Big Bang Theory - Earth Science Unit 1 - PDF

Unit 1 The Origin of the Universe and the Solar System Table of Contents Table of Contents 1 Introduction 3 Essential...

Unit 1 The Origin of the Universe and the Solar System Table of Contents Table of Contents 1 Introduction 3 Essential Questions 4 Review 4 Lesson 1.1: Big Bang Theory 5 Objectives 5 Warm-Up 5 Learn about It 7 Key Points 11 Web Links 12 Check Your Understanding 12 Challenge Yourself 13 Lesson 1.2: Steady State Theory and Oscillating Universe Theory 15 Objectives 15 Warm-Up 16 Learn about It 17 Key Points 21 Web Links 21 Check Your Understanding 22 Challenge Yourself 23 Lesson 1.3: Nebular Theory 24 Objectives 24 Warm-Up 24 Learn about It 27 Key Points 31 Web Links 32  Check Your Understanding 32 Challenge Yourself 34 Lesson 1.4: Encounter Theory 35 Objectives 35 Warm-Up 35 Learn about It 36 Key Points 38 Web Links 39 Check Your Understanding 39 Challenge Yourself 40 Laboratory Activity 41 Performance Task 42 Self Check 44 Key Words 44 Wrap Up 46 Photo Credits 46 References 47 2 EARTH SCIENCE | GRADE 11/12 Unit 1 The Origin of the Universe and the Solar System Do you have little siblings, nephew, or niece at home? Have you noticed that these kids are very curious about the things around them? They have too many questions such as why is the sky blue, why do stars seem to twinkle, why are plants green, who made us, why do I need to sleep early, why aren’t there any more dinosaurs, why do people have varying features and so many more. These endless questions are so tiring to answer. You end up saying, "It is just because things work that way." How about if they started to ask you how the universe began, how would you answer? How can you explain to a kid the origin of the universe in a 'nutshell'? 3  Essential Questions At the end of this unit, you should be able to answer the following questions. What are the possible explanations of the origin of the universe? How do the proponents of different theories come up with their ideas of the origin of the universe? Are the theories widely accepted? Review When a wave (either a sound wave or electromagnetic wave) travels between two objects, the wavelength seems to change if one or both of them are moving. ○ The Doppler effect is the change in the wavelength (or frequency) of a wave when there is a motion that increases or decreases the distance between the receiver and the source. ○ Redshift occurs when electromagnetic waves shift to longer wavelengths (shift towards the red end of the spectrum when the source of the waves is moving away from the observer). In 1916, Albert Einstein proposed the theory of general relativity describing the concept of space-time as a fabric that can be stretched (a concept originated by Hermann Minkowski in 1908). ○ The concept of redshift describes that as space-time stretches, any photon that travels in space also stretches, increasing its wavelength. Therefore, the photons that travel from far away galaxies are stretched more, making larger redshifts as compared to photons from nearby galaxies. 4  Lesson 1.1: Big Bang Theory Objectives In this lesson, you should be able to: explain the origin of the universe according to the big bang theory; identify different proponents that support the big bang theory; and enumerate the negative implications of the big bang theory. Have you ever wondered how the universe began? Don’t worry, you are not alone. Most people seek to find the answer to this question. The good thing is, scientists are working hard to find accurate answers to these questions. There are various theories trying to explain the origin of the universe. The most common is the big bang theory. How did the big bang theory explain the origin of the universe? Warm-Up Big Bang Balloon Activity Materials: balloon permanent marker string ruler clothespin Procedure: 1. Partially inflate the balloon. Use the clothespin to clip the end so that the air will not escape. 2. Using a permanent marker, draw six widely spaced dots on the balloon. 5  Label one dot "H" which indicates home and the other dots A to E. 3. Since the balloon is curved, a string could be used first to measure the distance from "H" to each dot. Then, use a ruler to measure the length of the string. Record each distance on the initial measurement column on the table provided. 4. Remove the clothespin. Then, inflate the balloon again to make it bigger. 5. Observe what happens to the dots. Repeat step 3 but record the distances on the Trial 1 column on the table provided. 6. Repeat steps 4 and 5 two more times. Record your measurements under Trial 2 and 3 column. Data and Results: Distances (cm) Location H to A H to B H to C H to D H to E Initial measurement Trial 1 Trial 2 Trial 3 Guide Questions: 1. As the balloon gets bigger, what happens to the distances from the "H" dot to the other dots? 2. What dot(s) move(s) the farthest? Is it the dot near the "H" or the dot farther from "H"? 3. If the dots correspond to groups of stars and the balloons represent the universe, how will you explain the concept of expanding universe? 6  Learn about It The big bang theory is a cosmological model explaining how the universe began. It suggests that the universe started its expansion about 13.8 billion years ago. Overview of the Big Bang Theory Some might think of the concept of the big bang as an explosion of something leading to the creation of the universe. However, the idea of the big bang theory is somewhat similar to the bread-raisin model. The bread is compared to the universe while the raisins are the galaxies. As shown in Fig. 1, the raisin does not expand. It only moves apart as the dough rises. Fig. 1. The raisin-bread model of expanding universe. The bread-raisin model is similar to the universe. As shown in Fig. 2, the galaxies, represented by dots, are not expanding. Distances in relation to other galaxies just increase because of the expanding universe. Fig. 2. In the big bang theory, matter dilutes as the universe expands. 7 The big bang theory suggests that the universe started as a “singularity”—an area predicted to be in the core of a black hole with very high temperature and density. The nature of the singularity is still a mystery to many scientists, but they stated that this singularity constantly expands and cools. The rate of expansion is almost equal to the rate of cooling. The intense heat led to the formation of matter and antimatter particles that were destroyed every time they collided with each other. Nucleosynthesis is the formation of elements, such as hydrogen and helium. The presence of these elements led to the formation of the stars and the galaxies. The presence of the stars led to the formation of other cosmic bodies such as planets, comets, and asteroids. Fig. 3. Nucleosynthesis of helium. Proponents of the Big Bang Theory There are different proponents who suggested an explanation of this expanding universe. They are Georges Henri Joseph Edouard Lemaître, Edwin Powell Hubble, Arno Penzias, and Robert Wilson. 8 Georges Henri Joseph Edouard Lemaître Georges Henri Joseph Edouard Lemaître, a Belgian priest, suggested the idea of the expanding universe. He is considered the first proponent of the big bang theory. In 1931, during the British Association meeting, he explained that the universe originated in an explosive act of primeval atom or the ‘Cosmic egg’ which was like a huge atomic nucleus. The immense energy from the explosion of this primeval atom was sufficient to initiate the expansion of the universe. However, his theory was not recognized by most cosmologists since it was not supported by empirical evidence at that time. Lemaître thought that if the universe came from a hot state, it would leave traces that can be subjected to analysis. He then realized that there were indeed traces in the form of cosmic rays. He explained that the cosmic rays were “ashes and smoke of bright but very rapid fireworks,” and they originated when the primeval atom disintegrated. He first visualized that the primeval atom would disintegrate into atomic stars. Then as the atomic stars disintegrate, they would produce cosmic rays and become ordinary matter. Therefore, cosmic rays were not the direct product of primeval atom but rather, of the early formation of the stars 10 billion years ago. In his publication, he stated that “Cosmic rays would be glimpses of the primeval fireworks of the formation of a star from an atom, coming to us after their long journey through free space.” Edwin Powell Hubble Edwin Powell Hubble was an American astronomer who established the Hubble’s law which provided evidence that the universe was not static but expanding. In 1923, Hubble spotted what he thought as a flaring nova star in the M31 nebula or the Andromeda constellation using a Hooker telescope. The Andromeda constellation is now known as Andromeda galaxy, the nearest galaxy in the Milky Way. 9  Fig. 4. The Hooker telescope (left) and the Cepheid star (right). Hubble carefully studied the photographic plates captured by other astronomers and realized that what he saw was a Cepheid star ― a star that pulsates radially, brightening and dimming periodically. Hubble used this radial pulse to measure the distance of the star from Earth. Based on his calculations, he was able to postulate the existence of other galaxies. He noted that there was more to the universe beyond the Milky Way. He then began to classify other nebulae, measuring their velocities based on their emitted spectral lights. Then in 1929, he noticed that all the galaxies seemed to be moving away from Earth with velocities that increased in proportion to their distance. This means that the amount of redshift is proportional to the distance of the galaxy, i.e. nearby galaxies have smaller redshifts than distant galaxies. This relationship of the velocities of distant objects in the universe in proportion to their distance from Earth is called Hubble’s law. He published a report in the same year about his discovery. This ultimately supported Lemaître’s proposal of the expanding universe. 10 Arno Penzias and Robert Wilson American astronomers, Arno Penzias, and Robert Wilson studied the cosmic radiation in 1964. They discovered that microwaves with wavelengths of about 7 centimeters were present in space. These waves were referred to as the cosmic microwave background (CMB) radiation. Arno Penzias Robert Wilson (born 1933) (born 1941) CMB radiation is believed to be the thermal energy released when the ionized gases became neutral particles as the early universe cooled down. This radiation served as a ‘leftover’ when the universe was formed. The discovery of this cosmic radiation provided strong evidence that the universe began from the sudden expansion of a singularity, which supported Lemaître’s study. Drawbacks of the Big Bang Theory One of the problems in the big bang theory is that it failed to explain how the universe was created. It just explains how it evolves and not where it originated. In addition, this theory also failed to explain how the galaxies formed. Key Points The big bang theory suggests that the universe started as a “singularity”— an area predicted to be in the core of a black hole with very high 11  temperature and density. There are different proponents who suggested an explanation of this expanding universe. They are Georges Henri Joseph Edouard Lemaître, Edwin Powell Hubble, Arno Penzias, and Robert Wilson. Hubble’s law states that the relationship of the velocities of distant objects in the universe is directly proportional to their distance from Earth. The big bang theory failed to explain how the universe was created. Web Links For further information, you can check the following web links: Watch this video clip from National Geographic to deepen your knowledge on the big bang theory National Geographic. 2009. ‘Before Time and Space.’ https://www.youtube.com/watch?v=nVsHjnY-o9s Try this interactive activity to have an idea of how big is the universe. Primax Studio. n.d.. ‘Scale of the Universe.’ http://scaleofuniverse.com Listen to this big bang song to remember the idea of big bang theory better. Barenaked Ladies. 2016. ‘The Big Bang Theory Song.’ https://www.youtube.com/watch?v=CMSYv_Z4SI8 Check Your Understanding A. Identify the proponent of the theory that explains the following statements. 1. He used the radial pulse of Cepheid star to measure the distance of the star from Earth. 2. He stated that the amount of redshift is proportional to the distance of the galaxy. 3. He concluded that the relationship of the velocities of distant objects in the 12  universe is in proportion to their distance from Earth. 4. He explained that the cosmic rays were “ashes and smoke of bright but very rapid fireworks,” and they originated when the primeval atom disintegrated. 5. He discovered cosmic microwave background radiation. 6. He used the Hooker telescope to support his idea. 7. He discovered that microwaves with wavelengths of about 7 centimeters were present in space. 8. He studied the photographic plates captured by other astronomers and realized that what he saw was a Cepheid star. 9. He is considered the first proponent of the big bang theory. 10. He proposed that the universe originated in an explosive act of primeval atom or the ‘cosmic egg'. B. Use the data provided in the table below to answer the following. Distance 0.45 0.9 0.9 1.7 2.0 2.0 2.0 (Mpc) Velocity 200 650 500 960 850 800 1090 (km/s) 1. Plot a graph based on the data given on the table above. 2. Calculate the range of distances to the galaxies (in light years) in the given sample. Take note that one megaparsec (Mpc) is equal to 3.26 million light years. 3. According to the data, are the distances and speeds of the galaxies correlated, anti-correlated or unrelated? 4. What can you conclude about the galaxy that is very far away from Earth? 5. How can you summarize the Hubble's law by using the data provided? Challenge Yourself Answer the following questions. Limit your answer in 2 to 3 sentences. 1. Why is the bread-raisin model compared to the big bang theory? 2. How will you explain the big bang theory by relating it to mass, volume, and density? 13 3. Who are the proponents of the big bang theory? What are their ideas that support the big bang theory? 4. How do the velocities of distant objects and distance from Earth related to Hubble’s law? 5. What is nucleosynthesis? Describe how nucleosynthesis leads to the formation of stars and galaxies. 14  Lesson 1.2: Steady State Theory and Oscillating Universe Theory Objectives In this lesson, you should be able to: explain the origin and the fate of the universe according to steady state theory and oscillating universe theory; identify different proponents of the steady state and oscillating universe theory; and enumerate negative implications of steady state and oscillating universe theory. Do you usually go to the grocery store with your mom? If you do, you should have noticed that grocery stores love promos. They usually asked you to buy a thing in packages. For instance, if plastic containers are on sale, it is usually sold in a package of 3 to 5 pieces with varying sizes. At a glance, you know that the bigger size of the plastic containers will be heavier to carry. If you don’t want your packed lunch to add weight on your bag especially if you carry a lot of other things, you will not ask your mom to use the bigger Tupperware for your packed lunch. However, choosing a smaller container means less food can fit inside. This is a problem especially if you want to eat more because you need more energy to accomplish tasks in school. In these situations, you could conclude that mass and volume is directly proportional. As the plastic container increase in volume, it gets heavier as well. How about the container’s density? Does it change as the object increases in size? How could this mass, volume, and density relate to a theory of the origin of the solar system called steady state theory? 15  Warm-Up Bar of Soap - A Model of an Expanding Universe Materials: square shaped bath soap (or any square-shaped object that can be sliced) plastic knife weighing balance ruler clean cloth Procedure: 1. Slice the square-shaped bath soap twice lengthwise and twice crosswise to form 9 equal pieces. 2. Get one slice of the soap and measure its side using a ruler. 3. Calculate the volume of a piece of soap by multiplying the length by width by height (l × w × h). Record the calculated volume of the soap. 4. Put the one slice of soap on a clean cloth first before putting on the weighing balance. Record its weight. 5. Calculate the density by dividing its mass by volume. Record. 6. Repeat steps 2 to 5 but this time using four slices of soap. 7. Repeat steps 2 to 5 but this time using nine slices of soap. Guide Questions: 1. What is the relationship between mass, volume, and density in the experiment? 2. What can you say about the density of the soap as the number of slices increases? 3. Relate this activity with this statement: "The density of the universe remains constant as it continuously expands while simultaneously creating matter". 16  Learn about It The Steady State Theory The steady state theory is another theory that tries to explain the origin of the universe. As opposed to the big bang, this theory states that the universe has no beginning and no end. Overview of the Steady State Theory The steady state theory suggests that the universe has always been here and will always be present. It also suggests that the universe always looks the same in any time or space, but the universe continuously expands while simultaneously creating matter. During expansion, the density of the universe remains constant; hence, the name steady state. It also explains that the rate of the death of stars is equal to the rate of birth of stars. Hence, as a whole, the universe is not evolving over time. Both the big bang and steady state theory explains that the universe is expanding. However, the difference is that the big bang shows that as the universe expands, the density of matter decreases over time. On the other hand, steady state shows that the universe maintains a constant density as it expands. This means that matter such as stars and galaxies are continuously being added to the universe. Fig. 6 illustrates the primary concept of the steady state theory. Fig. 6. In the steady state theory, matter is constantly created as the universe expands. 17 Proponents of the Steady State Theory The steady state theory was proposed by Hermann Bondi, Thomas Gold, and Fred Hoyle in 1948. These three physicists from Cambridge released the idea of the steady state theory by submitting two papers to Monthly Notices of the Royal Astronomical Society, one from Bondi and Gold, and the other one from Hoyle. Hermann Bondi Thomas Gold Fred Hoyle (1919–2005) (1920–2004) (1915–2001) The steady state idea of Bondi and Gold may have started when they watched a movie together late 1940s. It was a horror movie entitled “Dead of Night” which started and ended in the same way. The circular plot of the movie inspired them to suggest that the universe was dynamic but unchanging. This means that the universe is constantly changing yet remains the same. Some criticism arose since the theory did not explain how matter could be generated out of nothing. 18 Drawbacks of the Steady State Theory The steady state theory was so simple that it was widely accepted even before the proposal of the big bang theory. Other astronomers did not favor this theory since it is not parallel with the law of conservation of energy and mass where energy and matter cannot be created nor destroyed but can only change their form. The discovery of the cosmic microwave background radiation significantly supported the explanations given by the big bang theory and led many scientists to reject the steady state theory in 1965. The steady state theory explained that the cosmic radiation was a result of a supernova. However, after thorough research, it was proven that the radiation is equal in any direction of the universe and could not be a result of many supernovae. The Oscillating Universe Theory Have you ever wondered how many universes are there? Or is our universe the only one? If the oscillating theory holds true, our universe might be the first of the probable series of the universe or nth universe in the series. The oscillating universe theory discusses that the universe is expanding and will contract once all the energy after the big bang has been used up, only to expand again once it approaches the point of singularity (i.e., the beginning of a new universe). It is also referred to as the pulsating theory. Overview of the Oscillating Universe Theory The oscillating universe theory can be described as the combination of the big bang and the big crunch. The big crunch occurs when the universe expands and eventually reverses, then collapses causing the formation of a singularity or the occurrence of another big bang. The oscillating universe theory suggests that once the universe reverses and attains the point of singularity, another universe will be born. This is referred to as the big bounce. 19 Richard Tolman, an American mathematical physicist, and physical chemist theorized that the universe may be first in the cycle, or it could be a result of a previous big bounce event. Proponent of Oscillating Universe Theory Besides being a mathematical physicist and physical chemist, Richard Tolman was someone to look up to when it comes to statistical mechanics. He later became physical chemistry and mathematical physics professor at California Institute of Technology (Caltech). One of his students is Linus Pauling to whom he taught the pre-Schrödinger quantum theory. In the years after Einstein discovered the general relativity, Tolman made essential contributions to theoretical cosmology. In his monograph entitled, “Relativity, Thermodynamics, and Cosmology”, he documented and explained that the universe has zero energy because the positive mass energy and negative gravitational energy cancel each other. His theory on the oscillating universe caught attention to struggles regarding entropy and resulted in its demise. Drawbacks of Oscillating Universe Theory Like the steady state theory, scientists discovered many loopholes in the oscillating universe theory. This theory suggested that the universe would collapse on its own after it reached its full expansion, which would violate some current laws of physics, such as the postulated existence of dark energy. The dark energy is believed to be the driving force of the accelerating expansion of the universe. At present, the postulated end of the universe is by big freeze or heat death. The universe would continuously expand until it reaches a point wherein all its energy dissipates. 20  Key Points The steady state theory suggests that the universe has always been here and will always be present. ○ It was proposed by Hermann Bondi, Thomas Gold, and Fred Hoyle in 1948. The oscillating universe theory discusses that the universe is expanding and will contract once all the energy after the big bang has been used up, only to expand again once it approaches the point of singularity ○ It is also referred to as the pulsating theory. ○ Richard Tolman is the proponent of oscillating universe theory. Web Links For further information, you can check the following web links: Watch this video to study the difference between the big bang theory and steady state theory. Pichael Moon. 2014. ‘Big Bang Theory vs Steady State Theory.’ https://www.youtube.com/watch?v=SuslgoGJdiw&t=21s Watch this video to know more about the steady state theory. The Audiopedia. 2018. ‘What is the Steady State Theory?.’ https://www.youtube.com/watch?v=hsMerhcEcEM 21  Check Your Understanding A. Write S if the statement describes the steady state theory or O if it describes oscillating universe theory. 1. Other astronomers did not favor this theory since it did not follow the law of conservation of energy and mass 2. It states that our universe might be the first of the probable series of the universe or nth universe in the series. 3. During expansion, the density of the universe remains constant. 4. It suggests that the universe has always been here and will always be present. 5. The universe is not evolving over time. 6. It discusses that the universe is expanding and will contract once all the energy after the big bang has been used up, only to expand again once it approaches the point of singularity. 7. The universe continuously expands while simultaneously creating matter. 8. This theory can be described as the combination of the big bang and the big crunch. 9. This theory suggests that once the universe reverses and attains the point of singularity, another universe will be born. 10. It explains that the rate of the death of stars is equal to the rate of birth of stars. B. Draw a Venn diagram. Write two unique features of the steady state theory on the first outer circle and two unique features of the oscillating universe theory on the second outer circle. Then, write at least one similar feature in the inner circle. 22  Challenge Yourself Answer the following questions. Limit your answers in 2 to 3 sentences. 1. Why is the steady state theory termed as such? 2. What are the similarities and differences of the big bang theory and steady state theory? 3. Based on the steady state theory, how can the universe expand but maintained a constant density? 4. What makes the steady state theory unacceptable? 5. Why is the oscillating universe called such? 23  Lesson 1.3: Nebular Theory Objectives In this lesson, you should be able to: explain the origin of the solar system according to the nebular theory; describe how planets were formed based on the nebular theory; be familiar with the contribution of the proponent that support the nebular theory; and enumerate the negative implications of the nebular theory. Did you spend most of your childhood playing? It is undeniable that most kids love to play. One of the most common things that kids want to do with their playmates is playing with toy building bricks or molding clay. Most of the time, kids compete with their playmate in building better toy building bricks or clay structure. Both of these situations, building using toy bricks or molding clay, involves creating a larger structure out of the smaller parts. For instance, one toy building brick when combined with other blocks can form a robot or a building. The same is true in molding clay. A small amount of clay can make a certain object when extra clay is added. One theory regarding the origin of the universe also works this way. How can smaller structures become a huge matter such as planets? Warm-Up Modeling Accretion Materials: student role cards ○ interstellar dust card (red for metallic grains, blue for icy grains, and yellow for rocky grains) 24  ○ planetesimal card ○ protoplanet card Procedure: 1. Distribute the different interstellar dust card (metallic, icy, and rocky) evenly among the students. Make sure every student will have one interstellar dust card (A larger area is needed to do this activity because the students need to move around to tag other students). 2. Assign one student to stand in the middle of the circle of students. This represents the sun. First Round 3. The goal of the game is to tag other students with the same role card as theirs. They cannot tag other students with a different type of role card. For example, a student with a metallic grains card can only tag other students with the same role card. They cannot tag students with icy or rocky grains card. 4. Before the game will start, keep these reminders in mind. First, students should move in a counterclockwise circular path around the sun. One 25  student will act as the sun in the middle. Second, students should only jog as they move around. They are not allowed to run. Third, the arms should only stay at the sides as the students jog around. 5. Start tagging other students. If you are tagged, you should move together with the person who tagged you. 6. After several minutes, students should stop tagging others. 7. The winner of this round is the group who formed the largest clumps. Second Round 8. Students formed in clumps can now tag other students in clumps as well. However, only those with the same role card can be tagged and grouped. 9. After several minutes, students should stop tagging others. 10. The winner of this round is the group who formed the largest clumps. 11. Give each clump of interstellar dust another card with planetesimal written on it. Students in this stage simulated the first stage of solar system formation. Third Round 12. Each planetesimal can now tag other planetesimals with different role card. For example, a planetesimal consisting of a group of metallic grains can now tag planetesimals consisting of rocky or icy grains. 13. The final winner is the one with the largest group. 14. Hand out a protoplanet role card to the planetesimal group with different interstellar dust. Guide Questions: 1. What happens in the interstellar dust in the first round of the activity? 2. What is the difference between interstellar dust, planetesimals, and protoplanets in the activity? 3. What are the differences between the first stage and second stage of planet formation which is represented by the second and third round respectively? 4. How is the activity related to how planets were formed? 26  Learn about It Another theory that explained the origin of the solar system is the nebular theory. From the term itself, "nebula" means cloud. This indicates that stars originate from interstellar gas and dust. The shift from undifferentiated cloud to whole solar system formation complete with planets, moons, and stars takes approximately a hundred million years. Description of the Nebular Theory There are three major steps on how the solar system was formed according to nebular theory. These are cloud collapse, formation of the protoplanetary disk, and growth of planets. Cloud Collapse The origin of the planets and sun in the solar system is a huge cloud of molecular gas and dust. Then, something occurred that made the cloud to collapse. Possible reasons are shockwaves from a supernova or the effect of a passing star. Whatever the reason, the result was a collapse at the center of the cloud due to gravity. As shown in Fig. 8, the collapsing of the cloud makes it spin faster. Fig. 8. Cloud collapse. 27 Have you ever tried to watch a skating competition? One of the tricks of the contestant that amazes people is when they spin so fast without falling. If you are a keen observer, they can only do the trick if they bring in their arms. Extending their arms while attempting to spin fast will result to a failure of the act. As shown in Fig. 9, this is possible because rotational velocity is inversely proportional to radius. Fig. 9. Relationship of radius and rotational velocity. In relation to the nebular theory, the collapsed cloud of interstellar gas and dust results to a smaller radius which means it will spin faster. This resulted to a flattened disk of cloud with a central bulge. Formation of Protoplanetary Disk Metals and silicates could exist near the sun because these compounds have higher boiling points. As a result, terrestrial planets including Mercury, Venus, Earth, and Mars were eventually formed containing a high concentration of these compounds. 28 The terrestrial planets could not grow in huge diameter because of the limited reserve of metallic elements in the solar nebula. Fig. 10. Terrestrial planets. From left to right: Mercury, Venus, Earth, and Mars. Jovian planets composed of Jupiter, Saturn, Uranus, and Neptune are huge planets made up of gases without land surfaces. These planets were formed farther from the sun because the temperature is cool enough for the gases to condense, forming these massive, but low-density planets. Fig. 11. Jovian planets. From left to right: Jupiter, Saturn, Uranus, and Neptune. 29  Fig. 12. The formation of a protoplanetary disk in nebular theory. Growth of Planets As shown in Fig. 13, dust and grains surrounding the sun eventually formed clumps. These clumps then accreted forming planetesimals. Planetesimal is a small celestial body that once collide together, it tends to fuse to form the planets of the solar system. Fig. 13. Growth of planets in the nebular theory. 30 Proponents of the Nebular Theory The nebular theory can be credited to Emanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace. Emmanuel Swedenborg Immanuel Kant Pierre-Simon Laplace (1688–172) (1724–1804) (1749–1827) Drawbacks of the Nebular Theory One problem of the nebular theory is that it assumes that dust particles will be attached to each other forming a planet. However, this is not true for Saturn because the particles surrounding it repel each other. Another problem is that it does not follow the law of angular momentum. If it does, the sun should be spinning at a higher rate than the others. Moreover, this theory did not consider Uranus and Venus, which rotates in a clockwise direction. This is opposing to the counterclockwise rotation of other planets. If this theory is correct, all the planets should be moving in the same direction. Key Points Nebula means cloud. This indicates that stars originate from interstellar gas and dust. There are three major steps on how the solar system is formed according to nebular theory. These are cloud collapse, formation of the protoplanetary disk, and growth of planets. 31  Terrestrial planets include Mercury, Venus, Earth, and Mars. These would eventually form closer to the sun. Jovian planets composed of Jupiter, Saturn, Uranus, and Neptune are huge planets made up of gases without land surfaces. These planets were formed farther from the sun. The nebular theory can be credited to Swedenborg, Kant, and Laplace. Web Links For further information, you can check the following web links: Click this link to deepen your knowledge on the nebular theory. OHMS Science Class Videos. 2014. ‘The Nebular Theory.’ https://www.youtube.com/watch?v=PL3YNQK960Y Listen to this short lecture to make the nebular theory clear to you. London Jenks. 2014. ‘Nebular Hypothesis - Formation of the Solar System’ https://www.youtube.com/watch?v=y7eXbIPSYes Check Your Understanding A. Arrange the following events of the nebular theory in order by writing numbers 1 to 5 on the blank provided below. __________ Protoplanets and moon forming __________ Solar system __________ Protosun forming __________ Formation of the nebula __________ Spinning planetary disk 32 B. Complete the following flowchart. Choose the letter of the correct answer in the choices below. A. Interstellar cloud (nebula) F. Accretion B. Protoplanetary disk G. Terrestrial planets C. Protosun H. Jovian planets D. Sun I. Asteroids E. Gases, ice J. Comets 33  Challenge Yourself Answer the following questions. Limit your answers in 2 to 3 sentences. 1. How does the dust cloud become a planet? 2. Why did the interstellar gas and dust collapse? 3. Why did the nebula spin faster as they shrink or collapse? 4. What is the difference between inner and outer protoplanets? 5. What should be the composition of the materials in the core, mantle, and crust based on the nebular theory? 34  Lesson 1.4: Encounter Theory Objectives In this lesson, you should be able to: explain the origin of the solar system based on the encounter theory; differentiate the planetesimal and tidal theory; be familiar with the proponents of the planetesimal and tidal theory; and enumerate the negative implications of the planetesimal and tidal theory. Warm-Up Planet Formation Material: electronic gadget with an internet connection Procedure: 1. Click this link to watch a one-minute video clip on how dust traps aid in forming the planets. How does planet formation happen? Tech Insider. 2017. ‘Scientists have found how Planet Formation Occurs.’ https://www.youtube.com/watch?v=aeNixsYTdB4 2. Take down important notes while watching the video. 3. Answer the guide questions below. 35 Guide Questions: 1. What happens when two objects bump into each other too fast? 2. Give at least two characteristics of a dust trap. 3. What is the importance of dust traps? Learn about It The encounter theory proposes that the planets were formed from the material ejected from the sun during an encounter with another celestial object. This celestial object could have been another star. The encounter theory has several forms, including the planetesimal theory and the tidal theory. Fig. 14. The encounter theory proposes that the planets formed from the material ejected from the sun during an encounter with another star. The Planetesimal Theory According to the planetesimal theory, a passing star termed as intruding star nearly collided with the protosun. The massive gravitational pull of the intruding star causes the protosun to eject filaments of material. These materials condensed into planetesimals from which the planets were formed through accretion. Unlike the nebular theory which describes Earth starting from molten mass, the planetesimal theory describes Earth starting from a solid mass smaller than its present size. The oceans and the atmosphere were formed on Earth through volcanic activities. 36 Proponents of the Planetesimal Theory The planetesimal theory was proposed by an American geologist, Thomas Chrowder Chamberlin and an American astronomer, Forest Ray Moulton in 1905. Moulton started working with Chamberlin when he took graduate studies in Chicago. As opposed to what Kelvin proposed on the age of Earth, Chamberlin realized that Earth was older. He proposed that accretion of minute solid particles created planets and their moons rather than by gaseous or liquid material condensation. However, Moulton provides mathematical calculations to Chamberlin’s idea making it into a solid theory. Thomas Chrowder Chamberlin Forest Ray Moulton (1843–1928) (1843–1928) Drawbacks of the Planetesimal Theory This theory is no longer accepted today due to the fact that hot material from the sun expands and dissipates rather than contract. In addition, the force from the passing star will pull dust and gases far away from the sun, that they would not be able to form the planets in the solar system. The Tidal Theory The tidal theory explains that the solar system formed as a result of a near collision between a passing star and the sun. However, unlike the planetesimal theory, the tidal theory proposes that the hot gas from the passing star condensed into planets instead of condensing into planetesimals. When the star passed near 37 the sun, the gravitational attraction pulled the mass of dust and gas from the remaining nebula around the sun. The gas particles then condensed into liquid and solid states. The particles clump together to form cosmic bodies of different sizes. These bodies further condensed into planets. Therefore, the interaction from the gravity of the passing star and the sun led to the formation of the planets in the solar system. The materials closer to the sun are denser. This explains the positions of the terrestrial planets near the sun. In contrast, the materials from the passing star are less dense; thus, explaining the positions of the Jovian planets. Proponents of the Tidal Theory The tidal theory was proposed by James Jeans, an English physicist, and astronomer, and Harold Jeffreys, an English mathematician, and astronomer in 1918. Drawbacks of the Tidal Theory One problem of the tidal theory is that the hot material from either star cannot contract. Thus, planets will not form. Key Points The encounter theory proposes that the planets formed from the material ejected from the sun during an encounter with another celestial object. It has several forms, including the planetesimal theory and the tidal theory. The planetesimal theory describes Earth starting from a solid mass smaller than its present size. ○ It was proposed by an American geologist Thomas Chrowder Chamberlin and an American astronomer Forest Ray Moulton. ○ It is no longer accepted today due to the fact that hot material from the sun will expand and dissipate rather than contract. 38  The tidal theory proposes that the hot gas from the passing star condensed into planets instead of condensing into planetesimals. ○ It was proposed by James Jeans, an English physicist, and astronomer, and Harold Jeffreys, an English mathematician, and astronomer. ○ One problem of the tidal theory is that the hot material from either star cannot contract. Thus, planets will not form. Web Links For further information, you can check the following web links: Watch this video to make the difference of the planetesimal theory and nebular theory clear to you. Daniel Gaies. 2014. ‘Planetesimal Theory versus Nebular Theory’ https://www.youtube.com/watch?v=12PkSkgo_mU View this video to help you visualize what is the planetesimal theory talking about Rose Ann Antonio. 2013. ‘Planetesimal Theory’ https://www.youtube.com/watch?v=Ct-BMiK7NSE Check Your Understanding Arrange the following events in order. Write numbers 1 to 5. Planetesimal theory __________ Materials ejected from the protosun condensed into planetesimals. __________ The oceans and the atmosphere were formed on Earth through volcanic activities. __________ The planets formed by accretion. __________ The protosun ejects filaments of materials. __________ An intruding star nearly collided with a protosun. 39  Tidal theory __________ These bodies further condensed into planets. __________ The gravitational attraction pulled the mass of dust and gas from the remaining nebula around the sun. __________ The particles clumped to form cosmic bodies of different sizes. __________ The gas particles then condensed into liquid and solid states. __________ A star passed near the sun. Challenge Yourself Answer the following questions. Limit your answers in 2 to 3 sentences. 1. Why is the encounter theory called such? 2. What is the difference between the nebular theory and planetesimal theory? 3. Why is the planetesimal theory no longer accepted today? 4. What is the difference between planetesimal and tidal theory? 5. Is the tidal theory widely accepted? Why or why not? 40  Laboratory Activity Activity 1.1 Dust in the Universe Objectives At the end of this laboratory activity, the students should be able to: investigate different properties of dust; relate the features of dust collected to its location; and identify how astronomers investigate dust in space. Materials and Equipment clear tape clean short bond paper magnifying glass ruler Procedure 1. Choose five locations around the classroom or school where you will collect dust samples. 2. Use the sticky side of the clear tape to get dust samples on your chosen area. 3. Sort out the dust samples by their physical features (size, shape, and color). Put the sorted clear tape with dust samples on a separate sheet of paper. 4. List the properties of the dust groups that you formed. Record your observations. 5. Record your observation on the characteristics of each location where you find your dust samples. 6. Use a ruler and magnifying glass to measure the size of the dust samples. Record your observation. Waste Disposal Put the wastes in the appropriate trash bins. 41 Data and Results Table 1. Description of dust samples in five locations. Description Description of the Dust Samples Collected Location of the Area Size Shape Color Location A Location B Location C Location D Location E Guide Questions 1. Do you think there is a relationship between the kind of dust samples collected to the location where it is found? Explain. 2. What is the range of sizes of the dust samples that you collected? 3. What do you think will be the largest size that will qualify as dust? 4. How do astronomers investigate dust in space based on your dust investigation activity? Performance Task Infographics on the Origin of the Universe and Solar System Goal Your task is to make an infographic that shows illustration and information on the origin of the universe and solar system. Choose only one theory. Role You have been asked to become a graphic designer and Earth Science expert. Audience 42  Your target audience is Grades 7 to 12 students. Situation You need to have accurate information and related illustration in your infographics. Product You will create an infographic to spread awareness to other students in an interesting and creative way. Your product needs to be simple, creative and accurate. Standards Your work must meet the standards found in the rubric below. Below Needs Successful Exemplary Criteria Expectations, Improvement Performance Performance 0% to 49% 50% to 74% 75% to 99% 100% Accuracy Most information is Most information Most All the correct. With three is correct. With information is information in or more inaccurate two inaccurate correct. With the fact. facts. one inaccurate infographics fact. are correct Layout and Does not meet any Has met only 1 of Has met only 2 Met all of the of the criteria given. the criteria given. of the criteria following Neatness given. criteria: - text is relevant to the photo. - has a catchy, relevant title. - overall output is neat. Overall output The overall output The overall The overall The overall needs to be creative output is creative output is output is and informative but has some creative and exceptionally inaccurate facts. informative creative, unique and informative 43  Self Check After studying this unit, can you now do the following? Check I can… describe the different theories on the origin of the universe. identify the contribution of different proponents of the different theories on the origin of the universe. enumerate drawbacks of each theory of the origin of the universe. Key Words Big bang theory It suggests that the universe started as a “singularity”— an area predicted to be in the core of a black hole with very high temperature and density. Encounter theory It proposes that the planets formed from the material ejected from the sun during an encounter with another celestial object. Hubble’s law It states that the relationship of the velocities of distant objects in the universe is directly proportional to their distance from Earth. Jovian planets It is composed of Jupiter, Saturn, Uranus, and Neptune are huge planets made up of gases without land surfaces. These planets were formed farther from the sun. Nebula It means cloud. ir indicates that stars originate from interstellar gas and dust. Nucleosynthesis It is the formation of elements, such as hydrogen and helium. 44 Oscillating universe It suggests that the universe is expanding and will theory contract once all the energy after the big bang has been used up, only to expand again once it approaches the point of singularity Planetesimal theory It describes Earth starting from a solid mass smaller than its present size. Terrestrial planets It includes Mercury, Venus, Earth, and Mars. These would eventually form closer to the sun. Tidal theory It proposes that the hot gas from the passing star condensed into planets instead of condensing into planetesimals. 45  Wrap Up Origin of the Universe and the Solar System Photo Credits Fig. 4. Georges Henri Joseph Edouard Lemaître by Tonynetone is licensed under CC BY 2.0 via Flickr Fig. 5. Edwin Hubble via Wikimedia Commons; Hooker telescope by Andrew Dunn is licensed under CC BY-SA 2.0 via Wikimedia Commons. 46 Fig. 6. Cepheid star via Wikimedia Commons Fig. 8. Arno Penzias is licensed under CC BY-SA 3.0 via Wikimedia Commons; Robert Wilson is created under license CC BY 2.0 via Wikimedia Commons; Fig. 12. Richard Tolman via Wikimedia Commons Fig. 15. Terrestrial Planets via Wikimedia Commons Fig. 16. Jovian Planets via Wikimedia Commons Fig. 19. Emmanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace via Wikimedia Commons Fig. 20. Thomas Chrowder Chamberlin, and Forest Ray Moulton via Wikimedia Commons References Rodney Holder and Simon Mitton. 2013. Georges Lemaître: Life, Science and Legacy, Germany: Springer Science & Business Media. John Chambers and Jacqueline Mitton. 2013. From Dust to Life: The Origin and Evolution of Our Solar System, New Jersey: Princeton University Press. Michael Mark Woolfson. 2012. Time, Space, Stars and Man: The Story of the Big Bang, Singapore: World Scientific. J. Schombert. 2012. Origin of the Solar System. Accessed March 16, 2017 http://abyss.uoregon.edu/~js/ast121/lectures/lec24.html D. Darling. 2016. Chamberlin-Moulton planetesimal hypothesis. Accessed March 16, 2017http://www.daviddarling.info/encyclopedia/C/CMplanhypoth.html 47