Astronomy 1904
Wayne K. Trail
Review for Exam 1
The best thing you can do to review for tests is read the chapters, read your notes, and be
able to answer the questions at the start of the chapters.
This provides a list of some questions you should be able to answer for each chapter (in
addition to the questions at the start of the chapters—there are about 5-10 for each
chapter). Notice that I provide full or partial answers for some of the questions I am
listing.
Also, I give a list of key words for each chapter. I will expect you to be able to define
these words on the test. (Notice that my list does not include all the key words at the end
of the chapter—I will not expect you to know the others.)
Don’t forget to study the phases of the moon diagram that I handed out in class.
You need to be able to identify the phases on that diagram, which is similar to the
figure on p 42 of your book.
You do not need to know the star chart for this test.
You can also read the Key Ideas section at the end of the chapter.
Chapter 1:
The Greeks believed the universe is comprehensible.
What is the difference between a theory and a scientific hypothesis?
What does it mean when we say that a hypothesis must be falsifiable to be a scientific
hypothesis? (You must be able to prove it false. See the next example.)
Is “Oklahomans are the best-looking Americans.” a scientific hypothesis?
Is “All apples are red or green.” a scientific hypothesis?
How do powers of 10 work? (What is 106 equal to?)
What is the difference between a solar system and a galaxy?
Keywords to know: This is a selection of keywords from the list at the end of each
chapter. If you look at the list at the end of the chapter, it will tell you what page the
definition is on.
Angle
Powers-of ten notation
Angular measure
Solar System
Degree
Galaxy
Arcminute
Big Bang
Arcsecond
Astronomical Unit (AU)
Supernova
Light year
Scientific method
Chapter 2
How long ago were the earliest known stone structures that suggest a preoccupation with
viewing the sky? (4000-5000 years)
Astronomy 1904
Wayne K. Trail
Where were the structures found? (They have been found on most continents---all over
the world.)
Approximately how many stars can be seen from Earth with the naked eye? (6000)
If you go outside at night and look up, then go out a few hours later, how have the
positions of the stars changed? What causes this?
Which constellations are visible in the night sky changes over the course of the year.
Why is this?
What is the Celestial sphere? What did ancient people think the celestial sphere did
relative to the Earth? (They thought it rotated around us once per day).
Do astronomers still use the celestial sphere model today? How?
How many days of the year can we see Polaris (the North star)? (Every day.) Why?
What are right ascension and declination? They are the equivalent of latitude and
longitude, but on the celestial sphere. We use them to identify the positions of objects in
the sky.
What is the numerical value of the tilt of the Earth’s axis? (How many degrees is it
tilted?)
What causes seasons? How many hours of sunlight does Santa get on the summer
solstice?
What is the Arctic Circle? (the latitude above which you get at least one day per year that
is 24 hours long (the sun never sets), and one night per year that is 24 hours long (the sun
never rises).
What effect does the Moon have on the rotational axis of the Earth? The Moon causes
the Earth’s rotational axis to precess (what does it mean to precess?)
How long does it take the Earth to complete one precessional cycle? About 26,000 years.
What is a sidereal day (or an “apparent solar day)? (It is local noon to local noon, i.e.,
from one upper meridian transit of the Sun to the next.) Why is this different from the
time it takes the Earth to do one rotation? (Because the Earth is also moving along in its
orbit around the Sun.)
Why do we have time zones?
Apparent Solar day
Arctic circle
Equinox (autumnal and vernal)
Celestial equator, celestial sphere, celestial poles
Circumpolar
Diurnal motion
Ecliptic
Mean solar day
Meridian (upper and lower)
Meridian transit
Right ascension, declination
Sidereal day
Solstice (summer and winter)
Time zone
zenith
Chapter 3:
What causes the phases of the Moon (they are also called lunar phases)?
You should be able to identify all the phases of the Moon by their name and know the
position and lighting on the Moon at the various phases (see class handout, also diagram
on p 42 of your book.
Does the Moon rotate? (Yes.) What is special about the rotation of the Moon?
Astronomy 1904
Wayne K. Trail
What is the difference between a sidereal month, and synodic month? Which is longer?
What is the line of nodes? (It is where the equatorial plane of the Earth crosses the plane
of the ecliptic.)
What is the significance of the line of nodes for eclipses?
What is a lunar eclipse? What is a solar eclipse?
When there is a total lunar eclipse, who on Earth can see it? When there is a total solar
eclipse, who on Earth can see it? What is the difference?
What are some examples of astronomical measurements the Greeks made?
(Circumference of Earth, diameter of Moon, distance to Moon, diameter of Sun, distance
to Sun…)
Who was Eratosthenes? What did he measure?
Eclipses: annular, partial, total, penumbral
Eclipse path
Phases of Moon: (all of them)
Line of nodes
Penumbra
Umbra
Sidereal month
Synodic month
Plane of the ecliptic
Solar corona
Chapter 4:
Did ancient native Americans build structures for monitoring celestial objects? (Yes.)
The ancient Greeks believed the celestial sphere model was real. How did the Sun and
the Moon move in this model? What was different about the way the planets moved from
the way the Sun and Moon moved in the Ptolemaic model?
What are epicycles and what did they explain? What is a deferent? (These were the
orbits Ptolemy used in his geocentric model—see page 64 in the book.)
What is retrograde motion?
What is direct motion?
How does the Ptolemaic model work. For about how long was it used? (over a thousand
years)
What is the Heliocentric model? Who first thought it up? (Greeks.) Who thought it up in
the 1500’s? (Copernicus)
What is Occam’s Razor?
How do we explain retrograde motion in the heliocentric model?
What was Tycho Brahe’s contribution to astronomy? (27 years of accurate
measurements.) Why did Tycho not believe the heliocentric model? (Parallax.)
What is parallax?
What are superior planets? What are inferior planets. What is conjunction? What is
opposition? Can an inferior planet ever be at opposition? (No.) (See P. 66 for these.)
What did Kepler do? (He took Brahe’s data and came up with 3 laws of planetary
motion.) What are Kepler’s laws? (You should be able to recognize them.)
What did Galileo learn about Venus? What did this say about the Ptolemaic model?
At what point in an elliptic orbit is a planet moving fastest? (Aphelion? Perihelion?)
What did Newton do? (He came up with 4 laws that govern the motion of all objects.
From his laws he could derive Kepler’s laws.)
Astronomy 1904
Wayne K. Trail
What are Newton’s laws? (You should be able to recognize them.
According to Newton what were the possible shapes for orbits? (Conic sections.)
What causes tides? What is spring tide? What is neap tide?
Conic section
Deferent
Direct motion
Newton’s laws
Eccentricity
Opposition
Parallax
Epicycle
Focus
Sidereal period
Geocentric model
Superior conjunction
Gravity
Superior planet
Heliocentric model
Synodic period
Inferior conjunction
Tidal forces
Inferior planet
Kepler’s laws
Chapter 5
How fast does light travel? (186,000 miles per second) How fast does sound travel? (0.2
miles per second.) How did Galileo try to measure the speed of light? What did he learn?
What happens to the speed of light when it travels through other media such as glass?
What happens to white light when it passes through a prism?
What did Newton think light was composed of? (Tiny particles.)
How did Thomas Young show that light is a wave? (He showed it would create an
interference pattern when passed through a double slit—p93.)
Know that large wavelength means small frequency and small energy… and that small
wavelength means large frequency, and large energy.
The order of the bands of electromagnetic radiation is from large wavelength to small
Know these bands of light and their order.
Radio
Microwaves Infrared
Visible
waves
Long
wavelength
Low
frequency
Low
Energy
Ultraviolet X-rays
Gamma
rays
Short
wavelength
High
frequency
High
Energy
What is blackbody radiation? What happens to the light curve for an object as it gets
hotter? (It emits more light at all wavelengths and the wavelength of the peak gets
smaller—Wien’s law.)
What does the light from a heated gas look like through a diffraction grating? (A set of
colored lines.) What are these lines? (The characteristic emission spectrum of the gas.)
Why is the characteristic emission spectrum called the fingerprint of the element?
Astronomy 1904
Wayne K. Trail
What are the dark lines that we see in the spectrum of a blackbody if we are looking at it
through a cool gas? (This is the absorption spectrum).
What are the constituent parts of an atom? (protons, neutrons, and electrons.)
What causes the emission lines we see? (They are due to electrons falling from higher
energy orbits to lower energy ones—they give off photons when they do this and the
wavelength of the photon corresponds to the difference between the energy levels of the
two electron orbits).
What are Kirchoff’s laws? (p104)
What is a nanometer (nm)? 1 billionth of a meter (or 109 meters). How any nanometers
is the wavelength of visible light? (Blue light is about 400nm and red is about 700nm.)
How big is an atom? (About 0.1 nm)
What is the Doppler shift? What does it tell us about distant objects?
Absorption line spectrum
Continuous spectrum
Electromagnetic spectrum
Emission line spectrum
frequency
Periodic table
Spectral analysis
Atom
Doppler effect
Electron
Energy level
Neutron
Photon
spectroscopy
Blackbody
Electromagnetic radiation
Element
Excited state
Nucleus
Red shift