Topic/Objective:_______________
Full Name: _______________________________
_____________________________
Class: ___________________
_____________________________
Date: _________________
Tutor Use
Only:
Period: _____
Essential Question:
Chapter 28 Stars and Galaxies
28.1 Closer look at Light
 Light is a form of _________________________________, which is
energy that travels in waves.
 Waves of energy travel at 300,000 km/sec (speed of light
 Ex: radio waves and x-rays
 Electromagnetic waves do not need a ________________ to
travel, they travel through _________________
 Electromagnetic waves emitted by an object indicated what
___________________ are present and its motion
 Electromagnetic radiation waves are arranged into a
continuum call the __________________________________.
 Wide range of wavelengths
 _____________ wavelengths with ______________
frequencies at one end, ______________ wavelengths with
_____________ frequencies at the other end
 __________________ measured crest to crest/trough to trough
 __________________ the number of that crests of the same
wavelength that pass a point in one second.
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Summary:
Scientists study the visible light portion of the electromagnetic
spectrum.
________________ of stars allow for astronomers to learn
about the star’s elements and motion.
Spectra studied using a ________________________
Essential Question:

Three types of visible spectra
 ___________________ spectrum: unbroken band of colors,
emitting all colors of visible light
 glowing solids, such as a light bulb filament
 glowing liquids, molten iron
 hot, compressed gases inside a star
 ___________________ spectrum: unevenly spaced lines of
different colors, emitting light of only some wavelengths
 glowing thin gases
 every element has its own unique emission spectrum,
element’s finger print
 ____________________ spectrum: dark lines that cross a
continuous spectrum.
 forms when light from a glowing object pass through a
cooler gas which absorbs some wavelengths
 can determine what is present in the cooler gas by
comparing emission and absorption spectrum
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________________ Effect is the apparent change in the wavelength
of radiation or sound due to relative motion between the object and
the receiver.
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Doppler effect applies to ______________ as well as sound.
Shift of the __________________ spectra can indicate if the object is
moving towards or away from Earth
Shift towards the red end of the visible light spectrum, object moving
away Earth – ____________________
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Summary:
Essential Question:
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Shift towards the blue end of the visible light spectrum, object moving
towards Earth - _____________________
 Doppler effect determined that the universe is
_____________________
Telescopes
 ________________ Telescopes – gather far more light than an
unaided eye and magnify imagers
 ____________________
 Uses one lens at back to gather and focus light
 Image reflected on to a small mirror and then the eye
piece
 ____________________
 Uses two lenses
 Lens at the front gathers light
 Eyepiece magnifies image
 _______________ Telescopes
 Technical term for really big satellite dishes
 Use to detect energy waves at frequencies lower than visible
light
 Other
 Detects energy waves at frequencies higher than visible light
 Usually satellites in space
 Gamma ray
 Background radiation
 X-ray
 Hubble (infrared)
28.2 Stars and Their Characteristics
 Observation of stars has been going on for over ____________ years
 The grouping of stars are called _________________________
 Constellations
 _____________ grouping of stars
 only appear together as viewed from ___________ from a
different angle they do not look like the constellation
 Grouped together due to ______________ like they all have
the same brightness (_________________ magnitude)
Summary:
Essential Question:
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Summary:
Constellations will change shape over _________________ of
years due to the universe expanding
 Some constellations have been around for thousands of years
other were recently conceived
 Move across the sky from _________ to ___________
(though Earth rotates west to east)
 Big Dipper and Little Dipper two of the best know
constellations point to the ____________ ____________
North Star
 Current north star is called _______________
 Sits directly over the _________________ pole
 Does not ______________ to the naked eye
 Very powerful tool for _______________________
 Due to ___________________, Polaris will not always be the
“North Star”
Circumpolar Constellations – constellations around the north star
 Create star trails
evidence for Earth’s _______________
 North star appears ___________ in the sky as Earth rotates
 star trails from circumpolar constellations rotate
__________________ around the north star
 Circumpolar constellations seem to ____________ set from
some northern hemisphere latitude
Distances to stars and other objects in space
 Unit of measurements on Earth are __________ sufficient for
space measurements
 __________________ (AU) is used for the distance from
Earth to the Sun (150 million kilometers)
 ______________ is the distance light travels in one year (9.5
trillion kilometers)
 It is a ________________ measurement
 Example - 4.2 light-years means that the light we see
has been traveling for 4.2 years before we can see it
(4.2 X 9.5 trillion km)
 ________________ change in an object’s direction due to a
change in the observer’s position
 Parsec short for “parallax second” equal to 3.258 light-years.
Essential Question:
The further the object is
from the viewer, the less
the parallax shift.
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Summary:
Stars
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Elements
 ______________ ~69%
 ______________ ~29%
 Heavier elements ~2%
 No two stars have the same proportions of elements
 light that radiates is dependent on composition and
temperature, this differs in every star
 Star spectrum is its fingerprint
Mass, Size and Temperature
 Stars vary greatly in _________, _________, and
_____________
 Cannot observe directly so we are estimating what the mass
might be
 ________________ effect on bodies around the star
help with estimating its mass
 Star __________ is expressed as multiples of the mass
of our Sun (which has a stellar mass of 1)
 ____________ varies more than mass
 Smallest stars are ________________ than Earth
 Largest have diameters more than __________ times
that of our Sun
Essential Question:
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Stars differ even more in ______________
 Betelguese is about one ten-millionth of our Sun
 One star is so dense that one __________ would
weight more than a _______ on Earth
 __________________ of stars vary
 Stars have _______________ colors which indicate
different temperatures
 Cool stars are __________ in color
 Mid-temp are __________ in color
 Hot stars are ___________ in color
 Astronomers group stars by ______________ and
color into spectral classes.
Star Brightness
 Actual brightness of a star is __________________
 Dependent on __________ and ______________
 _____________ from Earth is not a factor
 If two stars are the same size the ____________ star
would be more luminous
 ______________ magnitude is how bright a star appears to an
observe on Earth
 Does not factor in ________________
 _____________ magnitude is the measure of how bright a star
would be is all stars were the same distance from Earth (10
parsec)
28.3 Life Cycle of Stars
See foldable for Star life cycle and HR Diagram
Summary:
Essential Question:
28.4 Galaxies and the Universe
Galaxies:
 The ________________ is everything that exists.
 The _________________________ is everything we can observe.
 Astronomers have are not sure how old the universe is since
the light from the beginning has not yet reach us. The estimate
is between 10-20 billion years
 Galaxies are hard to separate from stars without _________________.
 Hazy patches of light which when viewed through a telescope
reveals thousands to billions of stars.
 Astronomers estimate there are 50- 100 billion galaxies in the
observable universe.
 No two galaxies are the _____________, however, they are classified
based on ______________.
 There are ________________ classifications
 ______________ (ex. Milky Way)
 ________________ are near spherical to lens-shape
 ________________ (ex. The two Magellanic Clouds )
Origin of the Universe
 ____________________ – explains history of the universe from a tiny
fraction of a second after it came into being up to the present
 _____________ explanation for how the universe came to
being
 Developed due to ________________ of stars, galaxies and
other objects with telescopes and experimenting with matter
on Earth
 Approximately 10-20 billion years ago all matter in the
universe existed in an incredibly hot and dense state, from
which it expanded and cooled slowly condensing into stars and
galaxies.
 It is ________________ at a very slow rate and is still
expanding today
Summary:
Essential Question:
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Summary:
________________ for the Big Bang Model:
 The universes apparent ____________, distance between
galaxies and groups of galaxies seems to be increasing with
time.
 Edwin Hubble’s discovery of the _______________ in the
spectra of galaxies supports the expansion of the universe
 Discovery of radiation called ____________ background
radiation apparently left over from the universe’s beginning.
 Continues to be tested and examined to seek further evidence
to support it
 Some astronomers are considering alternative ways the
universe has reached its present state.
It is ____________ to know for certain how the universe began
as long as the Big Bang Model ______________ crucial tests, it
remains the best __________________ for the origin of the universe
If it were to ever fail a test, then astronomers will have to look for a
new theory/model