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 lighttravels 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 / Light Years
Mercury / .0000006 (3 light minutes)
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 theMilky 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 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. / Huge, contain stars, gas, and dust. / Huge, contain stars, gas, and dust.
Held together by gravity. / Held together by gravity. / Held together by gravity.
Pinwheel shape. / Round to oval shape. / No regular shape.
Rich in gas and dust / Little gas and dust / Rich in gas and dust
Young and old stars / Mostly old stars / Young and old stars

Solar System to Scale

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 ______

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.c. a measurement of distance.

b. a measurement of space.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
____8. Jupiter
____9. Mars
____10. Mercury
____11. Neptune
____12. Saturn
____13. Uranus
____14. Venus / A. 12.5 light minutes
B. 79 light minutes
C. 6 light minutes
D. 250 light minutes
E. 3 light minutes
F. 160 light minutes
G. 8 light minutes
H. 43 light minutes

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. Andromedac. Centaurus A

b. Black-Eyed. Whirlpool

Identify the galaxy type with its description.

_____17. Elliptical
_____18. Irregular
_____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.

Match the vocabulary term with its definition.

_____20. Galaxy
_____21. Light –year
_____22. Milky Way Galaxy
_____23. Speed of Light
_____24. Universe / A. 186,000 miles per second (mps)
B. A group of about 200 billion stars formed in a disk-shaped spiral that contains our Solar System.
C. A group of millions of stars held together by gravity.
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.

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.c. a measurement of distance.

b. a measurement of space.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

Match distance each planet is from the Sun in light minutes.

Note – There are 8 choices.

G 7. Earth
H 8. Jupiter
A 9. Mars
E 10. Mercury
D 11. Neptune
B 12. Saturn
F 13. Uranus
C 14. Venus / A. 12.5 light minutes
B. 79 light minutes
C. 6 light minutes
D. 250 light minutes
E. 3 light minutes
F. 160 light minutes
G. 8 light minutes
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. Andromedac. Centaurus A

b. Black-Eyed. Whirlpool

a. Andromeda

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
D 21. Light –year
B 22. Milky Way Galaxy
A 23. Speed of Light
E 24. Universe / A. 186,000 miles per second (mps)
B. A group of about 200 billion stars formed in a disk-shaped spiral that contains our Solar System.
C. A group of millions of stars held together by gravity.
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.

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

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