1. Solar System Sun is at the center, other objects orbit it
Sun is a star
Orbit- path an object takes around the sun
8 planets
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Inner Planets
Outer Planets

2. Solar System Moons- bodies that orbit planets
Earth has one moon
Jupiter and Saturn
have many moons
Mercury and Venus-no
moons
Asteroid- small rocky bodies that revolve around the sun, most found in asteroid belt
Comet- made up of ice, dust and small gritty particles, have “tail”, many come from Oort cloud, beyond Pluto
Meteroid- small particles of rock, most come from asteroids or comets, produce streaks of light called meteors, when they land on Earth they are called meteorites

3. Solar system Review
1.) Which statement best describes how the sun and Earth are related? a. Earth revolves around the sun b. The sun revolves around the Earth c. Earth rotates around the sun d. The sun rotates around Earth 2.) Which list gives the inner planets in correct order starting with the planet closest to the sun? a. Mercury, Earth, Venus, Mars b. Venus, Earth, Mars, Mercury c. Mercury, Venus, Earth, Mars d. Mars, Venus, Earth, Mercury 3.) Which of the following is a rock from space that lands on Earth? a. Meteoroid c. comet b. asteroid d. meteorite 4.) Which of these does NOT describe an outer planet? a. rocky c. has many moons b. has rings d. gasous

4. The sun and other Stars
Star- a sphere of hot glowing gases that gives off its own light and is held together by gravity
Sun =Medium star by size and mass, yellow in color, surface temp 5,500oC, diameter 1.4 million kilometers, mass 1.99 x 1030 kg
Sun- contains 99.8% of the mass of our solar system, the sun is a star, made of mostly hydrogen gas
Nuclear Fusion- process that provides sun’s energy
In nuclear fusion, two atoms of hydrogen combine to form helium producing extreme amounts of energy

5. The Sun and Other Stars Temperature of a star determines its color
Brightness determined by size and temperature
Absolute magnitude- describes actual brightness if it were a standard distance from Earth, measured from -10 to +15 (negative=brighter)
Color
Temperature
30,000oC
9,500oC
6,000oC
5,000oC
3,000oC

6. The sun and other stars HR Diagram Most stars fall with in
diagonal band of stars
called main sequence.
These stars show a
direct relationship
between temperature and
brightness
Hotter stars burn
brighter.
Cool red giants in the
upper right are bright because
of their size
Hot white dwarfs are
dim because they are so
small

7. The Sun and Other Stars Life Cycles of Stars
Stars form when clouds of gas become compressed enough to start the process of nuclear fusion,
**Its mass determines its life cycle
Most stars enter the main sequence phase
*lasts about 10 billion years,
nuclear fusion powers these
stars
**HOT STARS USE OF THEIR
HYDROGEN FASTER THAN COOL
STARS
Stars leave main sequence
Low mass left—collapse and
become white dwarf
Medium mass- enters period of
expansion and contraction, use
helium as fuel, becomes red giant,
after about a billion years collapses
to white dwarf, then cools to black dwarf
Very Massive- become super giant
(huge, cool, red stars), helium and carbon
used as fuel, if massive enough will
collapse to neutron star when it dies,
most massive collapse into black holes
(an object so dense light cannot escape
from it)
Sun
main sequence star
about 4.6 billion years old,
will burn hydrogen for about 5 billion more years
then it will become a red giant and burn helium
when helium runs out fusion will stop
red giant will become white dwarf
the sun will continue to give off energy as it cools into a black dwarf

8. The sun and other stars review
1.) What kind of star is our sun? a. supergiant c. white dwarf b. red giant d. main sequence 2.) Which of the following is MOST important in determining a star’s life cycle? a. its mass c. its color b. its diameter d. its brightness 3.) What fuel does a main-sequence star use for nuclear fusion a. oxygen c. helium b. petroleum d. hydrogen

9. Days, Years, and Seasons
Length of year-time in which a planet completes on orbit around the sun
365 days
Planets that are farther from the sun have longer years than those closer to the sun
Length of day-time in which a planet makes on full turn on its axis
24 hours
Length of day varies among the planets
Seasons-variation in length
of day and temperature
based amount of sunlight
received
Amount of sunlight
affected by tilt of the Earth
on its axis
Summer Solstice
Autumnal Equinox
Winter Solstice
Vernal Equinox
**Equinox  equal

10. Phases of the Moon Phases of the moon:
Same side of moon always faces the Earth
Moon takes the same amount of time to orbit Earth as it does to turn on its axis
Moon’s orbit around Earth is
angled so an eclipse does not
occur often
At any time half the moon
is lit, half the time its dark
Waxing- sunlit part of the
moon grows larger
Waning- sunlit part of the
moon grown smaller

11. Tides
Tide- rise or fall of surface of water due to gravitational force
High tide-highest level of water along shore
Low tide-lowest level of water along shore
Spring Tide-moon, sun, and earth in line during new or full moon, greatest difference between high and low tide
Neap Tide-moon, sun and earth at right angles during new or full moon, least differences between high and low tide

12. Eclipses
Solar Eclipse-moon blocks sun’s light and casts a shadow onto Earth
Only occurs during new moon
Moon passes between sun and Earth
Umbra-area of total eclipse, sky becomes dark as night
Penumbra-area of partial eclipse, not as dark as

13. Eclipses Lunar Eclipse-moon passes into Earth’s shadow
Earth is between sun and moon, this blocks sun’s light from reaching the moon
Only occurs during a full moon
Most lunar
eclipses are
partial