1. Astronomy Chapter 1 Charting the Universe

2. Obj.#1 What is Astronomy? Astronomy is the study of the Universe The universe is the total of all space, time, matter, and energy The universe is made up of galaxies

3. Our Galaxy …The Milky Way

4. Galaxy NGC 300

5. Light year- distance traveled by liht in one year Light years are used to measure the universe The speed of light is 186,000 per second

6. Obj. #2 What is a constellation? Humans made patterns of stars that they saw in the sky These patterns are by chance. Humans can see around 6,000 stars with the naked eye

7. The Big Dipper

8. Obj. 3 Describe the Celestial Sphere The celestial sphere is an imaginary sphere that surrounds Earth. The stars and planets appear to be attached to the sphere It is used to help locate stars and planets

9. Important parts of the celestial sphere North Celestial pole- directly over the north pole South Celestial pole- directly over the south pole Celestial equator- circle half way between the North and South Celestial Sphere

10. Celestial Sphere

11. Declination- angular degrees above and below the equator- ( similar to latitude line on an Earth globe) Vernal Equinox is the 0 point on the celestial equator line Right Ascension- measured in hours and measures distances eastward of the Vernal Equinox

12. Declination lines

13. Lines of Ascension

14. Zenith- Where ever you are located…the point directly over your head on the celestial sphere

15. Zenith

16. Obj. 4: Distinguish between a Solar Day and a Sidereal Day Solar Day- basic time unit of 24 hours that it takes the Earth to rotate on its axis Sidereal Day- a day measured with respect to the stars. It is 23 hours and 56 minutes

17. Solar and Sidereal Day

18. Obj. #5: Explain what causes seasonal changes Elliptic Plane is the Earth’s orbit around the Sun Summer Solstice- the point where the Earth’s North pole is pointed at the Sun Occurs on June 21…longest day of the year

19. Winter Solstice- shortest day of the year South pole faces the Sun Equinoxes- when the light during the day and night are equal

20. Reason for the Seasons The Earth is tilted at 23.5 degrees all year long. Sunlight strikes the Earth’s surface at different angles during the year causing the changes in the season. We are not closer to the sun in the summer!!!

21. Reason for the Seasons

22. Obj. 6: Describe precession Precession is the change of the Earth’s cycle over time. One complete cycle takes 26,000 years to complete

24. Objective 7: Explain the Phases of the Moon The Sun always lights half of the moon. What part of that light we see from Earth depends on where the Moon is located as it travels around Earth.

25. Phases of the Moon 1.New Moon- the near side of the moon faces away from the sun making observers on Earth see the dark side. 2.Waxing Crescent- this means that the right side is brighter and appears to be making a crescent.

26. New Moon

27. Waxing Crescent

28. 3.Quarter Moon- at this stage one would be one-half of the moon. Light is on the right. 4.Waxing Gibbous Moon- when the quarter moon begins to grow…almost full 5.Full moon-occurs two weeks after new moon.

29. Quarter Moon

30. Waxing Gibbous

31. Full Moon

32. 6.Waning Gibbous- when the light begins to shrink. 7.Third quarter moon- moon with ½ light on the left side 8.Waning Crecent- has a crescent on the left side.

33. Waning Gibbous Moon

34. 3 rd Quarter Moon

36. Phases of the Moon

37. Obj. # 8 Describe a lunar and solar eclipse Lunar eclipse-occurs when the Earth is directly between the Sun and Moon. Earth’s shadow falls on the moon. Solar eclipse- occurs when the moon is directly between the Sun and the Earth. The Moon blocks sunlight from hitting Earth.

38. Lunar Eclipse

39. Solar Eclipse