Earth Science: Lesson 1: The Universe And The Solar System PDF

Earth Science: Lesson 1 the Universe And The Solar System Prepared by: Mark C. Alderite, LPT Objectives: At the end of this lesson, the learners will be able to: 1. Describe the structure and composition of the Universe; 2. State the different hypothesis that preceded the Big Bang Theory of t...

Earth Science: Lesson 1 the Universe And The Solar System Prepared by: Mark C. Alderite, LPT Objectives: At the end of this lesson, the learners will be able to: 1. Describe the structure and composition of the Universe; 2. State the different hypothesis that preceded the Big Bang Theory of the Origin of the Universe. 3. Explain the red-shift and how it used as proof of an expanding universe; and 4. Explain the Big Bang Theory and evidences supporting the theory. Earth Science: Lesson 1 the Universe And The Solar System Prepared by: Mark C. Alderite, LPT Topic: Universe and the Solar System Let’s Play Trivia 1. What is the largest planet in our solar system? Answer: JUPITER 2. What is the name of the galaxy that contains our solar system? Answer: THE Milky way 3. Which planet is known as the “Red Planet”? Answer: MARS  4. What is the process by which a star converts hydrogen into helium, releasing a tremendous amount of energy? Answer: NUCLEAR FUSION 5. Which moon in our solar system is larger than the planet Mercury? Answer: Ganymede, a moon of Jupiter 6. What is the phenomenon where light from a star is stretched and shifted toward the red end of the spectrum due to the universe’s expansion? Answer: RED SHIFT 7. What is the name of the first artificial satellite launched into space? Answer: SPUTNIK 1  8. Which famous comet has a regular period of about 76 years and was last seen in 1986? Answer: Halley’s Comet 9. What is the region in space where the gravitational pull of a black hole is so strong that nothing, not even light, can escape? Answer: Event horizon 10. Which planet has the most extensive system of rings in our solar system? Answer: Saturn 11. What type of star is our Sun classified as? Answer: G-type main-sequence star (G dwarf star) 12. What is the name of the largest volcano in our solar system, located on Mars? Answer: Olympus Mons 13. Which space telescope, launched in 1990, has provided stunning images and data about the universe? Answer: Hubble Space Telescope 14. What is the process by which a star, much larger than the Sun, ends its life in a massive explosion? Answer: SUPERNOVA 15. What is the point in a planet’s orbit when it is closest to the Sun? Answer: PERIHELION 16. What is the name of the region beyond Neptune where many small icy bodies are located? Answer: KUIPER BELT 17. What is the primary force responsible for the expansion of the universe? Answer: GRAVITY 18. What is the term for the study of the origin, evolution, and properties of the universe as a whole? A. Astrobiology B. Cosmology C. Astrology D. Astronomy Answer: B. Cosmology 19. Which of the following is considered the most abundant form of matter in the universe? A. Dark matter B. Neutrons C. Protons D. Electrons Answer: A. Dark matter 20. Which of the following is NOT a characteristic of a star? A. Emits light and heat B. Orbits the Sun C. Has its own energy source D. Varies in size and brightness Answer: B. Orbits the sun Topic: Universe and the Solar System Let’s play Trivia How many scores did you get? Earth Science: Lesson 1 the Universe And The Solar System Prepared by: Mark C. Alderite, LPT What do we/you know about the universe today? STRUCTURE , COMPOSITION, AND AGE  Structure, composition and age The universe as we currently know comprises all space and time, and all matter and energy in it. It is made of 4.6% baryonic matter (“ordinary” matter consisting of protons, electrons, and neutrons: atoms, planets, stars, galaxies, nebulae, and other bodies), 24% cold dark matter (matter that has gravity but does not emit light), and 71.4% dark energy (a source of anti- gravity).  Structure, composition and age Dark matter can explain what may be holding galaxies together for the reason that the low total mass is insufficient for gravity alone to do so while dark energy can explain the observed accelerating expansion of the universe.  Structure, composition and age Hydrogen, helium, and lithium are the three most abundant elements. Stars - the building block of galaxies - are born out of clouds of gas and dust in galaxies. Instabilities within the clouds eventually results into gravitational collapse, rotation, heating up, and transformation into a protostar- the hot core of a future star as thermonuclear reactions set in.  Structure, composition and age Stellar interiors are like furnaces where elements are synthesized or combined/fused together. Most stars such as the Sun belong to the so-called “main sequence stars.” In the cores of such stars, hydrogen atoms are fused through thermonuclear reactions to make helium atoms. Massive main sequence stars burn up their hydrogen faster than smaller stars. Stars like our Sun burn-up hydrogen in about 10 billion years. BIRTH, EVOLUTION, DEATH, AND REBIRTH OF STARS Stars go through a natural cycle, much like any living beings. This cycle begins with birth, expands through a lifespan characterized by change and growth, and ultimately leads to death. The time frame in the life cycle of stars is entirely different from the life cycle of a living being, lasting in the order of billions of years. In this piece of article, let us discuss the life cycle of stars and its different stages. 1. Giant Gas Cloud/Nebula At the first stage of their lives, stars are formed by the gravitational collapse of giant clouds of dust and gas called Nebulae. This stage is the start of their life cycle. 2. Protostar A protostar is the result of the gravitational collapse of a nebula. It is the formative phase of a star. During this phase, the infant star strives to gain equilibrium between its internal forces and gravity. A Protostar starts very vastly. It can be billions of kilometers in diameter. It usually lasts for 100,000 years. During this period, the protostar spins very rapidly, generating intense heat and pressure and causing the gas cloud to collapse further. When the temperature reaches about 10 million K, hydrogen fusion can finally occur, and the star is born. 3. T-Tauri Phase Before fusion begins, the protostar goes through a period called the T-Tauri phase. At this stage, the core temperatures are still too low for hydrogen fusion, so all the star energy comes from the gravitational force only. The star at this point is about the same size as a low or medium mass star. However, it is much brighter. This period can last up to 100 million years and represents a period of fluctuations in the brightness of a star as it tries to balance its internal and gravitational forces. Once nuclear fusion starts and equilibrium is achieved, the star is considered a Main Sequence star. 4. Main Sequence (Small to Average Stars/Massive Stars) The Main Sequence signifies the portion of a star’s life where its core is capable of hydrogen fusion. 90% of a star’s life is spent in this stage. The stars in the Main Sequence are of many different masses, colors, and brightness. The amount of time a star spends on the Main Sequence depends directly upon its mass. average stars like the Sun stay on the Main Sequence for billions of years. The smallest stars, the red dwarfs, burn their hydrogen supplies so slowly that none of them have left the Main Sequence since the Universe was formed. On the other hand, the most massive stars, like Sirius, will use up their hydrogen quickly and exit the Main Sequence after only a few million years. When a star has fused all the hydrogen in its core to helium, it exits the Main Sequence and enters its death throes. 5. Red Giant When a star has fused all the hydrogen in its core, its nuclear radiation output ceases. As a result, the star once again starts collapsing due to gravity. The energy generated by this collapse heats the core enough that the hydrogen in the surrounding stellar atmosphere can be burnt. This process causes the star’s outer layers to expand and cool down to just around 2500-3500 K, thus becoming redder. This stage in a star’s life can last for up to a billion years, and the stars can swell up to 100-1000 times the size of the Sun. 5. Red Supergiant For stars with a mass 8-9 times that of the Sun, the core temperatures become so high that nuclear fusion can occur even after the helium is exhausted. They can swell up to truly spectacular sizes; for example, Betelgeuse, a red supergiant and the tenth brightest star in the sky, is so massive that if it were in the Sun’s place, it would stretch till Jupiter! The process of nuclear fusion in the core carries on till iron is formed. No further fusion can occur at this stage, as fusing iron consumes energy rather than release it. 6. White Dwarf Once the star’s outer layers are shed, only a tiny core comprising primarily carbon and oxygen remains. The star is called a White Dwarf. Here, the mass of an entire stellar core is condensed into a body roughly the size of the Earth. Such a small size is possible due to the pressure exerted by the fast-moving electrons. This fate is only for those stars whose cores are not bigger than 1.4 solar masses. These stars are scorching; hence, they glow white. 6. Supernova The moment the core of a supergiant star turns to iron, it has reached the end of its life. The star collapses instantly under the enormous gravity exerted on its heavy iron core. The core shrinks from around 5000 miles across to just a couple dozen in a matter of seconds, and the temperatures can reach 100 billion K. This collapse triggers an incredible explosion, known as a Supernova. Supernovae are some of the brightest and most violent events in the Universe; they can outshine entire galaxies! The energy released during a supernova is so great that a fusion of iron can finally occur, and all heavier elements are created in the explosion. 7. Black Dwarf Black dwarfs are the final stage in the life of a low to medium mass star. They are the remnants of white dwarfs, formed due to the gradual cooling and dimming as they burn their remaining fuel. Eventually, they will exhaust their fuel and keep dimming until they are no longer visible to us. This process takes such a long time that no black dwarfs have formed since the beginning of the Universe, so they are strictly theoretical. 7. Neutron Star/Blackhole After a supernova explosion, all that remains of the star is its core. What happens to this core depends on its mass. a) Neutron Star: If the collapsing core is of 1.4-3 solar masses, it forms a Neutron Star. A neutron star is a highly dense, heavy, and trim body comprised of neutrally charged neutrons. The force of gravity on the collapsing core is so enormous that the negatively charged electrons are pushed right into the nucleus, where they combine with the positively charged protons to form neutrons. As such, a vast mass is compressed into a body no more than 20 km in diameter. Neutron stars are the densest and heaviest objects in the Universe. 7. Neutron Star/Blackhole b) Black Hole: For stellar cores of more than 3 solar masses, the force of gravity is so strong that the collapse is unstoppable. Such a big mass collapses to a point known as a singularity. Here, the gravitational force is so strong that nothing can escape it, not even light. Such a phenomenon is called a Black Hole. Their gravity is so strong that black holes even pull in neighboring stars and planets and “eat” them! Since no light or other electromagnetic emissions can escape a black hole, our only way to detect them is to observe them “feeding” on the stellar matter. 50  A galaxy is a cluster of billions of stars and clusters of galaxies form superclusters. In between the clusters is practically an empty space. This organization of matter in the universe suggests that it is indeed clumpy at a certain scale. But at a large scale, it appears homogeneous and isotropic. Based on recent data, the universe is 13.8 billion years old. The diameter of the universe is possibly infinite but should be at least 91 billion light-years (1 light-year = 9.4607 × 10¹² km). Its density is 4.5 x 10⁻³¹ g/cm³. In 1929, Edwin Hubble announced his significant discovery of the “redshift” and its interpretation that galaxies are moving away from each other, hence as evidence for an expanding universe, just as predicted by Einstein’s Theory of General Relativity. 54 He observed that spectral lines of starlight made to pass through a prism are shifted toward the red part of the electromagnetic spectrum, i.e., toward the band of lower frequency; thus, the inference that the star or galaxy must be moving away from us. 55 Red shift – shows an increasing distance between us and other galaxies in the universe. If a source of light is moving away from an observer then the electromagnetic spectrum will be redshifted. If the source is moving toward the observer it is blue shifted. 56 Timeline of cosmological Theories Aristotle, building on the ideas of earlier astronomers, proposes that the Sun, Moon, planets, and stars revolve around a stationary Earth. This is known as the geocentric theory, meaning that the universe revolves around Earth. 58 Ptolemy created a mathematical model of the Aristotelian universe which the planet followed a small circle called an epicycle that slid around a larger circle called a deferent. By adjusting the size and rate of rotation of the circles he approximate the retrograde motion of the planet. 59 Nicolaus Copernicus publishes his heliocentric (Sun-centered) theory proposing that Earth is a planet in motion around the Sun. His model describes retrograde motion caused by relative planetary positions as Earth overtakes Mars compared to background stars. 60 Johannes Kepler polished the heliocentric model and proposed that planets move around the sun in an elliptical motion rather than in circular, orbits and that their movements in these orbits are governed by the set of laws, which will became known as Kepler’s Law of Planetary Motion. 61 Sir Isaac Newton publishes the laws of motion and gravity that are used to accurately predict the motion of the Moon and planets. 62 Albert Einstein publishes the General Theory of Relativity, proposing that mass and energy cause space and time to curve or warp. This can be used to describe large-scale motion throughout the universe. 63 Henrietta Leavitt discovers an important relationship concerning Cepheid variable stars, a type of star that pulsates in a regular pattern. She finds that the larger a Cepheid is, the slower it pulsates. Since larger stars are brighter, this pulsation can be used to find the exact brightness of a Cepheid star. 64 The Great Chain of Origins 1. NON-SCIENTIFIC THOUGHT ♦Ancient Egyptians believed in many gods and myths, which narrate, that the world arose from an infinite sea at the first rising of the sun. ♦The Kuba people of Central Africa tell the story of a creator god Mbombo (or Bumba) who, alone in a dark and water-covered Earth, felt an intense stomach pain and then vomited the stars, sun, and moon. 66 1. NON-SCIENTIFIC THOUGHT ♦In India, there is the narrative that gods sacrificed Purusha, the primal man whose head, feet, eyes, and mind became the sky, earth, sun, and moon respectively. ♦The monotheistic religions of Judaism, Christianity, and Islam claim that a supreme being created the universe, including man and other living organisms 67  2. STEADY STATE THEORY ⋆ The now discredited steady state model of the universe was proposed in 1948 by Bondi and Gould and by Hoyle. ⋆ It maintains that new matter is created as the universe expands thereby maintaining its density. ⋆ Its predictions led to tests and its eventual rejection with the discovery of the cosmic microwave background.’ 68 3. Oscillating Universe Theory ⋆ another Big bang will occur when the universe starts to run down. 69  4. THE BIG BANG THEORY The universe may have begun as an infinitely hot and dense initial singularity, a point with all of space, time, matter and energy. This means that there was no where, when or what. There is no space around the George Lemaitre singularity – just nothingness. Edwin Hubble 70 ⋆ The theory rests on two ideas: General Relativity and the Cosmological Principle. In Einstein’s General Theory of Relativity, gravity is thought of as a distortion of space-time and no longer described by a gravitational field in contrast to the Law of Gravity of Isaac Newton. General Relativity explains the peculiarities of the orbit of Mercury and the bending of light by the Sun and has passed rigorous tests. 71 ⋆ The Cosmological Principle assumes that the universe is homogeneous and isotropic when averaged over large scales. This is consistent with our current large-scale image of the universe. However, keep in mind that it is clumpy at smaller scales. 72 ⋆ The Big Bang Theory has withstood the tests for expansion: 1) the redshift 2) abundance of hydrogen, helium, and lithium, and 3) the uniformly pervasive cosmic microwave background radiation - the remnant heat from the bang. 73 Thank you! Do you have any questions? Prepared by: Mark C. Alderite, LPT