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Astronomy 101The Solar SystemTuesday, Wednesday, ThursdayTom [email protected] 101The Solar SystemTuesday, Wednesday, ThursdayTom [email protected] Planetary Surfaces• Impact Cratering• Volcanism•Tectonics•Tectonics• ErosionShaping Planetary SurfacesCrateringMeteor Crater, Arizonahttp://www.solarviews.com/eng/tercrate.htmCrateringMeteor Crater, Arizonahttp://www.solarviews.com/eng/tercrate.htmGalle Crater, MarsGalle Crater, MarsMercuryhttp://geologyindy.byu.edu/eplanet/chapter_5.htmMercuryhttp://geologyindy.byu.edu/eplanet/chapter_5.htmCallisto (Moon of Jupiter)http://ase.tufts.edu/cosmos/view_picture.asp?id=726Callisto (Moon of Jupiter)http://ase.tufts.edu/cosmos/view_picture.asp?id=726VolcanismVolcanismErosion•Processes that break down or transport rock through the action of ice, liquid, or gas•Movement of glaciers•Movement of glaciers•Formation of canyons by running water•Shifting of sand dunes by windErosionProcesses that break down or transport rock through the action of ice, liquid, or gasFormation of canyons by running waterShifting of sand dunes by windEnergy of Impact (K• v = 17 km/s• Density = 3,000 kg/m3•Diameter = 2*radius =10 km• Volume = 4/3*π*r3 = 5.23 x 10• Mass = density*volume• Mass = 1.57 x 1015kg• Kinetic energy = ½ mv2• Kinetic energy = 2.27 x 1023 • Kinetic Energy = 5.42 x 107 •Largest Nuclear Bomb is 100 Megatons of TNTEnergy of Impact (K-T)Diameter = 2*radius =10 km= 5.23 x 1011m323 Joules7 Megatons of TNTLargest Nuclear Bomb is 100 Megatons of TNTGene ShoemakerParts taken from talk of Bridget MahoneyGene ShoemakerParts taken from talk of Bridget MahoneyMeteor Crater, Flagstaff, Arizona•Shoemaker wrote his Ph.D thesis on Meteor Crater•Shoemakmechanics of meteorite impactsShoemaker wrote his Ph.D thesis on Meteor Crateremaker did seminal research in the mechanics of meteorite impactsMeteor Crater and Shoemaker•In 1952, ShMeteor Crater as well as lunar craters were created by asteroidal impactswere created by asteroidal impacts•USGS sent Shoemaker to the Yucca flats to inveto compare with Meteor Crater, Shoemaker at Meteor Crater, 1960’sMeteor Crater and Shoemaker52, Shoemaker hypothesized that Meteor Crater as well as lunar craters were created by asteroidal impactswere created by asteroidal impactsUSGS sent Shoemaker to the Yucca to investigate small nuclear events to compare with Meteor Crater,Quartz (SiOQuartz (SiO2)Coesite•While doing meteorite impdiscovered Coesite• Coesite(SiOproduced during violent impact •Different crystal structure than quartzearth.leeds.ac.ukCoesitedoing research in the Yucca flats on ite impact with David Chao, the pair discovered Coesite(SiO2) is a mineral that is produced during violent impact Different crystal structure than quartzChixculub CraterTaken from presentation by Amanda BakerChixculub CraterTaken from presentation by Amanda BakerK-T Boundary• 65 million years ago• Boundary in the rock record separating the Cretaceous and Tertiary Cretaceous and Tertiary Periods• Corresponds to one of the greatest mass extinctions in history• Global layer of clay separating the two periods• First proposed by Walter AlvarezT BoundaryWe know it happened but where?•We know it happened but where?A Circular geophysical anomaly, now known to define the Chicxulub structure, was originally identified on the northern identified on the northern edge of the Yucatan Peninsula during oil surveys in the 1950's.Chixculub•Translates to “tail of the devil” in Mayan•The meteorite's estimated size was about 10 km (6 mi) in diameter, releasing an estimated 4.3(equivalent to 191,793 gigatons of TNT) on impact. ChixculubTranslates to “tail of the devil” in MayanThe meteorite's estimated size was about 10 km (6 mi) in diameter, releasing an estimated 4.3×1023joules of energy (equivalent to 191,793 gigatons of TNT) on impact.Data• Seismic, gravity and magnetic data define a structure ~180 km in diameter. DataWhat happened?•An asteroid roughly 10 km (6 miles) across hit Earth about 65 million years ago. •This impact made a huge explosion and a crater about •This impact made a huge explosion and a crater about 180 km (roughly 110 miles) across. •Debris from the explosion was thrown into the atmosphere, severely altering the climate, and leading to the extinction of roughly 60% of species that existed at that time, including the dinosaurs. What happened?An asteroid roughly 10 km (6 miles) across hit Earth about 65 million years ago. This impact made a huge explosion and a crater about This impact made a huge explosion and a crater about 180 km (roughly 110 miles) across. Debris from the explosion was thrown into the atmosphere, severely altering the climate, and leading to the extinction of roughly 60% of species that existed at that time, including the dinosaurs.Environmental Damage•http://www4.tpgi.com.au/users/horsts/climate.htmEnvironmental Damagehttp://www4.tpgi.com.au/users/horsts/climate.htm•The worst hit organisms were those in the oceans.•On land, the Dinosauria of course went extinct, along with the Pterosauria. • Mammals and most non-seemed to be relatively unaffected. •The terrestrial plants suffered to a large extent, except for the ferns, which show an apparently dramatic increase in diversity at the Kboundary, a phenomenon known as the fern spike.The worst hit organisms were those in the oceans.On land, the Dinosauria of course went extinct, along with the Pterosauria. -dinosaurian reptiles seemed to be relatively unaffected. The terrestrial plants suffered to a large extent, except for the ferns, which show an apparently dramatic increase in diversity at the K-T boundary, a phenomenon known as the fern spike.•Pterosaurs were flying reptilesPterosaurs were flying reptiles•Dinosaurs lived during the Mesozoic Era, from •Dinosaurs lived during the Mesozoic Era, from late in the Triassic period (about 225 million years ago) until the end of the Cretaceous (about 65 million years ago).Dinosaurs lived during the Mesozoic Era, from Dinosaurs lived during the Mesozoic Era, from late in the Triassic period (about 225 million years ago) until the end of the Cretaceous (about 65•Modern birds are considered to be the direct descendants of dinosaursModern birds are considered to be the
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