reading and worksheet - mrscienceut.netmrscienceut.net/2017 how big is our universe... · web...

Learning Target – I can order size of objects in the universe.

How Big Is Our Universe?How many times have you wondered about all the things that we see in the night sky? The universe contains everything: all the star systems, galaxies, gas, dust, and everything else.

Stars are huge balls of gas held together by gravity. They are so far away. it would take more than a lifetime to reach the nearest star to the Sun. Planets are round balls of rock and/or gas that orbit a star. It can take months or years to reach a planet. Space probes nine months to travel to Mars. The fastest spacecraft ever launched traveled 36,000 miles per hour. It is the New Horizons spacecraft. New Horizons passed Pluto in July 2015. It took it 9.5 years to reach Pluto.

Stars and galaxies are so far away, measuring distances is difficult for our minds to understand. Scientists and astronomers sometimes use a light-year, the distance light travels in one year, to measure these distances.

Earth is about 93,000,000 miles away from the Sun. It takes light from the Sun 8.3 minutes to reach the Earth. We use the speed of light to measure the time it takes light to travel over long distances. The speed of light is 186,000 miles per second.

Light-Year Calculation 60 seconds per minute (x) 60 minutes per hour = 3,600

seconds per hour. 3,600 seconds per hour (x) 24 hours per day = 86,400

seconds per day. 86,400 seconds per day (x) 365 days a year = 31,536,000

seconds per year. 31,536,000 seconds per year (x) 186,000 miles per second =

5,865,696,000,000 miles per year (light-year in miles).

-or-

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Learning Target – I can order size of objects in the universe. 31,536,000 seconds per year (x) 300,000 kilometers per

second = 9,469,800,000 kilometers per year (light-years in kilometers).

The closest star to the Sun is Proxima Centauri. It is near Alpha Centauri.1 Alpha Centauri is about 4.3 light-years away. It would take about 4 years and 4 months to reach if you were traveling at the speed of light.

Distance from the Sun in Light Years to the Planets

Planet Light-YearsMercury 0.000006 (3.2 light

minutes)Venus 0.000011 (6 light

minutes)Earth 0.000016 (8.3 light

minutes)Mars 0.000024 (12.7 light

minutes)Jupiter 0.000082 (43.3 light

minutes)Saturn 0.000151 (79.5 light

minutes)Uranus 0.000304 (2.7 light

hours)Neptune 0.000476 (4.2 light

hours)Pluto (Dwarf 0.000625 (5.5 light

1 Alpha Centauri is in reality two stars that are slightly smaller that the Sun. They orbit each other at an average distance that is about the same as the distance between the Sun and Uranus.

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Planet) hours)Proxima Centauri

4.2

Alpha Centauri 4.3

Most stars belong to a galaxy, a group of hundreds of billions of stars held together by gravity. Our Solar System is about two-thirds from the center of our galaxy. Our galaxy is called the Milky Way. The Milky Way Galaxy is made up of about 100 to 400 billion stars.

The Milky Way Galaxy is about 100,000 light-years across. The diameter of our Solar System is about 0.004 light-years. The Milky Way Galaxy is only one of billions of galaxies in the universe.

One of the Milky Way’s neighboring galaxies is the Andromeda galaxy. It is about 2.5 million light-years away. What’s at the edge of the Universe?The universe doesn’t have an “edge.” Because space is expanding, the universe is always getting larger.

The Role of Gravity Gravity is a force of attraction. Anything with mass has gravity. The strength of the gravitational force depends on how much

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Learning Target – I can order size of objects in the universe. mass-the amount of matter in an object-the objects have and how far apart they are from each other. The greater an object’s mass, the greater the force of attraction; in addition, the greater the distance between objects, the smaller the force of attraction.

Human Understanding of the UniverseWhat did the ancient Greeks recognize as the universe? Their universe had Earth at the center. The Sun, Moon, and five planets revolved around the Earth. The stars were attached to a sphere around Earth. This idea held for many centuries. Galileo used his telescope, an instrument used to view distant objects. He saw there were more stars in

If I have seen further than others, it is by standing upon the shoulders of giants.

-Sir Isaac Newton

the sky than are visible to the naked eye. Later, astronomers learned they were part of the Milky Way Galaxy. They also observed many fuzzy, cloudy looking patches. They were called nebulae. This is the Latin word for clouds. Some of them appeared to be giant clouds of gas and dust inside the Milky Way. Astronomers debated whether these nebulae were within the Milky Way or outside.

In the early 20th century, Edwin Hubble saw stars in a nebula in the constellation of Andromeda. One particular type of star allowed him to calculate its distance. He showed that the Andromeda Nebula was far outside our Milky Way Galaxy. Hubble realized that many of the objects that astronomers called nebulae were not actually clouds of gas. They were what we now call galaxies – a collection of billions of stars.

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Hubble showed that the universe is much larger than our own galaxy. Today, we know that the universe contains hundreds of billions of galaxies. That is about the same number of galaxies as there are stars in the Milky Way Galaxy.

Name ______________________________________________________________

How Big Is Our Universe?Match the term with the definition

_____1. Distances A. A force of attraction

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_____2. Galaxy

_____3. Gravity

_____4. Light-year

_____5. Milky Way Galaxy

_____6. Planets

_____7. Speed of light

_____8. Stars

B. A group of hundreds of billions of stars held together by gravity.

C. How far one object is from another,

D. Huge balls of gas held together by gravity

E. Our home galaxy.

F. Round balls of rock and/or gas that orbit a star, have enough of their own gravity to become round.

G. The distance light travels in one year

H. The time it takes light to travel, about 186,000 miles per second

9. The universe contains everything: all the stars, galaxies, gas, dust, planets, etc.

a. True b. False

10. It takes a space probe ______ months to travel to Mars. (Enter a number.)

11. This is the fastest space probe every launched.

a. Cassini c. New Horizonsb. Mariner 9 d. Voyager 2

12. It took New Horizons ________ years to reach Pluto. (Enter a number; include the decimal point!)

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Learning Target – I can order size of objects in the universe. 13. Earth is _______,000,000 miles away from the Sun. (Enter a two digit number!)14. Earth is ______ light minutes from the Sun. (Enter a number; include the decimal point!)

Match the number of seconds with the length of time.

_____15. Distance light travels in a year (miles)

_____16. Seconds per day

_____17. Seconds per hour

_____18. Seconds per year

A. 31,536,000

B. 5,865,696,000,000

C. 3,600

D. 86,400

Place the planets/star in the proper order, 1 being the nearest, 10 being the farthest.

_____19. Alpha Centauri

_____20. Earth

_____21. Jupiter

_____22. Mars

_____23. Mercury

_____24. Neptune

_____25. Pluto

_____26. Saturn

_____27. Uranus

A. 1

B. 2

C. 3

D. 4

E. 5

F. 6

G. 7

H. 8

I. 9

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_____28. VenusJ. 10

29. The nearest star to Earth, Alpha Centauri, is _______ light years away. (Enter a number; include the decimal point!)

30. The Milky Way Galaxy is about ______,000 light years across. (Enter a three digit number!)

31. The Andromeda galaxy is about ______ million light years away. (Enter a number; include the decimal point!)

32. Gravity holds the universe together.

a. True b. False

33. The Greeks believed the Earth was the center of the universe.

a. True b. False

34. Using a telescope, Galileo saw more _______ than you can see with just your eyes.

a. galaxies c. nebulaeb. moons d. stars

35. There are about the same number of galaxies in the universe as there are stars in our galaxy.

a. True b. False

Scoring Guide

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95-100% - 4 90-94% - 3.585-89% - 3

75-84% - 2.565-74% - 255-64% - 1.5

45-54% - 1 1-44% - .5

How Big Is Our Universe? – Key I

Match the term with the definition

_____1. Distances

_____2. Galaxy

_____3. Gravity

_____4. Light-year

_____5. Milky Way Galaxy

_____6. Planets

_____7. Speed of light

_____87. Stars

A. A force of attraction

B. A group of hundreds of billions of stars held together by gravity.

C. How far one object is from another,

D. Huge balls of gas held together by gravity

E. Our home galaxy.

F. Round balls of rock and/or gas that orbit a star, have enough of their own gravity to become round.

G. The distance light travels in one year

H. The time it takes light to travel, about 186,000 miles per second

C 1. Distances

B 2. Galaxy~9~


A 3. Gravity

G 4. Light-year

E 5. Milky Way Galaxy

F 6. Planets

H 7. Speed of light

D 8. Stars

9. The universe contains everything: all the stars, galaxies, gas, dust, planets, etc.

a. True b. False

a. True

10. It takes a space probe ______ months to travel to Mars. (Enter a number.)

9

11. This is the fastest space probe every launched.

a. Cassini c. New Horizonsb. Mariner 9 d. Voyager 2

c. New Horizons

12. It took New Horizons ________ years to reach Pluto. (Enter a number; include the decimal point!)

9.5~10~


13. Earth is _______,000,000 miles away from the Sun. (Enter a two digit number!)

93

14. Earth is ______ light minutes from the Sun. (Enter a number; include the decimal point!)

8.3

Match the number of seconds with the length of time.

_____15. Distance light travels in a year (miles)

_____16. Seconds per day

_____17. Seconds per hour

_____18. Seconds per year

A. 31,536,000

B. 5,865,696,000,000

C. 3,600

D. 86,400

B 15. Distance light travels in a year (miles)

D 16. Seconds per day

C 17. Seconds per hour

A 18. Seconds per year

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Learning Target – I can order size of objects in the universe. Place the planets/star in the proper order, 1 being the nearest, 10 being the farthest.

_____19. Alpha Centauri

_____20. Earth

_____21. Jupiter

_____22. Mars

_____23. Mercury

_____24. Neptune

_____25. Pluto

_____26. Saturn

_____27. Uranus

_____28. Venus

A. 1

B. 2

C. 3

D. 4

E. 5

F. 6

H. 7

I. 8

J. 9

K. 10

J 19. Alpha Centauri

C 20. Earth

E 21. Jupiter

D 22. Mars

A 23. Mercury

H 24. Neptune

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Learning Target – I can order size of objects in the universe. I 25. Pluto

F 26. Saturn

G 27. Uranus

B 28. Venus

29. The nearest star to Earth, Alpha Centauri, is _______ light years away. (Enter a number; include the decimal point!)

4.3

30. The Milky Way Galaxy is about ______,000 light years across. (Enter a three digit number!)

100

31. The Andromeda galaxy is about ______ million light years away. (Enter a number; include the decimal point!)

2.532. Gravity holds the universe together.

a. True b. False

a. True

33. The Greeks believed the Earth was the center of the universe.

a. True b. False

a. True

34. Using a telescope, Galileo saw more _______ than you can see with just your eyes.

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a. galaxies c. nebulaeb. moons d. stars

d. stars

35. There are about the same number of galaxies in the universe as there are stars in our galaxy.

a. True b. False

a. True

How Big Is Our Universe? – Key II

1. C (8 choices)2. B (8 choices)3. A (8 choices)4. G (8

19. J (10 choices)20. C (10 choices)21. E (10 choices)22. D (10

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choices)5. E (8 choices)6. F (8 choices)7. H (8 choices)8. D (8 choices)9. a (2 choices)10. 911. c12. 9.513. 93 14. 8.315. B16. D17. C18. A

choices)23. A (10 choices)24. H (10 choices)25. I (10 choices)26. F (10 choices)27. G (10 choices)28. B (10 choices)29. 4.330. 10031. 2.532. a (2 choices)33. a (2 choices)34. d35. a (2 choices)

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How Big Is Our Universe?Scoring Guide

33-35 – 4 32 – 3.530-31 – 3 26-29 – 2.523-25 – 2 19-22 – 1.5

95-100% - 4 90-94% - 3.585-89% - 3 75-84% - 2.565-74% - 255-64% -

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16-18 – 1 1-15 – .50 – 0

1.545-54% - 1 1-44% - .5

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reading and worksheet - mrscienceut.netmrscienceut.net/2017 how big is our universe... · web...

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