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The Origin of the Earth, its Oceans and Life in the Oceans

Pertemuan ke-2. The Origin of the Earth, its Oceans and Life in the Oceans . ( Asal-usul bumi , laut dan kehidupan di laut ). Course Outline . 1. The Origin of the Cosmos (Universe) . The Galaxies and Stars The Elements. 2. The Sun and the Solar System. 3. The Origins of the Earth.

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The Origin of the Earth, its Oceans and Life in the Oceans

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  1. Pertemuan ke-2 The Origin of the Earth, its Oceans and Life in the Oceans (Asal-usulbumi, lautdankehidupandilaut) The big bang theory

  2. Course Outline 1. The Origin of the Cosmos (Universe) The Galaxies and Stars The Elements 2. The Sun and the Solar System 3. The Origins of the Earth The Geological Time Scale The Origin of the Oceans and Atmosphere The Original Continents The Moon Life Form in the Oceans asalod

  3. Hubble SpaceTelescope asalod

  4. Quintuplet Cluster Messier asalod Neutron Star Magnetar Dying Star

  5. BeberapaIstilah: • Star(bintang): ‘bola’ (sphere) masivberupa gas pijar (terlihatbanyakdiangkasa) • Galaxy: Kumpulan bintang, debu, gas dandebuangkasalainnya yang berotasidanberadabersamaolehgayatarikgravitasi. • Universeataucosmos (cakrawala): kumpulangalaxy. Kira2 terdapat 100 juta galaxy yang teramati dg teleskopkita. • Planetberadasatusistemdenganbintangdanbergerakmengitarinya • Satelit, bendaangkasa yang mengelilingi planet, mis. Bulan. • 1 TahunCahaya: Kec. cahaya (~3.105 km/s) x 1 tahun (31536000 s) = 9.8 . 1012 km asalod

  6. Galaxy Milky Way • Galaxy dimanatatasuryakitaberada) • diameter cakram: 100,000 tahuncahaya (TC); tebalcakram 10,000-15,000 TC • Tata suryabeserta ke-9 planetnyaberadasekitar 2/3 darisisiluar Galaxy ini. • Tata suryamengikutipergerakan Galaxy MW dengankec. ~ 280 km/s • didalam Galaxy MW terdapat ~1011bintang, ygmanapuluhanjutabinangitumemiliki planet danmakhluknya. asalod

  7. Tata Surya (Solar System) • 9 planet • Terdekat: Merkurius • Terjauh: Pluto a. Ukuran relatif planet dan surya Planet yang terdekatdgnmtharilebihkecil Karenaemisipartikeldarimthariygterionisasidanpemanasan internal planet itusendiri a. Orbitplanet dari Tata Surya asalod

  8. Denganmengamatienergicahaya yang memancar dari galaxy, astronomermampumenentukanbahwahampirsemuagalaxysedangmenjauhisatusamalainnya, padakecepatan ~240,000 km/s (3/4 keccahaya !). Salingmenjauhnyagalaxy 2 tersebutdidugasebagai serpihan2 hasil dari suatuledakan, yang berasal dari satu massa yang sama. Jikahalinisebagaikenyataan, waktu yang diperlukan dari ledakantsbsampaikeadaansaatiniadalah ~15 milyartahun. Big Bang Theory asalod

  9. The Origin of the Universe • The Big Bang Theory is the prevailing scientific explanation of the origin of the universe. • This theory proposes that at one time all matter was concentrated into a single, extremely dense body. • Then about 15 billion years ago, a tremendous explosion sent this matter hurling outward into space. asalod 1 billion=109

  10. DasarUtama • Energicahaya yang hasilradiasigalaxi, makinjauhmakinrendahenergi (shifting spektrum) • Galaxisalingmenjauhikarenaadaledakan • Apasemuapernahberkumpul, tidakpasti? • Waktuuntuksampaiposisisekarang ~15 miliarthn asalod

  11. Timeline of the Big Bang asalod

  12. THE COMPETITORS … FOR THE THEORY ON ORIGIN OF THE UNIVERSE • The Bubble Universe / Andre Linde's Self Creating Universe • The Inflationary Theory (1981, Alan Guth ) • The Proto-universe (white hole theory) • The Steady State Theory (late 1940’s ) • The Oscillating Universe Theory (1960’s -70’s ) asalod

  13. Formation of the Elements Within minutes, the universe expanded to an enormous size and cooled enough to allow protons and neutrons to fuse together to form atomic nuclei, a process known as nucleo-synthesis. Within just one day’s time, nucleo-synthesis produced nearly all of the hydrogen and helium nuclei in existence today. Hydrogen and helium are the lightest and most abundant elements in the universe. Heavier elements account for only about 0.1% of all the elements in the universe. asalod

  14. Evidences for the Big Bang • Galaxies are moving away from us at speeds proportional to their distance. This is called "Hubble's Law," named after Edwin Hubble (1889-1953) who discovered this phenomenon in 1929 • The abundance of the "light elements" Hydrogen and Helium found in the observable universe are thought to support the Big Bang model of origins • Cosmic Background Radiation predicted by Cosmologist George Gamov in 1948 and discovered by Arno Penzias & Robert Wilson of Bell Labs in 1965. asalod

  15. Expanding Universe The early universe continued to expand like a cloud of hot gases. Over the next billion years, gravity compressed pockets of these gases into the first stars and galaxies.

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  17. Galaxies and Stars A star is a massive sphere of incandescent gases (gas pijar). A galaxyis a rotating collection of stars, dust, gas, and other interstellar debris held together by gravitational attraction. The universe may contain as many as 50 billion galaxies, each with nearly 50 billion stars asalod

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  19. Production of Heavier Elements • Most stars “burn” hydrogen to produce helium and energy. Four hydrogen atoms fuse to form a helium atom. • In this process a small amount of matter is converted into a vast amount of energy. • After a star has burned most of its hydrogen, it collapses. • If it is large enough, the collapsed star then burns helium, forming the heavier elements of carbon and oxygen. • Red giants (massive stars) undergo this cycle of fuel burning/collapse several times, forming silicon, magnesium, and heavier elements. asalod

  20. Supernovas • When all of a large star’s fuel is consumed, it undergoes a final sudden collapse, then explodes violently in a supernova, propelling much of its matter into space. • The force of the supernova produces neutrons that collide with other atoms from the exploding star to form the heavier elements, which are thrust into space to become part of the interstellar dust. asalod

  21. Origin of the Solar System • The sun and the planets of the solar system have a common origin, all coalescing from the solar nebula, a rotating cloud of interstellar dust and gas enriched with heavy elements released by supernovas. • The rotation of the nebula caused it to flatten, and gravity contracted the material near the center into a protosun. • Material farther from the center accumulated into the planets. asalod

  22. The Solar Wind • Once the internal temperature of the protosun increased to the point where hydrogen atoms fused into helium, it became the sun. • The intense solar wind produced when the sun “lit” swept most of the gaseous elements out of the inner solar system. • The elements that remained to form the Earth were oxygen (mostly bound to metals), silicon, iron, aluminum, calcium, magnesium, sodium, and potassium, the elements that constitute most of the rocks found on the Earth today. asalod

  23. The Evolution of Earth Our planet accumulated from the interstellar material by accretion. Centimeter-sized particles and gases condensed into kilometer-scale planetesimals(small proto-planets). The planetesimals were drawn together by gravity and fused into a planet. asalod

  24. Differentiation of the Earth’s Interior • The earth’s original composition was uniform throughout. • Late in the accretion stage, frequent collisions with meteors and other debris from outer space caused the surface of the planet to heat up. • Additional heating from the decay of radioactive elements within the earth caused the whole planet to melt! • Gravity pulled the heavy iron inward to form the mantle and core. • Lighter materials of silicon, magnesium, aluminum, and oxygen-bonded compounds migrated upward. • About 4.6 billion years ago, the first hard surfaces crystallized into the crust. asalod

  25. The Geologic Time Scale • Scientists have detailed the Earth’s history dating back 4.6 billion years in the Geologic Time Scale. • This scale is divided into a hierarchical set of increasingly smaller units of time, such as eons, eras, periods, epochs, and ages. asalod

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  28. The Early Atmosphere • The atmosphere began to form about 4.4 billion years ago during the Precambrian period. • Frequent volcanic eruptions and earthquakes allowed carbon dioxide, nitrogen, and other gases trapped inside the planet to escape (outgas) and form the atmosphere. • The degassing of comets plunging to the earth’s surface also released quantities of ammonia, methane, and water vapor into the atmosphere. asalod

  29. Composition of the Atmosphere • The levels of carbon dioxide were as much as 1,000 times present levels. • Because oxygen rapidly bonded to metals in the crust to form oxides, like the rusting of iron, there was no oxygen present in the early atmosphere. • Water vapor was so abundant in the primordial atmosphere from out gassing that the atmospheric pressure was several times greater than today. asalod

  30. Origin of the Atmosphere • Suns energy stripped away 1st atmosphere • 2nd atmosphere formed from volcanic out gassing • Primitive atmosphere: CO2, water vapor, lesser atmsof CO, N2, H2, HCl, and traces of NH3 and CH4 (3.5 billion year ago) asalod

  31. The Blue Planet • After several million years, the atmosphere cooled sufficiently to allow the water vapor to condense into thick clouds which cloaked the entire planet. • Rain began to fall from the sky, cooling the surface. • Rainwater collected in craters and basins, where it evaporated, cooled and fell again. • A period of heavy rains deluged the planet for some 10 million years. • When the rains ceased and the skies cleared, the Earth emerged as a blue planet carpeted by an ocean almost two miles deep, sprinkled with volcanic islands. asalod

  32. Formation of Earth’s Oceans: • Off gassing of water vapor from volcano • Condensation • Rain asalod

  33. The Continents • Originally, there was little, if any, continental land mass. • Underlying the sea is a layer of oceanic crust about 8 km thick, primarily composed of basalt, a dense, iron-rich rock of volcanic origin. • Continental crust is thicker (20–70 km), and typically composed of lighter, granitic rock distilled from the repeated recycling of mantle material and oceanic crust (a process discussed in the next lesson). • The first continental crust probably came into existence at a few isolated island arcs and has accumulated over time into the large land masses we know today. • Explanations describing the origin and evolution of the continents are still highly speculative. asalod

  34. The First Supercontinent • By the end of the Precambrian period, approximately 700 million years ago, all land masses had gathered into the single supercontinent Rodinia, surrounded by the Panthalassic Ocean. asalod

  35. The Moon • Ocean tides are a primarily a result of an interplay of forces between the Earth and the Moon. The leading theory of the Moon’s origin is the giant impact hypothesis. At the time Earth formed, other smaller planetary bodies were also growing nearby. One of these bodies, about 1/3 to 1/2 the size of Earth, struck the Earth late in its growth process. Debris from that collision went into orbit around the Earth and aggregated into the moon. asalod

  36. The Moon and the Earth • The Moon, the largest in the solar system relative to its mother planet, may have stabilized the tilt of the planet’s rotational axis that produces the seasons. • Without the Moon, Earth might experience the extreme and hostile fluctuations in weather and climate observed on Mars. asalod

  37. Origin of life • Life began~ 3.5 billion-year-ago (bya) • Organic molecules (C H O N P S) swimming in shallow seas Stage 1: Abioticsynthesis of organic molecules such as proteins, amino acids and nucleotides asalod

  38. Stage 2: joining of small molecules (monomers) into large molecules asalod

  39. Stage 3: origin of self-replicating molecules that eventually made inheritance possible asalod

  40. Stage 4: packaging these molecules into pre-cells, droplets of molecules with membranes that maintained an internal chemistry asalod

  41. Thomas Huxley- Search for origin of life Bathybiasheckalii- primordial ooze (sedimenyglunak) Wyville Thompson: HMS Challenger (1872-1876) found it was actually diatomacous ooze reacting with seawater and ethyl alcohol Also, disproved Forbes’ Azoic Theory (1868-1870) asalod

  42. electrodes CH4 NH3 H2 water vapor spark condenser water containing organic compounds boiling water Miller & Urey (1953)- mixed water vapor, NH3, CH4, H2 + electric spark  amino acids and other organic compounds Synthesis of OrganicMolecules Methane, ammonia, and hydrogenadded

  43. Produced: • 20 amino acids • Several sugars • Lipids • Purine and pyrimidine bases (found in DNA, RNA & ATP) asalod

  44. chemosynthetic bacteria (extremophiles) Chemosynthesis: 02 + 4H2S + C02 CH20 + 4S +3H20 Stromatolites (bacteria &cyanobacteria) Oldest fossils found in western Australia and southern Africa ~ 3.5 bya Photosynthesis: 6H2O + 6CO2 + nutrients + light energy C6H12O6 + 6O2 asalod

  45. Stromatolites mostly cyano Stromatolites from Shark’s Bay Australia asalod

  46. Where did life begin?? asalod

  47. PANSPERMIA THEORY • Organic compounds arrived from outer space • It states that hydrocarbons and other organic molecules (molecules that organisms contain or that might lead to the genesis of life) have been found in meteorites – • It means that at least prebiotic chemistry that leads to the primordial soup might be going on there. asalod

  48. Evidences in support of this theory • In 1969, a meteorite landed in Australia that was 12% water and contained traces of 92 amino acids. • It points to not only the presence of organic compounds in outer space, but also the capacity of such compounds to reach earth. • Fred Hoyle and Chandra Wickramasinghehave argued persistently since the 1970s that complex organic substances, and perhaps even primitive organisms, might have evolved on the surface of comic dust grains in space and then been transported to the Earth's surface by comets and meteorites. asalod

  49. Where did life begin ??? • There is an ongoing debate regarding the most probable site of life's origins. • The prevailing paradigm - life began near the ocean's surface, bathed in sunlight. • Current Research - life arose near deep hydrothermal ventswhich is still under investigation. "Scientists have long suspected that life on Earth originated in the ocean and strong evidence now suggests that the earliest life on our planet occurred in the depths of the ocean in the absence of heat and light." -- Pulse of the Planet, American Museum of Natural History asalod

  50. Photograph from National Geographic magazine asalod

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