THE MILKY WAY

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THE MILKY WAY

• DAY 1 Intro Info

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The Milky Way

• Over 100billion stars
• One of tens of billions of galaxies in the
  observable universe

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Size and Shape

• Clouds of interstellar medium (dust and gas) fill
  the galactic disk and prevent our ability to see
  through it.
• This long fooled astronomers to think we lived
  near the centre of our galaxy
• In the 1920s, Harlow Shapley found that the
  Globular clusters orbit a point tens of thousands
  of light years from our Sun.
• This point is the centre of our galaxy, not our
  Sun!!

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Size and Shape

• Radio and infrared technologies allow us to see
  through the interstellar dust.
• Our Sun lies about 28 000 light-years from the
  centre

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Size and Shape

• Flat disk of stars with a bright central bulge
• Spiral arms
• Dimmer rounder Halo surrounding everything
• A few hundred Globular Clusters of stars orbit
  the galaxys centre
• In 2005, the Spitzer Space Telescope collected
  evidence that the Milky Way is a Barred Spiral

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What is in the middle?

• http//discovermagazine.com/1998/nov/themysterious
  mid1534
• Reading available at that web address