1. Our Place in the Universe
Really just our place in our galaxy.

2. Ancient Astronomers The earth is the center of the universe.
The universe consists of the solar system.

3. The Copernican Revolution
The sun is the center of the universe.
The universe consists of the solar system and surrounding stars.
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4. 1800’s: Herschel and Kapteyn
The solar system is the center of the universe.
The universe consists of the Milky Way galaxy.
Sun at
center
All images

5. Our galaxy is a disk shape with the sun at the center.
Our galaxy so far…
Our galaxy is a disk shape with the sun at the center.
Sun

6. Harlow Shapley
Used the distribution of and distance to globular clusters to determine the shape of the galaxy
Globular clusters: gravitationally bound group of tens of thousands of very old stars
Sun is
off-center

7. Our galaxy so far…
Our galaxy is a disk shape, with the sun off-center, surrounded by a halo of globular clusters.
Sun

8. Central Bulge
When observed using infrared light, there is a bright area of the sky in the direction of the center of our galaxy.
Infrared light can travel past the dust in the disk.
Central bulges are found in most other disk-shaped galaxies.
NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
Above: Atlas Image courtesy of 2MASS/UMass/IPAC-Caltech/NASA/NSF

9. Our galaxy so far…
Our galaxy is a disk shape, with the sun off-center, a central bulge and is surrounded by a halo of globular clusters.
Sun

10. Spiral Arms
Using radio waves (a type of EM radiation), clouds of hydrogen can be found to lie along bands or arms in our galaxy.
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11. http://en. wikipedia. org/wiki/File:236084main_MilkyWay-full-annotated

12. Our Place in the Universe Activity