Galaxies.notebook
Galaxies
January 06, 2014
Three Types of Gallaxies
Elliptical
Spiral
Irregular
Elliptical Galaxies
Virgo A
Elliptical Galaxies
70 percent of all galaxies
• ________
• Appear ____________ or elliptical in shape
60 x 106 ly from Earth
• Show a smooth distribution of light concentrated
in the ______________
Elliptical Galaxies
Elliptical Galaxies
70 percent of all galaxies
• ________
70 percent of all galaxies
• ________
round or elliptical in shape
• Appear ____________
round or elliptical in shape
• Appear ____________
• Show a smooth distribution of light concentrated
• Show a smooth distribution of light concentrated
in the ______________
center
in the ______________
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Galaxies.notebook
January 06, 2014
Elliptical Galaxies
Elliptical Galaxies
gas and _________
dust
• Very small amounts of _________
gas and _________
dust
• Very small amounts of _________
• Very little new star formation
• Very little new star formation
• Contains mostly ______________ stars
older
stars
• Contains mostly ______________
Note: Pop II stars
Spiral Galaxies
NGC 3370
Spiral Galaxies
15 percent of all galaxies
• ________
• Have pinwheel arms that spiral outward from the
center
New General Catalog
98 x 106 ly from Earth
Spiral Galaxies
30 to _____
50 percent gas and dust
• Contain about _____
• Contains ____________ generations of stars
• _______________ stars are in the arms
• _______________ stars are in the center bulge
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Galaxies.notebook
January 06, 2014
Spiral Galaxies
Spiral Galaxies
30 to _____
50 percent gas and dust
• Contain about _____
30 to _____
50 percent gas and dust
• Contain about _____
many generations of stars
• Contains ____________
many generations of stars
• Contains ____________
• _______________ stars are in the arms
Young
stars are in the arms
• _______________
• _______________ stars are in the center bulge
• _______________ stars are in the center bulge
Spiral Galaxies
30 to _____
50 percent gas and dust
• Contain about _____
many generations of stars
• Contains ____________
Young
stars are in the arms
• _______________
Pop I
Old
stars are in the center bulge
• _______________
Pop II
Irregular Galaxies
Bulge
Disk
Large Magellanic Coud
180 x 103 ly from Earth
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Galaxies.notebook
Irregular Galaxies
January 06, 2014
Irregular Galaxies
• ________ percent of all galaxies
15 percent of all galaxies
• ________
• No regular or symmetrical shape
• No regular or symmetrical shape
• More than _______ percent gas and dust
• More than _______ percent gas and dust
• Contain mostly young stars
• Contain mostly young stars
Irregular Galaxies
Galaxy Classification (the “Tuning Fork Diagram”)
15 percent of all galaxies
• ________
• No regular or symmetrical shape
50 percent gas and dust
• More than _______
• Contain mostly young stars
Galaxy Classification (the “Tuning Fork Diagram”)
Note: Irregular absent
Write one fact about each of the
three types of galaxies.
S0 = Transitional Galaxy (<1%)
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Galaxies.notebook
Which has the greatest density...?
With density...it's about SUBSTANCE,
not size.
January 06, 2014
Remember...computerized graph for lab:
Title (Mass and Volume of Pine Blocks)
Axis Labels (with units)
mass on y-axis ..... volume on x-axis
**Use the masses you found using the Digital
Scale (not the average of the triple beam balance).
Calculate the density for a sample with a mass
of 30 grams. Show you work (w/ proper units).
Theo: Poster project
Galaxy Classification (the “Tuning Fork Diagram”)
Not the same as types. For example, E7 is not a "type" of
galaxy -- it is a classification of an Elliptical galaxy (type).
Astro. Distances Conversion W/S
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Galaxies.notebook
January 06, 2014
1920's :People believed the
Milky Way WAS the
Universe....
Created by Edwin Hubble in the 1920’s
a distance measurement pioneer
E = Elliptical Galaxy
E0 through E7: The higher the number, the flatter the galaxy
SB = Barred Spiral
S = Spiral Galaxy
Sa, Sb, Sc: Based on “tightness” of the spiral arms
NOT an evolutionary sequence
SBa, SBb, SBc: Based on “tightness” of the spiral arms
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Galaxies.notebook
January 06, 2014
Each galaxy type (Elliptical, Spiral, Irregular)
is created by
different environmental settings
Each galaxy type (Elliptical, Spiral, Irregular)
is created by
different environmental settings
example: the amount of
available gas and dust
The Milky Way Galaxy
The Milky Way Galaxy
The Milky Way is a __________________ galaxy
The Milky Way is a __________________ galaxy
spiral
Computer Generated Model
The Milky Way Galaxy
spiral
The Milky Way is a __________________ galaxy
(type)
Classification ?????
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Galaxies.notebook
January 06, 2014
Computer Generated Model
Milky Way Dimensions
Width across =
100,000 ly
Classified as an SBa
Milky Way Dimensions
Milky Way Dimensions
30,000 ly
______________
Bar length =
00
100,000 ly
______________
Bulge thickness =
10,000 ly
______________
10,000 ly
ly
,0
30
100,000 ly
Milky Way Dimensions
Disk thickness =
Milky Way Dimensions
27,000
Our Sun (from center) = ______________
ly
2,000
______________
ly
Our
Sun
10,000 ly
100,000 ly
2,000 ly
10,000 ly
2,000 ly
100,000 ly
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Galaxies.notebook
January 06, 2014
Milky Way Dimensions
27,000
Our Sun (from center) = ______________
ly
Milky Way Dimensions
Fun Fact: Our Sun takes ~ 250 x 106 years to make
one revolution
Our Sun
Our Sun
,0
30
00
ly
27,000 ly
Andromeda Galaxy (~2 million ly away)
00
ly
,0
30
27,000 ly
Andromeda Galaxy (~2 million ly away)
Approaching us at about 500,000 km/h
300,000 MPH
Collision in 3.0 x 109 years
Magellanic Clouds (~200,000 ly away)
Triangulum Galaxy (3 million ly away)
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Galaxies.notebook
January 06, 2014
Local Group
Local Group
A local group normally contains 30‐50
galaxies within a 4 million ly radius
2nd Largest
Largest
3rd Largest
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