Astronomy

**>SOLAR SYSTEM MODELS**
 * **Geocentric || earth centered system developed by Ptolemy was accepted until the 1960's**
 * **Heliocentric || sun centered system developed - Copernicus. Modeled understanding of structure of the universe**
 * **Celestial objects- objects observed in the sky during the day or night ( Planets, Sun, Mood, Stars )**
 * **Constellation- a group of stars that make an identifiable pattern in the sky**

**>> ROTATION**
 * **Spinning about the north and south axis**
 * **Evidence: apparent daily counterclockwise motion celestial objects around Polaris ( North Star ) Is because of Earth's rotation toward the east ( rate = 15º per hour )**
 * **Solar day- amount of time required for the Earth to rotate from noon to next. 15º x 24 hours= 360º**

**>>CORIOLIS EFFECT**
 * **Horizontal deflection undergone by all moving materials on the Earth's surface**
 * **Northern Hemisphere || deflected to the RIGHT CLOCKWISE**
 * **Southern Hemisphere || deflected to the LEFT COUNTERCLOCKWISE**

**>>FOUCAULT PENDULUM**
 * **An experiment to demonstrate the rotation of the Earth**

**>>REVOLUTION**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**A slightly elliptical orbit around the sun ( counterclockwise )**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**365.25 Days for One Revolution**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Evidence : Seasonal change of the constellations, the solar diameter varies in a cyclic pattern**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Perihelion - sun is the largest, occurs in the N.H winter ( shortest distance between earth & sun )**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Aphelion - smallest, occurs in the N.H summer ( largest distance between the earth & sun )**

<span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**>>SEASONS**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**The Earth's tilt is 23.5**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Parallelism of the Earth's Axis - Earth axis remains parallel throughout its revolution around sun**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Local Noon - when the sun reaches its maximum altitude**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Zenith - the point directly overhead**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**The Sun's rays can only be directly overhead at solar noon between the tropics**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**( 23.5º North or South of the Equator )**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Equinox - the sun is in the zenith position at the equator ( March 21st - September 23rd )**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**12 hours of both daylight and darkness**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Summer Solstice - the sun is in the zenith position at the tropic of cancer ( June 21st )**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Longest daylight of the year in the northern hemisphere**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Winter Solstice - the sun is in the zenith position at the tropic of Capricorn ( December 21st )**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">**Shortest daylight of the year in the northern hemisphere**

<span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;"> >>ELLIPTICAL ECCENTRICITY
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">>>EARTH`S ORBIT **
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Parallelism of earth's axis ; every position of earth's axis in its orbit it parallel
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Earth`s distance to the sun
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Perihelion - 147,600,000 KM
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Aphelion - 152,4000,000 KM
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Kelper's Laws
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">planets travel in elliptical orbits therefore they will be at different distances from the sun throughout there revolution
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">the equal area law - states that each planet moves around the sun in such a way that an imaginary line joining the planet to the sun will sweep over equal areas of space in equal areas of time
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">the harmonic law - the farthest away from the sun, the longer its period of revolution
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Eccentricity - degree of the out of roundness of the ellipse
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Formula - distance between foci over length of major axis = eccentricity

<span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">>>THE PLANETS AND THE SOLAR SYSTEM
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Terrestrial ( inner ) planets ; Mercury, Venus, Earth, Mars
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Consists of rocky crust, a dense mantle layer and a very dense core
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Average density is above water
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Iron, silicon, oxygen, and other heavy elements


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Jovian ( Outer ) Planets
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Huge gaseous and much less dense
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">hydrogen and helium
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">have ring systems
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Centered around the planets equator


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Consists of many particles in independent orbits around the planet
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Meteoroid- rock or an icy fragment traveling in space
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Meteor- the light made by a meteoroid as it passes through earth's atmosphere
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Meteorite- part of a large meteoroid that survives its trip the atmosphere and strikes earth's surface
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">93% are stones ( resemble earth's dark igneous rocks but include 10-15 % iron )
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">irons most abundant source of meteorites is the antarctic ice cap

<span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">>>STARS AND GALAXIES
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Distance between the Earth and Sun is 150 Million km
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">150 MiL km- astronomical unit ( au )
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Light year ( ly ) = 9.5 X 10^12 km/yr
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">distance that a ray of light


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Physical Properties of stars
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Size- Range from smaller than earth to 2OOOx the diameter of the sun
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Density - differs greatly
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Mass - most stars are fairly close to the sun
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Color - depends on the surface temp ( red - cooler ) ( blue - hotter )
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Elements - contain mainly helium and hydrogen


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Brightness *
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Apparent magnitude how bright a star appears to an observer on earth
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Luminosity - true brightness of a star which depend only upon the size and temp of a star
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Absolute magnitude - expresses luminosity of stars as if they were seen from the same distance

<span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">>>ORIGIN OF A STAR
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Stars form from dense clouds of gas and dust
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">An outside force triggers the attraction of gravity causing particles to move toward each other
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Temperatures increases as the area contracts
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">if the cloud is large enough parts of it will start to glow
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Protostars - large glowing cloud sections
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Contraction continues protostars become hotter and brighter


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Red giants and supergiants
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">star loses stability
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">the star gets so hot it causes the outer layer
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">the star radiates more light and appears brighter


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">White Dwarfs *
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">most of the fusion is used up
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">temp and pressure of the core can no longer support the weight of its outside layers
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Glows faintly as it continues to cool


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Supernova *
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">As the star core cools it begins to collapse
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">pressure and temp rise dramatically
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">the star explodes violently


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Black Holes *
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Gravitational forces are so powerful that even light can not escape


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Galaxy - A group of millions or billions of stars held together by gravity


 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">We belong to the milky way galaxy
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Spiral - central lens shape and spiral arms which usually contain millions of stars as well as dust and gas

<span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px; line-height: 21px;">^ Red Shifts (or Doppler Effect)**^**
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px; line-height: 21px;">Big Bang Hypothesis
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">Universe was packed into one dense sphere of hydrogen
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">15 billion years ago the mass exploded, forming an expanding cloud
 * <span style="color: #2f48e9; font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif; font-size: 14px;">cloud parts condensed into galaxies

<span style="font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">
 * Earth's Moon
 * The moon revolves in an elliptical orbit around the earth
 * Revolution=27.33 days
 * Perigee- moons nearest the earth
 * Apogee- moon farthest the earth
 * Phases of the moon
 * Two Reasons:
 * The moon is seen by reflected light
 * The moon is in orbit around the earth
 * Full Moon:
 * [[image:full-moon.jpg]]
 * Waning Gibbous:
 * [[image:1466028701_45eecb5e1b.jpg]]
 * New Moon
 * [[image:new-moon1.jpg]]
 * Waxing Crescent
 * [[image:Waxing_Crescent_Moon.jpg]]
 * First Quarter
 * [[image:20060929_first_quarter_Moon_l.jpg]]
 * Eclipse
 * Umbra- the total shadow
 * Penumbra- the partial shadow surrounding the umbra
 * Lunar eclipse- occurs when the moon passes into earth's umbra
 * Only occurs at the full moon phase
 * The moon's and earth's orbit are inclined to each other by 5º so a month. (1 per year)
 * Solar Eclipse- occurs when the moon's umbra reaches earth's surface
 * Locations on the earth's surface within the umbra experience a total solar eclipse
 * Locations in the penumbra receive a partial solar eclipse
 * Can only occur at a new moon phase