Unit 8 Solar System At the end of this unit you will be able to: Calculate the number of degrees the sun moved, or the earth rotated, in a given time Calculate the eccentricity of an orbit Label a diagram of the hemisphere and show the setting and rising positions of the sun. Locate Polaris State what direction the earth rotates Differentiate between Geocentric and Heliocentric models State the difference between Jovian and Terrestrial Planets Define: Orbit, ellipse, Penumbra, Umbra, Eclipse, Rotation, Revolution, Constellation Read The Luminosity chart in the reference tables

Labs for this unit Ellipse Lab Diurnal Motions of the Sun Shadows and the Sun’s Path

Earth Science Picture of the Day http://epod.usra.edu/

Vocabulary: Astronomy Red shift: indicates that celestial objects are moving apart (distance is increasing, expanding) Galaxy: collection of stars, gases and dust held together by gravity Star: large ball of gas that produces energy and shines

Vocabulary: Astronomy Luminosity: how bright an object is compared to our sun Asteroid: solid, irregularly shaped object that orbits the sun Comet: an object with a very eccentric orbit, vaporizes as it travels leaving a tail behind it

Vocabulary: Astronomy Meteor: small solid fragment that burns up in the earth’s atmosphere Terrestrial: rocky core, high density Jovian: gaseous core, low density Rotation: to spin on an axis Revolution: to travel around an object

Vocabulary: Astronomy Orbit: path of an object revolving around another Aphelion (apogee): point in an orbit where it is farthest from the sun, least gravity, slowest orbiting speed Perihelion (perigee): point in an orbit where it is closest to the sun, greatest gravity, fastest orbiting speed Ellipse: shape of an orbit

Vocabulary: Astronomy Foci (focus): fixed object in space around which an object orbits (revolves) Eccentricity: how out of round an orbit is, degree of flatness, value between zero and one Gravitation: (gravity) attractive force between two objects Geocentric: Earth at the center Heliocentric: Sun at the center

Vocabulary: Astronomy Constellation: A group of stars that make a pattern Tides: rise and fall of the sea level caused by the moons gravity Eclipse: when a celestial object falls into the shadow of another celestial object

Vocabulary: Astronomy Penumbra: partial shadow Umbra: total shadow

I. Celestial Observations A. Night Sky 1. Constellations: A group of stars that make a pattern in the sky

Constellations 2. Polaris, aka north star, located above the North Pole and The Earth’s axis of rotation

Polaris a. the ALtitude of Polaris equals your LAtitude

Little dipper (Ursa Minor)

Big Dipper (Ursa Major)

Star Motion 4. Stars appear to move East to West in a Counterclockwise motion at the rate of 15 degrees per hour.

Star Trails Star trails are made by leaving your camera shutter open and pointed at the location that marks the Earth’s Axis of rotation. If the Camera is in the Northern Hemisphere you would point it at what? If you were in the southern Hemisphere would you have a star at the center of the trail?

Star Trail

Moon Phases

B. Day Sky 1. The Sun rises in the east and sets in the west 2. Moves across the Sky at the rate of 15 degrees per hour.

B. Day Sky 3. Sun looks like it moves because the earth is rotating. 4. At the poles your travel slower than you would at the equator.

B. Day Sky 5. Rotation of the earth evidence a. Focult pendulum and Coriolis effect. b. Sun rising and setting (once a day)

1. We have seasons because the earth is tilted C. Seasons 1. We have seasons because the earth is tilted a. the earth is tilted at an angle of 23 1/2 degrees from straight up.

Seasons diagram

What would happen if the earth were not tilted or tilted more than 23 1/2 degrees?

C. Seasons 2. Summer (Solstice) a. June 21st b. Longest day of sunlight c. Highest altitude of sun in the sky

C. Seasons 2. Summer (Solstice) d. shortest shadow e. longest arc or path of the sun f. Rises NE and sets NW

Summer Solstice

C. Seasons 3. Winter (Solstice) a. December 21st b. Shortest day of sunlight c. lowest altitude of sun in the sky

C. Seasons 3. Winter (Solstice) d. longest shadow e. shortest arc or path of the sun f. Rises SE, sets SW

Winter Solstice

C. Seasons 4. Fall and Spring (Equinox) a. Equal amounts of daylight and night time (12 and 12) b. March 21st and September 21st.

C. Seasons 4. Fall and Spring (Equinox) c. Rises on East ands sets on West. d. Sunlight rays are directly on the equator.

Fall and Spring Equinox

Suns path diagram for all equinoxes, and solstices

Eclipses Solar Eclipse: When the Sun and moon and earth are lined up. The moon is between the earth and the sun

Solar Eclipse Geometry

http://umbra.nascom.nasa.gov/eclipse/images/Freds_dundlod_movie.mpg

Lunar eclipse When the Sun and moon and earth are lined up. The earth is between the moon and the sun

Lunar Eclipse Geometry

Eccentricity Degree of “out of roundness” of an ellipse determined by the distance between the two foci divided by the length of the major axis of the ellipse

eccentricity= distance between foci length of major axis

Eccentricity has no label The value of eccentricity is between ZERO (which is a perfect circle) and ONE (which is a line)

http://www. starryskies. com/The_sky/events/lunar-2003/eclipse-Nov8 http://www.starryskies.com/The_sky/events/lunar-2003/eclipse-Nov8.html

Tides: are caused by the gravitational pull of the moon on the water of the earth

Spring tides occur during the full moon and the new moon. When the sun and the moon are lined up to both pull in the same direction or opposite directions, tides are especially strong. This is called a 'spring tide.' Spring tides occur during the full moon and the new moon.

Neap tides are especially weak tides Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are perpendicular to one another (with respect to the Earth). Neap tides occur during quarter moons.

HOMEWORK: In review book Page 64 (41-53) Page 53 (2-14) On a QUARTER SHEET DUE NEXT CLASS

III. Solar System A. Types of models

Model types 1. Geocentric: Earth is at the center of the solar system

Model types 2. Heliocentric The Sun is at the center of the solar system

B. Planets 1. Jovian planets: Gaseous planet, low density, these include: Saturn, Jupiter, Neptune, and Uranus

These include; Mercury, Venus, Earth, Mars Terrestrial planets These include; Mercury, Venus, Earth, Mars These planets have a rocky core and are the closest to the sun

1. We classify stars based on their luminosity, compared to our sun. C. Stars 1. We classify stars based on their luminosity, compared to our sun. 2. P 15, ESRT 3. Stars moving towards us are more of a blue or violet color

4. Stars moving away are colored red C.Stars 4. Stars moving away are colored red http://www.astro.princeton.edu/~clark/teachersguide.html Analogy: Bloody nose, fist has already hit you and is moving away from your face

C. Stars 5. The fact that the star colors are changing are indications that the universe is either expanding or contracting

D. Galaxy We live in the Milky Way Galaxy; it is called that because it looks Milky white in color

http://www.classzone.com/books/earth_science/terc/content/visualizations/es2808/es2808page01.cfm?chapter_no=visualization

Galaxy Shapes 1.Spiral

Galaxy Shapes 2. Lenticular

Galaxy Shapes 3. Elliptical

Galaxy Shapes 4. Irregular