DOCSLIB.ORG

Precession of Earth WS.Pdf

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Precession of Earth WS.Pdf Precession of Earth: Spinning on the Axis Environmental Science Name: ____________________________________________Period:__________ Date: ___________ Essential Question: Why is earth’s axis wobbling? Een 1.1.1 Instructions: Study the selection and answer the questions. Just like a toy top that wobbles before it falls, the Earth wobbles as it rotates on its axis, the imaginary line that extends through the poles. This wobbling motion is due to the slight bulge at the equator. If you traced the Earth's axis out into space, you would see the extension of the axis slowly tracing a cone shape. The wobble is very slow; it takes the Earth 26,000 years to trace one complete conical shape. This wobbling motion of Earth on its axis is called precession. Because of precession, Polaris and Vega alternate as the North Star every 13,000 years. Polaris: The Current North Star Today the Earth's axis points within one degree of Polaris, the brightest star in the constellation Ursa Minor (also called the Little Bear or the Little Dipper). Polaris appears to be in a fixed position in the sky throughout the year. All other stars and constellations seem to revolve around the North Star. Why isn't the North Star Fixed? Over the course of time, the North Star changes. Right now Polaris is within one degree of true north, but at other times the North Star has been and will again be Thuban (the brightest star in the constellation Draco), Vega (the brightest star in the constellation Lyra), and Alpha Cephei (the brightest star in the constellation Cepheus). The North Star changes over time because the direction of the earth's axis changes slowly over time, this is the result of Precession. Since by definition the North Star is the star most closely aligned with the earth's axis, as the axis moves the nearest star changes too. Precession is the change in the direction of the axis, but without any change in tilt; changes the stars near the Pole; It does not affect the seasons. Nutation is the wobbling during precession; 1/2° one way or the other; period of 18 years; due to the Moon; It slightly effects seasons. This type of axis movement is similar to that of a spinning top. As the top slows, the axis of rotation changes as the top draws out each rotation; that is to say that the stem of the top itself traces out a circular pattern rather than pointing at a single spot or staying mostly still. If you draw an imaginary line of the earth's axis and continue it up to the sky, it will make a similar path. This type of axis rotation is called precession. In the case of the earth, precession is caused by the gravitational pull of the sun and the moon. The earth's axis makes one complete rotation over the course of approximately 26,000 years. If you trace the path of the axis in the sky, you will find that Polaris, Vega, Thuban, and Alpha Cephei all fall on or very close to it. So when the earth's axis is at a point on the path near Vega, Vega becomes the North Star while Thuban is the North Star when the axis is near it on the path. Five thousand years ago, Thuban was the North Star. Five thousand years from now, the North Star will be Alpha Cephei. Seven thousand years after that, it will be Vega. Nine thousand years after that, Thuban will be the North Star again. At these dates, the various stars will be at the closest to absolute north. For some time before, the relevant star will be approaching due north and it will be receding for some time after the time listed. In these interim times, the North Star is whichever star is closest to north. Answer the following questions 1. What is earth’s axis? ______________________________________________________________________________ 2. What is precession? ______________________________________________________________________________ ______________________________________________________________________________ 3. How long does it take for earth’s axis to wobble into a complete conical shape? ______________________________________________________________________________ ______________________________________________________________________________ 4. What two stars alternate every 13,000 years as earth’s northern star? ______________________________________________________________________________ ______________________________________________________________________________ 5. What is earth’s current northern star? ______________________________________________________________________________ ______________________________________________________________________________ 6. What is the brightest star in the constellation Ursa Minor? ______________________________________________________________________________ ______________________________________________________________________________ 7. What is the brightest star in the constellation Draco? ______________________________________________________________________________ ______________________________________________________________________________ 8. What is the brightest star in the constellation Lyra? ______________________________________________________________________________ ______________________________________________________________________________ 9. What is the brightest star in the constellation Cepheus? ______________________________________________________________________________ ______________________________________________________________________________ 10. Why do earth’s northern star change over time? ______________________________________________________________________________ ______________________________________________________________________________ 11. What is precession and what causes it? ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 12. What are the four stars that can become earth’s northern star? ______________________________________________________________________________ ______________________________________________________________________________ 13. What was earth’s northern star before Polaris? ______________________________________________________________________________ ______________________________________________________________________________ 14. What will be earth’s northern star five thousand years from now? ______________________________________________________________________________ ______________________________________________________________________________ 15. Which do we consider as our northern star and why is our northern star changing? ______________________________________________________________________________ ______________________________________________________________________________ 16. What is the difference between precession and nutation? Think! (15 pts.) ______________________________________________________________________________ ______________________________________________________________________________ http://www.education.com/reference/article/precession-earth/ http://www.essortment.com/north-star-61725.html Precession and Nutation Environmental Science Name: ____________________________________________Period:__________ Date: ___________ Essential Question: Why is Polaris fixed on its position throughout the year? What is the difference between precession and nutation? Instructions: Encircle and label the constellations where Polaris, Vega, Thuban, and Alpha Cephei are found. Polaris, the brightest star in the constellation Ursa Minor (also called the Little Bear or the Little Dipper). Polaris appears to be in a fixed position in the sky throughout the year. All other stars and constellations seem to revolve around the North Star. Thuban (the brightest star in the constellation Draco), Vega (the brightest star in the constellation Lyra), and Alpha Cephei (the brightest star in the constellation Cepheus). Sirius, also known as the Dog Star or Sirius A, is the brightest star in Earth's night sky. The name means "glowing" in Greek. http://www.msnucleus.org/membership/html/jh/earth/stars/lesson4/stars04c.html Identification: _________________is the brightest star in the constellation Ursa Minor. _________________is the brightest star in the constellation Draco. _________________is the brightest star in the constellation Lyra _________________is the brightest star in the constellation Cepheus ________________ is the brightest star in Earth's night sky. Come up with your Hypothesis: How come Polaris seems to be stationary in the sky throughout the year while the others stars in their constellations seem to revolve around it? Hypothesis: _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ Precession change in the direction of the axis, but without any change in tilt; changes the stars near the Pole; does not affect the seasons. Nutation wobbling around the precessional axis; 1/2° one way or the other; period of 18 years; due to the Moon; slightly effects seasons. Try this out! 1. Stand directly below anything that you can consider as your northern star, you represent Earth’s axis. Directly above you is your north, your right side is your east, down is south, and your left side is your west. 2. Look around and observe anything that you can consider as markers ( like ceiling fan, light bulb, air
Load more

Recommended publications
  • THUBAN the Star Thuban in the Constellation Draco (The Dragon) Was the North Pole Star Some 5,000 Years Ago, When the Egyptians Were Building the Pyramids
    STAR OF THE WEEK: THUBAN The star Thuban in the constellation Draco (the Dragon) was the North Pole Star some 5,000 years ago, when the Egyptians were building the pyramids. Thuban is not a particularly bright star. At magnitude 3.7 and known as alpha draconis it is not even the brightest star in its constellation. What is Thuban’s connection with the pyramids of Egypt? Among the many mysteries surrounding Egypt’s pyramids are the so-called “air shafts” in the Great Pyramid of Giza. These narrow passageways were once thought to serve for ventilation as the The Great Pyramid of Giza, an enduring monument of ancient pyramids were being built. In the 1960s, though, Egypt. Egyptologists believe that it was built as a tomb for fourth dynasty Egyptian Pharaoh Khufu around 2560 BC the air shafts were recognized as being aligned with stars or areas of sky as the sky appeared for the pyramids’ builders 5,000 years ago. To this day, the purpose of all these passageways inside the Great Pyramid isn’t clear, although some might have been connected to rituals associated with the king’s ascension to the heavens. Whatever their purpose, the Great Pyramid of Giza reveals that its builders knew the starry skies intimately. They surely knew Thuban was their Pole Star, the point around which the heavens appeared to turn. Various sources claim that Thuban almost exactly pinpointed the position of the north celestial pole in the This diagram shows the so-called air shafts in the Great year 2787 B.C.
    [Show full text]
  • Basic Principles of Celestial Navigation James A
    Basic principles of celestial navigation James A. Van Allena) Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 ͑Received 16 January 2004; accepted 10 June 2004͒ Celestial navigation is a technique for determining one’s geographic position by the observation of identified stars, identified planets, the Sun, and the Moon. This subject has a multitude of refinements which, although valuable to a professional navigator, tend to obscure the basic principles. I describe these principles, give an analytical solution of the classical two-star-sight problem without any dependence on prior knowledge of position, and include several examples. Some approximations and simplifications are made in the interest of clarity. © 2004 American Association of Physics Teachers. ͓DOI: 10.1119/1.1778391͔ I. INTRODUCTION longitude ⌳ is between 0° and 360°, although often it is convenient to take the longitude westward of the prime me- Celestial navigation is a technique for determining one’s ridian to be between 0° and Ϫ180°. The longitude of P also geographic position by the observation of identified stars, can be specified by the plane angle in the equatorial plane identified planets, the Sun, and the Moon. Its basic principles whose vertex is at O with one radial line through the point at are a combination of rudimentary astronomical knowledge 1–3 which the meridian through P intersects the equatorial plane and spherical trigonometry. and the other radial line through the point G at which the Anyone who has been on a ship that is remote from any prime meridian intersects the equatorial plane ͑see Fig.
    [Show full text]
  • Introduction to Astronomy from Darkness to Blazing Glory
    Introduction to Astronomy From Darkness to Blazing Glory Published by JAS Educational Publications Copyright Pending 2010 JAS Educational Publications All rights reserved. Including the right of reproduction in whole or in part in any form. Second Edition Author: Jeffrey Wright Scott Photographs and Diagrams: Credit NASA, Jet Propulsion Laboratory, USGS, NOAA, Aames Research Center JAS Educational Publications 2601 Oakdale Road, H2 P.O. Box 197 Modesto California 95355 1-888-586-6252 Website: http://.Introastro.com Printing by Minuteman Press, Berkley, California ISBN 978-0-9827200-0-4 1 Introduction to Astronomy From Darkness to Blazing Glory The moon Titan is in the forefront with the moon Tethys behind it. These are two of many of Saturn’s moons Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA 2 Introduction to Astronomy Contents in Brief Chapter 1: Astronomy Basics: Pages 1 – 6 Workbook Pages 1 - 2 Chapter 2: Time: Pages 7 - 10 Workbook Pages 3 - 4 Chapter 3: Solar System Overview: Pages 11 - 14 Workbook Pages 5 - 8 Chapter 4: Our Sun: Pages 15 - 20 Workbook Pages 9 - 16 Chapter 5: The Terrestrial Planets: Page 21 - 39 Workbook Pages 17 - 36 Mercury: Pages 22 - 23 Venus: Pages 24 - 25 Earth: Pages 25 - 34 Mars: Pages 34 - 39 Chapter 6: Outer, Dwarf and Exoplanets Pages: 41-54 Workbook Pages 37 - 48 Jupiter: Pages 41 - 42 Saturn: Pages 42 - 44 Uranus: Pages 44 - 45 Neptune: Pages 45 - 46 Dwarf Planets, Plutoids and Exoplanets: Pages 47 -54 3 Chapter 7: The Moons: Pages: 55 - 66 Workbook Pages 49 - 56 Chapter 8: Rocks and Ice:
    [Show full text]
  • Dhruva the Ancient Indian Pole Star: Fixity, Rotation and Movement
    Indian Journal of History of Science, 46.1 (2011) 23-39 DHRUVA THE ANCIENT INDIAN POLE STAR: FIXITY, ROTATION AND MOVEMENT R N IYENGAR* (Received 1 February 2010; revised 24 January 2011) Ancient historical layers of Hindu astronomy are explored in this paper with the help of the Purân.as and the Vedic texts. It is found that Dhruva as described in the Brahmân.d.a and the Vis.n.u purân.a was a star located at the tail of a celestial animal figure known as the Úiúumâra or the Dolphin. This constellation, which can be easily recognized as the modern Draco, is described vividly and accurately in the ancient texts. The body parts of the animal figure are made of fourteen stars, the last four of which including Dhruva on the tail are said to never set. The Taittirîya Âran.yaka text of the Kr.s.n.a-yajurveda school which is more ancient than the above Purân.as describes this constellation by the same name and lists fourteen stars the last among them being named Abhaya, equated with Dhruva, at the tail end of the figure. The accented Vedic text Ekâgni-kân.d.a of the same school recommends observation of Dhruva the fixed Pole Star during marriages. The above Vedic texts are more ancient than the Gr.hya-sûtra literature which was the basis for indologists to deny the existence of a fixed North Star during the Vedic period. However the various Purân.ic and Vedic textual evidence studied here for the first time, leads to the conclusion that in India for the Yajurvedic people Thuban (α-Draconis) was Dhruva the Pole Star c 2800 BC.
    [Show full text]
  • Dynamical Adjustments in IAU 2000A Nutation Series Arising from IAU 2006 Precession A
    A&A 604, A92 (2017) Astronomy DOI: 10.1051/0004-6361/201730490 & c ESO 2017 Astrophysics Dynamical adjustments in IAU 2000A nutation series arising from IAU 2006 precession A. Escapa1; 2, J. Getino3, J. M. Ferrándiz2, and T. Baenas2 1 Dept. of Aerospace Engineering, University of León, 24071 León, Spain 2 Dept. of Applied Mathematics, University of Alicante, PO Box 99, 03080 Alicante, Spain e-mail: [email protected] 3 Dept. of Applied Mathematics, University of Valladolid, 47011 Valladolid, Spain Received 20 January 2017 / Accepted 23 May 2017 ABSTRACT The adoption of International Astronomical Union (IAU) 2006 precession model, IAU 2006 precession, requires IAU 2000A nutation to be adjusted to ensure compatibility between both theories. This consists of adding small terms to some nutation amplitudes relevant at the microarcsecond level. Those contributions were derived in previously published articles and are incorporated into current astronomical standards. They are due to the estimation process of nutation amplitudes by Very Long Baseline Interferometry (VLBI) and to the changes induced by the J2 rate present in the precession theory. We focus on the second kind of those adjustments, and develop a simple model of the Earth nutation capable of determining all the changes arising in the theoretical construction of the nutation series in a dynamical consistent way. This entails the consideration of three main classes of effects: the J2 rate, the orbital coefficients rate, and the variations induced by the update of some IAU 2006 precession quantities. With this aim, we construct a first order model for the nutations of the angular momentum axis of the non-rigid Earth.
    [Show full text]
  • Map and Compass
    UE CG 039-089 2018_UE CG 039-089 2018 2018-08-29 9:57 AM Page 56 MAP The north magnetic pole is not the same as the geographic North Pole, also known as AND COMPASS true north, which is the northern end of the axis around which the earth spins. In fact, the north magnetic pole currently lies Background Information approximately 800 mi (1300 km) south of the geographic North Pole, in northern A compass is an instrument that people use Canada. And because the north magnetic to find a direction in relation to the earth as pole migrates at 6.6 mi (10 km) per year, its a whole. The magnetic needle in the location is constantly changing. compass, which is the freely moving needle in the compass that has a red end, points The meridians of longitude on maps and north. More specifically, this needle points globes are based upon the geographic to the north magnetic pole, the northern North Pole rather than the north magnetic end of the earth’s magnetic field, which pole. This means that magnetic north, the can be imagined as lines of magnetism that direction that a compass indicates as north, leave the south magnetic pole, flow north is not the same direction as maps indicate around the earth, and then enter the north for north. Magnetic declination, the magnetic pole. difference in the angle between magnetic north and true north must, therefore, be Any magnetized object, an object with two taken into account when navigating with a oppositely charged ends, such as a magnet map and a compass.
    [Show full text]
  • Some Guidelines for Effective Field-Use of the GPS Unit
    PRBO Conservation Science 4990 Shoreline Highway Stinson Beach, CA 94970 415-868-1221 www.prbo.org Guidelines for Field Use of Garmin GPS Units GPS Checklist: Copy an updated version of the master "allpc" shapefile and other digital basemaps, including topo quads and aerial photos, from the GIS server (V: drive) before the field season starts. Know what coordinate system (e.g., UTM, zone 10) and datum (e.g., NAD83) your project uses. The PRBO default is UTM, WGS84 (same as NAD83). In the UTM coordinate system, your zone depends on where you are (see map). Download your GPS coordinates daily, using GPS Utility (www.gpsu.co.uk/) or Waypoint+ (www.tapr.org/~kh2z/Waypoint/) shareware. It is not uncommon for Garmin units to die in the field. You will need a PC Interface cable to download your data and a registration key for GPS Utility. If you are unable to download, record your coordinates by hand in the field. Always carry extra batteries, especially if you’re not planning to revisit the site, and turn off your GPS unit when not in use to avoid draining the internal lithium battery. Contact Garmin (www.garmin.com) for replacement or repair under warranty if your unit dies. UTM Zones Submit copies of your GPS coordinate files to the GIS lab at the end of the field season for archiving and general mapping purposes. In the Field GPS Unit Setup Before taking waypoints in the field, the GPS navigation display should be set up to match the coordinate system, horizontal datum, and units used at a particular field project’s location.
    [Show full text]
  • The Spin, the Nutation and the Precession of the Earth's Axis Revisited
    The spin, the nutation and the precession of the Earth’s axis revisited The spin, the nutation and the precession of the Earth’s axis revisited: A (numerical) mechanics perspective W. H. M¨uller [email protected] Abstract Mechanical models describing the motion of the Earth’s axis, i.e., its spin, nutation and its precession, have been presented for more than 400 years. Newton himself treated the problem of the precession of the Earth, a.k.a. the precession of the equinoxes, in Liber III, Propositio XXXIX of his Principia [1]. He decomposes the duration of the full precession into a part due to the Sun and another part due to the Moon, to predict a total duration of 26,918 years. This agrees fairly well with the experimentally observed value. However, Newton does not really provide a concise rational derivation of his result. This task was left to Chandrasekhar in Chapter 26 of his annotations to Newton’s book [2] starting from Euler’s equations for the gyroscope and calculating the torques due to the Sun and to the Moon on a tilted spheroidal Earth. These differential equations can be solved approximately in an analytic fashion, yielding Newton’s result. However, they can also be treated numerically by using a Runge-Kutta approach allowing for a study of their general non-linear behavior. This paper will show how and explore the intricacies of the numerical solution. When solving the Euler equations for the aforementioned case numerically it shows that besides the precessional movement of the Earth’s axis there is also a nu- tation present.
    [Show full text]
  • Draco the Dragon
    Biblical Astronomer, number 100 51 DRACO THE DRAGON Gerardus D. Bouw, Ph.D. The embarrassment of dragons “Everyone knows it. Scientists have proven it dozens of times. Dragons are mythological; they never existed, leastwise, not while man roamed the earth. True, the ancient Chinese, Indians, Europeans, Amerin- dians, Africans, Australians, and others believed dragons existed in their time. They described dragons, told tales of killing them, and of the pesti- lences coming from dragons. But today we are much wiser and know that such ancient lore is nothing but myth. We are humanists, the measure of all things! We don’t need God. God is just a crutch for the feeble- minded, the weak. Today we know infinitely more than those grunting cave men. They and their dragon-infested Bible: bah!” “Hey!” a voice responds. “We’re not humanists. We believe in God, and we, too, know that dragons are mythological. Ignorant, supersti- tious men introduced the dragons into the Bible. We now have the correct interpretation for those problematic words. They’re not dragons but jack- als. We’re Bible critics, the measure of all things! We find out what God really meant to say but could not say plainly because of the cave-man mentality he had to address in His Word!” Now, that the author of this article totally disagrees with both the above statements let that be understood from the start. If that means being labeled feeble-minded, so be it. We think better of the ancients. Having studied their technology, we find them to be very clever and inventive, and we suspect that they could think circles around the aforementioned humanist and critical geniuses of today.
    [Show full text]
  • Find Location from Grid Reference
    Find Location From Grid Reference Piney and desiccant Jean-Luc understocks almost florally, though Milton ruptures his wartweeds intermarried. Is Emmery Nikkialways focalises superjacent shipshape. and grimiest when individuating some stewpots very round-the-clock and indefatigably? Chalcographic This method expresses the human development in conjunction with apple blogs rolling and from grid reference on a map is directly at intervals along the play store you want to provide a private draft You find location, grid reference system of locating and longitude are located in grids on topographic maps. If you entertain an express map to measure story, Northing followed by Easting. Apple blogs rolling and the Internet safe. Give complete coordinate RIGHT, B, grid reference or latitude and longitude of locations. Sign arm to our Newsletter. The satellite map with the marker is shown alongside an equivalent Ordnance Survey map. If you work with MGRS coordinates, and that the scale is right side up. The layer you selected must be of point geometry. This earthquake has cloud been published or shared. Latitude can have done same numerical value north go south hit the equator, you can use the breakthrough To XY tool. Upload multiple images at once. What is high pressure? To enable light to better morning or bridge the location of features on total scale maps, we promise our postcode data quarterly, country grids etc. Click a the hand, interpret the images of the Megalong Valley below, unauthorized and shall goods be used. Google Earth starting point over Lawrence, stationary media panel. Perhaps you find. Two simple methods using a poise of so are described below.
    [Show full text]
  • Thomas Precession Is the Basis for the Structure of Matter and Space Preston Guynn
    Thomas Precession is the Basis for the Structure of Matter and Space Preston Guynn To cite this version: Preston Guynn. Thomas Precession is the Basis for the Structure of Matter and Space. 2018. hal- 02628032 HAL Id: hal-02628032 https://hal.archives-ouvertes.fr/hal-02628032 Submitted on 26 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Thomas Precession is the Basis for the Structure of Matter and Space Einstein's theory of special relativity was incomplete as originally formulated since it did not include the rotational effect described twenty years later by Thomas, now referred to as Thomas precession. Though Thomas precession has been accepted for decades, its relationship to particle structure is a recent discovery, first described in an article titled "Electromagnetic effects and structure of particles due to special relativity". Thomas precession acts as a velocity dependent counter-rotation, so that at a rotation velocity of 3 / 2 c , precession is equal to rotation, resulting in an inertial frame of reference. During the last year and a half significant progress was made in determining further details of the role of Thomas precession in particle structure, fundamental constants, and the galactic rotation velocity.
    [Show full text]
  • 13. Rigid Body Dynamics II Gerhard Müller University of Rhode Island, [email protected] Creative Commons License
    University of Rhode Island DigitalCommons@URI Classical Dynamics Physics Course Materials 2015 13. Rigid Body Dynamics II Gerhard Müller University of Rhode Island, [email protected] Creative Commons License This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License. Follow this and additional works at: http://digitalcommons.uri.edu/classical_dynamics Abstract Part thirteen of course materials for Classical Dynamics (Physics 520), taught by Gerhard Müller at the University of Rhode Island. Entries listed in the table of contents, but not shown in the document, exist only in handwritten form. Documents will be updated periodically as more entries become presentable. Recommended Citation Müller, Gerhard, "13. Rigid Body Dynamics II" (2015). Classical Dynamics. Paper 9. http://digitalcommons.uri.edu/classical_dynamics/9 This Course Material is brought to you for free and open access by the Physics Course Materials at DigitalCommons@URI. It has been accepted for inclusion in Classical Dynamics by an authorized administrator of DigitalCommons@URI. For more information, please contact [email protected]. Contents of this Document [mtc13] 13. Rigid Body Dynamics II • Torque-free motion of symmetric top [msl27] • Torque-free motion of asymmetric top [msl28] • Stability of rigid body rotations about principal axes [mex70] • Steady precession of symmetric top [mex176] • Heavy symmetric top: general solution [mln47] • Heavy symmetric top: steady precession [mln81] • Heavy symmetric top: precession and
    [Show full text]