ASTRONOMY. Evidence of Rotation:

Transcription

1 ASTRONOMY Rotation: - spinning of Earth on its axis - causes daylight and night - 1 day; 23 hours, 56 min, 4 sec - apparent motion of the sun around the Earth - 15 per hour Evidence of Rotation: Coriolis effect Foucault pendulum - causes deflection of winds and ocean currents - deflects to the right in the Northern Hemisphere -Circumpolar Stars - Star trails 1. A Foucault pendulum appears to change its direction of swing due to the (1) tilt of Earth s axis (2) spin of Earth on its axis (3) deflection of Earth s planetary winds (4) movement of Earth in its orbit around the Sun 2. Predictable changes in the direction of swing of a Foucault pendulum provide evidence that (1) Earth is tilted on its axis (3) Earth rotates on its axis (2) Earth s orbit is slightly elliptical (4) Earth s magnetic poles reverse over time 3. The apparent shift in the direction of swing of a the motion of a Foucault pendulum provides evidence of (1) the Sun s rotation (3) Earth s rotation (2) the Sun s revolution (4) Earth s revolution Astronomy 249

2 4. The apparent change in direction of a swinging Foucault pendulum is the result of the (1) rotation of Earth (3) revolution of Earth (2) tilt of Earth s axis (4) shape of Earth s orbit 5. Foucault pendulum is caused by Earth s (1) revolution (2) spherical shape (3) rotation (4) tilted axis 6. The best evidence that Earth spins on its axis is provided by (1) variations in atmospheric density (2) apparent shifts in the swing of a Foucault pendulum (3) changes in the position of sunspots on the Sun (4) eclipses of the Moon 7. The diagram below represents a Foucault pendulum swinging freely for 8 hours. The Foucault pendulum appears to gradually change its direction of swing due to Earth s (1) orbit around the Sun (2) tilted axis (3) curved surface (4) spin on its axis 8. The diagram below shows the equipment used to demonstrate a Foucault pendulum In the demonstration, a student swings the weight hanging in the pail and then spins the stool. The stool represents (1) the revolving Earth (2) the rotating Earth (3) the Coriolis effect (4) convection currents 250 ESworkbooks 2008cdunbar

3 Revolution: - Earth moving in its orbit around the Sun - takes 1 year, days - moves approximately 1 per day - cause the seasons Evidence of Revolution: - The location of the constellations in relationship to Polaris changes from month to month. Locating objects in the sky Celestial sphere The imaginary dome surrounding Earth Celestial Objects objects on the celestial sphere sun, stars, moon, planets Altitude the height above Earth s surface - celestial objects are measured in degrees - ex: the altitude of Polaris equals an observers north latitude Polaris Zenith E N S W Zenith the point located directly overhead of an observer altitude of 90 Astronomy 251

4 Azimuth - the angular measurement around Earth s surface - measured in degrees starting with due North located at 0 Azimuth and moving clockwise around the horizon. Direct ray of the sun Also known as the Sun s vertical ray - Occurs when the sun is directly overhead (at the zenith) - NEVER occurs in New York State Locations on Earth: Label the diagram below using the following locations. Equator ( 0 ) North Pole (90 N) South Pole (90 S) Tropic Cancer (23 ½ N) Tropic of Capricorn (23 ½ S) Axis of rotation Antarctic Circle (66 ½ S) Arctic Circle (66 ½ N North Pole - 90 N Arctic Circle - 66 ½ N Tropic of Cancer - 23 ½ N Equator - 0 Axis of rotation Tropic of Capricorn 23 ½ S Antarctic Circle - 66 ½ S South Pole - 90 S 252 ESworkbooks 2008cdunbar

5 Base your answers to questions 1 and 2 on the data table below, which shows the azimuths of sunrise and sunset on August 2 observed at four different latitudes. Azimuth is the compass direction measured, in degrees, along the horizon, starting from north. 1. On the outer edge of the azimuth circle below, mark with an X the positions of sunrise and sunset for each latitude shown in the data table. Write the correct letter code beside each X. The positions of sunrise and sunset for 30 N have been plotted and labeled with letters A and B. 2. State the relationship at sunrise between the latitude and the azimuth. As the latitude of the observer increases, the azimuth decreases. (or) As the latitude increases, Azimuth Circle the sunrise is farther north of east. X X X F D H G X E C X X Astronomy 253

6 3. Which statement about Polaris is best illustrated by the diagrams shown to the right? (1) Polaris is located in a winter constellation. (2) Polaris is located at the zenith at each location. (3) Polaris apparent movement through the sky follows a south - to - north orientation. (4) Polaris altitude is equal to a location s latitude. 4. In which diagram below, is the observer experiencing the greatest intensity of insolation? 5. The diagram below shows an observer on Earth measuring the altitude of Polaris. What is the latitude of this observer? (1) 43 N (2) 43 S (3) 47 N (4) 47 S 254 ESworkbooks 2008cdunbar

7 The diagram below illustrates Earth s position at the beginning of each season. Draw in the lines to show Earth s movement around the sun throughout the year. Label the seasons, the date it begins, location on Earth where the sun s vertical rays are and amount of daylight (in Northern hemisphere) for each position. N Summer Solstice June 21 Tropic of Cancer (23 ½ N) Longest day (just over 15 hrs) Vernal (spring) equinox March 21 Equator (0 ) 12 hours of daylight N N Winter Solstice December 21 Tropic of Capricorn (23 ½ S) Shortest day (just over 9 hrs) N Autumnal equinox September 23 Equator (0 ) 12 hours of daylight Astronomy 255

8 Angle of Insolation / Angle of Incidence Direct Ray At what location is the direct ray of the sun? Equator What seasons could this be? Spring or Fall Direct Ray At what location is the direct ray of the sun? Tropic of Capricorn What season would this be? Winter Direct Ray At what location is the direct ray of the sun? Tropic of Cancer What season would this be? Summer 256 ESworkbooks 2008cdunbar

9 Causes for the Seasons Tilt of Earth s axis - 23 ½ - causes different latitudes to have different amount of daylight - more daylight hours means warmer temperatures in that location Revolution around the Sun - Earth s orbit around the sun Parallelism of Earth s Axis - Earth s axis does not change direction Ex. Summer in the Northern Hemisphere - North Pole is tilted toward the Sun Altitude of the Noon Sun & Path through the Sky solar noon when the sun has reached its highest point in the sky NEVER directly overhead in New York State Shadow - longer when sun is lower in sky - direction at noon depends on your latitude 1. What is meant by within the tropics? Any place located between 23 ½ N and 23 ½ S of the equator 2. What determined where the Tropic of Cancer and the Tropic of Capricorn would be located on Earth s surface? It is the last place north or south of the equator where the sun is directly overhead Astronomy 257

10 Where the Sun's Rays are at the Beginning of each Season When the Sun is directly overhead at the Tropic of Cancer (23 1/2 N), it is the Summer Solstice Tropic of Cancer 23 1/2 N Equator 0 Tropic of Capricorn 23 1/2 S June 21 March 21 / September 23 When the Sun is directly overhead at the Equator, it is either the Autumnal Equinox or the Vernal Equinox. December 21 When the Sun is directly overhead at the Tropic of Capricorn (23 1/2 S), it is the Winter Solstice Determining the altitude of the noon sun during the equinoxes and solstices: How many degrees does the Sun move each season? 23 1/2 1. The altitude of the noon sun and path of the sun depends on two variables: Latitude and Season 2. When the direct ray of the sun is striking a location on Earth s surface, the altitude of the noon sun at that location is 90. For each of the following locations, name the month or months in which the noon sun is at the zenith for that location. Tropic of Cancer Tropic of Capricorn Equator New York State June December March & September Never 258 ESworkbooks 2008cdunbar

11 Location: Tropic of Cancer - 23 ½ N Date Altitude of noon Sun Direction of Noon Sun June Overhead September 23 Moves South Moves December South Moves March South Location: Tropic of Capricorn - 23 ½ S Date Altitude of noon Sun Direction of Noon Sun December Overhead Moves March North Moves June North September 23 Moves North w Date September 23 Location: Equator - 0 Altitude of noon Sun Direction of Noon Sun 90 Overhead Moves December South Moves March Overhead Moves June North Astronomy 259

12 For any other latitudes: In the northern hemisphere use June as a starting month. Determine if the noon sun is higher or lower in the sky then at the Tropic of Cancer. Follow the procedure below. Buffalo, NY: 43 N 1. What is the latitude of Buffalo? 43 N 2. What is the latitude of the Tropic of Cancer? 23 ½ N 3. What is the difference between the two latitudes? 19 ½ 4. What is the altitude of the noon Sun at the Tropic of Cancer on June 21? Subtract the difference between latitudes from the altitude of the noon Sun at the Tropic of Cancer. This is the altitude of the noon Sun in New York State on June 21. * Place this value in the data chart for New York State below ½ = 70 ½ Location: Buffalo, NY - 43 N Date Location: Buffalo - 43 N Altitude of noon Sun Direction of Noon Sun June ½ South September 23 Moves South Moves December ½ South Moves March South 260 ESworkbooks 2008cdunbar

13 This diagram illustrates the path of the sun and the altitude of the noon sun on the celestial sphere for an observer in New York State (latitude 43 N) at the beginning of each season. Label each month for the paths drawn in the diagram below C May June April B March July February August January September A October November December W S N E 1. Which letter represents the path and altitude of the noon sun on... March 21? B December 21? A June 21? C 2. In November, the noon sun would most likely be between points A and B 3. In August, the noon sun would most likely be between points B and C 4. In May, the noon sun would most likely be between points B and C 5. In January, the noon sun would most likely be between points A and B Astronomy 261

14 Base your answers to questions 6 through 8 on the world map below. The shaded portion of the map indicates areas of night, and the unshaded portion indicates areas of daylight on a certain day of the year. Dashed latitude lines represent the Arctic Circle (66.5 N) and the Antarctic Circle (66.5 S). Point A is a location on Earth s surface. 6. Which diagram shows the position of Earth relative to the Sun s rays on this day? 7. Approximately how many hours of daylight would occur at position A on this day? (1) 6 (2) 12 (3) 9 (4) On this day, the duration of daylight from the equator to the Arctic Circle (1) decreases, only (3) decreases, then increases (2) increases, only (4) increases, then decreases 9. The diagram to the right represents a plastic hemisphere upon which lines have been drawn to show the apparent paths of the Sun at a location in New York State on the first day of each season. Letters A through I represent points on the paths. Which point represents the sunrise location on the first day of winter? (1) G (2) F (3) E (4) D 262 ESworkbooks 2008cdunbar

15 10. A student in New York State looked toward the eastern horizon to observe sunrise at three different times during the year. The student drew the following diagram that shows the positions of sunrise, A, B, and C, during this one-year period. Which list correctly pairs the location of sunrise to the time of the year? (1) A June 21 B March 21 C December 21 (3) A March 21 B June 21 C December 21 (2) A December 21 B March 21 C June 21 (4) A June 21 B December 21 C March The diagram to the right shows the noontime shadows cast by a student and a tree. If the time is solar noon and the student is located in New York State, in what direction is the student facing? (1) north (3) south (2) east (4) west Base your answers to questions 12 and 13 on diagrams I through III below. Diagrams I, II, and III represent the length and direction of the shadow of a vertical stick measured at noon on three different dates at 42 N latitude. 12. Explain how the changing altitude (angle of incidence) of the noon Sun affects the length of the shadows shown in the diagrams. The higher the angle of incidence, the shorter the shadow. 13. Describe the length and direction of the noon time shadow on June 21. The shadow in June would be shorter than 10 cm and would still point North. Astronomy 263

16 Base your answers to questions 14 through 18 on the diagram below. The diagram represents the apparent path of the Sun observed at four locations on Earth s surface on March 21. The present positions of the Sun, Polaris, and the zenith (position directly overhead) are shown for an observer at each location. 14. The observer at location A casts a shadow at the time represented in the diagram. a State the compass direction in which the observer at location A must look to view her shadow. Northeast b Describe the change in the length of the shadow that will occur between the time shown and sunset. The length of the shadow will increase. 15. State the approximate time of day for the observer at location B when the Sun is at the position shown in the diagram. 3 PM 16. Explain why the intensity of sunlight at noon on March 21 is greater at location C than at the other locations. Because the sun is directly overhead 17. The observer at location D is located at a higher latitude than the other three observers. State one way that this conclusion can be determined from the diagram. Polaris is directly overhead must be at 90 N 18. State the other day of the year when the Sun s apparent path is exactly the same as that shown for these four locations on March 21. September ESworkbooks 2008cdunbar

17 19. The diagram below shows the apparent daily path of the Sun, as viewed by an observer at a certain latitude on three different days of the year. At which latitude were these apparent Sun paths most likely observed? (1) 0 (2) 43 N (3) 23.5 N (4) 66.5 N 20. Which diagram to the right correctly shows the apparent motion of Polaris from sunset to midnight for an observer in northern Canada? 21. The apparent daily path of the Sun changes with the seasons because (1) Earth s axis is tilted (2) Earth s distance from the Sun changes (3) the Sun revolves (4) the Sun rotates Astronomy 265

18 Base your answers to questions 22 through 24 on the diagram below, which shows a model of the apparent path and position of the Sun in relation to an observer at four different locations, A, B, C, and D, on Earth s surface on the dates indicated. The zenith (z) and the actual position of the Sun in the model at the time of the observation are shown. [The zenith is the point directly over the observer.] 22. According to the Sun s actual position shown in the diagrams, the most intense insolation is being received by the observer at location (1) A (2) B (3) C (4) D 23. Where on Earth s surface is the observer at location C located? (1) at the Equator (2) at the South Pole (3) at the North Pole (4) in Oswego, New York 24. From sunrise to sunset at location B, the length of the observer s shadow will (1) increase, only (2) decrease, only (3) increase, then decrease (4) decrease, then increase Base your answers to questions 25 and 26 on the diagram below, which shows numbered positions of the Sun at four different times along the Sun s apparent daily path, as seen by an observer in New York State. Numbers 1 through 4 represent apparent positions of the Sun. 25. The observer had the longest shadow when the Sun was at position (1) 1 (2) 2 (3) 3 (4) During which day of the year is the Sun most likely to follow the apparent path shown? (1) March 1 (3) October 1 (2) July 1 (4) December ESworkbooks 2008cdunbar

19 Solar System Models Geocentric Model: Earth Centered Explained the following: - Earth was stationary with the Sun, Moon and planets revolving around it Epicycle planet - Night and day Sun - Revolution of the moon moon Earth planet Did not easily explain the following: - Movement of the inner and outer planets Geocentric Model Sun Centered Heliocentric Model: Explained the following: planet - Places the sun in the center of our solar system - Day and night - Seasons planet Sun planet Earth moon - Motion of all celestial objects Heliocentric Model Copernicus, Brahe, Kepler, Galileo and other scientists in the 16 th and 17 th centuries supported this model. This is the model we use today. Astronomy 267

20 Star Paths - In the Northern sky, stars appear to move counterclockwise around Polaris. (Circumpolar stars) - In the Southern sky, stars appear to move from East to West in arcs just like the E S sun. - At the Southern horizon, stars appear to make very N W small arcs, seen for brief periods of time. Referring to the diagram above, which direction is an observer facing for each of the following star trails? Place the compass direction on the arrows next to each diagram. North West East South 268 ESworkbooks 2008cdunbar

21 Constellations - random patterns of stars in the night sky - Different constellations are visible at different times of the year - The big dipper is always visible in the northernn sky in New York State - evidence of revolution 1. The diagram to the right representss the major stars of the constellation Orion, as viewed by an observer in New York State. Which statement best explains why Orion can be observed from New York State on December 21 but not on June 21? (1) Orion has an eccentricc orbit around Earth. (2) Orion has an eccentricc orbit around the Sun. (3) Earth revolves around the Sun. (4) Earth rotates on its axis. 2. Which event is a direct result of Earth s revolution? (1) the apparent deflection of winds (2) the changing of the Moon phasess (3) the seasonal changes in constellations viewed in the night sky (4) the daily rising and setting of the Sun Astronomy 269

22 Base your answers to questions 3 through 6 on your knowledge of Earth science and on the table below, which lists the seven brightest stars, numbered 1 through 7, in the constellation Orion. This constellation can be seen in the winter sky by an observer in New York State. The table shows the celestial coordinates for the seven numbered stars of Orion. Locations of the Seven Brightest Stars I Orion Star Number Celestial Longitude (measured in hours) Celestial Latitude (measured in degrees) On the grid provided below, graph the data shown in the table by following the steps below. a Mark with an X, the position of each of the seven stars. Write the number of the plotted star beside each X. The first star has been plotted for you. b Show the apparent shape of Orion by connecting the Xs in the following order: X X X X 4. Star 1 plotted on the grid is the star Betelgeuse. Star 3 plotted on the grid is the star Rigel. How do the temperature and luminosity of Betelgeuse compare to the temperature and luminosity of Rigel? (ESRT pg 15) Rigel is hotter and its luminosity is slightly greater X X 5. The seven stars of the constellation Orion that were plotted are located within our galaxy. Name the galaxy in which the plotted stars of Orion are located. Milky Way 4. State one reason why an observer in New York State can never observe the constellation Orion at midnight during July but can observe the constellation Orion at midnight during January. Because Earth revolves around the Sun (axis is pointed in a different direction toward from the Sun in July) 270 ESworkbooks 2008cdunbar

23 5. Which statement provides evidence that Earth revolves around the Sun? (1) Winds at different latitudes are curved different amounts by the Coriolis effect. (2) Different star constellations are visible from Earth at different seasons of the year. (3) The Sun follows an apparent arc across the sky during the day. (4) The stars appear to circle Earth during the night. 6. In October, observers in New York State looking due south at the night sky would see a different group of constellations than they had seen in March. What is the best explanation for this change in the night sky? (1) Constellations revolve around Earth. (2) Constellations revolve around the Sun. (3) The Sun revolves around the center of our galaxy. (4) Earth revolves around the Sun. 7. In New York State, the constellation Pisces can be seen in the night sky between the middle of summer and the middle of winter. The constellation Scorpio can be seen in the night sky between early spring and early fall. The reason these two constellations can be viewed only at these times is a direct result of Earth s (1) spin on its axis (3) movement around the Sun (2) axis having a 23.5 tilt (4) distance from the Sun Base your answers to questions 8 through 10 on Diagram 1 and Diagram 2 below, which show some constellations in the night sky viewed by a group of students. Diagram 1 below shows the positions of the constellations at 9:00 p.m. Diagram 2 below shows their positions two hours later. 8. On both diagrams, extend an arrow through the pointer stars on the Big Dipper to locate Polaris. Then circle Polaris on each diagram. 9. In which compass direction were the students facing? North 10. Describe the apparent direction of movement of the constellations Hercules and Perseus during the two hours between student observations. Counter clockwise around Polaris Astronomy 271

24 Shape of Orbit The planets move in ellipses with the Sun at one focus Shape of Earth s orbit: Slightly elliptical with the Sun at one foci Eccentricit y How oval an orbit is. How out of round it is. Formula: Eccentricity = Distance between Foci Length of Major Axis Major axis Determine the eccentricity of the ellipse to the right: Distance between foci 1) A circle has an eccentricity of, 0 and is least eccentric. 2) The more oval an ellipse is the more eccentric it is. The Force of Gravity 1) Gravity An invisible force of attraction 2) Gravity depends on two things: mass and distance 3) The larger the mass, the greater the gravitational attraction. 4) The closer objects are together, the greater the attraction. 272 ESworkbooks 2008cdunbar

25 Planet Velocities and Area The line joining the Sun and a planet sweeps out equal areas in equal intervals of time C 1. Between which two letters is the orbital A and B speed the slowest? A B 2. Between which two letters is the orbital C and D speed the fastest? D 3. The area s covered by the Earth as it travels from A to B and from C to D are equal 4. The speed of a planet depends upon its distance from the. Sun 5. The closer the Earth is to the Sun, the it travels in its orbit. Distance of planets with respect to the Sun Closest point to the Sun Perihelion Farthest point from the Sun Aphelion The square of the time (T 2 ) of revolution of a planet divided by the cube of its mean distance (R 3 ) from the Sun gives a number that is the same for all the planets Base your answers to questions 1 and 2 on the diagram of the ellipse below. 1. Calculate the eccentricity of the ellipse to the nearest thousandth. Eccentricity = Distance between foci Length of Major Axis = 2.7 / 8.1 = State how the eccentricity of the given ellipse compares to the eccentricity of the orbit of Mars. Mars is less eccentric (.093) Astronomy 273

26 Base your answers to questions 3 through 5 on the diagram below, which represents the elliptical orbit of a planet traveling around a star. Points A, B, C, and D are four positions of this planet in its orbit. 3. The calculated eccentricity of this orbit is approximately Eccentricity = Distance between foci Length of Major Axis (1) 0.1 (2) 0.2 (3) 0.3 (4) The gravitational attraction between the star and the planet will be greatest at position (1) A (2) B (3) C (4) D 5. As the planet revolves in orbit from position A to position D, the orbital velocity will (1) continually decrease (2) continually increase (3) decrease, then increase (4) increase, then decrease 6. The diagram below is a constructed ellipse. F1 and F2 are the foci of the ellipse. The eccentricity of this constructed ellipse is closest to the eccentricity of the orbit of which planet? (1) Mercury (3) Saturn (2) Earth (4) Neptune 7. Which planet has an orbit with an eccentricity most similar to the eccentricity of the Moon s orbit around Earth? (1) Earth (2) Pluto (3) Jupiter (4) Saturn 274 ESworkbooks 2008cdunbar

27 Base your answers to questions 8 and 9 on the diagram below, which shows the orbit of planet D around the star Upsilon Andromedae. The dashed lines show where the paths of the first four planets of our solar system would be located if they were going around Upsilon Andromedae instead of the Sun. All distances are drawn to scale. 8. Describe the eccentricity of planet D s orbit relative to the eccentricities of the orbits of the planets shown in our solar system. Planet D s orbit is more eccentric than the planets in our solar system 9. Describe the changes in gravitational force between planet D and the star Upsilon Andromedae during one complete orbit around the star. Be sure to describe where the force is greatest and where the force is least. The velocity is greatest when it is closest to the star and lest when it is farthest from the star 10. The diagram to the right represents the elliptical orbit of a moon revolving around a planet. The foci of this orbit are the points labeled F1 and F2. What is the approximate eccentricity of this elliptical orbit? (1) 0.3 (2) 0.7 (3) 0.5 (4) The diagram to the right shows the elliptical orbit of a planet revolving around a star. The star and F2 are the foci of this ellipse. What is the approximate eccentricity of this ellipse? (1) 0.22 (2) 0.68 (3) 0.47 (4) 1.47 Astronomy 275

28 Base your answers to questions 12 through 15 on the diagram below, which represents an exaggerated model of Earth s orbital shape. Earth is closest to the Sun at one time of year (perihelion) and farthest from the Sun at another time of year (aphelion). 12. State the actual geometric shape of Earth s orbit. Elliptical with the Sun at one foci 13. Identify the season in the Northern Hemisphere when Earth is at perihelion. winter 14. Describe the change that takes place in the apparent size of the Sun, as viewed from Earth, as Earth moves from perihelion to aphelion. The apparent size of the Sun decreases as Earth moves from perihelion to aphelion 15. State the relationship between Earth s distance from the Sun and Earth s orbital velocity. The closer Earth is to the Sun the faster its velocity The diagram below represents Earth at a specific position in its orbit as viewed from space. The shaded area represents nighttime. 16. Which Earth latitude receives the greatest intensity of insolation when Earth is at the position shown in the diagram? (1) 0 (2) 66 N (3) 23 N (4) 90 N 276 ESworkbooks 2008cdunbar

29 Satellites Satellite any object moving in an orbit around another object Earth is a satellite of the. Sun The moon is a satellite of. Earth Because Earth s orbit is Why do the distances between the sun and earth change? elliptical Phases of the Moon Sun 1) The apparent shape of the moon depends on the changing positions of the, Earth and. moon One month (27.3 days) 2) How long does it take the moon to revolve around the Earth? 3) One complete orbit of the moon around the Earth takes about 27 1/3 days. 29 ½ 4) A complete cycle the moon's phases takes days. 5) Explain why there is a 2 ½ day difference between the revolution of the moon and the amount of time it takes to complete all of its phases. Because although the moons revolution of 360 takes 27 1/3 days, Earth is revolving around the Sun. It takes an additional 2 days for the Sun, moon and Earth to align to complete all of the phases Astronomy 277

30 3 2 Tell students to look and draw the phases of the moon using Earth as a reference point. Draw the arrows and lines for each view point as you go over each phase. Have them turn the books around so they are able to visualize it better The Sun s Rays New moon Full moon 2 6 Waxing Crescent Waning gibbous 3 7 First quarter Third quarter (last quarter) 4 8 Waxing gibbous Waning crescent 278 ESworkbooks 2008cdunbar

31 Eclipses of the Moon and Sun Penumbra The lighter part of a shadow partial shadow Umbra The darkest part of a shadow Lunar Eclipse: - occurs when the moon is in the full moon phase - the moon moves into Earth s shadow - because Earth s shadow is so large, it may last for an hour or more (until the moon moves out of Earth s shadow) Solar Eclipse: - occurs when the moon is in the new moon phase - the moons shadow moves over Earth s surface - the eclipse occurs where the point of the shadow hits Earth s surface Astronomy 279

32 Tides - The rising and falling of the ocean surface. - Change in tide is the result of the changing positions of the moon and sun relative to Earth - C lose to 2 high tides and 2 low tides per day Spring Tide: Neap Tide - Occurs when the moon and Earth - Occurs when the moon and Earth are aligned in a straight line with are at a right angle with the sun the sun - Occur twice a month - Occur twice a month - It is the lowest of the high tides and - It is the highest of the high tide and the highest of the low tide lowest of the low - Smallest change between high and - Greatest change from high to low low tide tide 280 ESworkbooks 2008cdunbar

33 Base your answers to questions 1through 3 on the graph below, which shows the water levels of ocean tides measured in Boston, Massachusetts, for a 2-day period. 1. The graph shows that high tides at Boston occur approximately every (1) 3.5 hours (2) 6.0 hours (3) 12.5 hours (4) 16.0 hours 2. If the trends shown by the graph continue, which statement best describes the next low tide at Boston that is expected to occur on Wednesday? (1) It will occur about 3 a.m. with a 0.4-meter water level. (2) It will occur about 6 a.m. with a 0.6-meter water level. (3) It will occur about 9 p.m. with a 2.6-meter water level. (4) It will occur about 10 p.m. with a 2.8-meter water level. 3. The gravitational pull of the Moon has the greatest influence on the water levels of Earth s ocean tides. If the distance between the Moon and Earth were to decrease steadily for the week following the time shown on the graph, which water level changes would be expected to occur? (1) High tides would get higher and low tides would get lower. (2) High tides would get lower and low tides would get higher. (3) Both high tides and low tides would get higher. (4) Both high tides and low tides would get lower. Astronomy 281

34 Base your answers to questions 4 through 8 on the diagram below, which represents the Moon orbiting Earth as viewed from space above the North Pole. The Moon is shown at eight different positions in its orbit. 4. The approximate time required for the Moon to move from position 3 to position 7 is (1) 1 hour (2) 3 months (3) 2 weeks (4) 4 days 5. As the Moon changes location from position 2 to position 6, the visible portion of the Moon as observed from Earth (1) decreases, only (3) decreases, then increases (2) increases, only (4) increases, then decreases 6. Which motion causes the Moon to show phases when viewed from Earth? (1) rotation of Earth (3) rotation of the Sun (3) revolution of Earth (4) revolution of the Moon 7. Which device when placed on the Moon would provide evidence of Moon rotation? (1) Foucault pendulum (2) thermometer (3) seismograph (4) wind vane 282 ESworkbooks 2008cdunbar

35 8. When the Moon is in position 2, which phase would be visible to an observer in New York State? The diagram below shows the relative positions of the Sun, the Moon, and Earth when an eclipse was observed from Earth. Positions A and B are locations on Earth s surface. 9. Which statement correctly describes the type of eclipse that was occurring and the position on Earth where this eclipse was observed? (1) A lunar eclipse was observed from position A. (2) A lunar eclipse was observed from position B. (3) A solar eclipse was observed from position A. (4) A solar eclipse was observed from position B. 10. The diagram below shows the Sun, the Moon, and Earth in line with one another in space. On the diagram, draw two dots ( ) on the surface of Earth to indicate the locations where the highest ocean tides are most likely occurring. Astronomy 283

36 Base your answers to questions 11 and 12 on the graph below. The graph shows the recorded change in water level (ocean tides) at a coastal city in the northeastern United States during 1 day. 11. Which inference about tides is best made from this graph? (1) The hourly rate of tidal change is always the same. (2) The rate of tidal change is greatest at high tide. (3) The tidal change is a random event. (4) The tidal change is cyclic. 12. According to the pattern shown on the graph, the next high tide will occur on the following day at approximately (1) 12:30 a.m. (2) 3:15 a.m. (3) 2:00 a.m. (4) 4:00 a.m. 13. The cyclic rise and fall of ocean tides on Earth is primarily caused by Earth s rotation and the (1) temperature differences in ocean currents (2) revolution of Earth around the Sun (3) direction of Earth s planetary winds (4) gravitational attraction of the Moon and the Sun 284 ESworkbooks 2008cdunbar

37 14. Which description of change is most closely associated with ocean tides and moon phases? (1) cyclic and predictable (3) noncyclic and predictable (2) cyclic and unpredictable (4) noncyclic and unpredictable 15. Ocean tides are best described as (1) unpredictable and cyclic (3) unpredictable and noncyclic (2) predictable and cyclic (4) predictable and noncyclic 16. The diagram below shows the Moon orbiting Earth, as viewed from space above Earth s North Pole. The Moon is shown at eight positions in its orbit. Spring ocean tides occur when the difference in height between high tide and low tide is greatest. At which two positions of the Moon will spring tides occur on Earth? (1) 1 and 5 (2) 3 and 7 (3) 2 and 6 (4) 4 and The diagram below represents the Sun s rays striking Earth and the Moon. Numbers 1 through 4 represent positions of the Moon in its orbit around Earth. The highest tides on Earth occur when the Moon is in positions (1) 1 and 3 (3) 3 and 2 (2) 2 and 4 (4) 4 and 1 Astronomy 285

38 Base your answers to questions 18 through 20 on the diagram below and on your knowledge of Earth science. The diagram shows the Sun, Earth, and the Moon s orbit around Earth as viewed from space. 18. On the diagram provided above, draw a circle of approximately this size to represent the Moon s position in its orbit when a solar eclipse is viewed from Earth. 19. Approximately how many complete revolutions does the Moon make around Earth each month? one 20. Explain why solar eclipses do not occur every time the Moon revolves around Earth. Because the moon s orbital plane is tilted about What is represented by the diagram below? (1) changing phases of the Sun (2) changing phases of the Moon (3) stages in an eclipse of the Sun (4) stages in an eclipse of the Moon 286 ESworkbooks 2008cdunbar

39 22. The diagram to the right shows Earth s orbit around the Sun and different positions of the Moon as it travels around Earth. Letters A through D represent four different positions of the Moon. An eclipse of the Moon is most likely to occur when the Moon is at position (1) A (2) B (3) C (4) D Base your answers to questions 23 through 24 on the world map below, which shows regions of Earth where a solar eclipse was visible on May 20, Locations A, B, C, and D are on Earth s surface. 23. At which location could an observer have viewed this total solar eclipse if the skies were clear? (1) A (2) B (3) C (4) D 24. Which statement best describes the visibility of this eclipse from locations in New York State? (1) A total eclipse was visible all day. (2) A total eclipse was visible only from noon until sunset. 3) A partial eclipse was visible only from noon until sunset. (4) Neither a partial nor a total eclipse was visible. Astronomy 287

40 Our Solar System Asteroid Belt Terrestrial Planets rocky planets primarily composed of silicate rocks examples Mercury, Venus, Earth, Mars Jovian Planets examples Asteroid belt Gas giants, very low density Jupiter, Saturn, Uranus, Neptune Located between Mars and Jupiter Is composed of thousands of asteroids meteor A streak of light in the sky that occurs when a meteoroid enters Earth s Atmosphere shooting star meteorite A meteor that reaches Earth s surface Comets A huge dirty ice ball that revolves around the sun - When close enough to the sun, exhibit a tail 288 ESworkbooks 2008cdunbar

41 Galaxy Galaxy - A huge system that includes billions of stars, planets, moons and all other space matter that is held together by gravitational attraction What is the name of our galaxy? Milky Way What kind of a galaxy do we live in? Spiral galaxy Where is our solar system located within the galaxy In one of its spiral arms The Universe The Universe Includes everything that exists from the smallest object to the largest galaxies Big Bang Theory About 15 billion years ago an massive explosion took place and started the formation of the universe evidencee The universe is still expanding in every direction Radioactive aftermath of the initial explosion (background radiation) Red shift of galaxies Astronomy 289

42 The diagram below illustrates three stages of a current theory of the formation of the universe. Spectral lines The separation of different colors based on wavelengths It is why we have rainbows. red shift: objects moving away - caused by the expansion of space - The farther away an object moves the more the wavelength is stretched out blue shift: objects moving towards another object The closer object moves the more the wavelength is decreased 290 ESworkbooks 2008cdunbar

43 A Star is Born Nebula cloud of dust hydrogen and plasma Protostar Black Hole Massive Star Super Red Giant Super Nova Neutron Star Main Sequence Star Red Giant Planetary Nebula White Dwarf Star formation: Stars start out is a nebula which is a massive cloud of dust, hydrogen and plasma. Due to gravitational attraction the cloud collapses and temperature increases significantly, nuclear fusion is taking place where hydrogen is becoming helium. A protostar forms. From there, stars can become a main sequence star or a massive star. Astronomy 291

44 Stars differ from each other in Mass, weight, size, temperature and brightness Our Sun Is an average size star located in the main sequence Classification of stars: Based on temperature and brightness Luminosity is relative to the sun Einar Hertzsprung and Henry Russell developed a graph called the H-R Diagram - compares the spectral class color / temperature of a star against their luminosity brightness Refer to the ESRT s pg 15 Luminosity and Temperature of Stars Diagram: 1. Within what area on the diagram is the Sun located? Main sequence 2. Name the star that has a similar temperature and luminosity as the Sun Alpha Centuri 3. What does Polaris and the Sun have in common? Color, temperature 4. What is the name of the hottest star located on the Diagram? Spica 5. What is the name of the brightest star located on the Diagram? Deneb 6. Name two Red Dwarf Barnard s Star and Proxima Centauri 7. Name a White Dwarf Procyon B 8. What is the approximate temperature of Rigel? 11,000 K Sunspots - An area of the Sun s surface that has lower temperatures. The appear to be dark spots on the Sun s surface What happens when they occur? May disrupt air line communication, GPS signals, cell phones, ATM transactions Speed of light - 299,792,458 meters per second - It takes 8.4 minutes for the Sun s light to reach Earth. Light year - The distance light can travel in one year Why is it said that when you see the light of distant stars you are gazing at the past? Some starlight takes millions of years to reach Earth, Star may not be there anymore 292 ESworkbooks 2008cdunbar

45 1. The graph below represents the brightness and temperature of stars visible from Earth. Which location on the graph best represents a star with average brightness and temperature? (1) A (3) C (2) B (4) D 2. The length of an Earth year is based on Earth s (1) rotation of 15 /hr (3) revolution of 15 /hr (2) rotation of approximately 1 /day (4) revolution of approximately 1 /day 3. The Milky Way galaxy is best described as (1) a type of solar system (2) a constellation visible to everyone on Earth (3) a region in space between the orbits of Mars and Jupiter (4) a spiral-shaped formation composed of billions of stars 4. Compared to Pluto, Mercury moves more rapidly in its orbit because Mercury (1) is larger (3) is more dense (2) is closer to the Sun (4) has a more elliptical orbit 5. The diagram to the right represents a simple geocentric model. Which object is represented by the letter X? (1) Earth (3) Moon (2) Sun (4) Polaris Astronomy 293

46 Base your answers to questions 6 through 10 on the Earth Science Reference Tables, the diagram below, and your knowledge of Earth science. The diagram shows a portion of the solar system. 6. Which scale diagram best compares the size of Earth with the size of Venus? 7. Which of the following planets has the lowest average density? (1) Mercury (2) Earth (3) Venus (4) Mars 8. The actual orbits of the planets are (1) elliptical, with Earth at one of the foci (2) elliptical, with the Sun at one of the foci (3) circular, with Earth at the center (4) circular, with the Sun at the center 9. Mercury and Venus are the only planets that show phases when viewed from Earth because both Mercury and Venus (1) revolve around the Sun inside Earth s orbit (2) rotate more slowly than Earth does (3) are eclipsed by Earth s shadow (4) pass behind the Sun in their orbit 294 ESworkbooks 2008cdunbar

47 10. Which graph best represents the relationship between a planet s average distance from the Sun and the time the planet takes to revolve around the Sun? 11. Which object orbits Earth in both the Earth centered (geocentric) and Sun-centered (heliocentric) models of our solar system? (1) the Moon (3) the Sun (2) Venus (4) Polaris 12. The Sun s position in space is best described as the approximate center of (1) a constellation (3) the universe (2) the Milky Way galaxy (4) our solar system 13. The diagram to the right represents two planets in our solar system drawn to scale, Jupiter and planet A. Planet A most likely represents (1) Earth (3) Saturn (2) Venus (4) Uranus 14. Compared to Earth s solar system, the universe is inferred to be (1) younger and larger (3) older and larger (2) younger and smaller (4) older and smaller 15. Terrestrial planets move more rapidly in their orbits than the Jovian planets because terrestrial planets are (1) rotating on a tilted axis (3) more dense (2) more massive (4) closer to the Sun 16. Which event is a direct result of Earth s revolution? (1) the apparent deflection of winds (2) the changing of the Moon phases (3) the seasonal changes in constellations viewed in the night sky (4) the daily rising and setting of the Sun Astronomy 295

48 Base your answers to questions 17 through 19 on the information, data table, and diagram below and on your knowledge of Earth science. Astronomers have discovered strong evidence for the existence of three large extrasolar (outside our solar system) planets that orbit Upsilon Andromedae, a star located 44 light years from Earth. The three planets are called planet B, planet C, and planet D. Some of the information gathered about these three new planets is shown in the table below. The period of revolution for planet C has been deliberately left blank. The diagram below compares a part of our solar system to the Upsilon Andromedae planetary system. Planet distances from their respective star and the relative size of each planet are drawn to scale. [The scale for planet distances is not the same scale used for planet size.] 17. Planet D s diameter is 10 times greater than Earth s diameter. What planet in our solar system has a diameter closest in size to the diameter of planet D? Saturn 18. As planet B travels in its orbit, describe the change in orbital velocity of planet B as the distance between Upsilon Andromedae and planet B decreases. Speed increase 19. If our solar system had a planet located at the same distance from the Sun as planet C is from Upsilon Andromedae, what would be its approximate period of revolution? Anywhere between days to less than days. 296 ESworkbooks 2008cdunbar

49 Base your answers to questions 20 through 22 on the data table below, which shows one cycle of equinoxes and solstices for the northern hemispheres of several planets in the solar system and the tilt of each planet s axis. Data for the planets are based on Earth s time system. 20. State the length, in years, of the spring season on Uranus.20,21 or 22 years 21. Describe the relationship between a planet s distance from the Sun and the length of a season on that planet. As distance increases, length of season increases 22. Identify two factors that cause seasons on Earth. tilt of axis, Earth s revolution 23. Which diagram sequence correctly shows the order of Moon phases, as viewed from Earth, for a period of 1 month? [Note that some phases have been omitted.] Astronomy 297

50 Base your answers to questions 24 and 25 on the diagram below, which shows the Moon, Earth, and the Sun s rays as viewed from space. Letter A indicates a certain position of the Moon in its orbit. 24. Which diagram correctly shows the direction of Earth s rotation and revolution? 298 ESworkbooks 2008cdunbar

51 25. Which diagram represents the phase of the Moon, as seen by an observer on Earth, when the Moon is located at position A in its orbit? 26. The diagram below shows a satellite in four different positions as it revolves around a planet. Which graph best represents the changes in this satellite s orbital velocity as it revolves around the planet 27. Which sequence correctly lists the relative sizes from smallest to largest? (1) our solar system, universe, Milky Way Galaxy (2) our solar system, Milky Way Galaxy, universe (3) Milky Way Galaxy, our solar system, universe (4) Milky Way Galaxy, universe, our solar system 28. Which list shows stars in order of increasing temperature? (1) Barnard s Star, Polaris, Sirius, Rigel (2) Aldebaran, the Sun, Rigel, Procyon B (3) Rigel, Polaris, Aldebaran, Barnard s Star (4) Procyon B, Alpha Centauri, Polaris, Betelgeuse 29. The passage of the Moon into Earth s shadow causes a (1) lunar eclipse (2) new Moon (3) solar eclipse (4) full Moon Astronomy 299

52 30. The symbols below are used to represent different regions of space. Which diagram shows the correct relationship between these four regions? [If one symbol is within another symbol, that means it is part of, or included in, that symbol.] 31. What is the main reason that the gravitational attraction between Earth and the Moon changes each day? (1) Earth s axis is tilted at (2) Earth s rotational speed varies with the seasons. (3) The Moon has an elliptical orbit. (4) The Moon has a spherical shape. 32. Which object in our solar system has the greatest density? (1) Jupiter (2) the Moon (3) Earth (4) the Sun 33. Which sequence of Moon phases could be observed from Earth during a 2-week period? 300 ESworkbooks 2008cdunbar

53 Base your answers to questions 34 and 35 on the diagram below, which shows an inferred sequence in which our solar system formed from a giant interstellar cloud of gas and debris. Stage A shows the collapse of the gas cloud, stage B shows its flattening, and stage C shows the sequence that led to the formation of planets. 34. From stage B to stage C, the young Sun was created (1) when gravity caused the center of the cloud to contract (2) when gravity caused heavy dust particles to split apart (3) by outgassing from the spinning interstellar cloud (4) by outgassing from Earth s interior 35. After the young Sun formed, the disk of gas and dust (1) became spherical in shape (3) became larger in diameter (2) formed a central bulge (4) eventually formed into planets 36. Compared to the temperature and luminosity of the star Polaris, the star Sirius is (1) hotter and more luminous (3) hotter and less luminous (2) cooler and more luminous (4) cooler and less luminous 37. The Big Bang Theory, describing the creation of the universe, is most directly supported by the (1) redshift of light from distant galaxies (2) presence of volcanoes on Earth (3) apparent shape of star constellations (4) presence of craters on Earth s Moon Astronomy 301

54 Base your answers to questions 38 through 40 on the diagram below, which shows two possible sequences in the life cycle of stars, beginning with their formation from nebular gas clouds in space. 38. According to the diagram, the life-cycle path followed by a star is determined by the star s initial (1) mass and size (2) temperature and origin (3) luminosity and color (4) luminosity and structure 39. Stars like Earth s Sun most likely formed directly from a (1) nebula (2) red giant (3) supernova (4) black dwarf 40. According to the diagram, a star like Earth s Sun will eventually (1) explode in a supernova (2) become a black hole (3) change into a white dwarf (4) become a neutron star 302 ESworkbooks 2008cdunbar

55 41. The diagram below represents the shape of the Milky Way Galaxy. The Milky Way Galaxy is best described as (1) elliptical (2) circular (3) irregular (4) spiral 42. A camera was placed outside at night and pointed directly at Polaris and several other stars. The lens was kept open and a time-exposure photograph was taken. The diagram below represents that photograph of Polaris and star trails, with an angular protractor to measure apparent motion. How many hours was the lens kept open to create the star trails in this photograph? (1) 1 hour (3) 3 hours (2) 6 hours (4) 4 hours Astronomy 303