Objective – Compare the size and distance of objects within systems in the universe.
Student Background Information
Size and Scale of the Universe
(modified from the UEN 6th Grade Teacher Resource Book)
You may have wondered how far away from Earth the bodies you see in space are.
Stars are so far away that it would take more than a lifetime to reach the nearest star.
Planets in our Solar System would take months to years to reach (depending on the
planet you wanted to visit). Rockets can travel about 75,000 mph. If we wanted to visit
Venus, our closest planet, it would take about 14½ days. To arrive at Pluto would take
5½ years.
Things in outer space are very far away. Using miles for distance would give us
numbers too large to understand. Astronomers use the light-year, the distance light
travels in one year, to measure these distances,
Let’s use the Sun and Earth to see how this works. Earth is about 93,000,000 miles
from the Sun. Light from the Sun takes about 8 minutes to reach us. The speed light
travels is 186,000 miles per hour. This is much faster than our rockets can travel today.
(source: Optics for Kids)
Distances to object outside the Solar System is measured in light-years. To find the
distance light travels in a year, follow these steps. A light-year is the distance light travels
in a year. A light year = about 6,000,000,000,+000 (trillion) miles
Distance From the Sun to the Planets (in light years)
Planet
Mercury
Light Years
.0000006 (3 light minutes)
~1~
Objective – Compare the size and distance of objects within systems in the universe.
Planet
Light Years
Venus
.000011 (6 light minutes)
Earth
.000016 (8 light minutes)
Mars
.000024 (12.5 light minutes)
Jupiter
.000082 (43 light minutes)
Saturn
.000151 (79 light minutes)
Uranus
.000304 (160 light minutes)
Neptune
.000476 (250 light minutes)
Most stars belong to a galaxy. A galaxy is a group of millions of stars held together by gravity.
Our Solar System is found on the outer edge of the Milky Way Galaxy. There around 200
billion stars in the Milky Way Galaxy. Our Solar System is a tiny dot compared to the
Milky Way Galaxy. The Milky Way Galaxy is 100,000 light-years from one end to the
other. This is how many years it would take someone to cross the Milky Way traveling
at the speed of light. Our Solar System is about 0.00125 of a light-year across. You can
see how small our Solar System is compared to the Milky Way. In the picture, most of
the celestial bodies you see in the sky are in the Milky Way Galaxy.
(source: Universe Today)
The Milky Way Galaxy is only one galaxy. There are billions of galaxies that span the
universe. One of the Milky Way’s neighboring galaxies is Andromeda. It is 2 million
light years away. It is so far away that you can’t see its individual stars. You can only
see a hazy spot in the night sky produced by the combined light of the stars. The
pictures below were taken by the Hubble Space Telescope. There are many galaxies
~2~
Objective – Compare the size and distance of objects within systems in the universe.
within the view of the Hubble Telescope. Even though our world seems big to us, in
the universe we are very, very small.
Galaxies
Spiral
Elliptical
Irregular
Huge, contain stars, gas,
and dust.
Held together by gravity.
Pinwheel shape.
Rich in gas and dust
Young and old stars
Huge, contain stars, gas,
and dust.
Held together by gravity.
Round to oval shape.
Little gas and dust
Mostly old stars
Huge, contain stars, gas,
and dust.
Held together by gravity.
No regular shape.
Rich in gas and dust
Young and old stars
~3~
Objective – Compare the size and distance of objects within systems in the universe.
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Science Language Students Need to Understand and Use
 Galaxy – A group of millions of stars held together by gravity.
 Light-year – The distance light can travel in one year.
 Milky Way Galaxy – A group of about 200 billion stars formed in a disk-shaped
spiral that contains our Solar System.
 Speed of light – 186,000 miles per second (mps).
 Universe – The space that consists of all matter and all light and other forms of
radiation and energy
Name ______________________________________________________________
~4~
Objective – Compare the size and distance of objects within systems in the universe.
Student Background Information Worksheet
Size and Scale of the Universe
(modified from the UEN 6th Grade Teacher Resource Book)
1. Travelling at about 75,000 mph, it would take about _______________½ days to
reach Venus. (Enter a number)
2. Travelling at about 75,000 mph, it would take about _______________½ years to
reach Pluto. (Enter a number)
3. A light year is…
a. a measurement of time.
b. a measurement of space.
c. a measurement of distance.
d. a measurement of the vastness of space.
4. The speed of light is _______________,000 miles per second (mps). (Enter a
number)
5. Traveling in a car, it would take _______________ years to reach the Sun. (Enter a
number)
6. The distance light travels in a year is _______________,000,000,000,000 miles.
(Enter a number)
Match distance each planet is from the Sun in light minutes.
____7. Earth
A. 12.5 light minutes
____8. Jupiter
B. 79 light minutes
____9. Mars
C. 6 light minutes
____10. Mercury
D. 250 light minutes
____11. Neptune
E. 3 light minutes
____12. Saturn
F. 160 light minutes
____13. Uranus
G. 8 light minutes
____14. Venus
H. 43 light minutes
~5~
Objective – Compare the size and distance of objects within systems in the universe.
15. It is 0.______________ light years across our Solar System. (Enter a number –
Include 0. in your answer!)
16. A neighboring galaxy of the Milky Way is the _______________ galaxy.
a. Andromeda
b. Black-Eye
c. Centaurus A
d. Whirlpool
Identify the galaxy type with its description.
_____17. Elliptical
A. Huge, contain stars, gas, and dust; held together by gravity;
no regular shape; rich in gas and dust; young and old stars.
_____18. Irregular
_____19. Spiral
B. Huge, contain stars, gas, and dust; held together by gravity;
pinwheel shape; rich in gas and dust; young and old stars
C. Huge, contain stars, gas, and dust; held together by gravity;
round to oval shape; little gas and dust; mostly old stars.
Match the vocabulary term with its definition.
_____20. Galaxy
A. 186,000 miles per second (mps)
_____21. Light –year
B. A group of about 200 billion stars formed in a diskshaped spiral that contains our Solar System.
_____22. Milky Way Galaxy
_____23. Speed of Light
C. A group of millions of stars held together by
gravity.
_____24. Universe
D. The distance light travels in one year.
E. The space that consists of all matter and all light
and other forms of radiation and energy.
~6~
Objective – Compare the size and distance of objects within systems in the universe.
Student Background Information Worksheet – Key
1. Travelling at about 75,000 mph, it would take about _______________½ days to
reach Venus. (Enter a number)
14
2. Travelling at about 75,000 mph, it would take about _______________½ years to
reach Pluto. (Enter a number)
5
3. A light year is…
a. a measurement of time.
b. a measurement of space.
c. a measurement of distance.
d. a measurement of the vastness of space.
c. a measurement of distance.
4. The speed of light is _______________,000 miles per second (mps). (Enter a
number)
186
5. Traveling in a car, it would take _______________ years to reach the Sun. (Enter a
number)
177
6. The distance light travels in a year is _______________,000,000,000,000 miles.
(Enter a number)
6
~7~
Objective – Compare the size and distance of objects within systems in the universe.
Match distance each planet is from the Sun in light minutes.
Note – There are 8 choices.
G 7. Earth
A. 12.5 light minutes
H 8. Jupiter
B. 79 light minutes
A 9. Mars
C. 6 light minutes
E 10. Mercury
D. 250 light minutes
D 11. Neptune
E. 3 light minutes
B 12. Saturn
F. 160 light minutes
F 13. Uranus
G. 8 light minutes
C 14. Venus
H. 43 light minutes
15. It is _______________ light years across our Solar System. (Enter a number –
include the decimal point!)
.00125
16. A neighboring galaxy of the Milky Way is the _______________ galaxy.
a. Andromeda
b. Black-Eye
c. Centaurus A
d. Whirlpool
a. Andromeda
~8~
Objective – Compare the size and distance of objects within systems in the universe.
Identify the galaxy type with its description.
Note – There are 3 choices.
C 17. Elliptical
A 18. Irregular
B 19. Spiral
A. Huge, contain stars, gas, and dust; held together by gravity;
no regular shape; rich in gas and dust; young and old stars.
B. Huge, contain stars, gas, and dust; held together by gravity;
pinwheel shape; rich in gas and dust; young and old stars
C. Huge, contain stars, gas, and dust; held together by gravity;
round to oval shape; little gas and dust; mostly old stars.
Note – There are 5 choices.
C 20. Galaxy
A. 186,000 miles per second (mps)
D 21. Light –year
B. A group of about 200 billion stars formed in a diskshaped spiral that contains our Solar System.
B 22. Milky Way Galaxy
A 23. Speed of Light
C. A group of millions of stars held together by
gravity.
E 24. Universe
D. The distance light travels in one year.
E. The space that consists of all matter and all light
and other forms of radiation and energy.
~9~
Objective – Compare the size and distance of objects within systems in the universe.
Student Background Information Worksheet –
Scoring Guide
22-24 – 4
20-22 – 3.5
16-19 – 3
14-15 – 2.5
12-13 – 2
11 – 1.5
9-10 – 1
1-8 – .5
~10~