TOPICS 3&4 ASTRONOMY PAGE 7 All the matter in the universe, is thought to be contained in an...

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TOPICS 3&4 ASTRONOMY

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All the matter in the universe, is thought to be contained in an area no larger than a grain of sand This area was under extreme pressure and measured an infinite density The matter exploded and traveled outward at an extreme rate This matter is still expanding and moving outward after billions of years This theory explains the origin of the universe

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Rotation-

A. Earth’s 1. Direction of Rotation:

Counterclockwise (CCW)

West to East (Left Right)

2. Rate of Rotation

a. 360 degrees

b. 24 hours

3. RATE= 15º/ hour

The movement or turning of a celestial body on its axis (spinning)

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What Happens If Earth’s Rotation slows down Video 2:53

The Earth and Its Motions

The rotation of the Earth causes day & night.

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Effects of Earth’s Rotation

The Apparent Motions of stars Star trail photographs looking North, South,

East, and West Try to identify the star trail photo and the

direction you would be facing

*15°/ hour*

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Effects of Earth’s Rotation

Apparent Motions of the Suna. Earth rotates from _______ to _______

b. Sun appears to move in an arc from ____________ to ____________ West

EastWest

East

*15°/ hour*

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Evidence of Rotation Pendulum- the Foucault Pendulum is a device

that proves (evidence) the Earth rotates on its axis

Coriolis Effect- is the deflection of planetary winds and ocean currents. In the Northern Hemisphere winds deflect to the right & to the left in the Southern Hemisphere

Classzone Animation

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Revolution-Revolution-

• A.A. Rate of RevolutionRate of Revolution 1. 1. 22. .

Earth revolves around the sunEarth revolves around the sun

1º/day1º/day

The orbiting of one celestial body around another celestial body

360 degrees

365 days

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Diagram of Earth’s RevolutionDiagram of Earth’s RevolutionLabel positions A-DLabel positions A-D

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Evidence of Earth’s Revolution1. Annual, cyclic changing of the

constellations seen at night

2. Seasonal Changes- the seasons

change in a cyclic pattern every

year

winter

spring

summer

autumn

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Evidence of Earth’s Revolution3. Annual, cyclic variations of the length

of daylight hours

Animate

http://www.learner.org/jnorth/images/graphics/mclass/SunlightAnimation_Year.gif

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Evidence of Earth’s Revolution4. Parallax- the slight changing of the position of

distant stars

Parsec- A unit of astronomical length based on the distance from Earth at which stellar parallax is one second of arc and equal to 3.258 light-years, 3.086 × 1013 kilometers, or 1.918 × 1013 miles.

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TERRESTRIAL PLANETS

Images: Lunar and Planetary Laboratory: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=178

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Rocky Dense Metal cores (iron) few moons AKA “inner planets”

Close to Sun small slow rotation fast revolution solid surfaces

Jovian Planets

Large (big diameters)

Massive

Gases and liquids

No solid surface

All have rings

Rotate rapidly

Slow revolution

Many moonsImage: Lunar and Planetary Laboratory: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=178

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Diagram of Earth’s Revolution11. Label positions A-D

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Season & Season & Approximate Approximate DateDate

Latitude Latitude of Sun’s of Sun’s Direct Direct RaysRays

Direction Direction of of Sunrise Sunrise & Sunset& Sunset

Altitude Altitude of the of the Noon Noon SunSun

Period of Period of DaylightDaylight

June 21June 21stst

SummerSummer SolsticeSolstice

23.5° 23.5° NorthNorth

North of North of East & East & North of North of WestWest

≈ ≈ 75°75° 15 Hours15 Hours

September 23rd

Autumnal Equinox (Fall)

0° Equator

Due East & Due West

≈ 50° 12 Hours

December 21December 21stst

WinterWinter Solstice Solstice23.5° 23.5° SouthSouth

South of South of East & East & South of South of WestWest

≈ ≈ 25°25° 9 Hours9 Hours

March 21March 21stst

VernalVernal Equinox Equinox (Spring)(Spring)

0° 0° EquatorEquator

Due East Due East & Due & Due WestWest

≈ ≈ 50°50° 12 Hours12 Hours

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Celestial Sphere1. Label horizon & zenith

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Celestial Sphere2. Blue= 12/21, Green= 3/21 &

9/23, Red=6/21

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Celestial Sphere3. 42°N b/c that’s the altitude

of Polaris

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Celestial Sphere4. South

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Kepler’s Laws of Planetary Motion

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Kepler’s 1st LawTitled the: Ellipse LawStates each planet moves around the

Sun in an ellipse with the Sun located at one focus

Focus Focus

Sun Sun

Planet

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Kepler’s 1st Law: Definitions• Ellipse: A closed curve around two

fixed points, called foci; shaped like an oval or flattened circle

• Foci: Two fixed points within the ellipse – Think of the ellipse as a smiley face with

the two eyes being the fociFocus Focus

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Kepler’s 1st Law

Label the parts of the Ellipse:

Focus Focus

Major Axis:

The longest diameter (axis) of an ellipse, running through the center and foci.

Minor Axis

Orbit:

The path of an object revolving around another object; such as the Earth around the sun.

Sun Sun

Planet

D= Origin

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Kepler’s 1st Law: Definitions• Eccentricity: is a numerical value

used to describe the degree of flatness or “ovalness” of an ellipse – How out of round the shape is – *Eccentricity of a perfect circle= 0

Circle= 0

Comet Straight line= 1

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Calculating eccentricity of an ellipse:

Formula: (e) eccentricity = (d) distance between foci (L) length of major axis

length of major axis

When the distance between foci get larger what happens to the ellipse?

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d. Relationship:As the distance between foci increases, the shape of the ellipse becomes more elliptical or oval

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ESRT Page 15

Which planet has the least perfectly circular orbit?

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Which planet has the most perfectly circular orbit?

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Kepler’s 2nd Law• Titled: Equal Time, Equal AreaStates as a planet revolves around the

Sun a straight line joining the center of the planet and the center of the Sun, the planets sweeps out equal areas in space in equal intervals of time

Eccentricity Website

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Kepler’s 2nd Law• Essentially what Kepler

discovered was the planets change speed during their orbit around the Sun

http://astro.unl.edu/

naap/pos/animations/kepler.swf

Glencoe

Another

Interactive Animation #2

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Increasing speed

PerihelionJan. 4thMax. speed

AphelionJuly 4thMin speed

Decreasing speed

Max. Gravitational Attraction

MAX Apparent DiameterMin. Gravity

Min diameterHINT: Study one know the other by default

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Kepler’s 3rd Law• Titled The Harmonic Law

States a planet’s orbital period (P) squared is proportional to its average distance from the sun (au) cubed:

What does it mean?

The further a planet is to the sun, the longer it takes to revolve around the Sun

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What are Kepler’s 3 Laws of Planetary Motion?

1. The Ellipse Law: Each planet moves around the Sun in an ellipse with the Sun at one focus

2. Equal areas in space in equal intervals of time (Planets change speed in orbit: Closer to sun= faster)

3. Period squared (2)= Distance cubed (3)(faster period of revolution when closer to sun)

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Increasing speedPerihelion

Jan. 4thMax. speed

AphelionJuly 4thMin speed

Decreasing speed

Min Gravitational Attraction

Min Apparent DiameterMax Gravity

Max diameterHINT: Study one know the other by default

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Increasing speed

Decreasing speed

5. THE SUN6. Heliocentric

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Earth’s MoonPAGE 11

Earth’s Moon PAGE 11

New Moon

Waning Gibbous

Full Moon

Waxing Gibbous

First Quarter

Waxing Crescent

Third Quarter

Waning Crescent

Lunar Phases- Seen from Earth

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Earth’s Moon2. 27.3 (ESRT page 15)

3. 27.3 (synchronous motion- this is why we only see one side of the moon)

4. 29.5 days

5. b/c the moon revolves around Earth

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Lunar Eclipse• Moon goes into Earth’s Shadow

• Can only happen in the Full Moon Phase

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Solar Eclipse• Moon blocks out sunlight from

reaching Earth- day turns to night• New Moon Phase

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