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

1. Pertemuan ke-2 The Origin of the Earth, its Oceans and Life in the Oceans (Asal-usulbumi, lautdankehidupandilaut) i.wayan.nurjaya@ipb.ac.id

2. The Universe • Galaxies • Stars • Planets

3. Cosmology • Is the study of the universes origin, evolution and current nature. • Observations are made by measuring electromagnetic radiation, observing the movement of stars, and by determining the mass and density of the universe. • Theories are developed by these observations.

4. Doppler Effect • Is the changing length of light or sound waves as an object moves closer or further away from an observer. • With light, as an object moves closer light waves are compressed and become blue-shifted, as an object moves away the light waves become stretched and becomered-shifted.

5. RED BLUE

6. The Origin of the Universe • The Big Bang Theoryis 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. 1 billion=109 i.wayan.nurjaya@ipb.ac.id

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8. Timeline of the Big Bang i.wayan.nurjaya@ipb.ac.id

9. Inflationary Model • Universe began a fluctuation in a vacuum, expanded explosively fast in fractions of a second, then went into ordinary expansion, H = expansion constant which is used to estimate the age of the universe.

10. 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 ) i.wayan.nurjaya@ipb.ac.id

11. Steady State Theory Universe looks the same on a large scale to all observers and has always looked that way. In order to maintain the same density matter is created as it expands.

12. Big Bang Favored Theory • Reason why: Steady state cannot explain- Cosmic Background Radiation (CBR) – this is the persistent background noise a radio antennae picks up. Believed to be the remnants of the Big Bang explosion. It comes from all directions in space and has a temperature that relates to an object of 273.5K (-2700C) .

13. 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. i.wayan.nurjaya@ipb.ac.id

14. Hubble’s Law • Hubble observed that more distant galaxies were moving away at a faster rate (larger red shifts) than closer galaxies. The relationship between distance and speed is known as Hubble’s Law, galaxies are not expanding, the space between them is. V= Hd v= speed (km/sec) at which galaxy is moving away, H = Hubble’s constant measured in km/sec/mpc (speed/distance), and d= distance to the galaxy measure in megaparsecs (Mpc) • He concluded that the universe is expanding. • Given the speed of a galaxy and a graph of the Hubble constant the distance of very remote galaxies can be determined.

15. 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 nucleosynthesis. Within just one day’s time, nucleosynthesisproduced 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.

16. Expanding Universe • The early universe continued to expand like a cloud of hotgases. Over the next billion years, gravity compressed pockets of these gases into the first stars and galaxies. i.wayan.nurjaya@ipb.ac.id

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18. Galaxies and Stars • A star is a massive sphere of incandescent gases (gas pijar). A galaxy is 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 i.wayan.nurjaya@ipb.ac.id

19. Galaxies

20. Galaxies are groups of stars that have a galactic center, nucleus, around which stars move. • Galaxies have different shapes and sizes. • Galaxies are classified according to their shape. • Clusters of galaxies exist in the universe.

21. Galaxy Classification Andromeda NGC1300 • Spiral Galaxies 1) Normal Spirals – arms extend directly from nucleus 2) Barred Spiral – elongated central region extends from nucleus with arms out from either side of bar.

22. Galaxy Classification • Elliptical Galaxies – are not flattened and there are no spiral arms. • Irregular Galaxies – all other galaxies that do not fit into spiral or elliptical.

23. Galactic Mass • Galaxies average range in size from as small as 1 million suns to as many as 100 billion suns. • Giant elliptical galaxies can be as massive as 100 trillion suns.

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25. A light year is a unit of measure used by astronomers to describe distance within the universe and is equal to the distance traveled by light at speed of 300,000 km/sduring a period of one year, almost 10 trilliun (9.8 x 1012 km)

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27. Democritus (460 – 370 B.C.) Greek astronomer who first discovered the “Milky Way” and claimed it was made up of billions of stars far away. (not confirmed until much later).

28. Edwin Hubble (1889 – 1953) Confirmed the existence of galaxies in 1924 when he measured the distance of Cepheid variable stars in the Andromeda constellation to be too far away to be in our galaxy.

29. Formation of the Milky Way Galaxy • Most likely started as an elliptical galaxy making up the halo and nucleus present today. Eventually collapsed under it’s own gravity and began to rotate forming a disc-like shape. Elliptical

30. Dimensions of the Milky Way Galaxy • It is a spiral shaped galaxy, possibly a barred spiral galaxy. • About 100,000 light years across. 946,073,047,258,080,000 km ~ 946 quadrillion km 587,862,537,318,361,000 mi. ~ 588 quadrillion mi. • About 1,000 light years thick. • Consists of 200 to 400 billion stars • Consists of a massive galactic center that bulges out with spiral arms extending outward from center.

31. 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. i.wayan.nurjaya@ipb.ac.id

32. 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. i.wayan.nurjaya@ipb.ac.id

33. Axis of rotation Axis of rotation Approx. 1 light year Axis of rotation Rotation retards collapse in this direction Gravity makes cloud shrink. As it shrinks it spins caster and flattens into a disk with central bulge. Slowly spinning interstellar cloud Approx. 100 AU

36. 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. i.wayan.nurjaya@ipb.ac.id

37. 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. i.wayan.nurjaya@ipb.ac.id

38. 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. i.wayan.nurjaya@ipb.ac.id

39. 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. i.wayan.nurjaya@ipb.ac.id

40. 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. i.wayan.nurjaya@ipb.ac.id

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43. 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. i.wayan.nurjaya@ipb.ac.id

44. 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. i.wayan.nurjaya@ipb.ac.id

45. Origin of the Atmosphere • Suns energy stripped away 1st atmosphere • 2nd atmosphere formed from volcanic out gassing • Primitive atmosphere: CO2, water vapor, lesser amts of CO, N2, H2, HCl, and traces of NH3 and CH4(3.5 bya) i.wayan.nurjaya@ipb.ac.id

46. 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. i.wayan.nurjaya@ipb.ac.id

47. Formation of Earth’s Oceans: Off gassing of water vapor from volcano Condensation Rain i.wayan.nurjaya@ipb.ac.id

48. 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. i.wayan.nurjaya@ipb.ac.id

49. 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. i.wayan.nurjaya@ipb.ac.id

50. 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 one-third to one-half 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. i.wayan.nurjaya@ipb.ac.id