Cahaba School                                                                                                                                                                                                                                                                                                  Astronomy Picture of the Day                                                                                                                              | Today's Picture | Archive | Search | Calendar | Cosmos Stars : Binary Stars * Black Holes * Globular Clusters * Individual Stars * Neutron Stars * Nurseries * Open Clusters * Sun * White Dwarfs Galaxies : Clusters of Galaxies * Colliding Galaxies * Elliptical Galaxies * Local Group * Milky Way * Spiral Galaxies Nebulae : Dark Nebulae * Emission Nebulae * Planetary Nebulae * Reflection Nebulae * Supernova Remnants Miscellaneous : Quasars/Active Galactic Nuclei * Dark Matter Solar System Sun * Mercury * Venus * Earth * Earth's Moon * Mars * Jupiter * Jupiter's Moons * Saturn * Saturn's Moons * Uranus * Neptune * Pluto Comets --- Hyakutake * Hale-Bopp * Halley Asteroids Space Technology Rockets/Launch Vehicles * Orbiting Observatories * Space Stations * Earth Observatories Sky Messier Objects * Sky Views People Scientists * Astronauts Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA) NASA Technical Rep.: Jay Norris. Specific rights apply. A service of: LHEA at NASA/ GSFC &: Michigan Tech. U.   Cahaba School Astronomy   You are responsible for all links & homework assignments   Take notes on each chapter   Lab    Portfolio of articles on astronomy (1 each month)     August:  Ch. 1 & 2 September:  Ch. 3 (Project 1 and Planetarium) Project 1:  Constellations What is a constellation? What is the real purpose? Pick a constellation and construct a model.  -Include both names (name and what it represents) -mythical background -which month is it best seen in the sky?  Suggestion: (black board with tack holes to represent stars, include names on front, on back you will include other information) October:  Ch. 4,  5, 6 November:  Ch. 7 December:  Ch. 8  & Project 2 1st Semester Exam Project 2:  Scientific Contributors Choose 1of the following & write a 2 page paper/MLA, Works Cited ·        Pythagoras of Samos (circa 580 - 500 BC) ·        Plato (circa 428 - 348 BC) ·        Eudoxus (circa 408 - 356 BC) ·        Aristotle (384 - 322 BC) ·        Heraclides (circa 388 - 310 BC) ·        Aristarchus of Samos (circa 310 - 230 BC) ·        Eratosthenes of Cyrene (276 - 194 BC) ·        Hipparchus of Rhodes (190 - 120 BC) ·        Ptolemy (circa 140 AD) ·        Nicholas Copernicus (1473 - 1543) ·        Johannes Kepler (1571 - 1630) and Tycho Brahae (1546 - 1601)                  Galileo Galilei (1564 – 1642)                  Isaac Newton (1642-1727) January:  Ch. 9 and Ch. 10 February:  Ch. 11 (Book- A Brief History in Time by Stephen Hawkings) March:  Ch. 12  & Project 3 Project 3:  Planets   (Make a model and include the Sun, all eight planets and their positions from the sun.  Be creative). April:  Ch. 13 May:  Final Exam (Write a paper about Astronomy Today and hopes in the future)   I.                  Chapter 1: Introduction A.     What is astronomy B.     The Scientific Method C.     Astronomy Vs. Astrology II.               Chapter 2:  Our Place in the Universe A.     Solar System Sizes B.     Cosmic Calendar C.     The motions of Earth III.           Chapter 3:  The Sky A.     The Sky B.     Constellations C.     Seasons IV.           Chapter 4:  The Moon A.     Phases of the Moon B.     Eclipses                                     i.      Solar                                    ii.      Lunar V.              Chapter 5:  A.     Shape and Size of Earth B.     Motion of the Planets VI.           Chapter 6:  Astronomy A.     History of Astronomy B.     Ancient Astronomy C.     Greek Contribution to Astronomy D.     Ptolemy E.      Astrology VII.       Chapter 7: A.     Islamic Contribution to Astronomy B.     Nicholas Copernicus C.     Johannes Kepler and Tycho Brahae D.     Galileo Galilei VIII.    Chapter 8: A.     Isaac Newton B.     Newton’s Laws of Motion C.     Circular Motion D.     Law of Gravity                                  i.      Kepler’s 3rd Law                                  ii.      Surface Gravity E.      Planetary Orbits F.      Tides IX.              Chapter 9:  Light A.     Light B.     Electromagnetic Spectrum C.     Doppler Effect D.     What can you learn from light? X.              Chapter 10:  Telescopes A.     Telescopes                                    i.      Purpose                                     ii.      Space telescopes                                      iii.      Detectors XI.              Chapter 11:  Solar System A.     Solar System B.     Planetary Facts C.     Mercury D.     Venus E.      Mars F.      Summary of the Jovian Worlds XII.       Chapter 12:  The Solar System A.     Jupiter B.     Saturn C.     Uranus D.     Neptune E.      Pluto and Charon F.      Asteroids G.     Comets H.     Summary XIII.    Chapter 13: A.     Meteors and Impacts B.     Formation of the Solar System C.     Other Planetary Systems Chapter 1 What is Astronomy? -- A Science. The study of the Cosmos - The Cosmos is all that ever was and all that will ever be - Cosmos is a Greek word meaning the Order of the Universe, it's the opposite of Chaos. The first science - Ancient people noticed that there were cycles in the sky and that the seasons changed with those cycles. Understanding the cycles meant being able to predict the seasons. - Cave drawings indicate that even Crow Magnon Man was aware of the celestial cycles. Astronomy vs. Astrology - Astronomy literally means the knowing (or naming) of the stars - Astrology literally means the study of the stars - But Astronomy has become associated with the scientific study of the stars and Astrology is associated with the mystical pseudoscience that believes that the heavens can directly influence our individual lives. What is Science? -- A Process of Inquiry. The Scientific Method Starts with a Question - the question may be brought on by an observation of a phenomenon - or it may be a "I wonder what if" type question Hypothesis - Once the question has been well formulated as many possible explanations or answers to that question should be formulated. Some times we call these models. - The major constraint on a hypothesis is that it must be testable. You must be able to do an experiment that could, at least in principle, disprove the hypothesis. - Religion and Pseudoscience are not scientific because their hypotheses are not testable. They cannot be disproved. - One should spin as many hypotheses as possible. Experimentation/ Observation - you must now conduct experiments or observations that will weed out your incorrect hypotheses. - this is perhaps the most important part of the scientific process. Report your findings - people make mistakes and the best way to guard against errors made in experiments is to report your findings to fellow scientists and allow them to review your work and repeat your experiments. - The phenomenon you are studying must repeat if it is to be testable in this way. If it does not, science cannot go further with it. - the process of peer review is one of the many error-correcting mechanisms built into the scientific method Draw Conclusions - Once everyone agrees on the experimental facts and observations, the remaining hypothesis that explains your phenomenon is accepted as a working theory. - If there are competing hypotheses that explain the data equally well, we choose the simpler one as the correct one. This is called the Principle of Occams' Razor - Generally a theory will generate new questions and the process repeats ad infinitum. - At many steps along the way new questions or new hypotheses might arise and the process repeats itself also. - If at any time in the future a new fact is discovered that contradicts a theory, the theory is first modified to include the new data. If it cannot be modified or becomes too complicated with the revisions, it must be thrown out. - Science is conservative in the acceptance of such new facts: "Extraordinary Claims Require Extraordinary Evidence" - Carl Sagan. Chapter 2 Our Place in the Universe Light has a a finite speed. Thus the information it brings is time delayed from its origin to us. The speed of light is 186,000 miles/second. The distance between Earth and Sun is 93,000,000 miles. Therefore it takes light about 8 minutes to travel from Sun to Earth. Thus we see the Sun as it was 8 minutes ago. It takes light 4 years to travel the distance to the nearest star system, Alpha Centauri. Thus we see Alpha Centauri as it was 4 years ago. We can define a convenient unit of cosmic distance: Light-Year - The distance that light travels in one-year. Alpha Centauri is 4 Light-Years distant. The Milky Way Galaxy is 100,000 Light Years across. The nearest big Galaxy is the Andromeda Galaxy at a distance of 2,500,000 Light-years. The most distant galaxies are 10,000,000,000 Light-years away or more. So we can See what the Universe was like 10,000,000,000 years ago, when the Universe was newly born. Scale of Space and Time Cosmic Calendar: Scale 12 Billion year History of Universe into one year. --> 1 month = 1 Billion years. Jan 1: The Big Bang Feb. : The Milky Way forms August 13: The Earth Forms December 13: Invertebrate Life Evolves December 25: Rise of Dinosaurs December 30: Dinosaurs Extinct December 31: 9:00 pm Earliest Human Ancestors December 31: 11:58 pm Modern Humans evlove December 31: 11:59:30 pm Agriculture Decmeber 31: 11:59:47 pm Pyramids are Built December 31: 11:59:59 pm Kepler and Galileo prove that Earth orbits the Sun.     Assignment: Chapter 1 & 2 Notes on chapter 1 & 2 (minimum 1 page) What is Cosmos? What is Occams' Razor? What is the speed of light? What is a light year? What is astronomy? What is the difference between astronomy and astrology? What are the steps to the scientific method and briefly explain each. Who is Carl Sagan? What is the nearest star system? How long does it take to travel to the nearest star system? Which planet has the largest diameter? Which planet is the third from the sun?     Chapter 3 The Sky What's in the Sky? (Click on links) Sun Moon Stars Planets     Milky Way Shooting Stars (Meteors) Meteor Showers  Comets  VERY IMPORTANT LINK: NASA http://science.nasa.gov   The Milky Way  A diffuse band of light stretching across the entire sky. Greek mythology held that it was the breast milk of Hera squirted across the sky. They called it Galaxy (which is Greek for "Milky Way"). African cultures referred to it as the backbone of night Galileo first observed that the Milky Way is in fact a vast cloud of countless stars. The Galaxy is a disk of stars in which we are embedded. This is why it looks like a band through our sky. Constellations (click on link for alphabetical listing of constellations and link to a minimum of 5) A constellation is an apparent grouping of bright stars in the night sky. The groupings are highly dependent on who is observing them. Currently, the International Astronomical Union (IAU) divides the sky into 88 regions it recognizes as Constellations. Stars in a Constellation are all in the same direction of the sky, but may not be physically close to one another in space. Stars so far away that there is no sense of depth in the sky. Everything appears as if it were on a sphere surrounding Earth. We call this imaginary sphere the Celestial Sphere. Seasonal Motions: As the Earth revolves about the Sun the Constellations visible at night change. Due to the tilt of Earth's rotation axis relative to it's orbital plane the Sun appears to change its location on the horizon where it rises and sets throughout the year. Cause of the Seasons (click on link)          Earth's Seasons Are Caused by the Axial Tilt! No Tilt, No Seasons. Solstices: Locations in Earth's orbit when the axis is pointed the most toward or away from the Sun. The longest and shortest day of the year depending on which hemisphere you live, North or South. Equinoxes: Locations in Earth's orbit when the axis is not pointed at all toward or away from the Sun, but tangent to it. Length of the day is the same for everyone on Earth. 12 hours of day and 12 hours of night. Seasons happen because sunlight is distributed over the surface of Earth differently throughout the year, NOT because the Earth is closer or farther away. When Sunlight is direct is delivers more energy per unit surface area than when it is indirect (or oblique). Tilt also causes length of days to change. During summer, days are longer and sunlight is more direct. During winter, days are short and sunlight is more oblique.     Assignment:   Notes on chapter What is the Milky Way? What is a constellation? Name and describe 5 constellations Are all constellations visible at night? Why/why not? What causes the seasons? What are solstices? What are equinoxes? What is the Celestial Sphere? What are days like during the summer and during the winter? Project #1:  Constellations  (Include the following information in your class presentation) Pick a constellation and construct a model.  -Include both names (name and what it represents) -mythical background -which month is it best seen in the sky?  Suggestion: (black board with tack holes to represent stars, include names on front, on back you will include other information) Chapter 4: The Moon  (click) Phases of the Moon  http://tycho.usno.navy.mil/vphase.html (click on to get today’s virtual reality phase of the moon)  Over the course of about a month the Moon is observed to cycle through a sequence of phases. As it changes its phase it also changes its position in the sky relative to the Sun. Hence, it rises and sets at progressively different times during the month. The phases and their positions relative to the Sun in the sky are given below: New Moon : With the Sun in the Sky Waxing Crescent : between 0° and 90° East of the Sun First Quarter : About 90° East of the Sun Waxing Gibbous : between 90° and 180° East of the Sun Full Moon : Opposite the Sun in the sky (180° East and West of the Sun) Waning Gibbous : between 180° and 90° West of the Sun 3rd (Last) Quarter : About 90° West of the Sun Waning Crescent : between 90° and 0° West of the Sun       Phase 1 - New Moon - The side of the moon that is facing the Earth is not lit up by the sun. At this time the moon is not visible.   Phase 2 - Waxing Crescent - A small part (less than 1/2) of the moon is lit up at this point. The part that is lit up is slowly getting bigger.   Phase 3 - First Quarter - One half of the moon is lit up by the sun at this point. The part that is lit up is slowly getting bigger.   Phase 4 - Waxing Gibbous - At this time half of the moon is lit up. The part that is lit is slowly getting bigger. Waxing means to slowly get bigger.   Phase 5 - Full Moon - The side of the moon that is lit up by the sun is facing the Earth. The entire moon is lit up at this point.   Phase 6 - Waning Gibbous - The moon is not quite lit up all the way by sunlight. The part of the moon this is lit is slowly getting smaller. Waning means to slowly get smaller.   Phase 7 - Last Quarter - Half of the moon is lit up but the sun. The part that we can see lit up is slowly getting smaller.