Download Part I: Modeling Light Years - The “Student Minute” Walker`s Name:

Light Years
Earth and Space
Part I: Modeling Light Years - The “Student Minute”
Walker’s Name:
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Trial Number
Distance in One Minute
(meters)
1
2
3
Average
1 Student Minute =
____________ meters
(Average )
1.  What distance is represented by a “student minute?”
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2.  How far could you travel in 14 “student minutes?”
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3.  If you are 100 meters away, how many “student minutes” are represented?
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4.  During this activity, you were modeling a light year. In the model, what did we use instead of a
“year?”
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5.  In this model, what represented the “light?”
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6.  How is a “student minute” similar to a “light year?”
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Light Years
Earth and Space
Part II: The Speed of Light
Chart 1: Calculation of the Distance Traveled by Light in One Year
Action
To find out how fast light travels per
minute, multiply the speed by 60
seconds per minute.
Calculation
300,000 km X 60 sec
sec
min
To find out how fast light travels per
hour, we must multiply our answer
above by 60 minutes per hour.
_________ km X 60 min
min
hr
To find out how fast light travels per day,
we must multiply our answer above by
24 hours per day.
_________ km X 24 hr
hr
day
To find out how fast light travels per
year, we must multiply our answer
above by 365 days per year.
_________ km X 365 days
day
year
Answer
______ km
min
______ km
hr
______ km
day
______ km
year
Part III: Calculating a Light Year
1.  Earth is 150,000,000 km from the Sun. Light travels at 18,000,000 km/min. How long does it
take for light from the Sun to reach Earth? You will have to cancel zeros when solving.
2.  The closest star to our Sun is Proxima Centauri. It is 39,700,000,000,000 km from the Sun.
Light travels at 9,460,800,000,000 km/year. How long does it take light from the Sun to reach
Proxima Centauri? You will have to cancel zeros when solving.
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Light Years
Earth and Space
Part IV: Traveling through Time
Are We There Yet?
Light travels 18,000,000 km/minute
Star
Distance
from Earth as
Determined by the
Speed of Light
Sol
8.33 light-minutes
Sirius A
8.6 light years
Ross 154
9.68 light years
Center of the
Galaxy
26,400 light years
Light travels at 9,460,800,000,000 km/year
Time light
has been
traveling
Distance from Earth in km
8.33 minutes
8.33 x 18,000,000 km
8.6 x 9,460,800,000,000 km
1.  Imagine a planet 15 light years away from Earth that is inhabited by people like us. They have
developed a very powerful telescope allowing them to see what is happening on Earth. If they
look through their telescope today, what year would it be on Earth? Would they be able to see
you? Explain.
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2.  On another planet, in the year 2010, they are looking at Earth and watching George
Washington cross the Delaware River in 1776. How many light years away is this planet from
Earth?
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3.  If there was a planet circling Ross 154 and inhabited by people, would those people be able to
see your first birthday party on Earth? Explain.
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Light Years
Earth and Space
Part V: Sizes in Our Universe
Object Name
Information
Distance From
Earth
Size
Milky Way Galaxy
Spiral
N/A
100,000 ly
Andromeda Galaxy
Spiral
2.5 million ly
220,000 ly
Sculptor
Supercluster
Large associations
of galaxies
1 billion ly
250 million ly
IC 1101 Galaxy
Elliptical
1.01 billion ly
6 million ly
Barnard’s Galaxy
(NGC 6822)
Dwarf Irregular
1.6 million ly
10,000 ly
Sombrero Galaxy
Spiral
28 million ly
50,000 ly
Black Eye Galaxy
(M64)
Spiral
19 million ly
51,000 ly
Hoag’s Object
Galaxy
Irregular
600 million ly
120,000 ly
M87
Elliptical
54 million ly
120,000 ly
1.  Which object is the largest in size? How big is it?
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2.  Which object is the smallest in size? What is its size?
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3.  Which object is closest to Earth, not including the Milky Way?
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4.  Why do astronomers use light years to describe sizes of objects in the universe?
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Light Years
Earth and Space
Reflections and Conclusions
1.  What travels the fastest in the universe?
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2.  What is a light year?
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3.  Why do astronomers need to use light years, rather than kilometers, to measure the distance
between stars and the sizes of large objects?
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4.  You are on a space ship that can travel the speed of light, and you are going to visit Proxima
Centauri. Proxima Centauri is 4.2 light years away. How long would it take you to travel there?
Explain your answer.
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5.  A scientist wants to travel to the center of the Milky Way Galaxy. It is 26,400 light years from
Earth. Would the scientist ever reach his destination? Explain your answer.
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