Download Stars, Galaxies & Universe

Stars, Galaxies &
Universe
Chapter 3
1
Tools 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, xrays, and gamma
rays.
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Refracting Telescope
• Refracting telescope
collects light using
lenses.
• The lenses bend the
light to the focal point.
3
Reflecting Telescope
• Reflecting telescope
uses a mirror to
collect the light.
• A concave mirror
bends the light inward
to a focal point.
4
Radio Telescope
• Radio telescopes
collects radio waves.
• The collector is a
concave dish.
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Observatory
• The building that
houses a telescope is
called an observatory.
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Other 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.
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Which type of telescope focuses
light using a mirror?
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A.
B.
C.
D.
Reflecting Telescope
Refracting Telescope
Radio Telescope
Infrared Telescope
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Which type of telescope focuses
light through transparent lenses?
A.
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Reflecting Telescope
Refracting Telescope
Radio Telescope
Infrared Telescope
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One of the greatest advancements in
astronomy was the telescope. Which is
the correct order of advancements?
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A. Radio- refracting-reflecting
B. Reflecting – refracting –
radio
C. Refracting-reflecting-radio
D. Radio- reflecting-refracting
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Which of the following is an advantage of
a space-based, satellite telescope like
Hubble?
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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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Characteristics of Stars
• A galaxy contains
hundreds of billions of
stars.
• The universe contains
billions of galaxies.
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Distances 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.
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A light year is a measurement of…
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Distance
Time
Speed
Acceleration
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Why do astronomers measure interstellar
distances in light years instead of
kilometers or miles?
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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One light year equals about how
many kilometers?
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365 km
9.5 trillion km
365 days
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Classifying 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.
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Hertzsprung-Russell Diagram
• H-R diagram is a
graph of the Milky
Way galaxy.
• Surface temperature
is graphed on the xaxis.
• Absolute magnitude is
graphed on the yaxis.
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Types 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.
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Why do stars appear to be different
colors?
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a) chemical
composition
b) distance
c) size
d) temperature
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Which color star would be the
hottest?
blue
red
white
yellow
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Which star would be the brightest?
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Main sequence
Red giants
Red super giants
White dwarf
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How would you classify our star,
the sun, on the H-R diagram?
Main sequence
Red giant
White dwarf
Red supergiant
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Birth 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.
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Length 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 910 billion years.
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During 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.
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Death 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.
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What is the first stage of the birth of
a star?
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b)
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Protostar
Nebula
Giant
dwarf
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What is the next likely stage of a
protostar?
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What happens to the most massive
stars as they near their death?
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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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What is the next likely stage of our
sun?
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White dwarf
Black dwarf
Red giant
Super nova
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Star 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.
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Galaxies
•
•
Galaxies are a group
of billions of stars.
Type of galaxies are
1. Elliptical
2. Spiral
3. Irregular
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Elliptical Galaxy
• Old galaxy.
• Contains red star that
are old.
• No gas or dust.
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Spiral Galaxy
• Middle aged galaxy.
• Contains blue stars.
• Has some dust and
gas.
• Our Milky Way is a
spiral galaxy.
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Irregular Galaxy
• Unorganized
collection of stars.
• Made of very young
stars.
• Has a great deal of
gas and dust.
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History 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.
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Big 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.
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Formation 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.
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Future of the Universe
• The universe may
continue to expand.
• Gravity may pull the
universe back
together.
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By what are galaxies classified?
Color
Temperature
Size
Shape
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What type of galaxy is illustrated in
the following picture?
a)
b)
c)
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:10
Irregular
Spiral
Elliptical
I have no
idea.. I need
help!
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What type of galaxies contain older
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Elliptical
Irregular
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Review 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
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Review 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
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Review 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
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Review 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
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Review 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
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Review 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
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Review 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
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Review 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
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Review 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
52
Practice Extended Answer
Questions
• 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.
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One of the greatest advancements in astronomy
was the telescope. Which is the correct order of
advancements?
1
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A. Radio- refractingreflecting
B. Reflecting –
refracting –radio
C. Refractingreflecting-radio
D. Radio- reflectingrefracting
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What is the next likely stage of a
protostar?
:10
Super Giant
Nova
Main Sequence
Neutron Star
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Why do astronomers measure interstellar
distances in light years instead of kilometers or
miles?
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measure of time.
Miles and kilometers are
too small of a unit.
Miles and kilometers are
too large of a unit.
I don’t have a clue . . .
help me!
m
ea
A.
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Which of the following correctly shows the age
progression of an average star?
A.
Main sequence→White
Dwarf→Red Giant
→Nebula
Red Giant →White
Dwarf →Main Sequence
→Nebula
Nebula →Main
Sequence →Red Giant
→White Dwarf
White Dwarf →Red
Giant →Main Sequence
→Nebula
B.
C.
D.
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What type of galaxy is shown in the
picture?
A. Irregular
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D. I have no idea … I need help!!!
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