Unit 7 Astronomy

1. Name:______________________ Period:____ Unit 7Astronomy

2. Focus Questions ___1. How and why do stars move through our sky? ___2. Explain the apparent motion of the Sun through our sky? How does the path of the Sun change throughout the year? ___3. Why do we have seasons? ___4. How does latitude and the angle of the Sun affect daylight hours? ___5. Explain why we see the Moon’s phases?

3. ___6. Explain what happens during a lunar and solar eclipse? ___7. Why do we have tides? ___8. What is the true shape of an orbit and what are the parts of an orbit? What is the equation to measure an orbit’s eccentricity? ___9. Explain what the HR diagram is used for? Explain our Sun’s properties by using the HR diagram. ___10. Describe galaxies and what theory is used to describe the formation of the universe? How can we tell if celestial objects are moving towards or away from us?

4. A. Celestial Observations celestial • The objects in the sky collectively are called ____________________ • _____________________ • --They include ____________________________________ • --They appear to move in the sky ______________________ • --The path they appear to take is in the shape of _______________ objects The Sun, planets, moons, stars, etc. From East to West An arc Celestial Sphere 2

5. All objects in the night sky appear to travel in a set path around ____________which is located almost directly over the North Pole of Earth. Polaris

6. Many of the stars form specific patterns, or ________________. Some of these never go below the horizon in New York State. Instead, they appear to circle Polaris over the course of a night. constellations This is about a ten hour time exposure of the northern sky. The arcs are the paths of the stars circling the North Star (Polaris) in the center. These stars can be seen year-round in the northern sky although their exact location each night will vary throughout the year. Orion 3

7. Other stars appear to move throughout the night from east to west. These are trails of stars that are further to the south in our night sky. Their trails appear almost straight. The constellations and the stars that make them up also appear in different locations throughout the year.

8. All celestial objects appear to move at a rate of 15 degrees per hour. (From horizon to horizon is about 180 degrees.) Why do these objects appear to move at a rate of 15 degrees per hour? _______________________________________________________ Because Earth rotates 15 degrees per hour We call this motion the _________________________________ Apparent daily motion • Apparent Solar Day: _________________________________ • _________________________________________ How long it takes the Sun to move through our sky. 5

9. Terrestrial Observations • There are two main motions of Earth: • Revolution: ___________________________________________ • ____________________________________________ The motion of one object around another object.  The planets revolve around the Sun.  Moons and satellites revolve around planets. Evidence: Different constellations appear in our night sky at different times of the year.

10. The spinning of an object on its axis. Earth rotates once every 24hrs. • Rotation: __________________________________________ • ____________________ • Evidence: • Foucault’s Pendulum: • _____________________________ • _____________________________ • _____________________________ • _____________________________ • _______________________ ______ A mass suspended from a wire at a single point.  When set in motion, its apparent change in position is the result of the rotation of the Earth. 7

11. Coriolis Effect: • ______________________________ • ______________________________ • ______________________________ • ______________________________ • ______________________________ The deflection of a an object that is moving above the Earth’s surface.  In the Northern Hemisphere, the Coriolis effect causes moving objects to be deflected to their right, while in the Southern Hemisphere, the deflection is to the object's left.

12. Apparent Motion of the Sun: It changes with the seasons and latitude due to: ________________________ Earth does not lie directly straight up and down, it is tilted _____________ Earth’s Tilt 23 ½ degrees 9

14. The Sun rises N of due East and sets N of due West. The noon Sun is highest in the sky Summer: __________________ __________________________ __________________________ ___________ but the sun is NEVER directly overhead for us! Because the path of the sun is longest in the summer, days are longest. 10

15. Occurs approx. on June 21st Summer Solstice: _____________________________ ___________________________________________ The Sun rises S of due East and sets S of due West. The noon Sun is lowest in the sky Winter: _____________________________________ ___________________________________________ Occurs approx. on December 22nd. Winter Solstice: ______________________________ ___________________________________________

16. Spring and Fall: ______________ ______________ ______________ ______________ The Sun rises due East and sets due West. The noon Sun is at approx. 48 degrees. Vernal Equinox: Approx. March 21st Autumnal Equinox: ______________ Approx. September 22nd Equinoxes At the _______________, day and night are 12 hours long everywhere on Earth. Latitude: The closer you are to the poles, the lower the noon time sun and the greater the difference between the winter and summer length of daylight. At the equator, day and night are 12 hours long all year. Important Note: We do not have summer in June because we are closer to the sun. We are actually closest to the sun in December, the beginning of winter. 11

17. Tropics of Cancer and Capricorn: 23.5o north and south latitude. Mark the furthest north and south travel of the direct rays of the sun. Sun is directly over the Tropic of Cancer on June 21st and the Tropic of Capricorn on December 21st. 12

18. Sun’s apparent path for four different observers on June 21st. Notice how the path and position of the noontime sun change for each location.

19. Because the sun is higher in the sky in the summer, the rays of the sun shine down at a more direct angle.

20. The length of shadows cast by a stick are also affected by the height of the sun. In the summer, the sun is high in the sky, so the shadows it casts are ______. Shadows cast in spring and fall are __________. In the winter, the sun is very low in the sky, so the shadow it casts is very ____. short longer long

22. C. Geometry of Orbits • Terms • A. Revolution: __________________________ • B. Orbit:_______________________________ • 1. Example: __________________________ • 2. Ellipse: ___________________________ • __________________________________________ • 3. Focus (foci): _______________________ The motion of one object around another object.  Path of movement of a satellite around its primary body. The moon around the Earth. Shape of planet’s orbits around the Sun (flattened or squashed circle). 13

23. Ratio of focal length to length of major axis of an ellipse.  (How flat an ellipse is) • Eccentricity: ___________________________ • _________________________________________ • Formula: • ____________ • ____________ • ____________ • ____________ • ____________ • Period: _________________________________ • __________________________________________ E=d/L 14

24. II. Force and Energy A. Gravity: __________________________ ________________________________________ B. Inertia: ___________________________ ________________________________________ C. Energy and Orbits 1. At perihelion: ____________________ ________________________________________ ________________________________________ 2. At aphelion: _____________________ ________________________________________ ________________________________________ The force that keeps all satellites moving inward in their curved orbits. The tendency of an object in motion to continue in motion in a straight path. Earth is closest to the Sun; pull of gravity is greatest Earth is furthest from the Sun; pull of gravity is weaker 15

25. III. Orbits and Johannes Kepler A. Orbital Velocity: _____________________ B. Earth’s Orbit 1. perihelion: ________________________ _________________________________________ 2. aphelion: _________________________ _________________________________________ Speed of orbiting object Earth is moving the fastest Earth is moving the slowest 16

26. Kepler’s Laws of Planetary Motion • -Johannes Kepler, a German astronomer during the late 1500’s to early 1600’s, developed three laws of motion of objects in the sky to help better explain and predict their motions. Before Kepler, most astronomers agreed that planetary orbits were circular. • 1. Elliptical Orbits: ______________________ • _________________________________________ • 2. Equal Areas: _________________________ • _________________________________________ The orbits of the planets are ellipses, with the Sun at one focus of the ellipse. The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse. 17

27. ________ Inertia Gravity _________ Orbit Note that as the orbiting body gets closer to the object it is orbiting, the pull of gravity becomes stronger. Therefore, its forward speed must also be greater to compensate. 18

28. the period for a planet to orbit the Sun increases rapidly with the radius of its orbit 3. Harmonic Motion: a. Astronomical Unit: ____________________ _________________________________________ The distance between the Earth and the Sun; 93 million miles. 19

29. D. Satellite Motions Earth’s natural satellite • The Moon: ____________________________ • A. Orbit _____________________________ • _________________________________________ • 1. Sidereal month: ___________________ • _________________________________________ • _________________________________________ • 2. Synodic (lunar) month: _____________ • _________________________________________ • _________________________________________ The moon revolves in its orbit at the same rate that it rotates The moon takes 27 days to complete one revolution around Earth. The moon’s phases take about 29 ½ days to go through one cylce. 20

30. (27 1/3 days) One synodic month later (29 ½ days) 21

31. The apparent change in the shape of the moon caused by the changing positions of Earth, the Sun, and the Moon. • Phases: ________________________________ • __________________________________________ • __________________________________________ • C. Phases change from: ____________ Waxing to Waning 22

34. New Moon New Crescent First Quarter Old Gibbous New Gibbous Full Moon Old Crescent Third Quarter

35. D. Because of the moon orbiting Earth, each day the moon rises over the eastern horizon ______________ ___________. in a different spot E. As a result, if you look at the moon two consecutive nights, the moon is farther ________ the second night and each night thereafter. East Day 1

36. The twice-daily rise and fall of the oceans due to the gravitational attraction of the moon and the Sun. • Tides: _________________________________ • __________________________________________ • __________________________________________ • 1. High and Low: ________________________ • __________________________________________ • 2. Normal: ______________________________ • __________________________________________ • NOTE: Even though the sun is much larger, the • moon is much closer so the primary force pulling on • the tides is the moon. 2 highs and 2 lows per day, every 6 hours Normal tidal change is less than 3 feet 23

37. Highest high tides and lowest low tides, moon phase is near full and new. • Spring:_________________________________ • __________________________________________ • Neap: __________________________________ • __________________________________________ Smallest change between high and low tides, moon is in the quarter phases. 24

38. The partial or complete obscuring (hiding) of one celestial body by another. • Eclipses: ________________________________ • __________________________________________ • 1. Shadow Geometry • a. umbra: ____________________________ • b. penumbra: _________________________ • __________________________________________ Inner, darker part Outer, lighter part 25

39. when sun "gets dark" because the moon blocks sunlight from reaching the Earth. Solar Eclipses happen during a New Moon. • Solar Eclipse: __________________________ • ________________________________________ • a. total: ______________________________ • b. partial: ____________________________ • c. annular: ___________________________ • _______________________________________ When the entire Sun is blocked out by the moon When some of the Sun is blocked out When the moon is further away from the Earth and you see an orange ring around the moon. 26

41. Lunar: _________________________________ • __________________________________________ • a. total: ________________________________ • __________________________________________ • b. partial: ______________________________ • __________________________________________ When the full moon moves into Earth’s shadow. When the moon is closer to Earth and the Earth’s shadow completely covers it. When the moon is further from Earth and the Earth’s shadow partially covers it. NOTE: Lunar eclipse does not occur during every full moon because the plane of the moon’s orbit is slightly off from Earth’s. 27

43. E. The Solar System A star and it’s surrounding planets. • Solar System: __________________________ • A. Models • 1. Geocentric: _________________________ • _________________________________________ • epicycle: ___________________________ • _________________________________________ • Retrograde Motion: ___________________ Model of the solar system with the Earth at the center. The planets revolve around the Sun in circular orbits called epicycles. 28

44. Geocentric Model of the Solar System Problem:_____________________________ ____________________________________ Did not explain the Focault Pendulum and the Coriolis Effect 29

45. First Heliocentric: _______________________ • _________________________________________ Had circular orbits. Did not explain the changing size of the Sun. Problem: __________________________________ _________________________________________ Planets move in ellipses. • Revised Heliocentric: _____________________ • _________________________________________ • _________________________________________ 30

46. Objects • 1. Sun: __________________________________ • ____________________________________________ • a. sunspots: ___________________________ • ___________________________________________ • b. flares/prominences: ___________________ • ____________________________________________ A star that is the basis of the solar system and that sustains life on Earth, being the source of heat and light. Dark, irregular spots that are cooler than the surrounding areas on the Sun. a brief powerful eruption of particles and intense electromagnetic radiation from the sun's surface 10,000-27 mil. Degrees F 31

47. A celestial body moving in an elliptical orbit around a star. 2. Planets: _______________________________ a. Terrestrial: __________________________ ____________________________________________ b. Jovian: _____________________________ ____________________________________________ 3. Asteroids: ______________________________ ____________________________________________ Small, inner planets made up of mostly solid rock; high density Large, outer planets made up of mostly gases; low density. A small rocky body orbiting the sun. Large numbers of these are found between the orbits of Mars and Jupiter

48. 32 Earth Sun Comet • Objects (cont.) • 4. Meteors: ____________________________ • _________________________________________ • _________________________________________ • _________________________________________ • 5. Comets: • _________________________________________ • _________________________________________ • _________________________________________ A meteoroid is a sand- to boulder-sized particle of debris in the Solar System. The visible path of a meteoroid that enters Earth'satmosphere is called a meteor, or a shooting star. If a meteoroid reaches the ground then it is called a meteorite. They are a mixture of ices (both water and frozen gases) and dust, “dirty snowballs”

49. F. The Universe • Parts of the Universe • A. Stars: ______________________________ • __________________________________________ • 1. Energy: __________________________ • _________________________________________ • 2. Composition: _____________________ • _________________________________________ • a. spectrum: _______________________ • _________________________________________ • b. spectroscope: ____________________ • __________________________________________ Objects in space that emit their own light. Stars create their energy through the process of nuclear fusion. stars are big exploding balls of gas, mostly hydrogen and helium. Pattern of lines that show the chemical makeup of a star. breaks down the light emitted or absorbed by chemical elements into specific lines of color. 33

50. Cloud of gas and dust where new stars are born. Nebula: ______________________________________ _____________________________________________ Star Life Cycle: Stars are like humans. They are born, live and then die.: