Science SOL

Origin and Evolution of the universe

Universe is vast and very old

Much information about our galaxy and universe coms from ground-based observations

Big Bang Theory

states the inverse began in a very hot and dense sphere that expanded and eventually condensed into galaxies; best current model of the origin of the universe

Solar Nebular Theory

explains the that plants formed through condensing of the solar nebula; best current idea for the origin of the solar system

Star

Have a finite lifetime and evolve over time; formed by condensation of interstellar gas

stars from from the condensation of interstellar gas

Hertzsprung-Russell diagram illustrate relationship between absolute magnitude and surface temperature of stars

mass of star controls its evolution, lifetime length, ultimate fate

Galaxies

collections of billions of stars

Basic types: spiral, elliptical, irregular

Light Year

Distance light travels in one year, most commonly used measurement for distance in astronomy

Solar System

Consists of many types of celestial bodies, including sun, nine planets (at this time) and their moons, comets, meteors, and asteroids

Still learning more about solar system though space exploration efforts (Apollo 11: first manned landing of the moon and Hubble Space telescope has greatly improved our understanding of the universe

Located in the Milky Way galaxy

Moons

natural satellites of planets that vary widely in composition

Sun:

star consisting largely of hydrogen gas: energy comes from nuclear fusion of hydrogen to helium

Comets

Orbit the sun and consists mostly of frozen gases

Asteroids

Rocky of metallic iron objects ranging in size from millimeters to kilometers; source of most meteorites

Order of planets from Sun

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Two types of planets in our Solar system …. and …..

terrestrial and gas giants

four inner terrestrial planets consist mostly of…… …………

Solid Rock

What do the four outer planets consist of (gas giants)

consists of thick outer layers of gaseous materials perhaps with small rocky cores

Earth

third planet from the sun: located between the sun and the asteroid; one natural satellite-the moon

Revolves elliptically around the sun (365.25 days=1 revolution) tilted on its axis-causes seasons (equinoxes and solstices)

Water’s state (ice, liquid, vapor) on Earth depends on Earth’s position in solar system

The Moon

revolves around Earth (1 revolution=24 hours) creating moon phases and eclipses

Solar eclipses occur when the moon blocs out sunlight from the Earth’s surface

Lunar eclipses occur when Earth blocks sunlight from reaching the moon’s surface

Tides

daily, periodic rise and fall of water level caused by the gravitational pull of the sun and the moon

The Origins of Earth’s atmosphere

Composition of Earth’s atmosphere has changed over geologic time

Early atmosphere contained little oxygen and more carbon dioxide that today’s atmosphere

Early photosynthetic life such as cyanobacteria (blue-green algae) contained carbon dioxide and generated oxygen

after early photosynthetic life generated oxygen, animal life became possible

Other Planets Atmosphere

Venus’s atmosphere is mostly carbon dioxide and is very dense

Mars’s atmosphere is mostly carbon dioxide and very thin

Earth’s Atmosphere Today

Earths atmosphere is unique in the solar system in that is contains substantial oxygen (21% oxygen, 78% nitrogen, 1% trace gases)

Human activities have increased the carbon dioxide content of Earth’s atmosphere

Man-made chemicals have decreased the ozone concentration in the upper atmosphere

Volcanic activity and meteorite impacts can inject large quantities of dust and gases into the atmosphere

ability of Earth’s atmosphere to absorb and retain heat is affected by the presence of gases like water vapor and carbon dioxide

Weather

describes day-to-day changes in atmospheric conditions energy transfer between the Earth’s surface and the atmosphere creates the weather

convection in the atmosphere is a major cause of weather

convection is the major mechanism of energy transfer in the oceans, atmosphere, and the Earth’s interior

Tornado

narrow, violent, funnel-shaped column of spiral winds that extend downward from the cloud base towards Earth

Hurricane

tropical cyclone (counterclockwise movement of air) characterized by sustained winds of 120 kilometers per hour (75 miles per hour) or greater

Climate

describes the typical weather patterns for a given location over a period of many years

four major affecting climate: latitude, elevation, proximity to bodies of water, position relative to mountains

Earth’s major climate zones: polar, temperature, tropical

both weather and climate are measurable to an extent predictable

The Sun

Earth’s surface is much more efficiently heated by the sun than is the atmosphere

Amount of energy reaching any given point on the Earth’s surface is controlled by the angle of sunlight striking the surface and varies with the seasons

Areas near the equator receive more of the sun’s energy per unit area than areas nearer the poles

Winds

winds are created by uneven heat distribution at the Earth’s surface by the sun and are modified by the Earth’s rotation (influenced by the Coriolis effect)

Coriolis effect

causes deflections of the atmosphere due to the Earth’s rotation

flows from high to low pressure

Clouds

the conditions for cloud formation are air at or below the dew point and the presence of condensation nuclei

cloud droplets can join together to from precipitation

Types of Clouds

Cirrus: light, thin, feathery (fair weather clouds)

Cumulus: puffy white clouds

Stratus: low gray clouds

(measuring devices)

thermometer:

barometer:

psychrometer:

measures temperature

measures atmospheric pressure

measures relative humidity

Weather Maps

weather moves from west to east in the US

symbols for cold fronts, warm fronts, pressure, and precipitation should be known

high pressure (H):

low pressure(L):

fair weather, circulates clockwise and air sink

bad weather, circulates counterclockwise and air rises (air from high pressure always moves to areas with low pressure gradients)

Cold Fronts:

Warm Fronts:

cold air invades warm air; rain and thunderstorms

warm air invades cold air; steady rain

Isotherms:

Isobars:

lines of equal temperature (like contours)

lines of equal pressure (like contours)

Rocks and Minerals

rocks and minerals are different

Minerals

naturally occurring inorganic solid substance with a definite composition and structure

can be identified by physical properties (hardness, color, luster, streak)

important to human wealth and welfare

Most abundant group: silicates (contains the elements silicon and oxygen)

Rocks

most made of one or more minerals

can be identified based on mineral content and texture

defined by the processes by which they are formed; igneous, sedimentary, metamorphic

Igneous

formed from molten rock that cools and hardens either below or on the Earth’s surface

Extrusive igneous rocks: have small or no crystals resulting in fine-grained or glassy textures

Intrusive igneous rocks; have larger crystals and a coarser texture

Sedimentary Rocks

may either form from rock fragments or organic matter bound together or by chemical precipitation

Clastic Sedimentary Rocks: made up of fragments of other rocks

Non-Clastic sedimentary rocks: formed from chemical processes than from taking rock fragments

limestone only rock that can be formed chemically and organically

Metamorphic Rock

form when any rock is changed by the effects of heat, pressure, or chemical actions; can be foliated or unfoliated (nonfoliated)

Foliated metamorphic rocks: have bands of different minerals

Unfoliated metamorphic rocks: have little or not banding are relative homogenous

Fossils

is the remains, impressions or other evidence preserved in rock of the former existence of life (can be ancient or often extinct)

some ways fossils can be preserved include molds, casts, and original bone or shell

nearly all fossils are found in sedimentary rocks

fossil evidence indicates that life forms have changed and become more complex over geologic time

Dating

Earth is very ancient: about 4.6 billion years old

history of Earth and age of rocks can be investigated and understood by studying rocks and fossils

Relative Time

places events in a sequence without assigning any numerical ages

fossils, law of superposition, and law of crosscutting relationships are used to determine the relative ages of rocks

Law of superposition

the oldest layers on the bottom and get younger as you go up in a undisturbed rock layer

law of crosscutting relationship

igneous intrusion (and fault) is younger than the layers it cuts across

Absolute Time

places a numerical age on an event

radioactive decay:

is used to determine the absolute age of rocks

carbon 14 dating: used for dating organic material up to 50,000 years old

uranium: dates the oldest rocks-up to 4.5 billion years

Half-life: amount of time it takes for 50% of a radioactive parent isotope to break down into its stable decay products

Geologic Time

three major divisions: eras, periods, epochs

Eras:

Periods:

Epochs:

largest division end with extinction events

based on index fossils (abundant, worldwide, short-lived)

smallest based on types of life (only in Cenozoic Era)

Precambrian Era

90% of all geologic history

oxygen not present

initially (carbon dioxide instead)

blue-green algae (cyanobacteria) produced oxygen leading to creation of ozone and our atmosphere today

Paleozoic Era:

Age of Invertebrates: creation of Pangaea

Mesozoic Era

Age of Reptiles; dinosaurs, Pangaea break apart

Cenozoic Era

Age of Mammals; man

Today

We live in Cenozoic Era; Quaternary Period; Recent Epoch

Earth’s Composition

Solid mostly, iron inner core, liquid, mostly iron outer core, a rocky, plastic mantle, and a rocky brittle crust

Core, mantle, and crust are dynamic systems-constantly in motion

Two types of crust: oceanic and continental- each as different characteristics

-ocean (basalt) crust is relativity thin, young, and dense

-continental crust is relatively thick, old and less dense

Earth’s crust major elements: oxygen, silicon, aluminum, and iron

Lithosphere

made of Earth’s crust and some mantle; is divided into plates that are in motion with respect to one another

Plate motion occurs as a consequence of convection in Earth’s mantle

Plate tectonics are driven by convection in the Earth’s mantle

Convergent:

Divergent:

(subduction and continental collision)

(sea-floor spreading), or transform

most geologic activity motion along plate boundaries

Convergent Boundaries’ features

collision zones (folded and thrust faulted mountains) and subduction zones (volcanoes, trenches)

Divergent Boundaries’ Features

mid-ocean-ridges, rift valleys, and fissure volcanoes

Transform boundaries’ features

strike-slip faults- San Andreas Fault