Astronomy 101 The Solar System Tuesday, Thursday 2:30-3:45 pm Hasbrouck 20 Tom Burbine [email protected] HoursHomeworkAstronomy InformationFinalHW #15Exam #3HW ReviewMercury/VenusMercuryDifficult to study MercurySlide 13Mariner 10Slide 15Caloris BasinCaloris Basin (Some of the hill are 1,800 meters tall)Slide 18Slide 19Slide 20Slide 21Weird TerrainMercury has high densitySlide 24Slide 25MessengerSlide 27Messenger videoSlide 29Slide 30Slide 31Slide 32Spectra of MercuryMercury’s SurfaceSlide 35Slide 36VenusSlide 38Venus’ atmosphereVenus’ cloudsGreenhouse EffectSlide 42Stefan-Boltzman LawSlide 44Slide 45Runaway Greenhouse EffectSlide 47Slide 48Why does Venus has such a thick atmosphere?SurfaceHow did it do it?Slide 52Slide 53CratersSlide 55Pancakes DomesCoronaeArachnoidsSlide 59Slide 60VeneraVenera 9Venera 9 picturesVenus ExpressSlide 65Mostly spare parts from Mars Express or RosettaAny Questions?Astronomy 101The Solar SystemTuesday, Thursday2:30-3:45 pmHasbrouck 20Tom [email protected]•Course Website:–http://blogs.umass.edu/astron101-tburbine/•Textbook:–Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny.•You also will need a calculator.Office Hours•Mine•Tuesday, Thursday - 1:15-2:15pm•Lederle Graduate Research Tower C 632•Neil•Tuesday, Thursday - 11 am-noon •Lederle Graduate Research Tower B 619-OHomework•We will use Spark•https://spark.oit.umass.edu/webct/logonDisplay.dowebct•Homework will be due approximately twice a weekAstronomy Information•Astronomy Help Desk•Mon-Thurs 7-9pm•Hasbrouck 205•The Observatory should be open on clear Thursdays •Students should check the observatory website at: http://www.astro.umass.edu/~orchardhill for updated information•There's a map to the observatory on the website.Final•Monday - 12/14 •4:00 pm•Hasbrouck 20HW #15•Due next TuesdayExam #3•This Thursday•Covers material from October 15th – November 5th•Bring pencil and a calculator•Review Session – Wed. at 6 pm in Hasbrouck 134•Formulas (I also would not forget the formulas that I learned earlier)Density = mass/volumeVolume = 4/3r3HW ReviewMercury/Venus•Mercury is the closest planet to the Sun•Venus is next closestMercury•orbit: 0.38 AU from Sun•diameter: 4,880 km (38.3% of Earth)•mass: 3.30 x 1023 kg (5.5% of Earth)•temperature: 90 K (minimum) 440 K (average)700 K (maximum)•Satellites: ZeroDifficult to study Mercury•Because of Mercury's proximity to the Sun–makes reaching it with spacecraft technically challenging–Earth-based observations difficult.Mercury•Videos•http://www.gecdsb.on.ca/d&g/astro/html/Mercury.htmlMariner 10•The only spacecraft to approach Mercury was NASA's Mariner 10 (1974-1975).Caloris BasinCaloris Basin(Some of the hill are 1,800 meters tall)Messenger dataMariner 10 dataCaloris Basin•A basin was defined by Hartmann and Kuiper (1962) as a "large circular depression with distinctive concentric rings and radial lineaments." •Others consider any crater larger than 200 kilometers a basin. •The Caloris basin is 1,550 kilometers in diameter, and was probably caused by a projectile larger than 100 kilometers in size. •The impact produced concentric mountain rings three kilometers high and sent ejecta 600 to 800 kilometers across the planet.Weird TerrainThe weird terrain is almost opposite Caloris Basin. It consists of hills, ridges and grooves that cut across craters. The weird terrain my have been formed by shock waves that raced through the center of the planet and outward early in Mercury's history.Mercury has high density•Its density is 5.44 g/cm3 which is comparable to Earth's 5.52g/cm3 density. •In an uncompressed state, Mercury's density is 5.5 g/cm3 where Earth's is only 4.0 g/cm3.http://www.psrd.hawaii.edu/WebImg/MercuryCore.gifMessenger•Mission to Mercury•Launched August 3, 2004•Flew by Mercury in 2008 and 2009•Will orbit Mercury in 2011Messenger video•A set of five 11-band images was captured by MESSENGER just after the spacecraft crossed the night/day line (the “terminator”), which are the highest-resolution color images ever obtained of Mercury’s surface. •At the beginning of this movie, it is dawn in that region of Mercury, and the Sun is just off the horizon. The long shadows that are cast by crater walls exaggerate the ruggedness of the terrain and highlight variations in topography. •Though Mercury’s true colors are subtle, the 11 color bands of MDIS were combined in a statistical method used to highlight differences in color units. Older, low-reflectance, and relatively blue material is encroached by younger, relatively red smooth plains. Several lobate scarps or cliffs are observed, which are places where compressional stresses caused Mercury’s crust to fracture and shorten.http://messenger.jhuapl.edu/news_room/presscon5_images/Robinson%20Image%205.7.movMercuryhttp://space.newscientist.com/data/images/ns/cms/dn14893/dn14893-1_450.jpgMuch of the image to the right of the Kuiper crater (in the centre here) had never been imaged by a spacecraft before. Researchers were surprised to see long crater rays that extend thousands of kilometers from a crater at the planet's north poleMercuryDark material, shown in deep blue in the enhanced colour image at right (a composite of visible and near-infrared images), was kicked up by impacts. The material seems to be widespread but patchy, suggesting the planet's interior is not homogenous. http://space.newscientist.com/data/images/ns/cms/dn15077/dn15077-1_600.jpgMercury•Double ringed basin•290 km in diameter•Appears young (few craters on it)•~ 1 billion years old•Lava may have covered up the central part of the basinhttp://messenger.jhuapl.edu/gallery/sciencePhotos/pics/presscon6_img4_5_lg.jpg•160 km in diameterhttp://en.wikipedia.org/wiki/File:Mercury_Double-Ring_Impact_Basin.pngSpectra of MercuryWeak to absent absorption features – no iron in the silicatesMercury’s Surface•Made of Enstatite (MgSiO3) – Mg-rich pyroxene•Made of material like the Lunar Highlands–Plagioclase feldspar - CaAl2Si2O8Venus• orbit: 0.72 AU from Sun• diameter: 12,103.6 km (94.9% of Earth) (called Earth‘s twin)• mass: 4.869 x 1024 kg (81.5% of Earth)•Temperature on surface: 726 K(average)•Satellites: ZeroVenus’ atmosphere•Atmospheric pressure at surface is 92 times the pressure on the Earth’s
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