Unit 11, Chapter 30

1. Unit 11, Chapter 30 Integrated Science

2. Unit Eleven: Astronomy Chapter 30 What is Astronomy? • 30.1 Cycles on Earth • 30.2 Tools of Astronomy

3. Chapter 30 Learning Goals • Relate keeping track of time to astronomical cycles. • Predict how the moon will appear based on its orbital position. • Describe what causes the seasons. • Describe what causes eclipses. • Convert large numbers to scientific notation. • Name the differences between stars, planets, galaxies, and the universe. • Convert between kilometers and light years. • Explain how refracting and reflecting telescopes work. • Name some telescopes that examine other types of electromagnetic waves. • Describe how satellites, space probes, and piloted spacecraft are used in astronomy.

4. axis calendar galaxy light year lunar eclipse planet reflecting telescope refracting telescope revolution Chapter 30 Vocabulary Terms • rotation • satellite • scientific notation • solar eclipse • star • telescope • universe

5. Key Question: How do we keep track of time? 30.1 Cycles on Earth *Read text section 30.1 AFTER Investigation 30.1

7. 30.1 Cycles on Earth • A calendar is a means of keeping track of all the days in a year. • The development of a calendar came from a need to be able to predict the seasons, annual floods, and other cyclical occurrences in communities’ lives.

8. The moon moves around Earth in a path called an orbit. How the moon appears to Earth dwellers at different positions in its orbit is shown below: 30.1 Phases of the Moon

9. The phases of the moon occur because of the positions of Earth, the moon, and the sun.

10. Earth’s axis is the imaginary line that passes through its center and connects the North and South poles. Earth’s spinning on its axis is called rotation and it brings about day and night. 30.1 Cycles on Earth

11. The movement of one object around another in space is called revolution. Earth’s path as it revolves around the sun is called its orbit. One year (365.25 days)is the amount of time it takes Earth to complete one revolution around the sun. 30.1 Cycles on Earth

12. What causes seasons?

14. The closest star to our sun, Alpha Centauri, is 41,000,000,000,000 kilometers away. Trying to write out astronomical distances requires a lot of zeros. Scientific notation is a mathematical abbreviation for writing very large (or very small) numbers. 30.2 Tools of Astronomy

15. The universe is defined as everything that exists, including all matter and energy. A star is a sphere of gas that undergoes a process called fusion. This process releases so much energy, the star gives off very bright light. A planet is a large, spherical piece of matter that revolves around a star. 30.2 Tools of Astronomy

16. 30.2 Tools of Astronomy • A light year is the distance light travels in one year through space (9.46 × 1012 kilometers). • ex. How many light years away is Alpha Centauri, the closest star to our sun? • Remember this star is 4.1 trillion km away... = 4.1 x 1013 km ? light years

17. 30.2 Tools of Astronomy 4.1 x 1013 km = ? light years light year 1 4.1 x 1013 km x 9.46 x 1012 km 4.3 = s

19. 30.2 Tools of Astronomy • A satellite is an object that travels in orbit around another object. • The Hubble Space Telescope (or HST) is a satellite that orbits Earth. This powerful telescope sends images from deep space to computers back on Earth.

20. 30.2 Tools of Astronomy • Space probesare unmanned spacecraft that carry scientific instruments on board.

21. 30.2 Tools of Astronomers • Space shuttlesare piloted spacecraft that launch from rocket “boosters” and can land back on Earth like an airplane. • A space shuttle consists of three big components: two solid rocket boosters (SRBs), an external fuel tank, and an orbiter.

22. Key Question: How does a telescope work? 30.2 Tools of Astronomy *Read text section 30.2 BEFORE Investigation 30.2