Galaxies

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Galaxies

• Big Things in the Universe
• Billions and Billions
• - Carl Sagan

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Nebula

• The early astronomers looked up at the sky and
  kept seeing faint fuzzy things. They named them
  Nebula which means cloud
• Their telescopes werent all that good ?

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Charles Messier

• Messier wanted to discover comets! Hed look up,
  see a faint fuzzy patch which is also what a
  new comet looks like get excited then notice
  that it didnt move.
• Frustrated, he made a list of 103 faint fuzzies
  so he wouldnt get distracted.
• He is more famous for the Messier List than for
  the comets he did discover.

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Faint Fuzzies Revealed

• Telescopes got better people realized that some
  of the Messier objects were gas clouds (M42),
  some were exploded stars (M1), some were groups
  of stars (M45), and some were vast groups of
  billions of stars (M31, M51, M101).
• Hubble finally saw specific kinds of stars in M31
  Andromeda and discovered how far away it was.

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Hubble and the Galaxies

• While he was working on the expansion of the
  universe, Hubble saw a LOT of galaxies. He
  noticed they had several basic shapes.
• Elliptical E
• Spiral S
• Barred Spiral SB
• Irregular Irr
• Hubble came up with an identification system
  called the Hubble Tuning Fork.

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Elliptical

• An Elliptical (M60) and a Spiral

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Elliptical II

• Two Ellipticals (M105)

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Spirals

• M51 a spiral seen face on with a companion
  galaxy

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Spirals II

• M101

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Spirals III

• NGC 891

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Spirals IV

• M104

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Spirals V

• Stephans Quintet

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Spirals VI (and some
Ellipticals)

• H
• E
• R
• C
• U
• L
• E
• S
• C
• L
• U
• S
• T
• E
• R

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Barred Spirals

• Jalf 350

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Barred Spirals II

• M109

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Barred Spirals III
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Barred Spirals IV

• NGC 7479

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Barred Spirals V

• NGC 613
• from ESO

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Barred Spirals VI

• NGC 4548

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Barred Spirals VII

• NGC 7479

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Irregulars

• L
• M
• C

S M C
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Irregular II

• LMC

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Irregular III

• M82

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Irregular IV

• NGC
• 4449

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Irregular V

• NGC 6822

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The Mystery of the Galaxies

• One of the cool debates going on now in Cosmology
  (the study of the origin of the Universe), is the
  question of Did stars form and fall into
  galaxies, or did galaxies (clumps of gas) form
  and then the stars formed and ignited.
• Both groups argue that there isnt enough time
  for the other groups hypothesis to work. ?

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Make a Galaxy Activity

• You now know the basic shapes of the galaxies.
  Choose one of the basic shapes and draw it on the
  top of a paper plate.
• Put your name / period / date on the bottom
• Put the type of galaxy shape it is E-S-SB-I on
  the bottom.
• We will suspend them from the ceiling, and
  hopefully they will not blow down!