1 Stars, Galaxies & Universe Chapter 3. 2 Tools of Astronomy Constellations are groups of stars that form a pattern. The electromagnetic spectrum is made.

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Stars, Galaxies & Stars, Galaxies & UniverseUniverse

Chapter 3Chapter 3

22

Tools of AstronomyTools of Astronomy

• Constellations are groups of stars that form a pattern.

• The electromagnetic spectrum is made of radio waves, infrared radiation, visible light, ultraviolet radiation, x-rays, and gamma rays.

33

Refracting TelescopeRefracting Telescope

• Refracting telescope collects light using lenses.

• The lenses bend the light to the focal point.

44

Reflecting TelescopeReflecting Telescope

• Reflecting telescope uses a mirror to collect the light.

• A concave mirror bends the light inward to a focal point.

55

Radio TelescopeRadio Telescope

• Radio telescopes collects radio waves.

• The collector is a concave dish.

66

ObservatoryObservatory

• The building that houses a telescope is called an observatory.

77

Other Tools of AstronomyOther Tools of Astronomy

• Telescopes have been put into space on satellites & space stations.

• Spectrographs gather information about stars such as a star’s composition & temperature.

88

Which type of telescope focuses Which type of telescope focuses light using a mirror?light using a mirror?

Ref

lect

ing T

eles

cope

Ref

ract

ing

Teles

cope

Rad

io T

eles

cope

Infra

red T

eles

cope

0 000

A. Reflecting Telescope

B. Refracting Telescope

C. Radio Telescope

D. Infrared Telescope

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99

Which type of telescope focuses Which type of telescope focuses light through transparent lenses?light through transparent lenses?

Ref

lect

ing T

eles

cope

Ref

ract

ing

Teles

cope

Rad

io T

eles

cope

Infra

red T

eles

cope

0 000

A. Reflecting Telescope

B. Refracting Telescope

C. Radio Telescope

D. Infrared Telescope

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1010

One of the greatest advancements in One of the greatest advancements in astronomy was the telescope. Which is astronomy was the telescope. Which is

the correct order of advancements?the correct order of advancements?

0 000

A. Radio- refracting-reflecting

B. Reflecting – refracting –radio

C. Refracting-reflecting-radio

D. Radio- reflecting-refracting

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1111

Which of the following is an advantage of Which of the following is an advantage of a space-based, satellite telescope like a space-based, satellite telescope like

Hubble?Hubble?

0 000

A. Satellite telescopes are much closer to the stars.

B. Satellite telescopes are able to see through solid objects.

C. Satellite telescopes can detect wavelengths that are blocked by the atmosphere.

D. Satellite telescopes have the ability to see the future.

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1212

Characteristics of StarsCharacteristics of Stars

• A galaxy contains hundreds of billions of stars.

• The universe contains billions of galaxies.

1313

Distances to StarsDistances to Stars

• A light year is the distance light travels in year.

• Astronomers often use parallax to measure distances to nearby stars.

• Parallax is the apparent change in position of an object when you look at it from different places.

1414

A light year is a measurement of…A light year is a measurement of…

Dis

tanc

e

Tim

e

Spee

d

Acc

eler

atio

n

0% 0%0%0%

a) Distance

b) Time

c) Speed

d) Acceleration

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1515

Why do astronomers measure interstellar Why do astronomers measure interstellar distances in light years instead of distances in light years instead of

kilometers or miles?kilometers or miles?

Lig

ht yea

rs a

re a

mea

...

Mile

s an

d kilo

met

ers

a..

Mile

s an

d kilo

met

ers

a..

I don’t

have

a cl

ue . .

....

0 000

A. Light years are a measure of time.

B. Miles and kilometers are too small of a unit.

C. Miles and kilometers are too large of a unit.

D. I don’t have a clue . . . help me!

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1616

One light year equals about how One light year equals about how many kilometers?many kilometers?

365

km

9.5

trill

ion k

m

365

day

s

9.5

day

s

0% 0%0%0%

a) 365 km

b) 9.5 trillion km

c) 365 days

d) 9.5 days

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1717

Classifying StarsClassifying Stars

• Stars are classified by size, temperature, and brightness.

• Temperature of a star is indicated by color, hot stars are blue & cooler stars are red.

• Apparent brightness is the brightness of a star as observed from earth.

• Absolute magnitude is the brightness of a star observed at the distance of 10 parsecs.

1818

Hertzsprung-Russell DiagramHertzsprung-Russell Diagram

• H-R diagram is a graph of the Milky Way galaxy.

• Surface temperature is graphed on the x-axis.

• Absolute magnitude is graphed on the y-axis.

1919

Types of StarsTypes of Stars

• Blue super giants have a high brightness and high temperature.

• Red giants & super giants have a high brightness and low temperature.

• White dwarfs have a low brightness and high temperature.

• 90% of all stars appear on the Main Sequence going from the upper right to the lower left corner.

2020

Why do stars appear to be different Why do stars appear to be different colors?colors?

chem

ical

com

positio

n

dis

tanc

e s

ize

tem

perat

ure

0% 0%0%0%

a) chemical composition

b) distance

c) size

d) temperature

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2121

Which color star would be the Which color star would be the hottest?hottest?

blu

e re

d

white

yel

low

0% 0%0%0%

a) blue

b) red

c) white

d) yellow

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2222

Which star would be the brightest?Which star would be the brightest?

Mai

n seq

uence

Red

gia

nts

Red

supe

r gia

nts

Whi

te d

war

f

0% 0%0%0%

a) Main sequence

b) Red giants

c) Red super giants

d) White dwarf

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2323

How would you classify our star, How would you classify our star, the sun, on the H-R diagram?the sun, on the H-R diagram?

Mai

n seq

uence

Red

gia

nt

Whi

te d

war

f

Red

supe

rgia

nt

0% 0%0%0%

a) Main sequence

b) Red giant

c) White dwarf

d) Red supergiant

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2424

Birth of a StarBirth of a Star

• A star begins as a cloud of gas and dust called a nebula.

• Gravity pulls the gas and dust together into a protostar.

• A star is born when the contracting gas and dust becomes so hot that nuclear fusion begins.

2525

Length of Life of a StarLength of Life of a Star

• More massive stars live short lives of millions of years.

• Less massive stars live long lives of billions of years.

• The sun will live for 9-10 billion years.

2626

During the Life Cycle of a StarDuring the Life Cycle of a Star

• Stars fuse hydrogen into helium during most of their lives.

• After all the hydrogen has been fused into helium, the star fuses helium into carbon, carbon into oxygen and then oxygen into iron.

2727

Death of a StarDeath of a Star

• Stars use up their hydrogen and expand their atmosphere.

• Stars that are less than 1.4 solar masses will shrink to a white dwarf.

• Stars between 1.4 -3.0 solar masses will produce a supernova and leave a neutron star.

• Stars more than 3.0 solar masses will produce a supernova and collapse into a black hole.

2828

What is the first stage of the birth of What is the first stage of the birth of a star?a star?

Pro

tost

ar

Neb

ula

Gia

nt

dw

arf

0% 0%0%0%

a) Protostar

b) Nebula

c) Giant

d) dwarf

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2929

What is the next likely stage of a What is the next likely stage of a protostar?protostar?

Super

Gia

nts

Nova

Mai

n Seq

uence

Neu

tron S

tar

0 000

A. Super Giants

B. Nova

C. Main Sequence

D. Neutron Star

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3030

What happens to the most massive What happens to the most massive stars as they near their death?stars as they near their death?

super

nova

to a

bla

ck...

super

nova

to a

neu

tr..

bec

omes

a w

hite d

war

f

noth

ing h

appen

s

0% 0%0%0%

a) super nova to a black hole

b) super nova to a neutron star

c) becomes a white dwarf

d) nothing happens

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3131

What is the next likely stage of our What is the next likely stage of our sun?sun?

Whi

te d

war

f

Bla

ck d

war

f

Red

gia

nt

Super

nova

0% 0%0%0%

a) White dwarf

b) Black dwarf

c) Red giant

d) Super nova

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3232

Star SystemsStar Systems

• Most stars are members of groups of two or more stars called star systems.

• Star systems with two stars are called double stars or binary stars.

• Binary eclipsing stars are stars where one star blocks the light from another.

3333

GalaxiesGalaxies

• Galaxies are a group of billions of stars.

• Type of galaxies are 1. Elliptical

2. Spiral

3. Irregular

3434

Elliptical GalaxyElliptical Galaxy

• Old galaxy.• Contains red star that

are old.• No gas or dust.

3535

Spiral GalaxySpiral Galaxy

• Middle aged galaxy.• Contains blue stars.• Has some dust and

gas.• Our Milky Way is a

spiral galaxy.

3636

Irregular GalaxyIrregular Galaxy

• Unorganized collection of stars.

• Made of very young stars.

• Has a great deal of gas and dust.

3737

History of the UniverseHistory of the Universe

• Edwin Hubble discovered that the farther away a galaxy is from us, the faster it is moving away from us.

• Stars moving away from us shows a red shift.

3838

Big Bang TheoryBig Bang Theory

• Big Bang Theory suggest that billions of years ago, the universe was small, hot and dense and then the universe exploded.

• The universe formed in this enormous explosion about 10 to 15 billion years ago.

3939

Formation of the Solar SystemFormation of the Solar System

• The solar system formed 5 billion years ago.

• The solar system formed from a giant cloud of gas and dust, or nebula.

4040

Future of the UniverseFuture of the Universe

• The universe may continue to expand.

• Gravity may pull the universe back together.

4141

By what are galaxies classified?By what are galaxies classified?

Colo

r

Tem

perat

ure S

ize

Shap

e

0% 0%0%0%

a) Color

b) Temperature

c) Size

d) Shape

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4242

What type of galaxy is illustrated in What type of galaxy is illustrated in the following picture?the following picture?

Irre

gular

Spira

l

Elli

ptical

I hav

e no id

ea..

I nee

d...

0% 0%0%0%

a) Irregular

b) Spiral

c) Elliptical

d) I have no idea.. I need help!

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4343

What type of galaxies contain older What type of galaxies contain older stars?stars?

Elli

ptical

Irre

gular

Bar

red s

hape

spira

l

0% 0%0%0%

a) Elliptical

b) Irregular

c) Barred shape

d) spiral

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4444

Review QuestionsReview Questions

• What are the three types of galaxies?

• elliptical, spiral & irregular

• Distances between stars are measured in units called _______.

• light years

• Stars begin as a cloud of gas & dust known as a __________.

• nebula

4545

Review QuestionsReview Questions

• What does the length of life of a star depends on?

• mass of the star• What is the name of our galaxy?• Milky Way• What type of galaxy is the Milky Way?• spiral• What is the name of the theory of the creation of

the universe?• Big Bang

4646

Review QuestionsReview Questions

• What type of tools are used to study the universe?

• telescope

• Which type of telescope uses mirrors?

• reflecting

• Which type of telescope uses lenses?

• refracting

4747

Review QuestionsReview Questions

• What indicates how hot a star is?

• color of the star

• During nuclear fusion, what does hydrogen fuse into?

• helium

• What is graphed on the H-R diagram?

• brightness & temperature

4848

Review QuestionsReview Questions

• What is the brightness of a star as seen from earth?

• apparent brightness

• What is the brightness of a star that is seen at a standard distance of ten parsecs?

• absolute magnitude

4949

Review QuestionsReview Questions

• What process is used to measure the distance of nearby stars?

• parallax

• What type of telescope collect electromagnetic waves other than light?

• radio telescope

• How long ago did the Big Bang occur?

• 10-15 billion years ago

5050

Review QuestionsReview Questions

• What are patterns of stars in the sky called?• Constellations• What is the building called that has a telescope?• Observatory• Which type of galaxy has red stars and no gas

or dust?• elliptical

5151

Review QuestionsReview Questions

• Which type of galaxy has blue stars and some gas & dust?

• spiral galaxy

• Galaxies are classified by their _______.

• shape

• Who proposed that the universe is expanding?

• Hubble

5252

Review QuestionsReview Questions

• What evidence do we have that the universe is expanding?

• red shift

• What happens to a small star at its death?

• white dwarf

• What happens to a very large star at its death?

• Supernova to a black hole

5353

Practice Extended Answer Practice Extended Answer QuestionsQuestions

• Describe the life cycle of a star.• What are the three types of telescopes and how

are they different?• Explain the H-R diagram.• How does the mass of a star affect the length of

life of a star?• How do the different types of galaxies compare?• Explain the Big Bang Theory.

5454

One of the greatest advancements in astronomy One of the greatest advancements in astronomy was the telescope. Which is the correct order of was the telescope. Which is the correct order of

advancements?advancements?

0 000

A. Radio- refracting-reflecting

B. Reflecting – refracting –radio

C. Refracting-reflecting-radio

D. Radio- reflecting-refracting

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24

5555

What is the next likely stage of a What is the next likely stage of a protostar?protostar?

Super

Gia

nt

Nova

Mai

n Seq

uence

Neu

tron S

tar

0% 0%0%0%

a) Super Giant

b) Nova

c) Main Sequence

d) Neutron Star

:10

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21 22 23 24

5656

Why do astronomers measure interstellar Why do astronomers measure interstellar distances in light years instead of kilometers or distances in light years instead of kilometers or

miles?miles?

Lig

ht yea

rs a

re a

mea

...

Mile

s an

d kilo

met

ers

a..

Mile

s an

d kilo

met

ers

a..

I don’t

have

a cl

ue . .

....

0 000

A. Light years are a measure of time.

B. Miles and kilometers are too small of a unit.

C. Miles and kilometers are too large of a unit.

D. I don’t have a clue . . . help me!

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24

5757

Which of the following correctly shows the age Which of the following correctly shows the age progression of an average star?progression of an average star?

0 000

A. Main sequence→White Dwarf→Red Giant →Nebula

B. Red Giant →White Dwarf →Main Sequence →Nebula

C. Nebula →Main Sequence →Red Giant →White Dwarf

D. White Dwarf →Red Giant →Main Sequence →Nebula

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5858

What type of galaxy is shown in the What type of galaxy is shown in the picture?picture?

0

0

0

0

A. Irregular

B. Spiral

C. Elliptical

D. I have no idea … I need help!!!

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