration Rovers current Mars Express (ESA mission) current Mars Reconnaissance Orbiter current Mars Phoenix Lander Mars Phoenix Lander 25 May 2008 Lands at 68 N latitude on Mars Science instrument packages Cameras Thermal and Evolved Gas Analyzer Microscopy, Electrochemistry, and Conductivity Wet Chemistry Results Confirms presence of subsoil water Identifies oxidizing agent perchlorate in soil Detects evidence for Calcium Carbonate in soil (forms in presence of liquid water) Mission over due to deteriorating weather 48 24

$Mineralogy X-Ray Diffraction Sample Analysis at Mars Instrument Suite Radiation Assessment Detector Detector of Albedo Neutrons Rover Environmental Monitoring Station (REMS) 49 50$

25 Mars Science Laboratory - Rover Instruments Mast camera Hand lens imager Alpha Particle X-Ray Spectrometer Laser-Induced Remote Sensing for Chemistry and Micro-Imaging Chemistry & Mineralogy X-Ray Diffraction Sample Analysis at Mars Instrument Suite Radiation Assessment Detector Detector of Albedo Neutrons Rover Environmental Monitoring Station (REMS)

26 Mars Science Laboratory Cost >= $2 Billion (initial estimate $650 million) Launched 26 November 2011 Arrive 6 August ???? Results Summary When does chemistry end and life begin? Have we found life on Mars and just don t realize it? Are Extremophiles possible candidates for Martian life? 52 26

27 Search for life elsewhere in the Solar System Back to looking for water

Lecture 27: Is There Life on Mars?

Lecture 27: Is There Life on Mars? Lecture 27 Is There Life on Mars? Astronomy 141 Winter 2012 This lecture is about the search for life on Mars The idea of a habitable Mars springs from telescopic observations in the 18 th and 19 th centuries,