Earth Science, Origin of the Univers, Study notes of Earth science

Download Earth Science, Origin of the Univers and more Study notes Earth science in PDF only on Docsity! 1.1. The Universe Earth is just one of the billions and billions of bodies in the universe. To appreciate how special the Earth is, let us first explore the universe; the theories of how it began and the origin of our own solar system. Let's see what you already know. Answer Pre-test 1 now to test your knowledge. LET'S EXPLORE How and when did the universe begin? No other scientific question is more fundamental or provokes such spirited debate among researchers. After all, no one was around when the universe began, so who can say what really happened? The best that scientists can do is work out the most foolproof theory, backed up by observations of the universe. The trouble is, so far, no one has come up with an absolutely indisputable explanation of how the cosmos came to be. The Big Bang Since the early part of the 1900s, one explanation of the origin and fate of the universe, the Big Bang theory, has dominated the discussion. Proponents of the Big Bang maintain that, between 13 billion and 15 billion years ago, all the matter and energy in the known cosmos was crammed into a tiny, compact point. In fact, according to this theory, matter and energy back then were the same thing, and it was impossible to distinguish one from the other. Adherents of the Big Bang believe that this small but incredibly dense point of primitive matter/energy exploded. Within seconds the fireball ejected matter/energy at velocities approaching the speed of light. At some later time—maybe seconds later, maybe years later—energy and matter began to split apart and become separate entities. All of the different elements in the universe today developed from what spewed out of this original explosion. Big Bang theorists claim that all of the galaxies, stars, and planets still retain the explosive motion of the moment of creation and are moving away from each other at great speed. This supposition came from an unusual finding about our neighboring galaxies. In 1929 astronomer Edwin Hubble, working at the Mount Wilson Observatory in California, announced that all of the galaxies he had observed were receding from us, and from each other, at speeds of up to several thousand miles per second. The Redshift To clock the speeds of these galaxies, Hubble took advantage of the Doppler effect. This phenomenon occurs when a source of waves, such as light or sound, is moving with respect to an observer or listener. If the source of sound or light is moving toward you, you perceive the waves as rising in frequency: sound becomes higher in pitch, whereas light becomes shifted toward the blue end of the visible spectrum. If the source is moving away from you, the waves drop in frequency: sound becomes lower in pitch, and light tends to shift toward the red end of the spectrum. You may have noticed the Doppler effect when you listen to an ambulance siren: the sound rises in pitch as the vehicle approaches, and falls in pitch as the vehicle races away. To examine the light from the galaxies, Hubble used a spectroscope, a device that analyzes the different frequencies present in light. He discovered that the light from galaxies far off in space was shifted down toward the red end of the spectrum. Where in the sky each galaxy lay didn't matter—all were redshifted. Hubble explained this shift by concluding that the galaxies were in motion, whizzing away from Earth. The greater the redshift, Hubble assumed, the greater the galaxy's speed. Some galaxies showed just a slight redshift. But light from others was shifted far past red into the infrared, even down into microwaves. Fainter, more distant galaxies seemed to have the greatest red shifts, meaning they were traveling fastest of all. An Expanding Universe So, if all the galaxies are moving away from Earth, does that mean Earth is at the center of the universe? The very vortex of the Big Bang? At first glance, it would seem so. But astrophysicists use a clever analogy to explain why it isn't. Imagine the universe as a cake full of raisins sitting in an oven. As the cake is baked and rises, it expands. The raisins inside begin to spread apart from each other. If you could select one raisin from which to look at the others, you'd notice that they were all moving away from your special raisin. It wouldn't matter which raisin you picked, because all the raisins are getting farther apart from each other as the cake expands. What's more, the raisins farthest away would be moving away the fastest, because there'd be more cake to expand between your raisin and these distant ones. That's how it is with the universe, say Big Bang theorists. Since the Big Bang explosion, they reason, the universe has been expanding. Space itself is expanding, just as the cake expanded between the raisins in their analogy. No matter whether you're looking from Earth or from an alien planet billions of miles away, all other galaxies are moving away from you as space expands. Galaxies farther from you move faster away from you, because there's more space expanding between you and those galaxies. That's how Big Bang theorists explain why light from the more distant galaxies is shifted farther to the red end of the spectrum. In fact, most astronomers now use this rule, known as Hubble's law, to measure the distance of an object from Earth—the bigger the redshift, the more distant the object. In 1965 two scientists made a blockbuster discovery that solidified the Big Bang theory. Arno Penzias and Robert Wilson of Bell Telephone Laboratories detected faint microwave radiation that came from all points of the sky. They and other physicists theorized that they were seeing the afterglow from the Big Bang's explosion. Since the Big Bang affected the entire universe at the same moment in time, the afterglow should permeate the entire universe and could be detected no matter what direction you looked. This afterglow is called the cosmic background radiation. Its wavelength and And it was indeed big. Penzias and Wilson had spotted the CMB, the predicted thermal echo of the universe's explosive birth. The landmark find put the Big Bang theory (Links to an external site.) on solid ground, suggesting that the cosmos did indeed grow from a tiny seed — a single point — about 13.8 billion years ago. The two radio astronomers won the 1978 Nobel Prize in physics for their work, sharing the award with Soviet scientist Pyotr Kapitsa. Source: https://www.space.com/25945-cosmic-microwave-background-discovery-50th-anniversary.html#:~:text=On%20May %2020%2C%201964%2C%20American,so%20pretty%20much%20by%20accident. (Links to an external site.) The cosmic microwave background (CMB) is thought to be leftover radiation from the Big Bang, or the time when the universe began. As the theory goes, when the universe was born it underwent a rapid inflation and expansion. (The universe is still expanding today, and the expansion rate appears different depending on where you look (Links to an external site.)). The CMB represents the heat left over from the Big Bang. You can't see the CMB with your naked eye, but it is everywhere in the universe. It is invisible to humans because it is so cold, just 2.725 degrees above absolute zero (minus 459.67 degrees Fahrenheit, or minus 273.15 degrees Celsius.) This means its radiation is most visible in the microwave part of the electromagnetic spectrum. Source: https://www.space.com/33892-cosmic-microwave-background.html (Links to an external site.) 1.2. The Evolution of Stars When you look at the sky at night, what do you see? The seemingly countless brilliant heavenly bodies that occupy the entire sky are our galaxies and stars. Have you ever wondered how they came to be? ___________________________________ Note: There are links on this page that will take you to a different webpage, outside of Canvas. You may explore them to learn more! __________________________________ LET'S EXPLORE! Star formation A star develops from a giant, slowly rotating cloud that is made up entirely or almost entirely of hydrogen and helium. Due to its own gravitational pull, the cloud behind to collapse inward, and as it shrinks, it spins more and more quickly, with the outer parts becoming a disk while the innermost parts become a roughly spherical clump. According to NASA, this collapsing material grows hotter and denser, forming a ball- shaped protostar (Links to an external site.) . When the heat and pressure in the protostar reaches about 1.8 million degrees Fahrenheit (1 million degrees Celsius), atomic nuclei that normally repel each other start fusing together, and the star ignites. Nuclear fusion converts a small amount of the mass of these atoms into extraordinary amounts of energy — for instance, 1 gram of mass converted entirely to energy would be equal to an explosion of roughly 22,000 tons of TNT. Evolution of stars The life cycles of stars follow patterns based mostly on their initial mass. These include intermediate-mass stars such as the sun, with half to eight times the mass of the sun, high-mass stars that are more than eight solar masses, and low-mass stars a tenth to half a solar mass in size. The greater a star's mass, the shorter its lifespan generally is. Objects smaller than a tenth of a solar mass do not have enough gravitational pull to ignite nuclear fusion — some might become failed stars known as brown dwarfs (Links to an external site.). Intermediate-mass stars An intermediate-mass star begins with a cloud that takes about 100,000 years to collapse into a protostar with a surface temperature of about 6,750 F (3,725 C). After hydrogen fusion starts, the result is a T-Tauri star (Links to an external site.) , a variable star that fluctuates in brightness. This star continues to collapse for roughly 10 million years until its expansion due to energy generated by nuclear fusion is balanced by its contraction from gravity, after which point it becomes a main-sequence star (Links to an external site.) that gets all its energy from hydrogen fusion in its core. The greater the mass of such a star, the more quickly it will use its hydrogen fuel and the shorter it stays on the main sequence. After all the hydrogen in the core is fused into helium, the star changes rapidly — without nuclear radiation to resist it, gravity immediately crushes matter down into the star's core, quickly heating the star. This causes the star's outer layers to expand enormously and to cool and glow red as they do so, rendering the star a red giant (Links to an external site.) . Helium starts fusing together in the core, and once the helium is gone, the core contracts and becomes hotter, once more expanding the star but making it bluer and brighter than before, blowing away its outermost layers. After the expanding shells of gas fade, the remaining core is left, a white dwarf (Links to an external site.) that consists mostly of carbon and oxygen with an initial temperature of roughly 180,000 degrees F (100,000 degrees C). Since white dwarves have no fuel left for fusion, they grow cooler and cooler over billions of years to become black dwarves (Links to an external site.) too faint to detect. (Our sun should leave the main sequence in about 5 billion years.) High-mass stars A high-mass star forms and dies quickly. These stars form from protostars in just 10,000 to 100,000 years. While on the main sequence, they are hot and blue, some 1,000 to 1 million times as luminous as the sun and are roughly 10 times wider. When they leave the main sequence, they become a bright red supergiant, and eventually become hot enough to fuse carbon into heavier elements. After some 10,000 years of such fusion, the result is an iron core roughly 3,800 miles wide (6,000 km), and since any more fusion would consume energy instead of liberating it, the star is doomed, as its nuclear radiation can no longer resist the force of gravity. When a star reaches a mass of more than 1.4 solar masses, electron pressure cannot support the core against further collapse, according to NASA. The result is a supernova. Gravity causes the core to collapse, making the core temperature rise to nearly 18 billion degrees F (10 billion degrees C), breaking the iron down into neutrons and neutrinos. In about one second, the core shrinks to about six miles (10 km) wide and rebounds just like a rubber ball that has been squeezed, sending a shock wave through the star that causes fusion to occur in the outlying layers. The star then explodes in a so-called Type II supernova. If the remaining stellar core was less than roughly three solar masses large, it becomes a neutron star (Links to an external site.) made up nearly entirely of neutrons, and rotating neutron stars that beam out detectable radio pulses are known as pulsars. If the stellar core was larger than about three solar Matter farther out in the disk was also clumping together. These clumps smashed into one another, forming larger and larger objects. Some of them grew big enough for their gravity to shape them into spheres, becoming planets, dwarf planets and large moons. In other cases, planets did not form: the asteroid belt is made of bits and pieces of the early solar system that could never quite come together into a planet. Other smaller leftover pieces became asteroids, comets, meteoroids, and small, irregular moons. Structure The order and arrangement of the planets and other bodies in our solar system is due to the way the solar system formed. Nearest the Sun, only rocky material could withstand the heat when the solar system was young. For this reason, the first four planets— Mercury, Venus, Earth and Mars—are terrestrial planets. They're small with solid, rocky surfaces. Meanwhile, materials we are used to seeing as ice, liquid or gas settled in the outer regions of the young solar system. Gravity pulled these materials together, and that is where we find gas giants Jupiter and Saturn and ice giants Uranus and Neptune Potential for Life Our solar system is the only place we know of that harbors life, but the farther we explore the more we find potential for life in other places. Both Jupiter’s moon Europa and Saturn’s moon Enceladus have global saltwater oceans under thick, icy shells. Source: https://solarsystem.nasa.gov/solar-system/our-solar-system/in-depth/ #:~:text=Our%20solar%20system%20formed%20about,spinning%2C%20swirling %20disk%20of%20material. 1.4. The Earth and its Moon Finally! We have landed on Earth. We have discussed so far the theories about the origin of the universe, the formation and evolution of stars, and the formation of our very own solar system in the Milky Way Galaxy. Now we explore the history of our own planet and its sole satellite, the moon. ___________________________________ Note: There are links on this page that will take you to a different webpage, outside of Canvas. You may explore them to learn more! __________________________________ LET'S EXPLORE! After the sun spun to light, the planets of the solar system began to form (Links to an external site.). Although planets surround stars in the galaxy, how they form remains a subject of debate. Despite the wealth of worlds in our own solar system, scientists still aren't certain how planets are built. Currently, two theories are duking it out for the role of champion. The first and most widely accepted theory, core accretion, works well with the formation of the terrestrial planets like Earth (Links to an external site.) but has problems with giant planets. The second, the disk instability method, may account for the creation of these giant planets. Scientists are continuing to study planets in and out of the solar system in an effort to better understand which of these methods is most accurate. The core accretion model Approximately 4.6 billion years ago, the solar system was a cloud of dust and gas known as a solar nebula. Gravity collapsed the material in on itself as it began to spin, forming the sun in the center of the nebula. With the rise of the sun, the remaining material began to clump up (Links to an external site.). Small particles drew together, bound by the force of gravity, into larger particles. The solar wind swept away lighter elements, such as hydrogen and helium, from the closer regions, leaving only heavy, rocky materials to create smaller terrestrial worlds (Links to an external site.) like Earth. But farther away, the solar winds had less impact on lighter elements, allowing them to coalesce into gas giants. In this way, asteroids (Links to an external site.) , comets (Links to an external site.) , planets, and moons were created. Earth's rocky core (Links to an external site.) formed first, with heavy elements colliding and binding together. Dense material sank to the center, while the lighter material created the crust. The planet's magnetic field probably formed around this time. Gravity captured some of the gases that made up the planet's early atmosphere. Early in its evolution, Earth suffered an impact by a large body that catapulted pieces of the young planet's mantle into space. Gravity caused many of these pieces to draw together and form the moon, which took up orbit around its creator. The flow of the mantle beneath the crust causes plate tectonics, the movement of the large plates of rock on the surface of the Earth. Collisions and friction gave rise to mountains and volcanoes, which began to spew gases into the atmosphere (Links to an external site.). Although the population of comets and asteroids passing through the inner solar system is sparse today, they were more abundant when the planets and sun were young. Collisions from these icy bodies likely deposited much of the Earth's water on its surface. Because the planet is in the Goldilocks zone, the region where liquid water neither freezes nor evaporates (Links to an external site.) but can remain as a liquid, the water remained at the surface, which many scientists think plays a key role in the development of life (Links to an external site.) . Exoplanet observations seem to confirm core accretion as the dominant formation process. Stars with more "metals" — a term astronomers use for elements other than hydrogen and helium — in their cores have more giant planets than their metal-poor cousins. According to NASA (Links to an external site.) , core accretion suggests that small, rocky worlds should be more common than the more massive gas giants. The disk instability model Although the core accretion model works fine for terrestrial planets, gas giants would have needed to evolve rapidly to grab hold of the significant mass of lighter gases they contain. But simulations have not been able to account for this rapid formation. According to models, the process takes several million years, longer than the light gases were available in the early solar system. At the same time, the core accretion model faces a migration issue, as the baby planets are likely to spiral into the sun in a short amount of time. According to a relatively new theory, disk instability (Links to an external site.) , clumps of dust and gas are bound together early in the life of the solar system. Over time, these clumps slowly compact into a giant planet. These planets can form faster than their core accretion rivals, sometimes in as little as a thousand years, allowing them to trap the rapidly-vanishing lighter gases. They also quickly reach an orbit-stabilizing mass that keeps them from death-marching into the sun. Source: https://www.space.com/19175-how-was-earth-formed.html (Links to an external site.) The Moon After the solar system was formed, it took another hundred million years for Earth's moon to spring into existence. There are three theories as to how our planet's satellite could have been created: the giant impact hypothesis, the co-formation theory and the capture theory. Giant impact hypothesis The prevailing theory supported by the scientific community, the giant impact hypothesis suggests that the moon formed when an object smashed into early Earth. Like the other planets, Earth formed from the leftover cloud of dust and gas orbiting the young sun. The early solar system was a violent place, and a number of bodies were created that never made it to full planetary status. One of these could have crashed into Earth (Links to an external site.) not long after the young planet was created. Earth's rocky core (Links to an external site.) formed first, with heavy elements colliding and binding together. Dense material sank to the center, while the lighter material created the crust. The planet's magnetic field probably formed around this time. Gravity captured some of the gases that made up the planet's early atmosphere. Early in its evolution, Earth suffered an impact by a large body that catapulted pieces of the young planet's mantle into space. Gravity caused many of these pieces to draw together and form the moon, which took up orbit around its creator. The flow of the mantle beneath the crust causes plate tectonics, the movement of the large plates of rock on the surface of the Earth. Collisions and friction gave rise to mountains and volcanoes, which began to spew gases into the atmosphere (Links to an external site.). Although the population of comets and asteroids passing through the inner solar system is sparse today, they were more abundant when the planets and sun were young. Collisions from these icy bodies likely deposited much of the Earth's water on its surface. Because the planet is in the Goldilocks zone, the region where liquid water neither freezes nor evaporates (Links to an external site.) but can remain as a liquid, the water remained at the surface, which many scientists think plays a key role in the development of life (Links to an external site.) . Exoplanet observations seem to confirm core accretion as the dominant formation process. Stars with more "metals" — a term astronomers use for elements other than hydrogen and helium — in their cores have more giant planets than their metal-poor cousins. According to NASA (Links to an external site.) , core accretion suggests that small, rocky worlds should be more common than the more massive gas giants. The disk instability model Although the core accretion model works fine for terrestrial planets, gas giants would have needed to evolve rapidly to grab hold of the significant mass of lighter gases they contain. But simulations have not been able to account for this rapid formation. According to models, the process takes several million years, longer than the light gases were available in the early solar system. At the same time, the core accretion model faces a migration issue, as the baby planets are likely to spiral into the sun in a short amount of time. According to a relatively new theory, disk instability (Links to an external site.) , clumps of dust and gas are bound together early in the life of the solar system. Over time, these clumps slowly compact into a giant planet. These planets can form faster than their core accretion rivals, sometimes in as little as a thousand years, allowing them to trap the rapidly-vanishing lighter gases. They also quickly reach an orbit-stabilizing mass that keeps them from death-marching into the sun. Source: https://www.space.com/19175-how-was-earth-formed.html (Links to an external site.) The Moon After the solar system was formed, it took another hundred million years for Earth's moon to spring into existence. There are three theories as to how our planet's satellite could have been created: the giant impact hypothesis, the co-formation theory and the capture theory. Giant impact hypothesis The prevailing theory supported by the scientific community, the giant impact hypothesis suggests that the moon formed when an object smashed into early Earth. Like the other planets, Earth formed from the leftover cloud of dust and gas orbiting the young sun. The early solar system was a violent place, and a number of bodies were created that never made it to full planetary status. One of these could have crashed into Earth (Links to an external site.) not long after the young planet was created. Known as Theia, the Mars-sized body collided with Earth, throwing vaporized chunks of the young planet's crust into space. Gravity bound the ejected particles together, creating a moon that is the largest (Links to an external site.) in the solar system in relation to its host planet. This sort of formation would explain why the moon is made up predominantly of lighter elements, making it less dense than Earth — the material that formed it came from the crust, while leaving the planet's rocky core untouched. As the material drew together (Links to an external site.) around what was left of Theia's core, it would have centered near Earth's ecliptic plane, the path the sun travels through the sky, which is where the moon orbits today (Links to an external site.) . According to NASA (Links to an external site.) , "When the young Earth and this rogue body collided, the energy involved was 100 million times larger than the much later event believed to have wiped out the dinosaurs." Co-formation theory Moons can also form at the same time as their parent planet. Under such an explanation, gravity would have caused material in the early solar system to draw together at the same time as gravity bound particles together to form Earth. Such a moon would have a very similar composition to the planet, and would explain the moon's present location. However, although Earth and the moon share much of the same material, the moon is much less dense than our planet, which would likely not be the case if both started with the same heavy elements at their core. Capture theory Perhaps Earth's gravity snagged a passing body, as happened with other moons (Links to an external site.) in the solar system, such as the Martian moons of Phobos and Deimos. Under the capture theory, a rocky body formed elsewhere in the solar system could have been drawn into orbit around Earth. The capture theory would explain the differences in the composition of Earth and its moon. However, such orbiters are often oddly shaped, rather than being spherical bodies like the moon. Their paths don't tend to line up with the ecliptic of their parent planet, also unlike the moon. Although the co-formation theory and the capture theory both explain some elements of the existence of the moon, they leave many questions unanswered. At present, the giant impact hypothesis seems to cover many of these questions, making it the best model to fit the scientific evidence for how the moon was created. Source: https://www.space.com/19275-moon-formation.html (Links to an external site.) 1.5. The Earth's subsystems LET'S EXPLORE! The Earth is considered as the living planet in the solar system. Life on earth needs three main components in order to survive. These are the source of heat, presence of liquid water and atmosphere. The sun is our source of heat. It provides the energy used for the production of carbohydrates that sustain life. Water, as was mentioned before, is capable of transforming between the different states of matter, e.g. solid, liquid and gas, but it was the presence of liquid water that initially gave rise to single-cell organisms that later on evolved into complex organisms. The presence of the atmosphere also ensures the availability of gases that organisms need to thrive. It also provided a barrier that protects the earth's surface from the harmful rays of the sun, and to maintain our surface temperature, a process known as greenhouse effect.  Think of the many ways that the hydrosphere and the atmosphere connect. Evaporation from the hydrosphere provides the medium for cloud and rain formation in the atmosphere. The atmosphere brings back rainwater to the hydrosphere.  In what way do the geosphere and hydrosphere connect? Water provides the moisture and medium for weathering and erosion of rocks on in the geosphere. The geosphere, in turn, provides the platform for ice melts and water bodies to flow back into the oceans.  The atmosphere provides the geosphere with heat and energy needed for rock breakdown and erosion. The geosphere, in turn, reflects the sun’s energy back into the atmosphere.  The biosphere receives gases, heat, and sunlight (energy) from the atmosphere. It receives water from the hydrosphere and a living medium from the geosphere. Source: https://eschooltoday.com/learn/interaction/ (Links to an external site.) ADDITIONAL READING Another way to look at the interaction of the different subsystems is through the biogeochemical cycles. Read about the different biogeochemical cycles to answer the following: 1. What are the common biogeochemical cycles? 2. Do you see the movement of energy and matter from one subsystem to another through these cycles? 3. Is Earth a closed system? Why or why not? 4. Are humans considered to be part of the biosphere? Do you or do you not agree? Here is your work: 1. Search a book or videos about "Did God Create the Universe?" by Stephen Hawking. 2. Make a reflection paper out of it, there should be an INTRODUCTION, BODY, and CONCLUSION. A guide questions were given for the content of your paper. 3. At least 200 words. Guide Questions: 1. How the Universe created based on what you've read or watched in the videos of Stephen Hawking? 2. What are the concepts relating to the Origin of the Universe topic that used to explain this matter? 3. How important to be open minded about the views of religious cosmology and scientific explanation about the Origin of the Universe?