Study Guide Exam 1- Solar System Astronomy
Study Guide Exam 1- Solar System Astronomy ASTR-1010-01
Popular in Solar System Astronomy
Popular in Art
This 5 page Study Guide was uploaded by Raven Hamilton on Sunday February 14, 2016. The Study Guide belongs to ASTR-1010-01 at Clayton State University taught by Bram Boroson in Spring 2016. Since its upload, it has received 156 views. For similar materials see Solar System Astronomy in Art at Clayton State University.
Reviews for Study Guide Exam 1- Solar System Astronomy
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/14/16
Astronomy 1010 – Review for Exam 1 – in-class February 18 Chapters Covered: 1, 2, 3, S1, 4 Review sessions (outside of class): TO BE ANNOUNCED Format: mostly multiple choice. There may be some short answer/essay questions for credit or just for extra credit. Closed-book. In bold are topics I think are especially important. Topics for Review: Ch. 1: Our Place in the Universe: What are the main things we know make up the Universe? What is a solar system, planet, moon, star, galaxy, and group of galaxies? The main things that make up our universe include galaxies which contain stars. Those stars have solar systems of their own, and in those solar systems are planets, moons, asteroids and other debris. Solar system- includes a star and all the materials that orbit it. Star- glowing ball of gas that generates heat through light and nuclear fusion. Planet- moderately large object that orbits a star and shines by reflected light. Moon- also called a satellite, an object that orbits a planet Galaxy- a mass of stars in space held together by gravity and orbiting a common center. Galaxy groups- a cluster of the masses described above. How old do we think the Universe is? How old is our solar system? 14 billion years as marked by the horizon of the observable universe, meaning we are unable to look back farther than this. What is a light year? What is an Astronomical Unit? A light year is a measure of distance, specifically how far light travels in a year. An Astronomical Unit is the average distance between Earth and the Sun which is 150 million kilometers. What is our motion in the Universe? Earth spins on its axis while simultaneously orbit the Sun. The Sun move randomly in relation to other stars and orbits the galaxy every 230 million years. At the same time the Milky Way Galaxy is spinning as well. Ch. 2: Discovering the Universe for Yourself: How do we measure angles in the sky? What are arc minutes and arc seconds? We measure angles by finding the direction/azimuth (north, northeast, northwest, east, west, south, southeast, and southwest) and determining the altitude in degrees. Arc minutes are subdivisions of degrees. Each degree is divided into 60 arc minutes, and each arc minute is then divided into 60 arc seconds. How is the angular size related to the linear size and distance? (If the Moon were moved further away, would its angle from side to side be larger or smaller?) Angular size is related to linear size and distance because the farther away you are from something, the smaller the angular size. Angular size is dependent on your location and your distance from that object. What is the ecliptic and what is the celestial equator? What is the meridian, the zenith, and the horizon? What is a constellation? What does it mean that some constellations are in the zodiac? Ecliptic- path the Sun follows as it circles around the celestial sphere. Celestial Equator- a projection of Earth’s equator into space Meridian- imaginary half circle stretching from the horizon due south. Zenith- point directly overhead Horizon- boundary between Earth and the sky Some of the known constellations are part of the 13 constellations (the zodiac) that the Sun travels through in a year. What is the precession of the Earth’s spin? Earth’s precession is like that of a spinning top. It precesses over a period of about 26,000 years. What causes the phases of the Moon? What are the phases called? Can you draw diagrams to show about what time a full moon rises, etc.? The Moon’s phases are caused by its orbit around the Earth. The phases are waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, waning crescent, and new moon [INSERT PICTURES] pg. 40 in txtbk. What causes the seasons? What causes the changing length of daylight? Where on Earth and in what times does the Sun ever get straight overhead (at the zenith)? Seasons are caused by the axis tilt of the Earth. The Sun is directly overhead at noon on two places once a year, The Tropic of Cancer in the Northern Hemisphere and The Tropic of Capricorn in the Southern Hemisphere. What are eclipses? What are solar and lunar eclipses? What is the umbra and what is the penumbra? What are partial, total, penumbral, and annular eclipses? Why aren’t there eclipses each month? What phase is the Moon in for a lunar or solar eclipse? Eclipse- one body is completely covered by the shadow of another. Eclipses occur when the Sun, Moon, and Earth fall into a straight line. Solar eclipse- the Moon is directly between the Sun and the Earth and its shadow falls on Earth. Lunar eclipse- Earth is directly between the Sun and the Moon and its shadow falls on the Moon. Umbra- one part of a shadow where sunlight is completely blocked. Penumbra- surrounds the umbra and sunlight is only partially blocked. Partial eclipse- only part of the object (Sun or Moon) is covered in shadow; part of full moon passes through Earth’s umbra (partial lunar eclipse), part of the Sun blocked by moon’s shadow (partial solar eclipse). We don’t have eclipses every month because the moon is tilted about 5 degrees to the ecliptic plane and spends most of its time either above or below this plane. The points where it is above this plane, which are called nodes, are the only opportunities for an eclipse to occur. For a lunar eclipse the phase of the moon must be full, and new for a solar eclipse. Ch. 3: The Science of Astronomy How did the ancient Greeks think that planets moved? What is retrograde motion? What is an epicycle? The ancients believed in a geocentric (Earth centered) universe and thought the planets orbited around the Earth in epicycles. Retrograde motion- the motion of an object in the sky appears to reverse after being watched for a long period. For example, if you were to watch a planet in the sky night after night it would appear to reverse from moving eastward and change direction westward. Epicycle- used as an explanation for retrograde motion, planets move around Earth in smaller circles that also orbit the Earth, The smaller circles are called epicycles. What were the historical roles of Ptolemy, Copernicus, Tycho Brahe, Johannes Kepler, and Galileo? Ptolemy- created the Ptolemaic model which involved epicycles and explain the occurrence of retrograde motion Copernicus- used mathematics to calculate planets’ orbits to support the Sun centered model of the universe. Publication of his findings in his book De Revolutionibus Orbium Colestium (Concerning the Revolutions of the Heavenly Spheres) spread the Sun centered model. Tycho Brahe- observed and accurately recorded the stellar and planetary positions in the sky Johannes Kepler- assistant to Tycho who carried on his work after his death. Kepler discovered that the planets travel in elliptical orbits and created the laws of planetary motion. Galileo- first to observe the sky through a telescope, he ruled out the main objections to the Sun centered model by proving that objects in motion will stay in motion unless a force acts upon them, showing objects in space were not perfectly round (heavenly perfect), and that stars and planets are much farther apart. Galileo’s findings did not sit well with the Catholic Church and he was ordered to recant and be exiled. How was retrograde motion explained by having planets orbit the Sun instead of the Earth? When planets orbit the Sun instead of the Earth, Earth crosses through the paths of the orbits of other planets making it look as though those planets have changed direction in the sky. What are Kepler’s 3 Laws, and why were they important in showing planets go around the Sun? What is an ellipse and what is a focus? What is a semi major axis and what is a period? Law 1- Planets orbit the Sun in an ellipse with the Sun at one focus. Law 2- As a planet orbits, it sweeps out equal area at equal times, meaning no point in its orbit is longer or shorter than any other point. Law 3- Distant planets orbit at slower speeds; formula p(squared)= a(cubed), where p is the orbital period in years, and a is the average distance from the Sun in astronomical units. Ellipse- a special type of oval with two focus points. Focus- point in an ellipse Semi major axis- half of the long axis of an ellipse which is called the major axis Period- the amount of time it take an object to revolve or orbit. What discoveries did Galileo make using a telescope that showed that the Earth was not at the center? How did Ptolemy's model predict Venus went through phases and what did Copernicus's model predict? Galileo observed sun spots on the Sun, mountains and valleys on the moon, and the distance between the stars which was too far for stellar parallax. Ptolemy explained phases through retrograde motion and epicycles, and Copernicus’s model predict planetary positions. Ch. S1: Celestial Timekeeping and Navigation: this chapter will be emphasized less (we had no homework on S1) What is a sidereal day and a mean solar day? Why is the orbital period of the Moon not the same as the period of its phases? Why is a tropical year a bit shorter than Earth's orbit? Sidereal day- rotation of Earth on its axis, 23 hours, 56 minutes, 4.07 seconds. Mean solar day- Sun makes a circuit around the sky in 24 hours The orbital period of the Moon is not the same as its period of phases because the moon must complete more than one orbit from one new moon to the next. It’s the same concept that derives from the sidereal day. The tropical year is shorter than Earth’s orbit because of the 26,000 year precession of the Earth that changes the locations on Earth where seasons occur. Since a tropical year is based on seasons and the precession changes season locations each year, it accounts for the small difference between the two. What factors make an apparent solar day not always exactly 24 hours? The Earth moves 1 degree in orbit in each day. How do we give coordinates to a star in the sky? Coordinates to a star are given using declination and right ascension. Declination is similar to latitude, and right ascension is similar to longitude. Ch. 4: Understanding Motion, Energy, and Gravity How did Newton advance our understanding of how planets move? Newton realized that the same laws that operate on Earth apply to space and discovered the laws of motion. What are Newton’s 3 laws of motion? What is acceleration, what is force, what is mass? Law 1- Objects move at a constant speed unless another force acts to change is speed or direction. Law 2- Force equals mass times acceleration. Law 3- For every force there is an equal and opposite reaction. Acceleration- change is velocity in any way. Force-changes an object’s momentum. Mass- the amount of matter in an object. What are conservation laws? What are examples of: total energy staying the same but changing form, momentum staying the same but changing among objects, angular momentum staying the same? Conservation Laws: Conservation of momentum- as long as there are no outside forces, the total momentum of interacting objects cannot change. Conservation of angular momentum- as long as there is no external torque, the total angular momentum of interacting objects cannot change. Conservation of energy- energy is never created nor destroyed, but transferred into different forms of energy. Examples- momentum staying the same but changing among objects (balls hitting each other on pool table), angular momentum staying the same (spinning ice skater), energy staying the same but changing form (food chain). What is Newton’s Law of Universal Gravitation? How does the force of gravity depend on the two things pulling each other together, and how does it depend on how far apart they are? Law of Universal Gravitation- Every mass attracts every other mass. Attraction is directly proportional to the product of their masses. Attraction is inversely proportional to the square of the distance between their centers. The strength of the pull of gravity depends on the mass of the attracting object. The farther apart object are the smaller the strength of the gravitational pull. How did Newton’s understanding of gravity help explain orbits better? What does it mean when something is in orbit about a center of mass? Newton’s understanding help to explain why certain objects orbiting other objects act in the manner that they do. For example, the orbit of Uranus around the Sun is longer because it is farther away. Also, Newton's laws of gravity and motion showed that the relationship between the orbital period and average orbital distance of a system tells us the total mass of the system. When something is in orbit about a center of mass it means that the object is in orbit around a mean of distributed mass; basically about the majority of mass/ matter. What causes tides? How are tides related to gravity? What do we see in the universe that is affected by tidal forces? Tides are caused by gravity, specifically the pull of the moon’s gravity on Earth. The moon’s gravity stretches Earth and its oceans. In the universe we see that tidal friction slows the Earth’s rotation slowly.
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'