1. The Sun and Other Stars & Rotation and Revolution
Unit 8
Lessons 1 & 2

2. VOCABULARY
Star – an object in space that produces its own energy, including heat and light
Astronomical unit – the mean, or average, distance between the Sun and Earth
Solar flares – occasional eruptions of energy from the Sun’s surface

3. Constellation – any of the patterns that are formed by a group of stars in the night sky
Solar system – a star and the objects that orbit it
Aurora borealis – also know as the northern lights; energy from solar flares causes a display of different colored lights in the Earth’s atmosphere

4. Solar wind – a fast moving stream of particle thrown into space by solar flares
Polaris – the North Star; it will always be directly north of your location
Magnitude – the brightness of a star

5. Absolute magnitude – a star’s actual brightness
Apparent magnitude – how bright a star looks in Earth’s night sky
Gravity – the force of attraction between any two objects due to their mass
Orbit – the path one object takes as it travels around another object

6. Inertia – the tendency of a moving object to keep moving and an object at rest to stay at rest
Rotation – a complete spin on an axis; the spinning of Earth on its axis
Revolution – one complete trip on a closed path of one object around another object; this is the movement that Earth does around the sun

7. Universe – everything that exists – planets, stars, dust, gases, and energy
Galaxy – a group of stars, gas, and dust
Light year – the distance light travels in one Earth year; 9.5 trillion km

8. 20. What are the layers of the Sun?
Radiation layer
next to the core
Moves the energy produced in the core in every direction
It can take millions of years for energy to move out of this layer

9. Core Most of the energy that the Sun produces is formed in its core
At its core, the Sun has a temperature of 10 million to 20 million degrees Celsius (18 million to 36 million degrees Fahrenheit)

10. Convection layer
Gases with different energies move in circles in a way similar to air with different densities
Energy moves out of this layer in about a week

11. Photosphere the visible surface of the Sun
It is not a solid surface, but a layer of gases
It is cooler that the core

12. Chromosphere The second layer
It is the inner layer of the Sun’s atmosphere
When it can be seen, it looks like a red circle around the Sun

13. Corona The outermost layer of the Sun’s atmosphere
It takes on different shapes around the Sun depending on changes in the temperature of the photosphere

14. 21. Facts about the Sun
The Sun is an average sized and temperature star
The largest object in the solar system
The Sun’s diameter is about 1,390,000 km or 863,706 miles
The Sun is a huge sphere made up mostly of two very light gases, hydrogen and helium

15. The Earth makes this trip in one year, or in 365 ¼ days
Solar Energy, the energy generated by the sun. This energy is in the form of electromagnetic radiation and travels to the earth in waves of various lengths.
The Earth makes this trip in one year, or in 365 ¼ days
The Sun produces two types of energy
Thermal energy, Light energy

16. The mass of the Sun makes up 99
The mass of the Sun makes up 99.8 percent of all the mass in the solar system.

17. 22. Why does the Sun appear much larger than other stars?
The Sun looks larger because it is much closer to Earth

18. 23. Why are the planets not stars?
Planets do not produce their own light

19. 24. Where in the Sun is energy produced?
In the core

20. 25. Why is it harmful to our eyes to look directly at the Sun?
The Sun emits powerful energy in the form of radiation, which can be damaging to our eyes

21. 26. Why did ancient cultures group stars into constellations?
Constellations can help provide a point of reference

22. 27. How were constellations used in the past?
If Polaris can be found or some other recognizable star whose direction was known, they would follow that star while you travel

23. 28. Why do astronomers today still use constellation?
They give us reference points for finding objects in the night sky

24. 29. What two constellations point to Polaris?
The Big dipper and the Little Dipper point to Polaris, the North Star

25. 30. What does a star’s color tell you?
A star’s color tells you about its surface temperature.
Red and orange colors indicate cooler stars
Yellow indicates hotter stars
Blue white indicates the hottest stars

26. 31. Why do some stars appear brighter than another?
Stars appear less bright the farther they are from Earth

27. 32. What does the strength of the pull of gravity depend on?
The strength of the pull of gravity is affected by the total mass of the two objects and by the distances between them.
The pull of gravity decreases when the total mass of the two objects decreases and when the objects are farther apart

28. 33. Why does an astronaut weigh less on the moon than on Earth?
The Moon has less mass than Earth and therefore the pull of gravity is not as strong.

29. 34. In what direction would the planets travel if the Sun suddenly disappeared?
Without the Sun’s gravity pulling the planets inward, the planets would fly off into space in a straight line from their position in their orbit.

30. 35. What two things make Earth follow its path?
As Earth orbits the Sun, it is pulled toward the Sun because of gravity.
At the same time, Earth’s inertia makes it move away from the Sun.

31. 36. What is the type of path does the Earth take?
As a result of the effects of gravity and inertia, Earth moves in a nearly circular orbit called and ellipse.

32. 37. Which movement causes day and night?
Earth’s rotation on its axis

33. 38. In which direction does Earth rotate?
Earth rotates from west to east

34. 39. Why does the Sun appear to rise in the east and set in the west?
As Earth rotates from west to east, objects in the sky such as the Sun, Moon and stars all appear to move in the direction opposite Earth’s movement

35. 40. What is standard time zone?
A standard time zone is a vertical belt, about 15 degrees wide in longitude, in which all locations have the same time.

36. 41. How many time zones are there in the U.S.?
The U.S. states have 6 time zones.

37. 42. List the 6 time zones Alaska Standard Time (AST)
Hawaii-Aleutian Standard Time (HAST)
Pacific Standard Time (PST)
Mountain Standard Time (MST)
Central Standard Time (CST)
Eastern Standard Time (EST)

38. 43. What would happen if you traveled west across the International Date Line?
West of the International Date Line it is 1 calendar day later than it is in places east of the line

39. 44. Why do the constellations seem to move across the night sky?
The constellations appear to move across the sky because Earth is rotating on its axis

40. 45. Why do many of the constellations seem to change from season to season?
As Earth revolves around the Sun, different constellations become visible on the night side of Earth while others become hidden in the glare of the Sun

41. 46. What causes Earth’s seasons to change?
As Earth revolves around the Sun, sunlight strikes different parts of Earth at different angles.

42. 47. Which star can help you find your way when you are lost?
Polaris, the North Star

43. 48. How did ancient cultures use constellations?
Constellations were used as seasonal calendars and for navigation.

44. 49. A pattern of stars in the night sky is called a….
Constellation.