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List the following words in order from smallest
to largest:
Constellation
Planet
Solar System
Star
Universe
Galaxy
How many of the smaller word can fit into the
next word on your list?
Example: If you thought stars were smaller than a solar
system you can say there are 1000 stars in a Solar
System.
“Galaxies”
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A. Galaxies are very
large groups of stars.
B. Most contain 100s
of billions of stars!
C. They are classified by
shape.
1. Spiral:
a) “Nucleus with Arms”
b) The center is full of many
yellow stars, which makes it look
like a nucleus.
c) Many spiral arms come out of
the nucleus.
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2. Elliptical:
a) Spherical, without spiral arms.
b) The oldest stars are in this type of
galaxy.
c) No new star activity.
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3. Irregular:
a) Does not have a definite shape.
b) Could be the result of two galaxies
colliding.
c) The Megallanic Clouds are an
example of a irregular galaxy.
III. Our Galaxy: “The Milky Way”
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A. Spiral shaped
B. 100,000 light years across.
C. Our solar system is located in one of
the spirals, 30,000 light years from the
nucleus.
E. The closest star in our galaxy, besides the sun, is
Proximi Centauri. (About 4 light years away.)
Alpha and Proximi Centauri
IV. How the Terms Fit Together:
A. A star and its planets
= A solar system!
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B. A group of stars
= A constellation!
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C. Billions of stars
= A galaxy!
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D. Several galaxies
= A Cluster!
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1. The cluster that the Milky Way is located
in is called the Local Group.
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2. The other galaxies in the local group are :
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- Amdromeda ( Spiral)
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- Megallanic Clouds
IRREGULAR
“Constellations”
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A. Constellations are groups of stars that appear to form some
type of pattern in the sky.
• B. Most of the time stars, in a particular constellation, do not
have a relationship with each other.
• C. Most constellations are named after Greek and Roman
mythological figures.
• D. Astronomers have divided the sky into 88 constellations.
• E. Constellations give stars specific location in the sky.
• Ex. 1. Polaris is in the handle of Ursa Minor. (Little Dipper)
• Ex. 2. Betelgeuse is in the right shoulder of Orion.
BETELGUESE
Why are Constellations Useful?
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A. Used as landmarks to locate other objects in space.
• B. Were used by sailors and explores as a navigational tool.
C. USED FOR ENTERTAINMENT
D. USED TO KEEP TRACK OF TIME/SEASONS FOR TASKS
• Seasonal Changes:
• A. Different constellations can be seen at different
times of the year..
• i. Due to the Earth’s revolution around the Sun.
• Ii. Ex. Orion can be seen in the winter and spring .
Pegasus can only be seen in summer and fall.
•
What is your Sign?
• A. Aries-
(March 21-April 19)
• B. Taurus- (April 20 - May 20)
• C. Gemini- (May 21 - June 20)
• D. Cancer- (June 21 - July 22)
• E. Leo- (July 23 - August 22)
• F. Virgo- (August 23 – September 22)
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G. Libra-
• H. Scorpius• I. Sagittarius-
(September 23 - October 22)
(October 23 - November 21)
(November 22 - December 21)
• J. Capricornus-
(December 22 - January 19)
• K. Aquarius-
(January 20 - February 18)
• L. Pisces-
(February 19 - March 20)
www.astro.wisc.edu/.../ extra/constellations.html
Circumpolar constellations
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B. Some Constellations can be seen all year long!
• These type of constellations are called
circumpolar.
• Ex. Of circumpolar constellations are Ursa Major &
Ursa Minor (Big & Little Dipper).
“The Life of Stars”
I. Intro. to Stars:
A. Star- hot, bright, sphere of gas.
B. Stars are classified by their luminosity.
1. Luminosity- How bright a star is.
C. There are many things that can affect stars
luminosity.
Distance
Size
Temperature
Optics
Stage of Life
D. Types of Magnitude:
1. Apparent Magnitude- The luminosity of a star as
we see it from earth.
– Apparent Magnitude tells you very little about
a star.
2. Absolute Magnitude- The measure of a star’s
actual luminosity.
a.) A formula is used to figure absolute
magnitude out.
b.) A chart of the brightest stars is then made.
c.) This chart shows how luminous each star
would look if they were all the same distance
from Earth.
E. Star Color:
1. Color – Can indicate the estimated temperature of
a star.
a.) Red- (Coolest star) 3000-4000 K
b.) Yellow- (The Sun) 4000-7000 K
c.) White- 7000-11,000 K
d.) Blue- (Hottest Star) 11,000-60,000 K
• II Life Cycle of Stars:
A. Stars are born in nebulas.
B. Nebula- A rapidly condensing cloud of gas and
dust.
C. Star “Pre-life Steps”
1. Gases rapidly condense to star dust.
2. Masses form
3. Masses collide with others to form larger pieces of
“star stuff”.
4. Gravitational forces increase.
5. This sets off a “snow ball effect” or chain
reaction.
6. One very large object collects most of the “star
stuff”.
7. Density increases.
8. Temperature increases.
9. Fusion begins to take place.
a.) Fusion- The process in which two atoms
fuse together to form another substance.
b.) In the suns case there were two atoms of
Hydrogen, which fused together to form
Helium.
10. When fusion out put becomes balanced with the
gravity of the large object, a star is born.
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D. Life Cycle Steps:
1. Main Sequence- The beginning phase of life for all
stars.
a.) Every Star has a main sequence.
b.) The star spends most of its life in this phase.
c.) Fusion continues for billions of years.
d.) When a star’s hydrogen begins to run out, the
star begins to enter its next phase.
e.) It can go in one of two directions depending
on
size:
* Red Giant Phase (Small & Medium
stars)
* Super Giant Phase (Large & Extra Large stars)
E. Small & Medium Stars: (low mass stars)
2. Red Giant Phase- Beginning stage of death for
small & medium size stars.
a.) The fusion and gravity of a star becomes
unbalanced do to hydrogen running out.
b.) This makes the star collapse in on it self.
c.) Another round of fusion is triggered. This time
helium fusses together.
d.) The star swells to several times its original size
f.) Remaining gas floats away as the star cools.
3. White Dwarf- The remaining core of a small or
medium star after the red giant phase is over.
a.) The stars weight during the red giant phase will
make the star collapse in on it-self.
b.) All that is left of the star now is a collapsed core.
c.) About the size of earth.
4. Black Dwarf- The final stage of death of a small
or medium size star.
a.) After the stars core cools enough that its
luminosity is zero a star enters this phase of
life.
b.) All that is left is a tiny ball of “lifeless
material”
F. Large & X-Large Stars: (high mass stars)
2. Super Giant Star Phase- A star enters this
phase when most of the stars hydrogen is
used up.
a.) This causes a Super Nova.
b.) Super Nova- A rapid expansion of
the star that appears to be an
explosion.
c.) Gases eventually escape to form
new nebulas.
3. Neutron Star Phase- The remaining core
after a super nova.
a.) Very small and dense. (10-15 Km
across)
b.) Can be double its original density.
4. Pulsar Star Phase- A rapidly spinning
neutron star.
a.) It is spinning so fast that it looks
like little pulses of light are coming off
of it.
b.) Total collapse of the star is near
when it enters this phase.
5. Black Hole Phase- This is the final stage
of death for a large/x-large star.
a.) A total collapse of the star’s core
takes place.
b.) A black hole is extremely dense and
has a very high gravitational force.
c.) Almost nothing can escape its
gravitational pull. (not even light)