Earth and Moon Seen from Mars Credit NASA JPL Curiosity Team Course Announcements Thanksgiving Week planning No classes Wednesday 23 Nov Extra Credit sessions still underway Quiz 5 Today Quiz 6 next Wednesday 16 Nov Exam 3 is Monday 21 Nov Final Exam Thursday 8 Dec 2 45 4 45 PM Course Announcements An Astronomy Club Astronomy Club Interest Meeting A group of enthusiastic students are starting a UT Astronomy Club They are holding an interest meeting for any people that want to be a part of it When Friday 18 November from 12 30 1 30 PM Where Nielsen Physics and Astronomy Room 307 Focus of the meeting is to determine level of interest potential student activities star parties learning astrophotography outreach opportunities etc Assignments Reading Assignments Chapter 10 Sections 10 5 10 7 Read by Friday 11 Nov Parallel Lectures CC Astronomy Episode 15 Mars Watch before Friday 11 Nov Mastering Astronomy Chapter 9 Homework short assignment Due Thursday 10 Nov at 11 59 EST The Overview Effect A reminder of unity and moving humanity forward In case you are thinking this today I want to remind you all of the Overview Effect Astronauts that have looked down upon the Earth from outerspace overwhelming report experiencing a cognitive shift toward a new understanding of the Earth as a small and precious place where unity amongst humans is the paramount feeling A reminder to move forward with unity And now to imagine Dr Farnsworth s dreams Edge of Credit Mt NASA JPL Sharp Caltech Foot of Credit Mt NASA JPL Sharp Caltech Jagged Landscape Credit NASA JPL Caltech Wafer Thin Rocks Credit NASA JPL Caltech Martian Sunset Credit NASA JPL Caltech Curiosity Selfie Credit NASA JPL Caltech Victoria Crater Credit NASA JPL Caltech MER Opportunity Tire Tracks Credit NASA JPL Caltech Martian Sunset Credit NASA JPL Caltech Orbital Properties Opposition is point of closest approach Sun Earth Planet all in a line Oppositions occur at roughly 780 day intervals Synodic Period opposition to opposition or conjunction to conjunction period 1 Psyn 1 1 PMars Oppositions near Mars perihelion less frequent occurring once every 15 years or so Earth Mars passages within 0 38 AU Earth at aphelion Mars at perihelion even more rare at about 3 times per century Mars Physical Properties And how we determine them and what they mean Rotation period easily obtained by tracking surface features One 360o rotation sidereal day every 24 62 hours 24 hours 37 min Martian Days are called sols Confirmed using radar Axial tilt also very similar to Earth s and is currently at 25 o Mars axial tilt or obliquity changes between perhaps lower than 10o and as high as 50 60o in a non period chaotic fashion over timescales of hundreds of thousands to millions of years Combine axial tilt and eccentric orbit 0 29 AU difference between perihelion and aphelion and Mars has extreme and complicated seasons Global Views Characteristic red color from high abundance of oxidized iron rust in the rocks and regolith on the surface Reddish color due to iron oxides i e rusts with dark and light patches that show seasonal variability Polar ice caps that show seasonal variability From Earth Hubble Space Telescope Viking Spacecraft 1976 Martian Surface from orbit Viking global view of Mars Mosaic of images taken with Viking spacecraft Major Large scale surface features Tharsis Bulge with four HUGE volcanoes Largest Olympus Mons Huge canyon called Valles Marineris Largest mountain Olympus Mons and canyon Valles Marineris in Solar System Martian Topography North south hemisphere dichotomy Lowland Northern hemisphere is several kilometers lower 5km than the southern hemisphere Characterized by smooth rolling volcanic plains not unlike the lunar maria Strewn with blocks of volcanic rock and ejecta boulders from impacts Highland Southern hemisphere is several kilometers higher 5km than the northern hemisphere Cratered highlands with dark mountainous regions Martian Topography Mars Global Surveyor MGS Northern hemisphere lower altitude much less cratered and therefore younger 3 Gya than the more heavily cratered and older southern highlands 4 Gya MGS mapped surface with accuracy of a few meters Martian Topography The Tharsis Bulge Tharsis Bulge is roughly the size of North America lies on the equator and rises about 10 km above the rest of the Martian surface Tharsis Bulge region in a MOLA on Mars Global Surveyor MGS elevation map Valles Marineris the biggest canyon in the SS is to the right east of Tharsis Bulge Diametrically opposite antipodal the Tharsis Bulge in the southern hemisphere is the Hellas Basin a very large impact basin estimated have an age of 4 Gya Late Heavy Bombardment times Likely caused a major restructuring of the Martian Crust and possibly the creation of the Tharsis Bulge Credit NASA JPL Caltech ASU Largest Valley in Solar System Valles Marineris Mariner Valley About 4000 km long East to West coast of US up to 120 km wide and as deep as 7 km Largest canyon in Solar System Largest Valley in Solar System Valles Marineris Mariner Valley Associated with the Tharsis Bulge Theorized to have formed from the same crustal deformation processes As Tharsis bulged Valles Marineris split and cracked open These type of features are called tectonic fractures Not formed by water NASA JPL Volcanism on Mars Largest volcanoes in Solar System While many shield volcanoes cover the surface the most prominent are found on the Tharsis Bulge Largest volcano in the Solar System is Olympus Mons 700 km across with surface area about the size of Arizona Rises 25 km above surrounding plains 3x taller than Everest 2 5 times taller than Mauna Kea ocean floor to peak Caldera is 80 km across Cool fact Super tall volcanoes result of lower surface gravity Volcanism on Mars Largest volcanoes in Solar System Olympus Mons Olympus Mons is 25 km tall rising above many of the clouds in the Martian atmosphere The giant shield volcano is surrounded by 8 km cliff Tharsis Bulge a ancient plate Is Tharsis Bulge geologic evidence of ancient plate tectonics Uplifted nature of Tharsis Bulge similar to what we expect from a plate Chain of three volcanoes very similar to a plate moving over a hot spot like the Hawaiian Islands and Canary Islands Intriguing evidence that Tharsis might have once been a tectonic plate Still unconfirmed Volcanism on Mars Are they still active No direct evidence of ongoing eruptions Crater counting dating based the number of craters on these volcanoes slopes
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