6th Grade The Universe and Its Stars

Transcription

1 Slide 1 / 120

2 Slide 2 / 120 6th Grade The Universe and Its Stars

3 Slide 3 / 120 Table of Contents: The Universe and Its Stars Click on the topic to go to that section Theoretical Beginning of the Universe / Big Bang Theory Galaxies Stars Black Holes and Supernovas

4 Slide 4 / 120 The Theoretical Beginning of the Universe / Big Bang Theory Return to Table of Contents

5 Slide 5 / 120 The Beginning... When most astronomers are asked how the Universe began, what do you believe they say is the answer? How long ago do we believe the Universe began?

6 Slide 6 / 120 The Beginning... You were correct if you said most will say the Universe began with the "Big Bang" which is an event said to have occurred about 14 billion years ago.

7 Slide 7 / Billion Years Ago A billion years is very hard for most people to understand. It is difficult to think of anything we can picture in terms of billions. Lets use an example to try and understand how many one billion is. With your group, try and decide what size jar you would need to hold 1 billion pennies hint: 1 billion = 1,000,000,000

8 Slide 8 / Billion Years Ago One billion stacked pennies would be the size of FIVE school buses! So if you wanted to represent 14 Billion pennies - how many school buses would you need? Image:

9 Slide 9 / 120 Big Bang Theory This theory states that all of the mass in the universe was once compacted into one small point thousands of times smaller than the head of a pin. How is that possible?

10 Slide 10 / 120 Big Bang Theory This one spot was also hotter and more dense than any object we know of today. It is believed our Universe began with a "Big Bang" when this small spot had a massive explosion.

11 Slide 11 / 120 Big Bang Theory During the fraction of a second following the explosion, the universe expanded rapidly. Think about what happens when you watch fireworks explode. The same thing happened after the Big Bang. Within a fraction of a second, the universe was bigger than a galaxy and has not stopped expanding since then. Expanding for 14 billion years. Think back to all 70 school buses!

12 Slide 12 / 120 Big Bang Theory You can also think of a stone hitting the surface of a pond. The water will ripple out from that one point and the ripples will expand larger and larger, much like the expansion of the universe.

13 Slide 13 / 120 Big Bang Theory This theory states that every piece of matter in the universe came from this one point... this one explosion. Since everything is made of matter, this means that the "stuff" that makes up everything in the universe came from this one point in time. Including you!

14 Slide 14 / The initial explosion that resulted in the creation and expansion of the universe is known as the. A B C D Big Bang Theory Milky Way Great Expansion Doppler Effect

15 Slide 15 / Following the Big Bang, the universe: A expanded and then rapidly stopped expanding. B expanded and has not stopped expanding since. C rapidly expanded and then shrunk back to its original size.

16 Slide 16 / Scientists believe the Big Bang happened: A 14 million years ago B 14 trillion years ago C 14 billion years ago D within the last 3000 years

17 Slide 17 / 120 Evidence Supporting the Big Bang Theory No people were around 14 billion years ago. So how did this theory come about? In the early 1900's, an astronomer* named Edwin Hubble, discovered that various galaxies were spreading apart by examining the patterns he found when tracing their locations in the sky. (astronomer: a scientist who studies planets, stars, and galaxies)

18 Slide 18 / 120 Evidence Supporting the Big Bang Theory Last year, you learned it is possible to estimate the distance a star is from Earth by looking at its brightness. Hubble used a number of methods to estimate how far away each star is. But he did much more. He used the color of each star's light to determine which direction they are moving...and how fast.

19 Slide 19 / 120 Evidence Supporting the Big Bang Theory The redder the light, the faster away from us a star is moving. His astonishing conclusion is that almost all stars are moving away from one another as if there were a massive explosion long ago. Scientists estimate that this occurred 14 billion years ago.

20 Slide 20 / When looking at the night sky, the brighter stars are typically: A farther from Earth than the dimmer stars. B closer to Earth than the dimmer stars. C the same distance from Earth as all other stars D constantly moving closer to Earth

21 Slide 21 / Which best describes the Big Bang Theory? A The universe has always been the way it is today. B C D The universe began from a dying star The universe was created by a single explosion The universe is full of explosions, or "big bangs," that are making it expand

22 Slide 22 / 120 Inflation Theory While almost all scientists believe in some version of the Big Bang theory, that theory only explains that there was a rapid expansion, not what caused it. Inflation theory explains the explosion itself, and is gaining acceptance as new data is discovered every year. photo: NASA

23 Slide 23 / 120 "Flattening" the Universe Inflation is said to have "flattened" the universe and it is easy to misunderstand what this means. In order to understand this, talk with your group right now about what happens to your hands and feet when you spend a lot of time swimming in a pool. What do they look like?

24 Slide 24 / 120 "Flattening" the Universe In the early stages of inflation, as the universe was very rapidly expanding, it looked much like your fingers do when you spend too much time in the water. Wrinkled. Inflation filled in all those ridges and flattened the surface of the universe, making it smooth, the way fingers revert once out of the water.

25 Slide 25 / 120 Dark Matter The study of the universe is far from complete...there is much more to do. In recent years, the effect of dark matter was discovered. This invisible matter makes its presence known by its effect on the motion of the stars and galaxies. Right now the problem is no one knows what dark matter actually is. Click on the image above for a 1 minute explanation of dark matter.

26 Slide 26 / 120 Dark Matter Scientists are working hard to find out what dark matter is. Dark matter would slow the spreading of the universe the same way that a more massive Earth would stop a ball from flying as high. It's now estimated to make up 27% of the mass of the universe!

27 Slide 27 / 120 Dark Energy Counteracting the effect that dark matter has in slowing the universe's expansion, dark energy has been discovered...and is seen to be speeding up the expansion of the universe. While the expansion of nearby stars is slowing down...like a ball would if thrown straight up in the air, the expansion of the farthest stars is actually speeding up!

28 Slide 28 / 120 Dark Energy This amazed scientists as much as if you threw a baseball in the air and when it reached the top where it should stop, it suddenly started to go upwards faster. It doesn't seem to make sense! Needless to say, dark energy is also not well understood yet; there are a lot of theories.

29 Slide 29 / 120 Dark Matter and Dark Energy Dark energy and dark matter were unknown 20 years ago. Now, they are believed to make up 95% of the mass of the universe. Everything we thought was the universe (i.e. the stars, planets, gases,and galaxies) we now believe to be only 5% of the universe. This is said to be the golden age of cosmology, the study of the universe. It's amazing how much more is left to be discovered and explained.

30 Slide 30 / 120 Our Expanding Universe According to the expanding universe theory, the space in our universe will always continue to expand, as it always has since the Big Bang occurred. Stephen Hawking is one of the most famous physicists in the world today. He has researched and spoken on the expanding universe. Click here to hear Stephen Hawking talk about this idea, the expanding universe

31 Slide 31 / 120 Improving the Big Bang Theory Just like with many ideas in Science, there are people who are critical of the Big Bang. The idea that there was a "Big Bang" is a theory. This means that it can not completely be assumed to be fact, but it has not yet been proven wrong. (Scientists don't aim to prove theories are true, they try to prove theories are false!)

32 Slide 32 / 120 The Universe No matter your beliefs, scientists continue to hunt for evidence of the Big Bang Theory. Either way, our Universe (and the stuff within it!) is here today for us to study.

33 Slide 33 / In addition to gravity, is believed to hold galaxies together. A Dark Energy B Dark Matter C Solar Systems D Stars

34 Slide 34 / An idea which has not yet been proven to be true, but has also not been disproved is known as: A an understanding B an idea C a concept D a theory

35 Slide 35 / Scientists believe only five percent of the universe is comprised of: A dark energy B all known objects C dark matter D gravity

36 Slide 36 / It is currently theorized that dark speeds up the expansion of the universe and dark slows it down. A matter, energy B energy, matter C matter, gravity D energy, gravity

37 Slide 37 / The rapid expansion of the universe following the Big Bang is known as: A Flattening B System Creation C Inflation D Bang Expansion

38 Slide 38 / 120 Galaxies Return to Table of Contents

39 Slide 39 / 120 What is a Galaxy? A galaxy is a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction. When you look at the night sky, are you seeing the whole universe or just our galaxy?

40 Slide 40 / 120 What is a Galaxy? 9 12 The truth is, we cannot see any stars in our sky which are outside our own galaxy, the Milky Way! 6 3 When we look at our galaxy in the sky, we are looking at a cross section, like we were standing on the face of a clock at 3, looking across at 9!

41 Slide 41 / 120 What is a Galaxy? If you were to travel to the other side of the world, would you still see the galaxy? Would you see the same stars? Discuss this at your table and write your ideas below.

42 Slide 42 / 120 Galaxy v. Universe Some people may think that galaxy and universe can be used to mean the same thing. Image: NASA The truth is, our galaxy, the Milky Way, is one of about 1.7 Billion that can be found in the entire universe!

43 Slide 43 / Which term represents a larger area? A universe B galaxy C they are the same

44 Slide 44 / A system of stars, gas, and dust held together by gravity is known as a/an. A star system B galaxy C universe D attraction

45 Slide 45 / 120 "Gravitational Attraction" This phrase came up in the 1st slide on Galaxies... but what does it mean? First, let's talk about gravity. Gravity is the force which keeps us on Earth. We experience gravity everyday! Right now, come up with 3 ways you experience gravity. Write them below.

46 Slide 46 / 120 Gravity That definition works when you are younger... but we need to come up with a more correct definition for Gravity. Click on Sir Isaac Newton, who first wrote about the theory of gravity, to discover our more complete definition. Gravity is the force of attraction between any two bodies, based on their mass and the distance between them.

47 Slide 47 / 120 Gravity Lab This lab will have you examining what happens when gravity acts on various everyday objects! What would happen if these three objects were dropped from the same height at the same time?

48 Slide 48 / 120 Review Mass and Weight: Mass is the amount of matter (or "stuff") in an object. It is measured in grams, g. Generally speaking, the more mass an object has, the more it weighs. A paperclip has a mass of about 1 gram Keep in mind for later mass and weight are two different things!

49 Slide 49 / Which of the following would NOT be an example of the force of gravity? A B The moon orbits around Earth Earth revolves around the Sun C D A ball hit in the air comes down into the outfielder's glove All of the above are examples of gravity

50 Slide 50 / Mass can be best defined as: A B C D The weight of an object The amount of matter in an object The volume of an object The size of an object

51 Slide 51 / 120 Gravity This means that Gravity is more than just the force between you and Earth - it is the force between any two objects in the Universe. Right now, there is an attractive force between you and your desk! The force is so small though because you and your desk are very tiny (compared to the whole Universe that is!)

52 Slide 52 / 120 Gravity Gravity is the force that holds each galaxy together. Everything in a galaxy has a gravitational pull on the other objects around it. Image: NASA How large that force is depends on two things: the size of the objects and the distance between those objects.

53 Slide 53 / Which of the following would have the most gravity between them? A two ping pong balls 1 meter apart B two ping pong balls 2 meters apart C two bowling balls 1 meter apart D two bowling balls 2 meters apart

54 Slide 54 / There is gravity between you and the moon. True False

55 Slide 55 / There is gravity between the Milky Way Galaxy and other galaxies. True False

56 Slide 56 / 120 Center of the Galaxy Due to gravity, galaxies are always revolving.. but what are they spinning around? Scientists believe that at the center of each galaxy is something called a black hole. To the right is a simulated image of a black hole. In a few days, we will focus more on black holes!

57 Slide 57 / 120 Take a Tour of a Galaxy Click on this space shuttle to be brought on a tour of our neighbor, the Andromeda Galaxy. Image: NASA

58 Slide 58 / The stars at the center of M31 are and than the stars close to the outside. A larger, brighter B smaller, hotter C older, cooler D farther away, brighter

59 Slide 59 / Just like in our galaxy, the spiral arms of M31 contain gas and dust needed to make new generations of. A stars B planets C supernovas D comets

60 Slide 60 / The Swift telescope allows distant objects to be studied using both and visible light. A Radiant B Solar C Ultraviolet D X-ray

61 Slide 61 / 120 Light-years Light-years play a large role in answering our questions about the Universe - particularly when it has to do with size. When you're trying to figure out how big a galaxy is (like in the previous video) or how far away in space something is, scientists measure not with meters or miles, but rather by using light-years. A light-year is the distance a beam of light travels in one year.

62 Slide 62 / 120 Speed of Light A beam of light travels in a straight line at about 300 million meters per second. If you turn a flashlight on in space, the beam of light will go on forever at 300 million meters per second!

63 Slide 63 / 120 Speed of Light In one year, that beam of light would have traveled just under 10 trillion kilometers (or about 6 trillion miles). That is equivalent to traveling around Earth's equator over 240 million times. We call this distance one light-year.

64 Slide 64 / 120 Distance from Earth Remember the tour you just took of our closest neighbor galaxy, the Andromeda galaxy? Do you remember how far away it is from Earth? Once you have your guess, click on the light beam to find out

65 Slide 65 / A light-year is defined as: A The time it takes for light to travel from a flashlight to your eyes B The distance a beam of light can travel in a year C The time it takes for a beam of light to rotate around Earth one time (one yeaar) D The distance from one side of the Sun to the other

66 Slide 66 / If you shine a light out into deep space, what would best describe its motion? A B C D The light would eventually stop traveling after a given amount of time The light would bend on its own The light would not shine in space The light would continue on in a straight line as long as nothing was in its way

67 Slide 67 / The distance between the Milky Way and Andromeda galaxies is best described as: A 2.5 million light years B 25 light years C 2.5 light years D 1 light year

68 Slide 68 / When we look at Andromeda, the image we see through our telescopes is: A what the galaxy looks like today B what it looked at 2.5 million years ago C what it looks like a 2.5 light years away D unknown how old it is

69 Slide 69 / 120 Stars Return to Table of Contents

70 Slide 70 / 120 What Are Stars? Look up in the sky on any clear night and you can see a never-ending amount of small twinkling lights - we know them as stars. If you let your eyes adjust to the dark for about 20 minutes, you will notice something amazing. Some stars are bright.. some are dim.. some are blue.. some are yellow.. some are even red!

71 Slide 71 / 120 What Are Stars? Come up with ideas about each of the questions below at your table right now. What exactly are stars? What are they made of? How many stars are there? Why do they seem to move across the sky?

72 Slide 72 / 120 Stars We're used to drawing stars that look like this: Actually, stars don't look like this at all. Stars are massive balls of gas, like in this picture. We have already discussed what force holds stars together. Do you remember what it is called?

73 Slide 73 / 120 How Many Stars Are There? Scientists have an analogy which helps us imagine how many stars are in the universe. In order to understand it, we will have to imagine one star is the size of a grain of sand. Are you ready?

74 Slide 74 / 120 How Many Stars Are There? 1 star = 1 grain of sand One thimble of sand would hold the most stars you would possibly have seen had you been there on the darkest and clearest night in the history of Earth. A thimble isn't very big, is it?

75 Slide 75 / 120 How Many Stars Are There? 1 star = 1 grain of sand 1 thimble = all the stars we can see A wheelbarrow could hold every star in our Milky Way Galaxy. How many thimbles do you think it would take to fill that wheelbarrow? Even still, a wheelbarrow doesn't hold very much sand, does it?

76 Slide 76 / 120 How Many Stars Are There? 1 star = 1 grain of sand 1 thimble = all the stars we can see 1 wheelbarrow = Milky Way Galaxy To imagine the number of stars in the universe, we need a freight train carrying loads of sand. But you need to know something about this particular train..

77 Slide 77 / 120 How Many Stars Are There? We would need to watch this train pass by us very quickly - one car per second. In order to count the total number of stars (which remember are grains of sand), how long do you think you would you have to watch the train go by? Write your guess below.

78 Slide 78 / 120 How Many Stars Are There? We would have to watch this train pass by us (without stopping) for... Only then could we have seen a representation of how many stars are in the universe. Can you even imagine that number?

79 Slide 79 / 120 How Many Stars Are There? We probably don't even have a number large enough to count the number of stars in the entire universe! (Some astronomers give a rough estimate that there are stars, although this is always changing!) = 10,000,000,000,000,000,000,000 (Comparison: 1 billion = 10 9 = 1,000,000,000)

80 Slide 80 / What are stars? A chunks of debris that burn as they pass through our atmosphere B massive balls of gas C D celestial bodies that orbit the galaxy celestial bodies that orbit a planet

81 Slide 81 / What are stars made of? A glowing rock B dark matter C very hot gas D star dust

82 Slide 82 / How many stars are there? A B C 10 1 D 10 50

83 Slide 83 / 120 Brightness of Stars Why do some stars look brighter than others? There are a few factors that affect how luminous a star is, and how bright it looks to us here on Earth. We mentioned these earlier in the unit. Can you remember? Write your answers below.

84 Slide 84 / The further a star is from Earth, the it appears in the sky. A brighter B larger C dimmer D redder

85 Slide 85 / The increasing brightness indicates stars which are than others. A cooler B hotter C redder D older

86 Slide 86 / Large stars appear in the sky. A dim B yellow C larger than other stars D bright

87 Slide 87 / 120 Brightness of Stars Why do some stars look brighter than others? Temperature : Size: Distance from Earth: The the star, the brighter it is. The the star, the brighter it is. The the star, the brighter it is.

88 Slide 88 / 120 Brightness of Stars The Sun! What is the brightest star in our sky? Click to reveal!

89 Slide 89 / 120 The Sun The Sun is so important to us on Earth that we could not possibly survive without it. At your table, try and come up with 5 reasons the Sun is so important and write them below. Be ready to share your ideas so we can make a list together!

90 Slide 90 / 120 Our Most Important Star The Sun is responsible for giving off light and heat (energy). These two things play important roles in every food chain on Earth. The Sun also powers the water cycle on our planet! Another very important role the Sun plays is as the center of our Solar System - all the planets (including Earth) orbit the Sun.

91 Slide 91 / How long does it take Earth to make one full orbit around the sun? A 1 day B 1 month C 1 year D 1 century

92 Slide 92 / 120 The Energy of The Sun The surface of the sun is 10,000 degrees Fahrenheit. So how much radiant energy does the sun actually provide? A light bulb typically radiates between 40- and 100-watts. How many 60-watt light bulbs would it take to give off the same radiation (per meter) as the sun?

93 Slide 93 / 120 The Energy of The Sun The Sun provides 1,360 Watts per square meter. This means, an astronaut facing the sun (with a surface area of 0.85 square meters) would receive the energy equivalent to NINETEEN 60-watt lightbulbs!

94 Slide 94 / 120 The Sun The Sun is 93 million miles from Earth. The photons of light which leave the Sun, travel across the vacuum of space at the speed of light to reach our eyes. How long does it take for the light to reach Earth? Make a guess with your table. (Hint: the speed of light is about 186,000 miles per second)

95 Slide 95 / 120 The Sun If you did your calculation, you probably found it took about 500 seconds (8 minutes 20 seconds) for the light from the Sun to finally reach the Earth.

96 Slide 96 / 120 The Sun The Sun is a yellow dwarf star. This means that it is a relatively young star. The Sun is only about 4 billion years old. Compare that to the age of the universe. Can anyone recall how old the universe is? Yellow dwarf stars are also small compared to other older stars. In diameter, the Sun is only about 100 times larger than Earth.

97 Slide 97 / 120 Star Sizes

98 Slide 98 / The Sun is: A B C D the closest star to Earth the only star in our Solar System one of billions of stars in the Milky Way all of the above are true about the Sun

99 Slide 99 / 120 The Sun's Motion As the day goes by, what do you notice about the Sun in the sky? Click on the Sun image to watch an amazing time lapse video of the Sun's motion (and you will also see the moon rising as well!). Pay attention to how quickly the light fades once the Sun moves beyond the horizon.

100 Slide 100 / 120 Does the Sun Revolve Around the Earth? When astronomers first started to think about the stars above us, they believed that this motion of the Sun in the sky was because the Sun revolved around Earth. In fact, they believed that Earth was at the center of the Solar System, as seen to the right.

101 Slide 101 / 120 Heliocentric Model Copernicus This belief was challenged by an astronomer named Copernicus (left) who said that the Sun was the center of the solar system (heliocentric). This was later proven by a scientist named Galileo (right). Galileo We will spend more time on the motion of Earth in later units!

102 Slide 102 / Which best describes the heliocentric idea of Copernicus and Galileo? A The Sun revolves around Earth B Earth revolves around the Sun C D Earth and the Sun revolve around each other Both B and C are correct

103 Slide 103 / 120 Earth's Rotation and Revolution Right now Earth is moving in two different ways: Earth is rotating or spinning about on its axis (or center-line) Earth is also revolving or moving around the Sun

104 Slide 104 / Earth around the Sun. A Revolves B Rotates

105 Slide 105 / 120 Observing Earth's Rotation You can see Earth rotating from right here on the ground! Look up at the stars on any given night and notice their position.if you look up later that night, they will have appeared to have moved! Click the picture above to see this is action.

106 Slide 106 / 120 Observing Earth's Rotation The stars in the video appeared to be moving throughout the course of that night. This is due to Earth's rotation. Even though the stars seem to be moving, it is Earth that is moving! This photograph is also of the starry sky at night. How do you think the photographer took the picture?

107 Slide 107 / The rise and fall of the Sun each day is because of the of Earth. A Revolution B Rotation C Size D Gravity

108 Slide 108 / 120 Observing Earth's Revolution Earth's revolution is a little more difficult to identify, but you definitely have noticed its results during the year! Because of the tilt of Earth and its revolution around the Sun, the Sun appears to be at different heights throughout the year. Click on the animation below to learn about years.

109 Slide 109 / 120 Observing Earth's Revolution Equator Winter Summer Sun Summer Winter Equator The Sun appears to be higher in the sky during the Summer months and lower in the sky during the Winter months! We will be looking at how this affects our global temperatures in the next unit.

110 Slide 110 / 120 Observing the Sun from the ISS In May 2014, NASA Astronaut Rick Wiseman posted a Vine (a short time lapse video) from the International Space Station of the Sun in the sky. Click on the image and see if you notice anything unusual in the video. Can you or your group members come up with any explanation for this?

111 Slide 111 / 120 LAB: Earth's Motion - Interpreting Shadows The Apparent Motion of Stars We can use our shadows to tell us a little bit about the relationship between Earth and the Sun, or any other star for that matter. During the day, our shadows move as the Sun "moves" across the sky. During the course of the year, our shadows are affected by the height of the Sun in the sky.

112 Slide 112 / 120 Black Holes and Supernovas Return to Table of Contents

113 Slide 113 / 120 Black Holes Revisited Two sections ago, we learned about galaxies. At the center of each galaxy, we mentioned scientists believe there is a black hole. What exactly is a black hole?

114 Slide 114 / 120 Black Holes Black holes are objects that have an incredibly large mass and, therefore, have the strongest gravity of anything in the universe. They get their name "black" hole because not even light can escape its pull! This makes them colorless.

115 Slide 115 / 120 Black Holes The pull of gravity in a black hole works the same way as spiral wishing wells you may see at a museum. The closer objects (and light) gets to the black hole, the faster they rotate around it. Click on the image to see this in action!

116 Slide 116 / 120 LAB: Black Holes - Interactive Activity Click the image below to access the Black Holes Activity The Student Handout is provided on the NJCTL website For this activity, each student will need a computer with Internet access. If there are technological limitations, students may be grouped to complete this assignment.

117 Slide 117 / 120 Supernovas Simply put, supernovas are exploding stars. Just like humans and animals, stars have a lifespan. When a star reaches the end of its lifespan, it dies. Unlike humans and animals though, when it reaches this point, it explodes!

118 Slide 118 / 120 Supernovas The explosion of a star emits enough light to outshine a whole galaxy! (and remember how many stars are in a galaxy?) All the matter of the star is expelled at a large velocity. With your knowledge of galaxies and the universe, where do you think all the expelled matter from the star goes?

119 Slide 119 / Which best describes a supernova? A A star that is being "born" B A star that has absorbed another star C A star that has planets revolving around it D A star that has reached the end of its life

120 Slide 120 / A black hole got its name because not even can escape. A planets B galaxies C light D gravity