1. The scale of the universe
How did the Millennium Falcon make the Kessel Run in less than 12 parsecs?
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2. What is a light year?
A light year is the distance that light can travel in one year
9.5 X 1015 m
Space is so big that we use light years to describe distances in light years
The Sun is less than one light year away, in fact, it is 7 or 8 light minutes away
This means that is takes light 7 ish minutes to get to us from the surface of the sun
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3. So, what is a parsec? A parsec is 3.26 light years
Assuming we could travel the speed of light…
The way that the Millennium falcon traveled that far, that fast, is by using the gravity of the black holes to propel itself faster and faster
It was quite dangerous as you can see in this scene…
watch?v=41vELuUbDPM
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So, what is a parsec?

4. Parallax
Astronomers often use parallax to determine how far away close stars are
Hold out your thumb, close one eye, now put your thumb over my face
Now, switch eyes
Notice your thumb is no longer over my face, you have to move it to cover my face again.
This is parallax, you can use it and geometry to determine distances to nearby stars
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5. How are stars classified?
Characteristics used to classify stars include color, temperature, size, composition, and brightness
Remember mass and size are not the same
The mass of the star determines its color, its size does not matter
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6. Brightness
Apparent brightness is the brightness of a star seen from earth
Absolute brightness is the brightness you would see if all of the stars were lined up the same distance from the Earth
Absolute brightness also takes into consideration the atmosphere and removes distortion
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7. How to we keep track of how stars change over time?
The HR diagram, or Hertzsprung-Russell diagram, allows us to classify stars and understand how they change over time
The y-axis is where the brightness is plotted
The x-axis is where the temperature is plotted
The main sequence is where stars once they have gained their mass, live out most of their lives
Once they move out of the main sequence, they are dying, or are already dead
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8. What is a galaxy?
A galaxy is a huge group of stars, star systems, and star clusters, gas and dust, bound together by gravity
Astronomers classify most galaxies into the following types: spiral, elliptical, and irregular
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9. Spiral galaxies Disk shaped Bulge in the middle
Arms that spiral outward like pinwheels
The arms contain dust and many stars
The sun is located on the edge of an arm of the spiral galaxy the Milky Way
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Spiral galaxies

10. Elliptical galaxies Not all galaxies have spiral arms
Elliptical galaxies look like flattened balls
They have millions of stars, but very little gas and dust between the stars
Most elliptical galaxies contain only old stars
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11. Irregular galaxies Typically smaller than other types of galaxies
Generally have many bright young stars
Lots of gas and dust to form new stars
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