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Home , El Capitan (Mars)

Astronomy 330 HW 2

•! Daniel Cohen This class (Lecture 12): http://www.newscientist.com/article/dn9943- Life in the Solar System top-10-controversial-pieces-of-evidence-for- Dave Dreiser extraterrestrial-life.html Feifei Lian Next Class (Thursday): •! Katherine Woodruff Life in the Solar System http://www.abduct.com Maura Walsh Carolyn Buesing HW 4 is due tonight

Music: We Are All Made of Stars– Moby

Presentations Outline

•! Dave Dreiser •! Life on Venus? Star Lies •! Life on ?

•! Feifei Lian Extremophiles Drake Equation Life on Venus? Frank That’s 9.75 planetary systems/year Drake •! Surface is far too hot –! If lead is liquid, think of what heat would do to complex organic polymers –! No cooler polar regions exist N = R f n f f f L •! Heat is uniform! * ! p ! e ! l ! i ! c ! •! But, high in the clouds it should be cooler?! # of # of Star Fraction Fraction •! Maybe life can still exist in advanced Earthlike Fraction Fraction Lifetime of formation of stars that civilizations planets on which that evolve advanced rate with commun- the clouds? we can per life arises intelligence civilizations planets icate contact in system •! At 50 km up, the temperature is our Galaxy not too hot and the pressure is today 15 0.65 planets/ life/ intel./ comm./ yrs/ 1 atmosphere. stars/ systems/ system planet life intel. comm. yr star

Chemical Disequilibrium Life on Venus?

•! High clouds in the atmosphere contain •! One possibility is that microbes living in the clouds could chemicals that hint at the presence of be combining sulfur dioxide with carbon monoxide and some kind of biological activity. possibly hydrogen sulphide or carbonyl sulphide in a metabolism similar to that of some terrestrial micro- •! Hydrogen sulfide and sulfur dioxide - two organisms (extremophiles). gases that react with each other– exist in •! Given that the temperature on Venus was once much the clouds. cooler, there may once have been oceans on the planet. Life –! So, something may be producing them. could have started there and retreated to stable niches once the runaway greenhouse effect began. •! Hardly any carbon monoxide, which •! Maybe a mission to scoop up some atmosphere? should be there. –! So something may be removing CO.

http://www.manson-valley.de/fotogalerie/manson/images/acss/acss_32.jpg Earth – Mars comparison What we used to think.

•! Similar to the Earth in many ways. •! Life was argued to exist on Mars. •! The astronomer Schiaparelli announced Radius 0.53 Earth that he saw regular linear Surface gravity 0.38 Earth markings on the surface, Mass 0.11 Earth which he named canali. Mars has the Solar Distance from Sun 1.5 AU • Technically, in Italian System’s largest Average Temp -63 C ! Volcano, Olympus Max Temp 20 C means channels, but it Mons – 27 km tall. Year 687 Earth days was mistranslated to canals. Length of Day 24 hours 39 minutes

Atmosphere CO2 95%

Percival ’s Canals

•! Evidence for intelligent life? •! Mapped the civilization. •! Influenced culture. The Atmosphere The Surface of Mars •! 95% carbon dioxide •! Mars is a desert! •! Atmospheric pressure 0.6% of Earth’s – •! Large daily and seasonal •! Iron oxide in soil gives reddish cast. like 40 km altitude on Earth swings in surface !!Too thin for significant greenhouse temperature effect. !!Pressure is too low for liquid water. •! Not protected by a global magnetosphere like Earth’s

http://www.grc.nasa.gov/WWW/PAO/html/marspath.htm

Water on Mars Liquid ? •! Water erosion features visible from space •! There is water on Mars •! Atmospheric pressure too low for liquid water –! North and to exist

polar caps (mostly CO2) •! Perhaps at some point in the past? –! Some water vapor in the air –! Frost on rocks –! Clouds (ice crystals)

•! No liquid water now “Islands”

Valley networks Erosion Features Flood erosion New Water? The Surface of Mars:

http://antwrp.gsfc.nasa.gov/apod/ap040303.html

Roving on Mars

Roving on Mars: and Opportunity find evidence of ancient liquid water

http://antwrp.gsfc.nasa.gov/apod/image/0403/ emptynest_opportunity_big.jpg Feb 26, 2008 Standing Water on Mars Mars Missions Now • The new data from the rovers are highly suggestive of ! •! Mars Reconnaissance ancient standing water on the Meridiani Planum. Orbiter •! 3 pieces of evidence: –! Studying the geology –! Physical appearance of rocks and –! Rocks with niches where crystals appear to have grown –! Look for ancient sea –! Rocks with sulfates left after the water evaporated shores •! Is it a former sea floor or just an area that had ground- –! Survey potential water? landing sites

El Capitan

Mars Missions Now Mars Missions Now •! Phoenix –! Analyze water ice at Mars’ north pole •! Phoenix –! Confirmed water ice on the surface of Mars –! Sublimates too slowly for dry ice (CO2)

http://www.nasa.gov/mission_pages/phoenix/images/ http://www.nasa.gov/mission_pages/phoenix/images/ press/PSP_008591_2485_RGB_Lander_Inserts.html press/PSP_008591_2485_RGB_Lander_Inserts.html Mars Missions Now Mars’ Watery Past

•! Phoenix –! Blobs on lander legs –! Blobs merge ( 8 & 31) –! Liquid! –! Saltwater most likely

http://www.planetary.org/blog/article/00001890/

What Happened to the Water? The

•! That is the big question –! Quite a lot of evidence for water now and in the past. –! Did the surface water escape to space with the air? –! How much is still frozen ! beneath the surface? Opportunity ! Spirit The Surface of Mars

•! The largest mountain in the volcanoes Solar System rising 26 km high •! A shield volcano, Hellas Impact Basin like Hawaii on Earth •! Its caldera is 90 km across

http://hyperphysics.phy-astr.gsu.edu/hbase/solar/marsoly.html

Mars Global Surveyor

Olympus Mons Valles Marineris

•! Its base is more than 500 •! A series of fault km in diameter canyons •! As long as the entire •! 5000 km long Hawaiian island chain –! A big as the U.S.! •! Rimmed by a 6 km high •! A giant crack in the cliff crust of Mars •! Last erupted 25 million –! Formed as the planet years ago cooled •! Probably so big, due –! Expanded by water flow to lack of plate tectonics Mars’ Interior Mars’ Past

•! Like Earth, Mars has •! Early in Mars’ history it was an iron core Core likely more Earth-like –! About half of the –! Geologically active planet’s radius in size –! Volcanic eruptions created a thick carbon dioxide, nitrogen –! Heavily contaminated atmosphere with sulfur –! Greenhouse effect made it –! Weak magnetic field warm enough for liquid water suggests a thin layer –! Oceans? Rivers? Glaciers by of liquid iron, mostly Crust Mantle the poles? solid –! Life?

What Happened? The “Face” of Mars? (1976) •! Mars was too small Mars Global –! Not enough internal heat Surveyor (1998) •! Plate tectonics stopped –! Volcanoes sat over “hotspots” grew to immense sizes •! Volcanic activity slowed as the interior cooled •! The atmosphere escaped

•! The planet froze http://antwrp.gsfc.nasa.gov/apod/ap980406.html •! Did life move underground? http://antwrp.gsfc.nasa.gov/apod/ap010528.html Other Faces Other Places

Mars Global Surveyor (1998) " Mars Global Surveyor (1998) "

http://antwrp.gsfc.nasa.gov/apod/ap990315.html http://www.solarviews.com/cap/mgs/heart.htm

The Search for Mars Life ?

•! Viking 1 and 2 carried several In August 1996, evidence for fossil microbial life experiments to detect life was found in a . •! The results were ambiguous. The soil reacted vigorously with the –! ALH84001 (3Gyrs): Viking nutrients, then tapered off Found in Antarctica, in activity. composition suggests it was knocked from •! The conclusion of most scientists Mars is that the reactions were due to –! About 14 such Mars inorganic chemical reactions. rocks have been •! Dirk Schulze-Makuch suggested found on Earth that Mars might harbor peroxide- based life forms which the landers could not detect Martian Microbe Fossils? &

•! Microscopic shapes that •! Mars’ moons resemble living and fossil bacteria on Earth– •! Likely captured nanobacteria, but much smaller than on Earth. •! small •! Microscopic mineral grains –! About 15-25 km in size like some produced by living –! Shaped like potatoes and fossil bacteria on Earth •! Organic chemical compounds that resemble the decay products of bacteria on Earth. •! In the end, not impelling enough. Non-biological processes can probably produce the observed features

Manned Mars Exploration Question

•! NASA’s plans to We know for sure that send a manned expedition to Mars •! Obama estimated a a)! Mars used to have water. manned orbit to Mars b)! Mars has life. in mid 2030’s with a landing soon after. c)! The people of Mars need soap. •! Russia and Europe are d)! The is gone. discussing options e)! Mars has water just under the surface now and •! China may be considering it too. used to have surface water. Question Life in the Solar System •! Venus may have life in the clouds. The face on Mars •! Mars might still have life under the soil. •! But what about the outer solar system? a)! was a huge NASA cover-up. •! It isn’t in our definition of the habitable zone, but it still is interesting. b)! might have been created by Martians or ETs, but •! We will now focus on Jupiter, Io, Europa, and Titan. we’ll never know for sure. c)! was an optical illusions, like cloud shapes. d)! will be the major focus of any follow-up rover missions. e)! was really a statue that had fallen over.

143,000 km 1,400,000 km We are here ! Earth – Jupiter comparison Jupiter, King of the Planets

•! Named for the king of the Roman gods •! A truly immense planet –! Over 11 times the diameter of Earth –! Over 300 times the mass of Earth –! Over twice the mass of all the other planets combined! Biggest and most –! Has over 63 moons, its own mini-solar system! massive planet, has the •! Visited by 4 spacecraft The big Radius 11.2 Earth –! Pioneer 11 - Flyby in 1979 largest gravity, has the Cloud-top gravity 2.5 Earth largest number of –! Voyagers 1 & 2 - Flybys in 1980 & 1981 Mass 318 Earth –! Galileo - Went into orbit and dropped a probe into Jupiter’s moons (>63), yet has (more than 2.5 times the rest combined) atmosphere, 1990-2003 the shortest day in Solar Distance from Sun 5.2 AU System. Radiates Year 11.88 Earth years more energy than it Solar day 9 hours 55 minutes absorbs. Causes a bulge at the equator.

Jupiter’s Interior Jupiter’s Atmosphere

•! Average density only 30% greater than water •! Although mostly gas, by 20,000 km in, • 25% that of the Earth’s average ! the pressure is 3 million atmospheres! density •! By 20,000 km, the pressure is 3 •! Due to an internal heat source, the million times that on the temperature rises as one penetrates the Earth’s surface! atmosphere. –! Hydrogen becomes a liquid metal •! The outer atmosphere is made of •! Core of rock & “ice” freezing clouds of ammonia, methane, 10-12 Earth masses and ice. •! The swirling patterns are evidence of great storms. The Great Red Spot Driving Jupiter’s Weather •! A huge storm 25,000 km across – twice size of the Earth! •! On Earth, solar heating drives weather •! First observed > 300 years ago! •! On Jupiter, internal heat drives weather –! Winds maintain speeds to great depths –! Jupiter radiates 70% more heat than it receives from the Sun –! The heat is from Jupiter contracting under its own powerful gravity –! As it contracts, the gas is squeezed, and the temperature increases

Voyager 1 image images

Little Red Spot Life?

•! Carl and Edwin Salpeter devised a scheme for life in the clouds of Jupiter. •! They argued that the atmosphere must be rich in organic chemistry, so why not expect Earth-like life?

http://tierra.rediris.es/merge/Carl_Sagan/192a.jpg http://www.aip.org/history/esva/catalog/images/salpeter_edwin_a3.jpg Floating Life Floating Life

•! The problem is that any life in the clouds •! The sinkers became the basis of that sank too far down would be destroyed a proposed ecology. by the temperature or pressure. •! They proposed a simple life form like •! They also posited “floaters”– oceanic plankton called “sinkers”. large hydrogen balloon-like life •! Small (0.1 cm) life that grew and fell, but that “swim” in the Jovian then replicated by “splitting-up” and atmosphere. getting circulated back into the upper atmosphere.

http://www.wackerbaits.com/sf/media/bellsinker.jpg http://www.firaxis.com/smac/nativelife.cfm http://www.mantapacific.org/mantapacific/information/images/plankton.jpg

Floating Life Floating Life

•! They could be huge •! Maybe there are also “hunters” that fed on the creatures, as large as 1 floaters? to 2 km in diameter. •! Of course, this is all •! Maybe similar to speculative, and there is whales– mixture no way to detect such life. between jellyfish and •! Science fiction from birds? scientists really. •! Big bags of hydrogen gas.

http://www.epilogue.net/cgi/database/art/list.pl?gallery=3126 http://img.photobucket.com/albums/v154/superminyme/National %20Geographic%20Picture%20Atlas%20of%20Our %20Universe/Pg4JupiterPic.jpg