Galaxies & Objects in the Universe

1. Galaxies & Objects in the Universe State Correlation 4e and 4f

2. Part A: The Earth’s Motion and Seasons

3. Earth’s Motion and Seasons • A. Motions of the Earth • 1. Axis- the imaginary line drawn from the north geographic pole through the Earth to the south geographic pole • 2. Rotation- the spinning of the Earth on its Axis; Causes day and night. • What do you think: What would happen if the earth stopped rotating?

4. Earth’s Motion and Seasons • 3. Revolution- the motion of Earth traveling around the sun • a. Earth’s revolution causes seasons. • b. Earth’s elliptical path around the sun is called an orbit.

5. Earth’s Motion and Seasons • 4. Solstices and Equinoxes • a. Because the Earth’s axis forms a 23.5 degree angle, the Sun’s position relative to the equator constantly changes. • Because of this daylight hours are longer for the hemisphere that is tilted towards the sun, and the sun is higher in the sky for longer periods of time.

6. Earth’s Motion and Seasons • B. Summer and winter solstices- the longest and shortest days of the year; when the sun reaches its greatest distance north or south of the equator. • Directly above the Tropic of Cancer or the Tropic of Capricorn.

7. Earth’s Motion and Seasons- Summer Solstice

8. Earth’s Motion and Seasons- Winter Solstice

9. Earth’s Motion and Seasons • Summer Solstice (Longest Day) for the northern hemisphere is June 21 or 22 and December 21 or 22 for Southern Hemisphere • The opposite of this is Winter Solstice (Shortest Day)

10. Earth’s Motion and Seasons • c. Equinox- when the sun is directly above the equator • Length of day equals length of night all over the world. • In the northern hemisphere – • Spring (vernal) equinox is March 21 or 22 • Fall (autumnal) equinox is September 21 or 22

11. Earth’s Motion and Seasons- Equinox

12. Copy and Answer this Question • When you watch a sunset are you observing an effect of the Earth’s rotation or the Earth’s revolution? Draw this diagram in your notes

13. Click on the link below to view a video discussing how ancient cultures used the position of the sun to determine seasons, planting times, and other events. • http://sunearthday.nasa.gov/2011/multimedia/ancient_observatories.php

14. Part B: Stars, Galaxies, and The Universe

15. What do You Already Know? • Using a Circle Map: round – table what you know about the universe and galaxies • Share what you know in order to make a class circle map

16. Telescopes • Telescopes are instruments that allow us to view distant objects. • They use forms of energy in the electromagnetic spectrum to view these objects. • The electromagnetic spectrum includes radio waves, infrared waves, visible light, ultraviolet rays, X-rays and gamma rays.

17. How the Electromagnetic Spectrum Determines Celestial Bodies

18. Refracting Telescopes • Refracting telescopes use curved lensto gather and focus light. • This convex lens is a piece of transparent glass, curved so the middle is thicker than the edges. • See fig. 2 page 710 • Draw and label the refracting telescope. • Use a bubble map to describe a refracting telescope.

19. Reflecting Telescopes • The first reflecting telescope was built by Isaac Newton in 1668, • A reflecting telescope uses a curved mirror to collect and focus light • The larger the mirror, the more light the telescope can collect. • The largest telescopes are reflecting telescopes. • Draw and label the reflecting telescope in fig. 2 page 710.

20. Radio Telescopes • Devices used to detect radio waves from objects in space. • Most have curved, reflective surfaces that focus radio waves the way reflecting telescopes focus light. • The larger the radio telescope the more radio waves it can collect. • Other types of telescopes collect the shorter waves such as gamma rays, X-rays, and ultraviolet rays.

21. Group Time Mexico City at Night • The light from street lights, businesses, and signs make it difficult to objects in the night sky. This is known as light pollution. • Round table brainstorm how our community could develop a plan to reduce light pollution. What can we do within our own communities to help? New York City skyline Owachomo Bridge in Utah's Natural Bridges National Monument- one of the few clear night views left

22. Observatories • A building that contains one or more telescopes. • However, some observatories are located in space. • One of the best observatory sites on Earth is on the top of Mauna Kea, a dormant volcano, on the Island of Hawaii.

23. Advanced Telescopes • Many large optical telescopes are equipped with systems that improve the quality of their images. • Some are equipped with computers for automatic adjustments, and lasers

24. Telescopes in Space • The Hubble Telescope is a reflecting telescope with a mirror 2.4 meters in diameter. • Because it orbits Earth above the atmosphere, it can produce very detailed images. • Hubble images have changed how astronomers view the universe. • The most recent addition to NASA’s lineup of telescopes in space is the Spritzer Space Telescope launched in 2003. • It produces images in the infrared portion of the spectrum.

25. Images from the Hubble Telescope

26. Measurement in Space • Parallax: apparent shift in the position of an object when view from two different locations • measures the distance of stars from earth that are relatively close • Light Years: Unit of measurement for large distances in space • Distance light travels in 1 year • Light travels 300,000 km/s or 9.5 trillion km /year • Proxima Centauri: closest star to earth • (4.3 light years away – 40 trillion km)

28. Size of the Planets and Stars • Click on the link below to see a comparison of the Sizes of the Planets, the Stars, and the Galaxies • http://www.cleanvideosearch.com/media/action/yt/watch?v=HEheh1BH34Q

29. Proxima Centauri Video

30. Nebulae • Large cloud of gas, plasma & dust within a galaxy • Typically a few light-years wide • Two types: • Diffuse nebulae • Planetary Nebulae

31. Diffuse nebula • Gas & dust particles are spread out and irregular • Provides the raw materials that will form new stars • A star is born by fusion of hydrogen at 10 million K

32. Planetary Nebula • Forms when a star dies and throws off some of its outer material to form a cloud of gas, dust, & plasma • Does not contain enough material to create a new star.

33. Group Time Use a double-bubble map to compare and contrast planetary & diffuse nebulae

34. Life Cycle of Stars Video

35. Life Cycle of a Star • Main Sequence Star: hydrogen fueled star • Makes up about 90% of stars • Our sun is a main sequence • Two types • Low mass – remains a main sequence star longer and are smaller in size • High mass – goes through main sequence much faster and are much larger in size

36. Life Cycle of a Low mass Star • Giants: fueled by helium from a low mass star • Outer layers Cool & expands with a carbon core • Planetary nebula: occurs as the core collapses on itself & shells of gas are thrown outward • White dwarf: outer layer of gases escapes into space, core contracts leaving a hot dense small star

37. Life Cycle of a High mass Star • Super Giant: Fueled by helium from a high mass star • Outer layers cool & expands with an iron core • Super Nova: iron core collapses and the star explodes • Neutron star: collapsed core of super giant with extremely high density • Black Hole: tremendously big supernova that collapses to a point of no volume

38. Neutron Stars and Black Holes

39. Relative size of stars

40. The Color of Stars

41. Show Video “The Color of Stars” Hertzsprung-Russell diagram (H-R):

42. Brightness of Stars-Apparent Brightness • Apparent Brightness- How bright a star seems as seen from Earth. • But can’t be used to tell how much light a star actually gives off. • Just as a flashlight looks brighter the closer it is to you- a star will look brighter the closer it is to Earth. • Our sun looks bright just because it is close

43. Brightness of Stars-Absolute Brightness • Absolute Brightness- the brightness the star would have if it were a standard distance from Earth • The brightness of stars can vary tremendously. The brightest stars are more than a billion times brighter than the dimmest stars!

44. Use a flow chart to show the cycle of a star linguistically and non-linguistically based on the information in the notes. Round-table

45. Galaxies Huge collection of stars, gas, & dust Galactic Cluster is a group of gravitationally bound galaxies--- They are the largest gravitationally bound celestial bodies in the universe

46. Three Types of Galaxies • Elliptical • Spiral • Irregular

47. Elliptical • Range from spherical to elliptical • No typical size or brightness • Contains old cool red stars & small amounts of gas & dust, so no new stars are forming • Most common type • Ex. Maffei 1 Follow this Link

48. Spiral • Spiral: stars arranged in two or more spiral arms • Ex. Milky Way & Andromeda • New blue stars form in arms • Center is often bulging disk of older red stars • Barred Spiral: sub-group with a vast straight bar of stars lying across the center with a spiral arm at the end of each bar

49. Irregular • lack regular pattern & shape, and are small & faint • Two types: colliding & gravitational interaction distorting the shape • Mixture of young & old stars with lots of gas & dust for new star formation • Ex. Clouds of Magellan

50. Group Time Use a tree map to categorize types of galaxies Round Table