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Download Our Home - Upper Arlington Library Summer Astronomy Series
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Our Home Upper Arlington Library Summer Astronomy Series . Jordan C. Hanson ([email protected]) July 26, 2016 CCAPP @ OSU Outline I. Our Neighborhood A. Our Neighbors, the planets and their moons B. The history of the Pluto discovery, and what we've learned II. Recent NASA missions, and why they are important A. New Horizons (arrived at Pluto in 2015) B. News from Juno (arrived at Jupiter in 2016) III. The Future 1 Our Neighborhood . Our Neighborhood - The Milky Way 2 Our Neighborhood - Nebulae 3 Our Neighborhood - Our Star, the Sun 4 Our Planet - The Earth 5 Exploration of Our Neighborhood Fun fact: Science is messy. Discoveries are sometimes accidents, and we are either not ready to hear them, or we don’t recognize them right away. Consider the example of the planet Neptune: We knew that there could be another planet beyond Uranus as early as the 1840s. Urbain Le Verrier was able to predict the location of Neptune, because its gravity was pulling on Uranus. The next question was to ask: How far this idea could be taken? More on this later. 6 Our Neighbors, the Planets When I was little, we knew of only 9 planets, in the whole Universe: Mercury, Venus, Earth, and Mars: the small, rocky planets Jupiter and Saturn: the gas giants Uranus and Neptune: the ice giants Pluto: no longer considered a planet...but why? Today we will focus on the farthest planet in the list, and the largest planet in the list, Pluto, and Jupiter. How many planets are there really? Ask me at the end :-) 7 Pluto Fact Sheet Official classifcation: Kuiper Belt Object Aphelion = 48.871 AU (farthest from the Sun) Perihelion = 29.657 AU (closest to the Sun) Orbital Period = 247.68 years (Pluto hasn't gone around once :-) Number of Moons = 5 Radius = 0.18×Earth Mass = 0.00218×Earth Density = 1870 kg/m3 , or a few times water Surface Gravity = 0.063 g's (How high could you jump on Pluto?) Surface Temperatures = 33 − 44 K (-240 to -229 C) Pressure of atmosphere 0.3 Pascals (Earth: 100,000 Pascals) 8 Percival Lowell (1855-1916), from Boston, MA Mathematician. Discovered hundreds of asteroids, and hypothesized a ninth planet in our solar system, which he called Planet X. His prediction turned out to be correct! But he passed away before the planet was found. He used his wealth to commission the Lowell observatory in Flagstaff, NM. 9 Percival Lowell (1855-1916), from Boston, MA Two surveys of the predicted location of Planet X in March and April, 1915, (100 years ago!) caught a faint image of a star that appeared to move. It is a giant game of spot-the-difference! 10 Clyde Tombaugh made the definitive observations 11 Clyde Tombaugh made the definitive observations 12 What is a planet, really? Three requirements for a plantet: Something that orbits a star (no one-time comets) Something that is a sphere (asteroids don't count) Something that clears a path around its orbit (Pluto doesn't count) Pluto fails the third test, but passes the first two. But this implies that things like Pluto are NUMEROUS. 13 The Third Rule of the Definition of a Planet 14 Exoplanet (Our Solar System) . All The Little Ones 15 Recent NASA Missions . Recent Planetary Missions Name Pioneer 10 Pioneer 11 Voyager 1 Voyager 2 Ulysses Galileo Cassini Ulysses (2nd pass) New Horizons Juno Agency NASA NASA NASA NASA NASA/ESA NASA NASA/Germany/Italy ESA/NASA NASA NASA Year 1973 1974 1979 1979 1992 1997 2000 2003 2006 2011 Destination Jupiter/Saturn Jupiter/Saturn Jupiter/Saturn Uranus/Neptune Sun Jupiter Saturn Sun Pluto Jupiter 16 Jupiter and Saturn - (This one is from Cassini mission) 17 Jupiter and Saturn - (This one is from Cassini mission) 18 Jupiter and Saturn - (This one is from Cassini mission) 19 Uranus and Neptune - (Only fly-by from Voyager 2 Mission) 20 Uranus and Neptune - (Only fly-by from Voyager 2 Mission) 21 Pluto, and the New Horizons Mission . NASA New Horizons Probe 22 NASA New Horizons Probe 23 NASA New Horizons Probe 24 NASA New Horizons Probe The LORRI instrument (long range reconnaissance imager) captured the images of Pluto as the probe approached: http://pluto.jhuapl.edu/ 25 NASA New Horizons Probe 26 NASA New Horizons Probe 27 Exoplanent: exoplanets .
