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EARTH AND LIFE SCIENCE REVIEWER
© angelica garcia
EARTH SCIENCE
all the sciences that collectively seek to understand Earth and its neighbors in space
I. ASTRONOMY
- the study of the universe
- very useful in probing the origins of our own environment II. METEOROLOGY
- study of the atmosphere and the processes that produce weather and climate III. GEOLOGY
- Study of the earth
- Study of solid earth , the rocks of which it is composed and the processes by which they change. A. Physical Examines the materials composing earth and the processes that operate beneath and upon its surface. B. Historical Aim to understand the origin of Earth and development of the planet through its 4.5- billion-year history IV. OCEANOGRAPHY
- the study of the composition and movements of seawater, coastal processes, seafloor topography and marine life
THE UNIVERSE
Theories on the Creation of the Universe
1. BIBLICAL CREATION - came from the bible - States that the entire cosmos was created in 6 days by a Supreme Being. 2. BIG BANG THEORY (1920) - Alexander Friedman and George Lamaitre - Universe started with a huge explosion 13.7 Billion years ago. - Explains what happened at the very beginning - “The Universe started with a cataclysm that created space and time and all the matter and energy that has ever existed in the universe” - Caused by random fluctuation in an empty void. Then there was a great explosion and expansion. Evidences:
- The red shift of galaxies supports the big bang and the expanding universe theories.
- Scientists discovered a type of energy called cosmic background radiation (CMB). Scientists think that this radiation was produced during the big bang.
- Abundance of light elements: helium, hydrogen, and lithium beryllium confirms occurrence of the big bang nucleosynthesis. Red Shift aka Doppler Shift
- Red shift, or a Doppler shift toward the red end of the spectrum, occurs because the light waves are “stretched,” which shows that Earth and the source are moving away from each other.
Hubble’s Law
- Hubble’s law is a law that states that the galaxies are retreating from the Milky Way at a speed that is proportional to their distance.
- Analogy for an expanding universe: as the dough rises, raisins (galaxies) originally farthest apart travel greater distances than those located closer together. Thus, in an expanding universe (as with the raisins) more space is created between two objects that are farther apart than between two objects that are closer together. Fate of the Universe
- Scenario 1: the outward flight of the galaxies will slow and eventually stop
- Scenario 2: the universe will continue to expand 3. Steady State Theory (1948)
- Bendi, Gold, and Hoyle
- “The Universe has no beginning and end.”
- Density of matter is constant over time
- The universe remained the same all throughout time
- Proposed that the universe is **unchanging in time and uniform in space
- Inflation Theory**
- Alan Guth, Andrei Linde, Paul Steinhart, and Andy Albrecht
- Extension of the Big Bang Theory
- Proposed a period of exponential expansion of the universe.
- It could appear flat even though it has been curved at the start
- Offers solution to unresolved problems of the big bang theory. a. FLATNESS Big bang states there should be curvature Things will appear flat even though it is curved b. MONOPOLE Big bang predicts production of magnetic poles Monopoles dropped exponentially to undetectable level during rapid expansion c. HORIZON Big bang states that space in opposite direction are so far apart they could never have contact with each other Exponential expansion in early universe presupposes that the distant regions were much closer to each other prior to inflation 5. STRING THEORY
- Suggests that subatomic particles do not exist. Instead, tiny piece of vibrating string is too small to be observed in today’s instrument replaced the subatomic particles
- Before the Big Bang
- Form the combination of Einstein’s theory of relativity and Quantum Mechanics
- Strings may be open or closed (measures roughly around 1.6 x 10-35^ mm)
- Replaced by a fundamental block that can either be closed or open.
- The vibration may represent the different particle types. (Electron and Photon)
6. M-THEORY
- Unification of Strings
- Universe is a result of the contact of two hyper-dimensional branes.
- Considers 11 space-time dimensions:
a. We are familiar with the x, y, z and time
b. The other 7 space-time dimensions are so tiny and curled up that they are undetectable.
5. Solar-Nebular Theory - Describes the formation of our solar system from condensation of interstellar gas and dust cloud. Due to gravity , it began to condense the solar nebula, with the center becoming a protostar. As the cloud continued to shrink, rotational speed increased and became a rapidly rotating disk. The contraction converted gravitational energy into heat energy and caused the center to glow. When the temperature is sufficient enough, a nuclear reaction began at the core of the protostar and became the SUN. - The remaining gas and dust cloud form diskshaped bodies (due to rotation) called SOLAR NEBULAE. Formation of the planets involved: a. Accretion of grain-sized particles to form cm-sized particles which later grew to several km in distance b. Formation of more massive objects from coalescing planetisimals PROTOPLANETS PLANETS 6. Condensation Theory - The solar system formed a large spinning cloud of gas and dust, called the solar nebula. - Once gravity pulled it to a diameter of less than 100au, the solar nebula had become a wide rotating disc 7. Fission Theory - One day, our sun burst open , and planets, and moons shot out at high speeds and went to their respective places, then stopped, and started orbiting the sun, as the moons began orbiting the planets. 8. Capture Theory - Planets and moons were flying around, and some were captured by our sun and began circling. 9. Accretion Theory - A pile of space dust and rock chunks pushed together into our planet , and another pile pushed itself into our moon. Then the moon got close enough and began circling the earth. 10. Planetary Collision Theory - Our world collided with a small planet, and the explosion threw off rocks which became the moon and then it began orbiting us. 11. Stellar Collision Theory - Our planets, moons, and stars **spun off from the collision between stars
- Gas Cloud Theory**
- Gas clouds were captured by our sun but instead of being drawn to it, they began whirling and pushing themselves into the planets and moons.
Our Solar System
1. The sun 2. Four terrestrial inner planets. (MVEM) - Mercury - Venus - Earth - Mars
3. Four gas giant outer planets. (JSUN) - Jupiter - Saturn - Uranus - Pluto 4. An asteroid belt composed of small rocky bodies and comets.
What is a Solar System?
The sun, its planets, and all the objects moving around them collectively Entirely dependent on the Sun and the only one which is self-luminous Rest of the planets reflect the light received from the sun
Sun
Star of the Solar System Scientific name is “Sol” Heaviest among the Solar System Ball of hot, burning gases
Nearest star to the Earth Light from the Sun takes approximately 8 minutes to reach the Earth.
Classification of Planets by Composition
1. Terrestrial Planets (Earth-like planets or Inner Planets) - Composed mostly of dense, rocky, and metallic materials - Mercury, Venus, Earth, Mars - Formed within the frost line where rocks and metals condense, and hydrogen compounds remain as gas. 2. Jovian Planets (Jupiter-like planets or Outer Planets) - Composed mostly of Hydrogen and Helium - Jupiter, Saturn, Uranus, Neptune - These planets are formed outside the frost line where light elements condense into ice.
Classification of Planets by Position Relative to the Sun
1. Inner Planets - Mercury, Venus, Earth, Mars 2. Outer Planets - Jupiter, Saturn, Uranus, Neptune
Classification of Planets by Position Relative to the Earth
1. Inferior Planets - Mercury, Venus 2. Superior Planets - Mars, Jupiter, Saturn, Uranus, Neptune
What is a Dwarf Planet?
Celestial body that has the following characteristics: a. Is in orbit around the sun b. Has sufficient mass for its self-gravity to overcome rigid body forces c. Has not cleared the neighborhood around it d. Is not a satellite Haumea, Pluto, Makemake, Eris
- Only celestial body other than Earth on which humans have set foot. (Neil Armstrong [American Mission Apollo] on July 21, 1969) 4. Mars (The Red Planet)
- Named after Roman god of war
- Red Planet: Iron oxide is prevalent on its surface that gives the planet its reddish appearance
- Home to Olympus Mons 5. Jupiter (The Giant Planet)
- Named after ruler of Roman gods
- Largest planet in the Solar System
- Has a great red spot, it is a rotating storm inside the planet 6. Saturn (The Jewel Planet; Ringed Planet)
- Sixth planet from the sun
- Second largest planet
- Named after roman god, Saturn
- Classified as gas giant planet 7. Uranus (Ice Giant)
- Named after Roman god of the sky
- A planet on its side
- Only planet which rotates on its axis from east to west 8. Neptune (Big Blue Planet)
- Most distant gas planet
- Named after Roman god of the sea
- Most windy planet
Properties of the Solar System
The orbits of all planets are almost in the same plane.
- Solar system is flat. The planetary orbits are nearly circular. The orbits of the planets are nearly in the same plane as the rotation of the sun. The calculated distances (Bode’s law) and the observed distances of the planets from the sun are almost the same (except of Neptune & Pluto) The satellite systems of Jupiter and Saturn are nearly identical in their arrangements with the solar system. The satellites and planets contain almost all the rotational motion of the solar system. The solar system contains asteroids and comets.
Asteroids
A celestial body bigger than 10m orbiting the Sun, mainly between Mars and Jupiter.
Comets
A smaller celestial body mainly composed of ice and dust. If a comet approaches the Sun it can generate a tail of gas and/or dust.
Meteoroids
Similar to an Asteroid, but significantly smaller. Mostly debris of comets, sometimes debris of asteroids.
Meteors
A bright tail of light caused by a meteoroid during its atmospheric flight, also called a shooting star or falling star. Types of meteors: a. Fireball
- Another term for very bright meteor , generally brighter than magnitude -4, which is about the same magnitude of the planet Venus in the morning or evening sky, sometimes even brighter. b. Bolide
- A fireball that explodes during its atmospheric flight , often with visible fragmentation.
- Refers to a fireball approximately as bright as the full moon, and it is generally considered a synonym of a fireball.
- Described as a fireball reaching the apparent magnitude of -14 or brighter – more than twice as bright as the full moon.
Meteorites
The part of a meteoroid or asteroid that survives the passage through our atmosphere and reaches the Earth’s surface.
GEOLOGIC TIME SCALE
Divides up the history of the earth based on lifeforms that have existed during specific time since the creation of the planet. Model of the history of the Earth showing the major events that occurred along the way 88% of Earth’s History (Precambrian – very little evidence of life); Other 12% (Phanerozoic – sudden development of life in the oceans, hard parts developed which increased the fossil record)
1. Eons - Longest units of time - Precambrian: Earliest Span of time - Phanerozoic: Everything since
NOTE:
The brightness of a star is referred to as magnitude. There are two kinds of magnitude:
a. The brightness of the star observed from the Earth is referred to as the Apparent Magnitude. b. If the star is at 10 parsecs (32.6 light years) distance from the Earth, then it would be referred to as Absolute Magnitude.
Asteroids Comets Meteoroids Meteors Meteorites
- Rocks that are folded or tilted must have been moved into that position AFTER their formation 3. Original Lateral Continuity
- Original deposited layers of rock extend laterally in all directions until either thinning out or being cut off by a different rock layer.
James Hutton (1726 – 1797)
- Scottish Physician
- “The present is the key to the past”
- Theory of Uniformitarianism
Theory of Uniformitarianism
- Advocated by Charles Lyell
- What happens today is what happened in the past
- Supports very old age of Earth
- Earth is believed to be 4.6 billion years old
Neocatastrophism
- Blends uniformitarianism and catastrophism
- Earth developed and changed at a very slow rate like today but had some catastrophic events that caused some sudden changes.
Geologic Dating
1. Absolute - Determines how many years old something is - Know DATES - Uses Radiometric Radioactive Decay ( half-life ): occurs when the nuclei of unstable atoms break down, changing the original atoms into atoms of another element. Half-life is the amount of time it takes for half the atoms of a substance to decay into another element. Different substances have different half-life’s Ex: Uranium 238 and Carbon 14 ( Carbon 14 – date biological remains since Carbon is incorporated into the cells of living organisms and begins to decay when the organism dies; Uranium 238 – used to date rocks [larger half-life]) Half-lives of radioisotopes vary depending upon the isotope 2. Relative - Used to determine if one thing is younger or older than another - Know ORDER OF EVENTS BUT NOT DATES - Superposition, Index Fossils, Correlation of Rock layers - Comparing of rock units to decipher their age relative to one another a. Principle of Horizontal Originality b. Principle of Superposition c. Principle of Crosscutting Relationships – any feature (fault or intrusion) that cuts across rocks is younger than the youngest rock that is cut. d. Principle of Inclusion – states that objects enclosed in rock must be older than the time of rock formation.
Fossils
Remains of Ancient Plants and Animals, Evidence of Life Commonly Preserved (Hard Parts) a. Bones b. Shells c. Hard Parts of Insects d. Woody Material Rarely Preserved (Easily Decayed Parts) a. Internal Organs b. Skin c. Hair d. Feathers
Types of Fossils
1. Mold - When sediments bury an organism and the sediment hardens into rocks. - The organisms decay slowly inside the rocks leaving a cavity in the shape of the organism. 2. Cast - The cavity or mold can be filled with mud. - When the mud hardens, it takes on the shape of the organism. 3. Petrified - Permineralized fossil - Forms when minerals soak into buried remains - The materials replace the remains, changing them **to rock
- Carbonized**
- Forms when organisms or parts like leaves, stems, flowers, fish, are pressed between layers of soft mud or clay that hardens, squeezing almost all the decaying organism away and leaving the **carbon imprint on the rock.
- Trace**
- When mud or sand harden into rock where a foot just trail or burrow was left behind
EARTH: STRUCTURE AND SUBSYSTEMS
Layers of the Earth:
1. Inner Core - Discovered by Inge Lehmann in 1936 - Radius of 1250 km - Solid Fe-Ni alloy - Magnetic - approximately 6000ºC - 3.6 million atm 2. Outer Core - Discovered by Richard Dixon Oldham (earth’s core as a whole) in 1906. - 2300 km thick - Lehmann discontinuity - Boundary between the inner and outer core. - Liquid Fe and Ni - Magnetic - 4000-5000ºC
Three Types: b.1 Chemical - Formed by precipitation of materials from water b.2 Biological/organic - form from the accumulation of plant and animal debris b.3 Clastic - formed from the debris due to mechanical weathering of rocks
c. Metamorphic Formed through the transformation, either by heat or pressure, of existing rocks. The original rock (protolith) can be igneous, sedimentary, and can also be metamorphic. Two major types: c.1 Foliated – metamorphic rocks that exhibited layering. It occurs during recrystallization c.2 Non- foliated – rocks that has no foliation
Geomorphic Processes
- Natural processes that result in the change and or modification of the landforms on the Earth’s surface.
- Two Processes: A. Exogenic Process External Process Transform Rocks to sediments through weathering Also called Weathering Types of Weathering: a. Physical Weathering – Physical, Block disintegration, exfoliation, frost weathering b. Chemical Weathering – Oxidation, Carbonation, Hydration c. Biotic Weathering – Plants, Animals, Humans After Weathering? a. Mass Wasting – Downslope movement of a mass of rocks, soil, and other sediments; Commonly caused by water b. Soil Erosion – The removal of soil at a greater rate than its replacement; More gradual than the mass wasting
B. Endogenic Process Internal Process Reshaping the Earth’s landforms Transform the Earth from within the crust Two types: a. Volcanism Volcano – An eruption of molten rock, called magma on the surface of the Earth Magma from the mantle rises through the crust and, ultimately, unto the surface. Lava is the primary material expelled from a volcano, in addition to rocks, ash, and dust. b. Tectonic Forces The Lithosphere can be broken up into smaller parts called Tectonic plates. These plates are subjected to stress and, eventually, deformation. (Deformation is any change in the shape and size of a rock as a response to stress.) Folding Deformation: Occurs when the plates are subjected to compressional stress on both sides, causing them to fold. Faulting Deformation: Fracture or displacement of the plates along a fault plane. Three Types:
1. Normal 2. Reverse 3. Transform
Plate Movement
- The movement of the plates is the result of convection currents. (Convection currents are currents that carry heat from the lower mantle and the core to the lithosphere.)
- Seafloor Spreading: A process in which tectonic plates split apart from each other due to mantle convection; The slow churning of the Earth’s mantle 1. Convergent – towards; forms trenches, mountains, and volcanic arcs 2. Divergent – away; creates seafloor spreading, oceanic ridges, and continental drifting 3. Transform – slide past each other; creates earthquakes
Geologic Hazards
1. Earthquakes – A sudden perceptible shaking of the Earth due to the sudden release of energy in the Earth’s crust or volcanic eruption. The Philippines is largely susceptible to earthquakes due to its location, which is within the pacific ring of fire. (PRoF – Major area in the pacific ocean where 90% of the earthquake occurs.) The Philippines Institute of volcanology and Seismology (PHIVOCS) overlooks the seismic and volcanic activities in the Philippines. 2. Landslides – Also known as landslips; A form of mass wasting in which a great amount of soil, rocks, and or sediments move downslope; Common cause of landslides: Earthquake, Volcano Eruption, Water (raining) 3. Tsunamis – An event caused by earthquakes, volcanic eruption and or other seismic activities that affect bodies of water, thus, also known as seismic sea wave; Generated by a large displacement of water; The Philippines is susceptible to tsunami due to its location.
Other Subsystems:
2. Atmosphere - layer of gases, such as nitrogen and oxygen, that surrounds the planet. - Came from the greek word “atmos” (vapour) and “sphaira" (sphere). - Four layers: a. Troposphere The lowest part of the Atmosphere; The layer that we live in Contains all of the weather Colder as the distance from sea level increase (due to decreased pressure). Contains 75% of all the air in the atmosphere
Boundary layer: lowest part of the troposphere. Tropopause: boundary between troposphere and stratosphere. Poles: 7-10 km Equator: 17-18 km
b. Stratosphere Area between the tropopause to about 50 km above sea level. It contains most of the ozone (O3) in the atmosphere. The temperature increase with height due to the absorption of Ultraviolet (UV) light by the ozone. Stratopause: boundary between stratosphere and mesosphere.
