1. Satelite

2. Planet

3. Star

4. Terrestrial Planets

5. Jovial Planet

6. Orbit

1. A body that orbits a planet

2. A body that orbits a star

3. Huge ball of energy producing gas

-99% of our SS' mass is because of the sun

-Gravitational pull of the sun is what holds everything else together

4. Rocky inner planets (Mercury,Venus, Earth, Mars)

5. Gaseous outer planets or "Gas Giants" (Jupiter, Saturn, Uranus, Neptune)

6. Elliptical paths that everything in our SS follow when going around the sun 

Where would you see these moon phases in the sky @ 3pm?

1. New Moon

2. Waxing Cresent

3. Waning Cresent

1. Low in the Southern sky (setting)

2. High in the Southern Sky

3. Barely visible; setting on western horizon

Eclipses

(When do they occur?)

1. Lunar Eclipse

2. Solar Eclipse

1. When Earth's shaddow hits the moon perfectly & blocks the sun's light (earth blocks sunlight from hitting moon)

-Only happens during Full moon phase

-moon looks red b/c sunlight goes thru Earth's atmosphere then onto the moon

*You can see lunar eclipse from anywhere on Earth (as long as it is at night and the full moon is visible)

2. When moon's shaddow hits Earth and blocks sunlight from hitting Earth (moon blocks sunlight from hitting Earth)

-Only happens during New moon phase (during the day)

-You can only see a solar eclipse if you are in the specific place on Earth where the moon's shaddow hits

1. Penumbra

2. Umbra

3. Annular Eclipse

1. Earth's Shaddow

(We see a partial eclipse when we are in the Penumbra)

2. The Moon's shaddow

(We see a total eclipse when we were in the umbra)

3. When the moon is too far away from Earth for umbra to reach Earth

How long is a month? 

1. Lunar Month

2. Sidereal Month

1. It takes 29.5 days for the moon to get back to the same phase

2. It takes 27.3 days for moon to get back to the same stars in the sky

Motion of the moon

1. Daily

2. Monthly

1. The moon rises in the East and sets in the West as the Earth spins

2. Moon moves through all Zodiac constellations within a month

1. Planets move along the ecliptic b/c their orbits all lie, more or less, on the same plane

2. They also appear to move through the zodiac constellations

3. " appear to move from west to east over several months (compared to the stars) but they rise in East and set in West from day to day

Models of universe in which everything revolves around Earth

-In early Greek times, Geo models were used to describe heavens

- Model explained most things accurately, but does not explain how sometimes planets' paths go backwards (retrograde)

1. Retrograde Motion

2. Ptolmy's Epicycle Theory

When the normal motion of planet (west to east) compared to background stars is reversed to East to West

-This phenomena was unexplained for a while until Ptolmy's Epicycle

2. States that planets are attached to small circles (epicycles) that rotated and attached to a larger circle centered on Earth causing the illusion of retrograde motion

-*This theory is supportive/representative of Geocentric models of universe*

-Before telescopes, planets looked just like stars

-But they were "stars" that moved around the sky (not staying in the same constellation)

-Ancient Greeks called them "planetai" or "wanderers"

Nicolas Copernicus (1473-1543)

-Explored a heliocentric model (sun-centered) in which everything, including Earth, revolves around the Sun

-Explains retrograde motion as an apparent motion caused when one planet moves from being behind another planet to being in front of the other planet

Parallax

(heliocentric model)

-If stars are @ different distances, then closer stars should shift back & forth compared to background stars

Johannes Kepler

(3 Planetary Laws)

1. Planets don't move in perfect circles around the sun

-They follow a shape called an ellipse (oval) 

-Eccentricity: how round or stretched our an ellipse is

-ranges from 0 (perfect circle) and 1 (flat line)

______________________________________________

2. A line joining a planet and the sun sweeps out equal areas in equal intervals of time (it takes the same amt. of time for planets to move these distances)

-Planets move faster near the Sun

______________________________________________

3. The amt. of time a planet takes to orbit the sun is related to it's orbit's size

-Planets closer to the sun go around faster than farther planets

*mass makes no difference*

1. Mass

2. Inertia

3. Velocity

4. Force

5. Accelleration

1. The amt. of matter an object contains (measured in kilograms)

2. The tendency of mass to stay in motion

3. Speed & direction

4. Something that causes a body to chance velocity

-If an object's velocity is not changing: a) no forces are present orrr b) forces acting on it are balanced & cancel each other out

5. Change in a body's velocity over time (how quickly motion is changing)

*A change in direction counts as accelleration even if speed is the same*

Isaac Newton (3 motion laws and one gravity law)

1. Law 1- Law of Inertia

2. Law 2 

3. Law 3

4. Law of Gravity

1. A body continues in a state of rest, or in uniform motion in a straight line @ a constant speed unless made to change state

-a body maintains the same velocity unless forces act on it

2. The Force (F) acting on an object equals the product of its Mass (M) and it's Accelleration

-The same force on a more massive body will cause less accelleration than on a lighter body

3. When 2 bodies interact, they create equal and opposite forces on each other

4. Two bodies attract each other w/a force that is directly proportional to the product of their masses