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Download Last Class Today`s Class What does the solar system look like?
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3/16/2015 Today’s Class: Exploring the Solar System: Where can we go? March 16, 2015 Homework: 1. Exam 2 is on Wednesday! 2. Exam 2 covers all material beginning with Feb. 13 lecture including: a) All the assigned reading (see class webpage). b) All homework assignments. c) Space in the News articles/discussions. d) All material discussed in class including in-class group exercises & clicker questions. 3. Review session on Mar. 17 at 5 pm in G130 (this room). 4. Friday’s class will be at the Fiske Planetarium on The Earth as a Planet. Reading: http://en.wikipedia.org/wiki/Earth Astronomy 2020 – Space Astronomy & Exploration Today’s Class • Overview of Solar System • Tour through the Solar System – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Nepture, dwarf planets. • How do robotic spacecraft work? – Flybys – Orbiters – Landers – Sample Return Astronomy 2020 – Space Astronomy & Exploration Clicker Question: Which of the following is NOT true about a low frequency radio telescope on the lunar farside? a) It’s an excellent way to detect exoplanets around other stars. b) The lunar farside is free of radio frequency interference & ionospheric effects so its an ideal location for such a telescope. c) It observes the redshifted 21-cm signal from the vicinity of the first stars and black holes. d) Such a telescope might be deployed remotely by astronauts aboard Orion at the L2 Earth-Moon Lagrange Point. Astronomy 2020 – Space Astronomy & Exploration Last Class • The Lunar Farside • Cis-lunar space with Orion – Earth-Moon L2 – Distant Retrograde Orbit • Low frequency radio array on lunar farside • First luminous objects in the Universe • Surface Telerobotics from the Moon Astronomy 2020 – Space Astronomy & Exploration Clicker Question: Which of the following is NOT true about a low frequency radio telescope on the lunar farside? a) It’s an excellent way to detect exoplanets around other stars. b) The lunar farside is free of radio frequency interference & ionospheric effects so its an ideal location for such a telescope. c) It observes the redshifted 21-cm signal from the vicinity of the first stars and black holes. d) Such a telescope might be deployed remotely by astronauts aboard Orion at the L2 Earth-Moon Lagrange Point. Astronomy 2020 – Space Astronomy & Exploration What does the solar system look like? • There are eight major planets with nearly circular orbits. • Dwarf planets are smaller than the major planets and some have quite elliptical orbits. Astronomy 2020 – Space Astronomy & Exploration 1 3/16/2015 What are the major features of the Sun and planets? Mercury • Made of metal and rock; large iron core • Desolate, cratered; long, tall, steep cliffs • Very hot, very cold: 425C (day), –170C (night) • Sun and planets to scale Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration Venus Earth • Nearly identical in size to Earth; surface hidden by clouds • Hellish conditions due to an extreme greenhouse effect • Even hotter than Mercury: 470C, day and night • An oasis of life • The only surface liquid water in the solar system • A surprisingly large moon Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration Mars Jupiter • Much farther from Sun than inner planets • Mostly H/He; no solid surface • 300 times more massive than Earth • Many moons, rings • Looks almost Earth-like, but don't go without a spacesuit! • Giant volcanoes, a huge canyon, polar caps, more • Water flowed in distant past; could there have been life? Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration 2 3/16/2015 Jupiter • • • • Saturn Jupiter's moons can be as interesting as planets themselves, especially Jupiter's four Galilean moons. Io (shown here): active volcanoes all over Europa: possible subsurface ocean Ganymede: largest moon in solar system Callisto: a large, cratered "ice ball" • Giant and gaseous like Jupiter • Spectacular rings • Many moons, including cloudy Titan Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration Saturn Uranus Cassini probe arrived July 2004 (launched in 1997). • Smaller than Jupiter/Saturn; much larger than Earth • Made of H/He gas and hydrogen compounds (H2O, NH3, CH4) • Extreme axis tilt • Moons and rings Huygens probe separating from the main spacecraft on its descent to Titan Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration Neptune Dwarf Planets: Pluto, Eris, and more • Similar to Uranus (except for axis tilt) • Many moons (including Triton) • • • Astronomy 2020 – Space Astronomy & Exploration Much smaller than major planets Icy, comet-like composition Pluto's main moon (Charon) is of similar size Astronomy 2020 – Space Astronomy & Exploration 3 3/16/2015 Clicker Question Clicker Question What process created the elements from which the terrestrial planets were made? What process created the elements from which the terrestrial planets were made? a) b) c) d) a) b) c) d) the Big Bang nuclear fusion in stars chemical processes in interstellar clouds their origin is unknown. the Big Bang nuclear fusion in stars chemical processes in interstellar clouds their origin is unknown. Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration How do robotic spacecraft work? Flybys Curiosity on Mars • A flyby mission flies by a planet just once. • Cheaper than other mission but less time to gather data Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration Orbiters Probes or Landers • Go into orbit around another world • More time to gather data but cannot obtain detailed information about world's surface Lunar Reconnaissance Orbiter • Land on surface of another world • Explore surface in detail Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration 4 3/16/2015 Sample Return Missions Combination Spacecraft • Land on surface of another world • Gather samples • Spacecraft designed to blast off other world and return to Earth • Apollo missions to Moon are one example, Hyabusa to an asteroid is another. • Cassini/Huygens mission contains both an orbiter (Cassini) and a lander (Huygens). Astronomy 2020 – Space Astronomy & Exploration Astronomy 2020 – Space Astronomy & Exploration 5
