Astronomy.



__**Solar System Models **__  **Geocentric **


 * Earth centered system developed by ptolemy
 * Was accepted until the 1960's

**Heliocentric **

 Celestial Objects- Objects observed in the sky during the day or night (planets, sun,moon,stars) Constellation- A group of stars that make an identifiable pattern in the sky
 * Sun centered system developed by copernicus
 * Modern understanding of the structure of the universe

**Rotation : **  A spinning about the north and south axis Evidence: The apparent daily counter- clockwise motion of celestial objects around polaris (north star) is because of earth's rotation toward the east. (Rate - 15 degrees per hour)Solar Day: The amount of time required for the earth to rotate from noon to the next. 15 degrees X 24 hours = 360

Coriolus 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 (counter clockwise) **

An experiment to demonstrate the rotation of the earth **
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Foucault Pendlum

Revolution : A slightly elliptical orbit around the sun (counter clockwise) //<span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">365.25 for one revolution Evidence: Seasonal change of the constellations The solar diameter varies in a cyclic pattern

// <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> Seasons The earth's tilt is 23.5 degrees Parrallelism of the Earth's Axis- the earth axis remains parallel throughout its evolution around the sun. Local Noon- When the sun reaches its maximum altitude Zanith- The point directly overhead <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Equinox- The sun is in the Zenith position at the equator (March 21st and sept 23rd.) 12 hours of both daylight and darkness Summer Solstice: The sun is in the zenith position at the tropic of cancer (June 21) Longest daylight of the year in the northern hemisphere Winter Solstice:The Sun is in the Zenith position at the tropic of capricorn (Dec 21) Shortest daylight of the year in the northern hemisphere
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Perihelion; sun is the largest ocurrs in the n.h. winter (shortest distance between the earth and sun)
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Aphelion; Smallest, occurs in the n.h. summer (largest distance between the earth and sun)
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">THE SUNS RAYS CAN ONLY BE DIRECTLY OVERHEAD AT SOLAR NOON BETWEEN THE TROPICS (23.5 degrees north of south of equator)

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<span style="font-family: Verdana,Geneva,sans-serif;">__**<span style="font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif;">NOTES FROM 5/16- 5/28 **__

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VIII The planets and the solar system 1) Terrestrial (inner) planets a) mercury,venus,earth,mars b)consist of a rocky crust, a dense mantle layer and a very dense core c)average density is above water d)iron, silicon, oxygen, and other heavy elements

2) the astroids that orbit between mars and jupiter divide the two groups

3) Jovian(outer) planets a) huge, gaseous and much less dense b) hydrogen and helium c) have ring systems <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">4) Meteoroid -A rock or an icy fragment traveling in space
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Centered around the planets equator
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Consist of many particles in independent orbits around the planet.

5) Meteor- the light made by a meteoroid that survives its trip through the atmosphere and strikes earth's surface

6) Meteorite- part of a large meteoroid that survives its trip through the atmosphere and strikes earths surface <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 7) The most abundant source of meteorites is the antarctic ice cap
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">93% are stones (resemble earth's dark igneous rocks but include 10-15% iron)
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Irons (85-95% iron the rest is nickel
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Stony-irons (rare mixture of stone and iron)

IX Stars and galaxies 1) Distance between the earth and sun is a 150 million KM <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 2) Physical properties of stars <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 3) Origin of a star <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 4) Red giants and super giants <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 5) White dwarfs <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 6) Supernova <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 7) Black holes <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 8) Galaxy- a group of millions or billions of stars held together by gravity
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">150 mil. KM= astronomical unit (au)
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Light year (ly) = 9.5x10^12 km/yr distance that a ray of light travels in one year
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Size- Range from smaller than earth to 2000X the diameter of the sun
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Density - differs greatly
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Mass- most stars are fairly close to the sun
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Color- depends on the surface temp.
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">red- cooler
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">blue- hotter
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Elements- contain mainly helium and hydrogen
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Brightness
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Apparent magnitude- How bright a star appears to an observer on earth
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Luminosity- True brightness of a star which depends only upon the size and temp of a star
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Absolute magnitude- expresses luminosity of stars as if they were seen from the same distance
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Stars form from dense clouds of gas and dust
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">An outside force triggers the attraction of gravity causing particles to move toward eath other
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Temperature increases as the area contracts
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">If the cloud is large enough parts of it will start to glow
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Protostars- large glowing cloud sections
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Contraction continues protostars become hotter and brighter
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">the center becomes so hot fusion begins (hydrogen nuclei unite to form helium
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Star loses stability
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">the star gets so hot it causes the outer layers to expand, enlarging its surface area
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">The star radiates more light and appears brighter.
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Most of the fusion is used up
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Temp. and pressure of the core can no longer support the weight of its outside layers
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Glows faintly as it continues to cool
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">as the star core cools it begins to collapse
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Pressure and temp. rise dramatically
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">the star explodes violently
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">gravitational forces are so powerful that even light can not escape

9) We belong to the milky way galaxy <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 10) Big bang hypothesis <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> V Earth's Moon
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Spiral - central lens shape and spiral arms which usually contain millions of stars as well as dust and gas
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Universe was packed into one dense sphere of hydrogen
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">15 billion years ago the mass exploded, forming and expanding cloud
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Cloud parts condensed into galaxies
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">EVIDENCE RED SHIFT
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Dopler Effect

1) The moon revolves in an elliptical orbit around the earth <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 2) Phases of the moon <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> 3) Lunar Month- The time from one new moon to the next <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;"> VI Eclipse UMbra- the total shadow Penumbra- the partial shadow surrounding the umbra
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Revolution = 27.33 days
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Perigee- moon nearest the earth
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Apogee- moon farthest the earth
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Two Reasons
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">The moon is sen by reflected light
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">The moon is in orbit around the earth
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Full Moon-
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Waning Gibbous-
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Quarter-
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Waning crescent-
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">New Moon-
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Waxing Crescent-
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">First Quarter
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Waxing Gibbous
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Length= 29.5 days


 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Lunar Eclipse- occurs when the moon passes into earth's umbra
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Only occurs at the full moon phase
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">The moons and eaths orbit are inclined to each other by 5 degrees so a lunar eclipse does not occur every month. (1 per year)
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Solar Eclipse- Occurswhen the moons umbra reaches earth's surface
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Locations on te earth's surface within the umbra experience a total solar eclipse
 * <span style="color: #ed7e1d; font-family: 'Comic Sans MS',cursive;">Can only occur at the new moon phase