Super Normal and Wimpy Moons Wimpy 14 bigger 30 brighter than smallest and dimmest Wimpy Moon Credit Catalin Paduraru Note Most astronomers do not like the term Super Moon Super Normal and Wimpy Moons 7 bigger 15 brighter than normal Full Moon Credit Catalin Paduraru Note Most astronomers do not like the term Super Moon Course Announcements Thanksgiving Week planning No classes Wednesday 23 Nov Last week of Extra Credit Sessions All Extra Credit materials must be turned in by the start time of the Final Exam Quiz 5 Graded Quiz 6 this Wednesday 16 Nov Hints today Exam 3 Monday 21 Nov Study materials released as soon as possible Study session Thursday 17 Nov at 5 PM Location TBD Final Exam Thursday 8 Dec 2 45 4 45 PM Astronomy Club Interest Meeting Friday 18 Nov 12 30 1 30 PM Nielsen 307 Online Course Evaluations now available Please complete one for this course Assignments Reading Assignments Chapter 11 Sections 11 5 11 6 Read by Wed 16 Nov Parallel Lectures CC Astronomy Episode 16 JupiterCC Astronomy Episode 17 Jupiter s Moons Watch before Wed 16 Nov Mastering Astronomy Chapter 10 Homework short assignment Due Wed 16 Nov at 11 59 EST Available now on Mastering Astronomy Quiz 5 Results Very low attendance Perhaps hardest quiz Adjusted Mean 8 3 Median 8 5 Raw Mean 6 8 Median 7 0 Reward for taking the quiz with lowest attendance to date 0 5 points Difficulty Adjustment 1 0 pts As this material is a bit more difficult and nuanced yet integral to understanding stars I will use some form of all the questions from Quiz 5 on Exam 3 Be sure to know the Formation and Evolution sequences A few helpful guidelines on next slide Quiz 6 Hints Quiz 6 Covers end of Ch 9 Ch 10 and start of Ch 11 General concepts to know What is the runaway greenhouse effect What planet is it important for understanding its atmosphere What is the definition for a habitable zone What is a synodic period and why do we care about synodic periods in relation to space exploration missions In what characteristics is Mars similar to Earth In what ways is it different Consider rotation rate axial tilt atmosphere weather Quiz 6 Hints Sample questions 1 What is the largest mountain in the Solar System A Mauna Kea B Mount Everest C Olympus Mons D Maxwell Montes E Caloris Heights Additional information to know What planet is this located on What is the name of the largest canyon in the Solar System and what planet is it on Quiz 6 Hints Sample questions 2 Which of the major water related surface features on Mars provides evidence that Mars once had a thicker atmosphere that could support a water cycle including rain rivers lakes and perhaps even oceans A Outflow Channels B Amazonian Channels C Rilles D Runoff Channels Additional Information Which feature is indicative of episodic flooding Which of the two is older and what are their approximate ages Quiz 6 Hints Sample questions 3 What is the name for a Martian day A Sol B Helios C Sidereal Day D Ares E Mercurial Day Additional Quiz information Material from today s lecture is fair game Which terrestrial planets have moons What happened to Mars s atmosphere Blue bolded words about Jupiter What happened to Mars s atmosphere Once was thick enough to support liquid water perhaps even global oceans Methods of Loss 1 Atmospheric Stripping from Solar Wind 2 Jean s Escape Lower gravity allows more of the atmosphere to just drift away All planets slowly leak atmosphere this way 3 Reverse Runaway Greenhouse Effect Runaway Refrigerator Effect 4 Large impacts blasting away chunks of it An atartist s a time conception of a Solar storm stripping away Mars s atmosphere Atmospheric Stripping via Solar Wind Solar wind erosion of Mars s atmosphere Recent result 2015 from MAVEN Amount of atmosphere stripped significantly increases during Solar storms increased Solar Wind Charged solar wind particles carry off ions of Oxygen and Carbon measured by MAVEN An artist s conception of a Solar storm stripping away Mars s atmosphere Atmospheric Stripping via Solar Wind Solar wind erosion of Mars s atmosphere Majority stripped rapidly after loss of global magnetic field Over the course of the past 4 Billion years or so this process has eroded away the Martian atmosphere Sun expected to have higher levels of activity and stronger solar wind 4 billion years ago rapid loss of atmosphere Current non solar storm stripping rate 100 grams s Calculation reveals that replenishing this loss would provide an atmosphere thicker and capable of supporting liquid water Reverse Runaway Greenhouse So called Runaway Refrigerator Effect Sort of the reverse of Venus s Runaway Greenhouse Effect Distance from Sun has cooler temperatures so CO 2 locked in rocks like Earth and remember when Mars had a thicker atmosphere the oceans helped with this Atmospheric loss thins atmosphere and makes it cooler as well about 4 Gyr Colder temperatures make it so CO2 goes into surface and eventually condenses as CO2 ice dry ice on the surface polar caps This makes it colder so more CO2 out of atmosphere and it runs away Internal Structure of Mars Largely unknown but we have a good idea of what it should be like via comparative planetology Measurements of the gravity field from spacecraft reveal that a core exists and it is between 1 500 and 2 100 km in radius Avg Density 3 900 kg m3 indicates differentiated and more dense core exists Lower density suggests a core made of Iron Sulfide FeS Crust is 50 km thick Volcanoes hint at convection in mantle NASA InSight mission will have seismometers to explore Mars internal structure with much higher precision Launch in May 2018 original launch March 2016 right about 780 days later The synodic period of Mars with Earth The Moons of Mars Phobos Fear and Deimos Panic The Moons of Mars Phobos Fear and Deimos Panic Only other terrestrial planet to have a moon 2 Moons Phobos and Deimos Tiny compared with Earth s Moon Phobos mean radius 11 3 km Deimos mean radius 6 2 km Thought to be captured asteroids although origin remains a hotly debated topic Irregular in shape Very dark Albedo 0 06 reflects 6 of light Both in nearly circular equatorial synchronous 1 1 spin orbit resonance orbits Prograde orbits The Giant of the Solar System JUPITER Jupiter vs Earth A scaled side by side comparison Jupiter Data Sheet I Orbital Properties Semimajor Axis 5 2 AU 5th planet from the Sun Orbital Period 11 86 years Thanks Kepler s 3rd Law Orbital Eccentricity e 0 049 Inclination 1 31o to ecliptic Known Satellites 67 Rings
View Full Document
Unlocking...