The document provides an overview of key concepts in physics and astronomy. It defines important terms like planets, satellites, phases and eclipses. It describes the structure of the solar system including terrestrial and gas giant planets. It explains theories of how the solar system formed and evolved over time from the geocentric to heliocentric models. It also summarizes characteristics of objects in our solar system like planets, moons, asteroids and comets.

1. Physics
I. Vocabulary
1. Planet- a celestial body that orbits the sun, is round because of it’s
own gravity, and has cleared the neighborhood around it’s orbital
path
2. Solar system- the sun and all of the planets and other bodies that
travel around it
3. Satellite- a natural or artificial body that revolves around a celestial
body that is greater in mass
4. Phase- the change in the illuminated area of one celestial body as seen
from another celestial body; phases of the moon are caused by the
positions of Earth, the sun, and the moon
5. Eclipse- an event an event in which the shadow of one celestial body
falls on another
6. Terrestrial planet- one of the highly dense planets nearest to the sun;
Mercury, Venus, Earth, and Mars
7. Hydrosphere- the portion of the Earth that is water
8. Asteroid- a small, rocky object that orbits the sun; most asteroids are
located in a band between the orbits of Mars and Jupiter
9. Dwarf planet- a celestial body that orbits the sun, is round because of
it’s own gravity, but has not cleared it’s orbital path
10. Gas giant- a planet that has deep, massive atmosphere, such as Jupiter,
Saturn, Uranus, or Neptune
11. Nebular Hypothesis- a model for the formation of the solar system in
which the sun and planets condense from a cloud (or nebula) of gas
and dust
12. Nebula- a large cloud of dust and gas in interstellar space; a region in
space where stars are born
13. Comet- a small body of ice, rock, and cosmic dust that follows an
elliptical orbit and that gives off gas and dust in form of a tail as it
passes close to the sun
14. Exoplanet- a planetlike body that orbits a star other than the sun
15. Perihelion - the point in the path of a celestial body that is nearest to
the Sun
16. Aphelion- the furthest point from the Sun
17. Umbras- well defined if they are produced by big and far sources of
light or by small and close sources of light
18. Penumbras- partial shadows, when the light is blocked but there is
another source of light or when the light from the source is patially
blocked
II. Section Reviews
1. Explain why objects in the sky appear to move.
- The positions of objects in the sky change over time because Earth,
and everything else in the universe, is constantly moving.
2. Describe the star that’s closest to the Earth.
- The Sun is the closest star to the Earth. The Sun is the brightest
object in the sky because it is so close to us. The Sun is an average
star. It is not particularly hot or cool and is of average size. It’s
diameters is 1.4 million kilometers. The sun has a mass that is
about 330,000 times the mass of Earth.

2. 3. Describe the basic structure of the solar system.
- the sun is the most important part of our system and makes up
nearly 99% of the total mass of the solar system. The eight planets
and their moons make up the remaining 1%. The solar system also
contains many other smaller objects, such as planets, asteroids,
comets, dust, and gas.
4. Explain how gravity keeps planets in orbit around the sun.
- The gravity of the sun keeps the planets in their orbits. They stay
in their orbits because there is no other force in the solar system,
which can stop them.
5. Explain what happens in a lunar eclipse and what phase the moon is
in during a lunar eclipse.
- A lunar eclipse occurs when the Moon passes directly behind the
Earth into its umbra (shadow). The moon is in the phase of a full
moon.
6. State the moon’s role in the formation of tides.
- The moon’s gravitational pull is the strongest on the side of Earth
nearest the moon. On this side, the ocean is pulled toward the
moon, so a slight bulge is created. The solid Earth also moves
slightly under the moon’s gravity, but the movement of water is
more noticeable because it is water.
7. List ways in which the 4 terrestrial planets are similar to one another.
- The four terrestrial planets are similar to one another because:
a. They are relatively small
b. Have a solid and rocky surface
c. Scientists can study them by using telescopes and other
instruments
d. Similar compositions: metallic cores (iron-nickel alloys)
e. Similar surface features: mountains, canyons, craters
8. Identify the only terrestrial planet that supports life.
- The only terrestrial planet the supports life is the Earth.
9. Explain why the surface of Venus is so hot.
- The result is a “runway” greenhouse effect that raises atmosphere
temperatures and keeps the surface temperature greater than 700
K. (A greenhouse effect occurs when infrared radiation is absorbed
and heat builds up.)
10. Describe the features that distinguish a gas giant from a terrestrial
planet.
- The features that distinguish a gas giant from a terrestrial planet
is:
a. While the terrestrial planets have a solid surface the gas giants
are gas.
b. While terrestrial planets are small gas giants are huge.
c. While terrestrial planets have metallic cores, the cores of gas
giants are rock and ice.
d. While terrestrial planets don’t have rings, gas giants do.

3. 11. Explain why Saturn is thought to still be forming.
- Scientists think that helium in Saturn’s outer layer is condensing
and falling inward. As the helium nears the central core, the gas
heats up. When Saturn uses up its atmospheric helium, this
process will stop and Saturn will reach a state of equilibrium. Until
then, Saturn is considered to still be forming.
12. Explain how our current model of the solar system differs from
Ptolemaeus’ model.
- It differs from our model because he thought that the Sun, Moon
and the planets orbited the Earth, while in reality it was the Earth
and other planets that orbited the Sun.
13. What are the phases of the moon?
- First Quarter, Waxing Crescent, New, Waning Crescent, Third
Quarter, Waning Gibbous, Full, and Waxing Gibbous.
14. How was the moon made?
- Incidentally, that big something that hit our earth, causing it to tilt,
also knocked a chunk out of it, which became our moon.
III. Power point
- History of the Astronomy
Basically, Aristotle, a Greek philosopher, made the
geocentric model, which consists that the sun orbits the Earth
in a circle. He also gave the theory about the five elements,
which are: fire, earth, water, air, and ether.
Then came Claudius Ptolemaeus, an astronomer, and
proposed the best geocentric model, explaining the paths of the
Sun and Moon, and of the five known planets, supporting
Aristotle’s geocentric model.
Then Nicolas Copernicus, an astronomer, came and
started the scientific revolution. He made the heliocentric
model, which consists that the Earth orbits the Sun while it
spins around itself.
Then Galileo Galilei “The father of science” discovered
Jupiter’s satellites, the Milky Way, Neptune and Venus. He also
builded a telescope right after hearing about it.

4. - Laws of Kepler
First Law: Law of Orbits- the planets move on elliptical orbits with
the Sun in one of the foci.
Second Law: Law of Areas- An imaginary line from the center of
the Sun to the planet wipes equal areas in equal periods of time.
Consequence: The speed of the planet is greatest when the planet
is closer to the Sun and least when it if the furthest.
Third law: Law of periods- the square of the orbital perion of a
planet is directly proportional with the cube of the mean distance
from the planet to the Sun.
- Sir Isaac Newton
He created the law of universal gravitation. Newton was a
physicist; he created the laws of motion and created one of the
fundamental laws of the universe (Newton’s Law of Universal
Gravitation):
 Every particle in the Universe attracts every other particle
with a force that is directly proportional to the product of
the masses of the particles and inversely proportional to
the square of the distance between them.
 The magnitude of the gravitational acting on an object of
mass m near Earth’s surface is called the weight of an
object, given by:W=mg
- The Solar System
A. Terrestrial Planet Interiors
 Mercury, Venus, Earth, Mars
 Highly dense planets nearest to the Sun
 Similar compositions: metallic cores (iron-nickel alloys)
 Similar surface features: mountains, canyons, craters
B. The Gas Giants
 Jupiter, Saturn, Uranus, Neptune
 Heavy, dense atmospheres
 They are large and have rings.
 Have many satellites
 Have a rocky and icy core
C. Mercury
 Extreme temperatures
 Mercury year (orbits the Sun in 88 days)
 Mercury day = 59 Earth days
 No atmosphere and no water

5. D. Venus
 Morning and evening star
 Sulfuric acid atmospheric content
 Atmospheric pressure 90 times higher than on Earth
 Spins slowly in the opposite direction than most of the
planet
 No mountains or plains
 1 Venus year = 225 Earth days
 1 Venus day = 243 Earth days (less than the year)
E. Earth
 Hydrosphere : the water portion of Earth and helps
moderate the temperature
 Magnetosphere: protects the Earth form radiation and
high-energy particles
 Atmosphere: Protects the Earth from radiation and
particles, space debris
 Why does Earth have seasons?
- Something very big hit young Earth knocking it
off-kilter. So instead of rotating with its axis
perpendicular, it rotates 23.45 degrees from its
perpendicular.
 Seasons:
- The summer solstice day (around June 21) is
the day with the most hours of daylight
- The winter solstice day (around December 21)
is the day with the fewest hours of daylight
- The Vernal and Autumnal equinoxes (March
20, September 22) are the only days with equal
amount daylight and nighttime
F. Moon
 The only natural satellite of the Earth
 Has craters and dark patches called Maria
 Why do high tides occur when the moon is new and
full?
- The sun’s pull is almost as strong as the moon’s
so when they work together oceans bulge
higher.
G. Mars
 Polar ice caps
 2 small satellites: Phobos and Deimos
 Volcano: Olympus Mons is the largest mountain in the
Solar System
 No plate tectonics
 Many impact craters
 Color red due to iron oxide in the soil
 Strong dust storms which form red large dunes

6. H. The asteroid belt
 Between Mars and Jupiter
 Ceres- the oldest asteroid and a dwarf planet
I. Jupiter
 The largest planet
 Enormous storms
 1 day = 10 Earth days
 It has 4 satellites discovered in 1610 by Galileo:
 Ganymede
 Callisto
 Io (thin atmosphere, active volcanoes)
 Europa (may have liquid water under ice)
J. Saturn
 Has the most extensive ring system
 Made of dust, rock, and ice
 Planet still in formation until all atmospheric is
consumes
 Radiates 3x more energy than it receives from the Sun
K. Uranus
 Thick, gaseous atmosphere
 Discovered in 1846
 Has the most extreme seasons due to its tilt
L. Neptune
 Discovered in 1781
 Same characteristics as Uranus
 Storms similar to Jupiter
M. Magnetism
 All magnets have one South pole and one North pole
 It’s not possible to separate the magnetic poles
 The magnetism is the effect of the motion of electrons:
rotation around the nucleus and the rotation around its
own axis.
N. Aurora australis/borealis
 Protons and neutrons impacting the Earth’s atmosphere
O. Eclipses
 The sun eclipse- the moon is in between the Sun and the
Earth and the shadow of the moon is projected on the
Earth
 Total eclipse of the Sun- the observer in the shadow
(umbra)
 Partial eclipse of the sun- the observer is in the
penumbra
 Moon eclipse- the moon is in the shadow (umbra)
produced by the Earth