AIM: HOW DO STARS
FORM?
DO NOW:
How many stars are in our
Solar System?
Homework:
What are stars?
v Balls of gases that
give off light & heat
energy.
v Most stars are
made up of hydrogen
& helium.
What is the
closest star
to the
Earth?
The Sun:
• One of billions of
stars
• Avg. size (main
sequence star)
• A million times
greater volume than
the earth
Why does the
sun look big
compared to
other stars?
• Other stars are so
far away that they
look like points of
light.
• There are huge
distances between
stars.
• We only have one star
(the sun) in our solar
system.
How are stars
formed?
v From a spinning
cloud of gas & dust
called a nebula.
Continued spinning &
gravity causes
materials to squeeze
together to form a
protostar
What is the v The temperature &
pressure builds up due to
lifecycle of a
nuclear reactions (fusion of
star?
hydrogen to helium)
creating energy
v The protostar becomes a
star when it gives off light
& heat.
v A star will continue to go
through stages as nuclear
reactions continue.
The Lifecycle of a Star
What is the
measure of a
stars
brightness
called?
MAGNITUDE!
This depends upon its
temperature, its size
and its distance from
the earth.
The brightness of a star as seen from earth is
its__________
apparent brightness.
The actual brightness of a star is
its__________brightness.
absolute
LETS REVIEW…
• WHY DO STARS APPEAR SO SMALL?
• WHAT IS A SPINNING CLOUD OF GAS &
DUST?
• WHAT 2 GASES MAKE UP MOST STARS?
• WHY IS THE SUN SO IMPORTANT?
• WHAT IS A MEASURE OF A STARS
BRIGHTNESS CALLED?
• WHICH TYPE OF STAR IS HOTTER, A BLUE
STAR OR RED STAR?
(WHY DID YOU PICK YOUR ANSWER?)
AIM:
What objects are located in
our solar system?
DO NOW: What are stars?
Homework:
Handout 16-1 & 16-9
Big 8 Review pgs 65-74 due Thursday
What are the
names of the
planets that
orbit the sun?
1. Mercury
My
2. Venus
Very
3. Earth
Excellent
4. Mars
Mother
_____________________
5. Jupiter
Just
6. Saturn
Served
7. Uranus
Us
8. Neptune
Nachos
What does the
word “planet”
mean?
“Wanderer” because
they change their
positions among the
stars
What are the sun
& all the objects
that orbit the sun
called?
What other
objects orbit
the sun?
1. Asteroids – large groups of
rocks between Mars & Jupiter
(asteroid belt)
2. Comets – made of rock, ice,
dust, & frozen gases that
make up the 3 parts:
The core (nucleus), coma
(together = the head) & Tail
3. Meteoroids – pieces of rock &
metal
What happens
if a
meteoroid
enters into
the earth’s
atmosphere?
What are
meteors that
hit the earth’s
surface?
It is called a Meteor,
which will burn up due
to friction from the
earth’s atmosphere.
v Also called a
shooting star
Meteorites
What are the
rings around
some of the
planets?
What are
satellites?
• Small particles of rock
or ice
• considered tiny
satellites
Object(s) that orbit
a body in space
Example: The moon
Do other planets • Yes
have moons?
• Saturn = the most
• Earth & Pluto have 1
• Mercury & Venus = 0
What are 3
features on
the moon’s
surface?
1. Maria: meaning
“seas”
-Broad, flat plains
2. Highlands: mountains
3. Craters: round pits
Other Facts About the Moon:
•American astronauts landed July 20, 1969
•It has no water or atmosphere &
•Has 1/6th less gravitational pull than the
earth
LETS REVIEW…
• What are the 4 inner planets?
• What are the outer planets?
• What does the word “planet”
mean?
• What other objects orbit the sun?
• What is a satellite?
• What is another name for a shooting star?
• What have you learned about the moon?
AIM:
How do planets orbit in
space?
DO NOW:
What are the differences between
Asteroids, Comets, & Meteoroids?
Homework: Handout 16-2 & 16-3
Why do
planets orbit
the sun?
Gravitational attraction
between the sun & the
planets keep them moving
in curved elliptical orbits
around the sun.
The Earth’s orbit around
the sun is a slightly oval
ellipse
What is an
ellipse?
A flattened circle, or oval
What is an
orbit?
The curved path of one
object around another
object in space
Because of its
elliptical orbit, is
• Perihelion – the point
the earth the
in a planet’s orbit
same distance
when it’s closest to
from the sun at
the sun. (January)
all times of the
year?
• Aphelion - earth
farthest from the sun
(July)
Does each planet
take the same
amount of time to
travel around the
sun?
No
Each planet has
its own orbital
velocity
What is orbital
velocity?
The speed at
which a planet
travels in its orbit
What does
orbital velocity
depend upon?
The gravitational pull
of the sun.
As distance decreases
gravitational pull
increases
Does the earth
have the same
orbital velocity
all year? Why?
When does the
earth have the
greatest orbital
velocity?
No
It’s not always the
same distance from the
sun
During Perihelion
Which planets
have the
fastest orbital
velocity?
The inner planets
What
causes the
curved path
of an
orbit?
The combination of 2
motions:
1. A forward motion
&
2. An inward pull
What causes
the inward
pull?
Gravity from the sun
LETS REVIEW…
• Why do planets orbit the sun?
• What is the shape of the earth’s orbit?
• What happens to gravitational pull as
distance increases?
• What causes the curved path of an orbit?
AIM:
1. How did the solar system form?
2. What is a galaxy?
DO NOW: Why do planets orbit the
sun?
Homework: Study for Quiz
Test on Astronomy on Friday
Big 8 Review pgs 65-74 due Tomorrow
How did the
Solar System
form?
We only have
theories to explain
this.
What does the
Nebula Theory
state?
A spinning cloud of
hot gases called a
nebula shrank to
form the sun,
planets, & objects
in the solar system
-It happened over a
long period of time.
What does the • The universe began
with a giant
Big Bang Theory
explosion from a
state?
single point about
15 billion years
ago.
• Matter & energy
formed stars &
galaxies, which
continue to expand
outward.
What is a
galaxy?
How are
galaxies
grouped?
A large system of stars
Based upon shape
1. Spiral Galaxies:
What are
composed of a nucleus of
characteristics
bright stars & 2 or more
of the 3 types
arms that branch out.
of galaxies?
-3 out of 4 fall in this
group
2. Elliptical Galaxies: almost
round, or flat disks
-small
-oldest stars are found
here
What are
characteristics
of the 3 types
of galaxies?
(continued…)
What is the
name of our
galaxy?
3.Irregular Galaxies:
no definite shape
-smallest & least
common
The Milky Way
– Spiral Galaxy
LETS REVIEW…
• Brainpop.com – Big Bang
Aim:
1. Take & Go over Quiz
2. Review:
What do you know about Astronomy?
Do Now: Prepare for Astronomy Quiz
Homework:
1. Bring #2 Pencil
2. Study your notes for
tomorrow’s Astronomy Exam
Name ________________
1. Name the 2 main gases that make up most
stars.
2. What is a spinning ball of gas & dust that is
drawn together by gravity called?
3. Which planet is presently furthest from the
sun?
4. The sun & all the objects that orbit the sun is
know as __________________.
5. 3 features of the moon’s surface are Marias,
highlands & ___________.
6. The moon is a natural satellite that has (give a
fraction) less the gravitational pull of the Earth.
7. During what month is the Earth experiencing
perihelion?
8. What 2 motions cause the curved path of an objects
orbit in space?
9. How are galaxies grouped?
10. A meteor is also know as ______________.
Bonus: A group of stars that forms a pattern (or picture)
in the sky is known as _____________.
Aim: Exam
What do you know about Astronomy?
Do Now: Prepare for Astronomy Exam
Homework: Big 8 Review
Book pgs 75-79