LIGO detection of Gravitational Waves Mfinal 62 MSun M1 29 MSun M2 36 MSun Black Hole Merger 1 3 Glyr away Credit LIGO NSF Aurore Simonnet Ph D Comics video expl aining gravitation al waves Credit LIGO Nature news release Course Announcements Exam 1 grading complete Exams available for pickup Current grades on Blackboard soon I promise Quiz 3 is on the horizon Lab ASTR153 Announcements Lab Midterm next week Lunar Observation Labs due next week Assignments Reading Assignments Chapter 6 Sections 6 4 6 7 Read by Wednesday 12 Oct Parallel Lectures CC Astronomy Episode 9 Intro to Solar System Watch by Monday 10 Oct Mastering Astronomy Chapter 6 Homework Due Thursday 13 Oct at 11 59 PM EDT available on MA by tomorrow Exam 1 Results Exam 1 Results Mean 77 5 Median 79 5 Standard Deviation 15 6 N 140 Number A s 38 Number B s 29 Number C s 31 Top Scores 1 104 12 100 13 100 0 2x Number of Scores over 95 19 Very impressive Solar System Inventory Planets dwarf planets moons small bodies interplanetary dust solar wind Stars 1 The Sun 99 8 of the Solar System s mass Planets 8 Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Dwarf Planets 5 Ceres Pluto Haumea Makemake Eris Moons 181 Asteroids Estimated Millions More than 200 over 100km in diameter Over 600 000 discovered Comets Estimated Billions About 4 000 discovered ExtraSolar System Inventory It s weird wild whacky planetary world out there Current count is 1955 3 394 extrasolar planets sometimes exoplanet planets outside of our Solar System confirmed NASA Exoplanet Archive Currently an additional 4 696 Kepler Candidate exoplanets Most are larger than Jupiter and orbit their host stars closer than Mercury orbits the Sun Habitable Zone Earth like Exoplanets Kepler 186f 1 17 Earth radii and in habitable zone Kepler 62f 1 4 Earth Radii and in habitable zone Proxima Centauri b 1 1 1 4 Earth Radii and in habitable zone Credit NASA Exoplanet Archive ExtraSolar System Inventory Pepe et al 2014 Nature 153 Planetary Terminology And how we typically determine it Units in green Semimajor Axis a or distance from sun AU Known from Kepler s 3rd Law once orbital period known Orbital Period P Sidereal Time to make a single revolution around the Sun years Known through careful observations of planetary positions and orbital mechanics the physics of orbits Radius R or center to surface distance km or m Known through angular diameter measurements coupled with knowing the distance to the planet Mass M or number of kilograms of matter kg Known through Newton s Law of Gravity and exploiting moons and using spacecraft Planetary Terminology And how we typically determine it Units in green Rotational Period or length of day hours or days through observations of surface features clouds storms etc Average Density or on average how much mass M is there in a standard volume V can be calculated if the mass and radius are known Density kg m3 or g cm3 A measure of the compactness of matter The mass of an object per unit volume Average density is the mass of an object divided by its volume Density Mass Volume Dr Sean Lindsay s Research All projects relate to the origins of the Solar System Primary Research Interested in understanding the origins of our Solar System from initial formation to present I do spectroscopy in the infrared wavelengths 0 75 40 m part of the EM spectrum of comet dust particles and asteroid surfaces in order to constrain their composition what they are made out of Study mineral grains chemical compounds similar to molecules but more complex which are the first solid materials formed in the early Solar System Determining the composition of the small leftovers of our Solar System formation helps constrain what materials and what physical processes went into the formation of our Solar System Dr Sean Lindsay s Research Building a recipe book Research Allegory Given a few cookie crumbs from an unknown type of cookie Chocolate chip sugar oatmeal raisin snickerdoodle etc can I determine the recipe for how to make that cookie Need ingredient list chemical composition Need relative amounts of ingredients mineralogy Need baking instructions how hot and for how long In reality it s not just crumbs from one cookie but from many and it s not just cookies it s like the crumbs from an entire bakery and the challenge is to determine the entire recipe book for that bakery Dr Sean Lindsay s Research I study the leftovers of planet formation Comet Project I generate computer models of spectra and tweak them until they match data from infrared space telescopes Comets are coldest most primitive objects in SS Asteroid Project I do mathematical analyses to near infrared spectra of asteroid surfaces to determine what minerals are there and what are their chemical compositions e g how much iron versus how much magnesium Main Belt asteroids are small rocky objects Trojan Asteroid Project Similar analysis as Comet Project but trying to determine where they originally formed which provides constraints on the dynamical models of how our SS evolved Trojan asteroids are primitive asteroids that share an orbit with Jupiter Sun Planets to Scale sizes Be able to list all eight planets in order Our Solar System Outer Reaches Outer Oort Cloud 1 500 50 000 AU Kuiper Belt 30 55 AU Scattered Disk 30 100 AU Inner Oort Cloud 100s 1 500 AU Planetary Realm 0 30 AU Asteroids Small primarily rocky bodies Main Asteroid Belt The tiny terrestrials Small sub km to 1000 km composed mostly of rock with some metal Jupiter Trojan Asteroids Transition objects Very interesting group where little is known Meteorites Bits of asteroids that contain snapshots of Solar System formation history Radioactive dating of meteorites gives us an age of the Solar System at 4 568 about 4 6 Billion Years Old Most Primitive Unaltered Least Primitive Highly Altered Rock Metal Rock with metal grains Carbonaceous Chondrite Rock and Organics Ordinary Chondrite Metal Pallasite IronRock meteorite Iron Rock Iron Meteorite Comets Small leftovers of formation Small km to sub km Made of Ice Rock and have organics Quite complex organics add water and energy and get all the amino acids Formed far away from forming Sun Comet stuff largely unaltered a peak at the ingredient list Nucleus of a comet These dust grains are the building blocks of the Solar System Comet 67P C G Comet Hale Bopp Comet McNaught ESO S Deiries Comet Dust Dust likely left over from cometary activity Very small and most likely amongst the most primitive and
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