Geocentric Model: All celestial objects revolve around Earth. Heliocentric Model: All celestial objects revolve around the sun. Which is heliocentric and which is geocentric? Click to see if you were right.

Our Universe * Is 25 billion light years wide * It is billion years old * It was created from the “Big Bang” * It is continually expanding (objects are moving away from one another)

The Milky Way Galaxy Spiral * It is 100,000 light years wide arms billion It is a ________Galaxy It is a ________Galaxy Our Solar System is located in one of the __________ It contains over 200 ________stars

The Milky Way Galaxy

15 ◦ /hr. W E counter-clockwise Earth’s Rotation: * The Earth rotates at a rate of ______. It takes 24 hrs. to complete one rotation. * The Earth spins in a __________________direction.

Proof of Earth’s rotation: * Foucault Pendulum * Coriolis Effect

Apparent Motion of Stars: Explains how an object appears to move in the sky. circle around Polaris 1. From the North Pole, stars appear to move in a_______________________.

remain still. 2. From the North Pole, Polaris appears to __________________

Earth WE Solar Noon east Solar Noon: Is the point when the sun appears to be the highest in the sky. 3. The sun appears to rise in the _____ and set in the _________. west

WestEast Stars appear to rise in the EAST and set in the WEST.

4. Constellations appear to move from ___________east to west.

Ellipse: Is a closed curve around two fixed points known as foci. * Each planet’s orbit around the sun is an ellipse. S Imaginary foci E The earth’s eccentricity is (very close to being a circle)

Most eccentric Least eccentric 1 0 elongated or oval circle ______ eccentricity Low Earth’s orbit is close to being a circle. High ______ eccentricity Number is closer to ____ Shape is ______________ Number is closer to ____ Shape is close to being a _____________

Calculating Eccentricity: E = the distance between the foci the length of the major axis 1. Eccentricity has NO UNITS! 2. The calculated value of eccentricity has to be between 0 and 1.

Major Axis: runs through BOTH foci. S E Distance between foci Foci distance= 2cm Major Axis = 6cm E = 2cm 6cm =.333

The Earth revolves counter-clockwise around the sun once every 365 days. Earth’s Revolution: AphelionPerihelion

Aphelion furthest less smaller toward Perihelion closest strongest greatest largest away from Earth is _________from the sun Gravitational pull is _________ Velocity is _________ Earth is _________to the sun Apparent diameter is _________ Northern Hemisphere is tilted_________the sun Southern Hemisphere is tilted______________ the sun

A D C B June December September March 23 ½ ◦ Label the months represented by positions A thru D on the diagram. What is paraellelism? How is the earth tilted in relation to the sun in positions B and D ? When is the earth furthest from the sun? What happens to the earth’s velocity as it travels from position A to D ? 1. Earth’s axis is in parallelism, which means it remains at a constant 23 ½ degree tilt. 2. In positions B and D the earth is neither tilted toward or away from the sun. 3. As the earth revolves around the sun from position A to D its velocity will begin to increase and then decrease again. 4. Earth is furthest from the sun during June.

Proof of a Heliocentric Universe: 1. Constellations appear to move across the sky throughout the year. 2. Seasons change throughout the year.

Moon Facts The sun is 400 times larger than the moon yet it looks the same size to an observer on Earth. The moon appears as big as the sun because it is closer to us.

Moon phases occur because the moon is revolving around the earth.

New Moon Full Moon Waxing Crescent Waning Crescent Waxing Gibbous Waning Gibbous First Quarter Last Quarter

Occurs during a NEW MOON. Solar Eclipse

Total eclipse March 29, 2006

Lunar Eclipses Moon moves into Earth’s shadow – this shadow darkens the Moon Moon moves into Earth’s shadow – this shadow darkens the Moon –Umbra –Penumbra About 2-3 per year About 2-3 per year Last up to 4 hours Last up to 4 hours

Eclipses of the sun and moon occur equally often, but lunar eclipses are seen by more people. An eclipse of the moon is visible everywhere on the dark side of the earth, while a solar eclipse can only be seen by observers in the shadow of the moon as it passes across the earth’s surface.

New Moon Spring Tides Also Full Moon

Quarter Moon Phases Neap Tides

Origin of Moon Unknown Unknown Popular theory: Popular theory: –Early earth was hit by Mars-sized object –Debris from this collision formed moon –Composition of moon is similar to earth’s mantle

1. Stars are born from a cloud of dust in a nebula. Black Dwarf 2. Massive stars follow the bottom path. 3. Massive stars burn their fuel fast and die quickly. 4. Our sun will eventually become a black dwarf.

20,000 10,000 5,000 2,500 Temperature ‘ C White Dwarfs are less luminous than our sun, but have a high temperature Betelgeuse is very large and bright, but has a low temperature Our sun is a medium star and is on the main sequence

1. Energy from our sun comes in the form of electromagnetic waves. 2. Each type of energy has its own wavelength. 3. The only visible portion of the spectrum is light.

The Electromagnetic Spectrum Gamma RaysX Rays Ultraviolet Infrared Microwave Radio Waves SHORT waves LONG waves Visible Light

This barcode helps identify the product it is attached to. The spectrum of this star helps to identify it as well.

Name three things that the spectrums of stars can tell us: 1. What gases the star is burning. 2. The temperature of a star. 3. If the star is moving away or towards us.

The Doppler Shift 1. If the dark lines shift toward the red end of the spectrum, the distance is _______________. (the star is getting further away) 2. If the dark lines shift toward the blue end, the distance is _______________. (the star is getting closer) increasing decreasing

How does this explain the universe expanding? Well…when astronomers look at distant galaxies, they see a red shift in the spectrum, therefore the galaxies are moving away and the universe is expanding!

N E W S Summer Solstice June 21 Highest Longest Short shadow The angle of insolation is ____________ The duration of insolation is _____________ Sun rises NE and sets NW

N E W S Spring or Fall Equinox March 21 September 23 Equal days and equal nights Sun rises due east and sets due west Slightly longer shadow

N E W S Winter Solstice December 21 Lowest Shortest Sun rises SE and sets SW Long shadow Angle of insolation is _________ Duration of insolation is ___________

Polaris Zenith June 21 March 21 September 21 December 21 Where is the zenith? Label March, June,Sept. and Dec. Where would the path for May be?

Polaris Zenith What latitude is the observer standing at? 38 ◦ 38◦ N Because the altitude of Polaris is equal to the latitude of an observer in the Northern Hemisphere!