Active Learning Worksheets to Pair with Openstax Astronomy
Overview
These worksheets were developed by Bryanne McDonough (PhD Candidate, Boston University) for a 6 week summer AS101 course taught at Boston University using the Openstax Astronomy 2e textbook. Each lesson was two hours long, so modification may be necessary for using these worksheets in a shorter class format, although many are already split into two parts.
I'm open to feedback and would love to hear if you decide to use this resource in anyway: please contact Bryanne McDonough (bnmcd@bu.edu).
Summary of Included Worksheets
These worksheets were developed by Bryanne McDonough (PhD Candidate, Boston University) for a 6 week summer AS101 course taught at Boston University. Each lesson was two hours long, so modification may be necessary for using these worksheets in a shorter class format, although many are already split into two parts. Worksheets were typically introduced with example problem(s).
Google Drive link to all worksheets
The worksheets contain adaptations from other material, including questions from Openstax Astronomy 2e (indicated by numbers referencing the textbook), original problems (OP) written by the compiler, and a few questions from Cosmic Perspective (Pearson). Actual text of Cosmic Perspective questions were omitted for intellectual property reasons, question numbers reference the 9th edition.
Below is an outline of the worksheets, including details about the topics covered, associated Openstax Astronomy 2e chapters, and learning objectives for the associated lesson. Learning objectives are mostly taken from Astronomy 2e, with minor modifications or reductions. Not all of the learning objectives for a lesson will be reinforced by the worksheets.
Class 2
Worksheet Topics: Observing the sky, celestial sphere, and Eratosthenes measurement of Earth
Chapters: 2.1, 2.2, 2.4
Lesson Learning Objectives:
Define the main features of the celestial sphere
Describe how motions of the Sun, Moon, planets, and stars appear to us on Earth
Explain how Greek astronomers were able to calculate Earth’s size
Describe Ptolemy’s geocentric system of planetary motion
Explain how Copernicus developed the heliocentric model of the solar system
Explain how Galileo’s discoveries tilted the balance of evidence in favor of the Copernican model
Class 3
*Uses Kepler’s Law activity from University of Colorado Boulder (p45) (requires computer)
Worksheet Topics: Kepler’s laws, ellipses, escape speeds
Chapters: 3.1, 3.4, 3.5
Lesson Learning Objectives:
Explain Kepler’s three laws of planetary motion
Compare the orbital characteristics of the planets in the solar system
Explain how an object (such as a satellite) can be put into orbit around Earth
Explain how an object (such as a planetary probe) can escape from orbit
Quantitatively analyze a planet’s period knowing its orbital distance or vice versa
Class 4
Worksheet Topics: acceleration, velocity, forces, gravity
Chapters: 3.2, 3.3, 3.6
Lesson Learning Objectives:
Describe Newton’s three laws of motion
Define mass, volume, and density and how they differ
Explain how Newton’s three laws of motion relate to momentum
Define angular momentum
Explain what determines the strength of gravity
Describe how Newton’s universal law of gravitation extends our understanding of Kepler’s laws
Explain how the planet Neptune was discovered
Class 5
*Uses Stellarium (requires computers)
Worksheet Topics: celestial coordinates (and more celestial sphere practice), seasons
Chapters: 4.1, 4.2, 4.3, 4.4
Lesson Learning Objectives:
Explain how right ascension and declination are used to map the sky
Describe how the tilt of Earth’s axis causes the seasons
Explain the difference between the solar day and the sidereal day
Explain mean solar time and the reason for time zones
Understand how calendars varied among different cultures
Explain the origins of our modern calendar
Class 6
Worksheet Topics: Moon phases, angular sizes, eclipses
Chapters: 4.5, 4.6, 4.7
Lesson Learning Objectives:
Explain the cause of the lunar phases
Understand how the Moon rotates and revolves around Earth
Describe what causes tides on Earth
Explain why the amplitude of tides changes during the course of a month
Describe what causes lunar and solar eclipses
Differentiate between a total and partial solar eclipse
Explain why lunar eclipses are much more common than solar eclipses
Understand and calculate angular sizes
***End material on Exam 1***
Class 7
Worksheet Topics: electromagnetic spectrum, frequency & wavelength, inverse square law
Chapters: 5.1, 5.2, 5.3
Lesson Learning Objectives:
Describe the relationship between wavelength, frequency, and speed of light
Explain how and why the amount of light we see from an object depends upon its distance
Understand the bands of the electromagnetic spectrum and how they differ from one another
Understand how each part of the spectrum interacts with Earth’s atmosphere
Explain how and why the light emitted by an object depends on its temperature
Describe the properties of light
Explain how astronomers learn the composition of a gas by examining its spectral lines*
Discuss the various types of spectra*
*in reading but discussed following class after exam
Class 8
*Exam
Class 9
Worksheet Topics: spectra, energy levels, photon energy, frequency & wavelength, Doppler effect
Chapters: 5.4, 5.5, 5.6
Lesson Learning Objectives:
Explain the behavior of electrons within atoms and how electrons interact with light to move among energy levels
Explain how emission line spectra and absorption line spectra are formed
Identify the various types of spectra
Describe what ions are and how they are formed
Explain why the spectral lines of photons we observe from an object will change as a result of the object’s motion toward or away from us
Describe how we can use the Doppler effect to deduce how fast astronomical objects are moving through space
Class 10
Worksheet Topics: solar energy and lifetime, fusion energy, hydrostatic equilibrium
Chapters: 16.1, 16.2 (abbreviated), 16.3
Lesson Learning Objectives:
Identify different forms of energy
Understand the law of conservation of energy
Explain ways that energy can be transformed
Explain how matter can be converted into energy
Summarize the key nuclear reaction in the solar interior
Describe the state of equilibrium of the Sun
Understand the energy balance of the Sun
Explain how energy moves outward through the Sun
Class 11
*Adapted from Sun | NOVA Labs | PBS, makes use of NASA helioviewer tool, requires computers
Worksheet Topics: Sunspots, solar activity
Chapters: All of 15
Lesson Learning Objectives:
Explain how the composition of the Sun differs from that of Earth
Describe the various layers of the Sun and their functions
Explain what happens in the different parts of the Sun’s atmosphere
Describe the sunspot cycle and, more generally, the solar cycle
Describe the various ways in which the solar activity cycle manifests itself, including flares, coronal mass ejections, prominences, and plages
Explain what space weather is and how it affects Earth
Class 12
*Entirely original questions
Worksheet Topics: climate change, CO2 cycle, solar cycle, interpreting graphs
Chapters: 8.1, 8.3, 8.4, 8.5
Lesson Learning Objectives:
Specify the origin and effect of Earth’s magnetic field
Describe the chemical composition and possible origins of our atmosphere
Explain the difference between weather and climate
Explain the ways that life and geological activity have influenced the evolution of the atmosphere
Describe the causes and effects of the atmospheric greenhouse effect and global warming
Describe the impact of human activity on our planet’s atmosphere
Describe the evidence for recent impacts on Earth
Describe how impacts have influenced the evolution of life on Earth
Discuss the search for objects that could potentially collide with our planet
Outline the origins and subsequent diversity of life on Earth
Explain the scarcity of impact craters on Earth compared with other planets and moons
Class 13
Worksheet Topics: solar system formation, frost line, exoplanet orbits and transits, Planet Hunters
Chapters: 14.3, 21.3, 21.4, 21.5, 21.6 (only section on habitable exoplanets)
Lesson Learning Objectives:
Describe the motion, chemical, and age constraints that must be met by any theory of solar system formation
Explain the formation process of the terrestrial and giant planets
Trace the evolution of dust surrounding a protostar, leading to the development of rocky planets and gas giants
Evaluate evidence for planets around forming stars based on the structures seen in images of the circumstellar dust disks
Compare the indirect and direct observational techniques for exoplanet detection
Explain what we have learned from our discovery of exoplanets
Discuss the kinds of planetary systems we are finding around other stars
Class 14
*Inspired by The Drake Equation – What are the Chances of Extraterrestrial Life? — Information is Beautiful, from which numbers are sourced
Worksheet Topics: Drake equation
Chapters: 30.1, 30.2, 30.3, 30.4
Lesson Learning Objectives:
Discuss the assumption underlying the Copernican principle and outline its implications for modern-day astronomers
Understand the questions underlying the Fermi paradox
Describe the characteristics of a habitable environment
Identify where in the solar system life is most likely sustainable and why
Describe some key missions and their findings in our search for life beyond our solar system
Explain the use of biomarkers in the search for evidence of life beyond our solar system
Understand the various SETI programs scientists are undertaking
Describe the chemical and environmental conditions that make Earth hospitable to life
List efforts by humankind to communicate with other civilizations via messages on spacecraft
Describe some of the extreme conditions on Earth, and explain how certain organisms have adapted to these conditions
***End of material on Exam 2***
Class 15
Worksheet Topics: surface-area-to-volume ratio, radioactive dating (simple)
Chapters: 7.1, 7.2, 7.3 (optional: 7.4 for review of solar system formation)
Lesson Learning Objectives:
Describe how the objects in our solar system are identified, explored, and characterized
Describe the types of small bodies in our solar system, their locations, and how they formed
Model the solar system with distances from everyday life to better comprehend distances in space
Describe the characteristics of the giant planets, terrestrial planets, and small bodies in the solar system
Explain what influences the temperature of a planet’s surface
Explain why there is geological activity on some planets and not on others
Explain how astronomers can tell whether a planetary surface is geologically young or old (lab)
Describe different methods for dating planets
Class 16
Exam, no worksheet
Class 17
*Part 1 adapted from GEOLOGIC MAPPING OF THE MOON
Worksheet Topics: lunar and Mercurian geological features
Chapters: 9.1, 9.2, 9.3, 9.4, 9.5
Lesson Learning Objectives:
Discuss what has been learned from both manned and robotic lunar exploration
Describe the composition and structure of the Moon
Differentiate between the major surface features of the Moon
Describe the history of the lunar surface
Describe the properties of the lunar “soil”
Explain the process of impact crater formation
Discuss the use of crater counts to determine relative ages of lunar landforms
Summarize the current “giant impact” concept of how the Moon formed
Describe Mercury’s structure and composition
Explain the relationship between Mercury’s orbit and rotation
Describe the topography and features of Mercury’s surface
Summarize our ideas about the origin and evolution of Mercury
Class 18
*This activity refers to the CORGI tool, which received mixed feedback when used in class, so I included the activity in the worksheet format instead
Worksheet Topics: atmospheric weight (Venus and Mars), water on Mars
Chapters: Chapter 10.1, starting at “Rotation of the Planets”, 10.3-10.5; Overview | Venus – NASA Solar System Exploration (subbed for the longer 10.2)
Lesson Learning Objectives:
Compare the basic physical properties of Earth, Mars, and Venus, including their orbits
Describe the general features of the surface of Venus
Explain why the surface of Venus is inhospitable to human life
Describe the general composition and structure of the atmosphere on Venus
Explain how the greenhouse effect has led to high temperatures on Venus
Discuss the main missions that have explored Mars
Compare the volcanoes and canyons on Mars with those of Earth
Describe the general conditions on the surface of Mars
Describe the general composition of the atmosphere on Mars
Explain what we know about the polar ice caps on Mars and how we know it
Describe the evidence for the presence of water in the past history of Mars
Class 19
Worksheet Topics: storms, wind speeds, rate of change
Chapters: 11.1, 11.2, 11.3
Lesson Learning Objectives:
Provide an overview of the composition of the giant planets
Chronicle the robotic exploration of the outer solar system
Summarize the missions sent to orbit the gas giants
Describe the basic physical characteristics, general appearance, and rotation of the giant planets
Describe the composition and structure of Jupiter, Saturn, Uranus, and Neptune
Compare and contrast the internal heat sources of the giant planets
Describe the discovery and characteristics of the giant planets’ magnetic fields
Discuss the atmospheric composition of the giant planets
Describe the cloud formation and atmospheric structure of the gas giants
Characterize the giant planets’ wind and weather patterns
Understand the scale and longevity of storms on the giant planets
Class 20
Worksheet Topics: jovian moons, orbital resonance, dwarf planets
Chapters: 12.1, 12.2, 12.3, 12.4, 12.5
Lesson Learning Objectives:
Briefly describe the system of moons around each of the jovian planets
Describe key characteristics of the Galilean Moons, Titan, Triton and Charon
Explain how tidal forces generate the geological activity we see on Europa and Io and the tidal locking of Pluto and Charon
Compare the orbital characteristics of Pluto with those of the planets
Describe information about Pluto’s surface deduced from the New Horizons images
Describe the two theories of planetary ring formation
Explain how the rings of Uranus and Neptune differ in composition and appearance from the rings of Saturn
Describe how ring structure is affected by the presence of moons
Class 21
Worksheet Topics: mass of asteroids & Kuiper belt, comets
Chapters: 13.1, 13.2, 13.3, 13.4
Lesson Learning Objectives:
Describe the composition, classification, and orbits of the various types of asteroids
Discuss what was learned from spacecraft missions to several asteroids
Recognize the threat that near-Earth objects represent for Earth and possible defensive strategies
Characterize the general physical appearance of comets
Explain the range of cometary orbits
Describe the size and composition of a typical comet’s nucleus
Discuss the atmospheres of comets
Explain the proposed fate of comets that enter the inner solar system
Describe the composition of the Oort cloud and Kuiper Belt
Class 22
Class topic: meteors (no worksheet)
Class 23
Exam 3
(Chapters 2.1, 2.2, 2.4) Observing the Sky
Worksheet Topics: Observing the sky, celestial sphere, and Eratosthenes measurement of Earth
Chapters: 2.1, 2.2, 2.4
Lesson Learning Objectives:
Define the main features of the celestial sphere
Describe how motions of the Sun, Moon, planets, and stars appear to us on Earth
Explain how Greek astronomers were able to calculate Earth’s size
Describe Ptolemy’s geocentric system of planetary motion
Explain how Copernicus developed the heliocentric model of the solar system
Explain how Galileo’s discoveries tilted the balance of evidence in favor of the Copernican model
In-Class Worksheet: Class 2 - Observing the Sky
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 1 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on May 25.
Guidance: Solving celestial sphere problems can seem tricky, and there’s many ways to think about them. Here’s one:
Identify where the celestial equator is on the sky. Work backwards from the poles or equator. On the equator (latitude = 0°), the celestial equator would be directly overhead (altitude = 90°). On a pole (latitude = ± 90°), the celestial equator would be on your horizon (altitude = 0°). So the celestial equator is always at an altitude of (90°-your latitude).
Identify where the object of interest (usually a point on the ecliptic plane) lies with respect to the celestial equator. The ecliptic plane is tilted by 23.5° with respect to the equator. The equinoxes are the points where the ecliptic crosses the celestial equator, and the solstices are where the ecliptic is ± 23.5° above the celestial equator.
Part 1: The Celestial Sphere
(2.35) a. What is the altitude (degrees above horizon) of the north celestial pole (NCP) in the sky from your latitude?
b. What is the altitude of the NCP at the North Pole?
c. At the equator?
OP: a) At what altitude will the Sun appear in the sky in Boston (latitude ~ 42°) at noon on the vernal equinox?
b) On the Summer Solstice?
Part 2: Eratosthenes
Optional space for notes - Instructor will complete the following question on the board:
(2.41) Suppose Eratosthenes had found that, in Alexandria, at noon on the first day of summer, the line to the Sun makes an angle 30° with the vertical. What, then, would he have found for Earth’s circumference?
OP: You are part of a group of humans in the far future exploring new planets in different solar systems. Unfortunately, you have crash landed on a new world and most of the useful scientific equipment is broken. To leave the planet without this equipment, you’ll need to know the planet’s mass and radius. The captain has tasked you with figuring out the planet’s radius. Some members of your crew are 1500 km South of you, and report that the planet’s tall, narrow, tree-like plants cast no shadow when the Sun is on the Zenith (local noon). At your location, you find one of these trees and measure that it is 20 meters tall, and the shadow it casts at noon is 2.5 meters long. What is the radius of this planet? (Hint: tan(angle) = opposite/adjacent)
(Chapters 3.1, 3.4, 3.5) Kepler's Laws and Escape Speeds
*Uses Kepler’s Law activity from University of Colorado Boulder (p45) (requires computer)
Worksheet Topics: Kepler’s laws, ellipses, escape speeds
Chapters: 3.1, 3.4, 3.5
Lesson Learning Objectives:
Explain Kepler’s three laws of planetary motion
Compare the orbital characteristics of the planets in the solar system
Explain how an object (such as a satellite) can be put into orbit around Earth
Explain how an object (such as a planetary probe) can escape from orbit
Quantitatively analyze a planet’s period knowing its orbital distance or vice versa
Part 1: https://www.colorado.edu/sbo/sites/default/files/attached-files/1010manual_s20.pdf
Part 2: Escape speeds
(OP1)Complete the following table
Planet/moon | Mass (kg) | Radius (m) | Escape Speed (m/s) |
Earth | 5.97 x 1024 | 6,378,000 | 11,200 |
(Earth’s) Moon | 7.3 x 1022 | 1,738,000 | |
Mars | 6.42 x 1023 | 3,397,000 | |
Jupiter | 1.9 x 1027 | 71,492,000 |
If you have time, discuss this as a group:
Some groups have proposed using the Moon as a base for future exploration of the rest of the solar system. What would be the advantages and disadvantages of that?
(Chapters 3.2, 3.3, 3.6) Gravity and Newton
Worksheet Topics: acceleration, velocity, forces, gravity
Chapters: 3.2, 3.3, 3.6
Lesson Learning Objectives:
Describe Newton’s three laws of motion
Define mass, volume, and density and how they differ
Explain how Newton’s three laws of motion relate to momentum
Define angular momentum
Explain what determines the strength of gravity
Describe how Newton’s universal law of gravitation extends our understanding of Kepler’s laws
Explain how the planet Neptune was discovered
In-Class Worksheet: Class 4 - Gravity and Newton
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 1 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on May 31.
Part 1: Motion and Forces
OP1a: You get a chance to drive a pretty nice car. It accelerates at a rate of 30 m/s2 and weighs 1,500 kg. What force does the engine need to apply to achieve that acceleration?
OP1b: After 1 second, the car stops accelerating and is going at a constant velocity of 30 m/s. How long will it take to travel 3 km?
OP2: How long does it take light to travel between Earth and the Sun (1.5 x 1011 m)? Convert your answer to minutes. Recall, the speed of light: c = 3 x 108 m/s.
(3.25) Two asteroids begin to gravitationally attract one another. If one asteroid has twice the mass of the other, which one experiences the greater force? Which one experiences the greater acceleration?
(3.26) How does the mass of an astronaut change when she travels from Earth to the Moon? How does her weight change? (Mass of Earth = 5.97 x 1024 kg; mass of Moon = 7.3 x 1022)
(3.31) Suppose astronomers find an earthlike planet that is twice the size of Earth (that is, its radius is twice that of Earth’s). What must be the mass of this planet such that the gravitational force (Fgravity) at the surface would be identical to Earth’s?
OP2a: In class 2, you were asked a question about identifying a planet’s radius based on shadows. You found that the radius was about 12,000 km. Through careful experimentation, your colleagues have determined that the acceleration due to gravity on this planet is 5.3 m/s2. What is the mass of this planet? Be careful with your units!
OP2b: What is the density of this planet? (Remember: density = mass / volume)
Part 2: Proportional Reasoning
(3.30) By what factor would a person’s weight be increased if Earth had 10 times its present mass, but the same volume?
OP3: If a planet has 0.6 times the mass of Earth and 0.7 times the radius of Earth, what would its density be, as a factor of Earth’s density (⍴⊕)? (Use proportional reasoning, you don’t need to know the density of Earth!)
OP4: A planet has the same density as Earth, but a radius that is 1.2 times the Earth’s. What is this planet’s mass in Earth masses (M⊕)?
(Chapters 4.1, 4.2, 4.3, 4.4) Coordinates, Seasons, and Time
*Uses Stellarium (requires computers)
Worksheet Topics: celestial coordinates (and more celestial sphere practice), seasons
Chapters: 4.1, 4.2, 4.3, 4.4
Lesson Learning Objectives:
Explain how right ascension and declination are used to map the sky
Describe how the tilt of Earth’s axis causes the seasons
Explain the difference between the solar day and the sidereal day
Explain mean solar time and the reason for time zones
Understand how calendars varied among different cultures
Explain the origins of our modern calendar
Worksheet: Class 5 - Coordinates, Seasons, and Time
Part 1: Launch Stellarium - https://stellarium-web.org/
Step 1: The Sun
Set the time and day to now.
Select the Sun, what is the RA and dec coordinates of the Sun right now?
Predict: will the RA and dec of the Sun be different one day from now?
Test: Set the time forward by one day and record the RA and dec coordinate of the Sun.
Predict: What will be the RA and dec coordinates of the Sun on the Summer Solstice?
Test: Set the time to the Summer Solstice and record the Sun’s coordinates.
Predict: what will be the RA and dec coordinates of the Sun on the Autumnal Equinox?
Test: Set the day to the Autumnal Equinox and record the Sun’s coordinates.
Predict: What will be the RA and dec coordinates of the Sun on the Autumnal Equinox in 2030?
Test: Set the day to the Autumnal Equinox and the year to 2030. Are the RA and dec coordinates significantly different?
Predict: What will the RA and dec coordinates of the Sun be on the Winter Solstice? On the Vernal (Spring) Equinox?
Test: What are the RA and dec coordinates of the Sun on the Winter Solstice? On the Vernal Equinox?
Explore: By changing the time of year, can you find the range of RA that the Sun could be found in at some point in the year? The range of declination that the Sun covers in one year?
Step 2: A different star
Set the time to tonight and select a random star (not a planet or the Sun). Record the RA and dec coordinates, along with the name of the star.
Predict: Will the RA and declination position of this star change significantly over one year?
Test: Change the time month by month, does the RA and declination of the star change significantly?
Think: Why does the Sun change coordinates significantly over the year? Why don’t the RA/dec coordinates of other stars change significantly?
Part 2: Celestial Coordinates practice
What is the altitude of the Sun at noon on the summer solstice, as seen from a place on the Tropic of Cancer? What is the Sun’s RA and dec?
From the same location, what is the altitude of the Sun at noon on one of the equinoxes? What is the Sun’s RA and dec?
(4.52) What is the altitude of the Sun at noon on December 22, as seen from a place on the Tropic of Cancer?
Mars is tilted by 25° relative to its orbital plane. At what latitude (measured in degrees from the equator) is the arctic circle? At what latitudes would be the equivalent of the Tropics of Cancer and Capricorn
Optional: (4.35) The day on Mars is 1.026 Earth-days long. The martian year lasts 686.98 Earth-days. The two moons of Mars take 0.32 Earth-day (for Phobos) and 1.26 Earth-days (for Deimos) to circle the planet. You are given the task of coming up with a martian calendar for a new Mars colony. Would a solar or lunar calendar be better for tracking the seasons?
(Chapters 4.5, 4.6, 4.7) Moon, Eclipses, Tides
Worksheet Topics: Moon phases, angular sizes, eclipses
Chapters: 4.5, 4.6, 4.7
Lesson Learning Objectives:
Explain the cause of the lunar phases
Understand how the Moon rotates and revolves around Earth
Describe what causes tides on Earth
Explain why the amplitude of tides changes during the course of a month
Describe what causes lunar and solar eclipses
Differentiate between a total and partial solar eclipse
Explain why lunar eclipses are much more common than solar eclipses
Understand and calculate angular sizes
In-Class Worksheet: Class 6 - Moon, Eclipses, Tides
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 1 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on June 2.
Guidance: Draw a picture that represents the Earth (with the North Pole coming out of the page) the Sun, and the orbit of the Moon. Indicate the motion, Earth should rotate in the same direction as the Moon orbits. Recall that the Sun appears at its highest at local noon and is on the opposite side of Earth from a person at local midnight.
Part 1: Moon Phases and Times
(OP1) Fill out the table:
Phase | Draw relative positions: Sun, Earth, Moon | Time Moon rises | Time Moon is on meridian | Time Moon sets |
New Moon | ||||
First Quarter | ||||
Full Moon | ||||
Third Quarter |
(OP2) From this table you can interpolate, or continue to draw simple diagrams to answer:
About what time would a waxing crescent rise?
About what time would a waning gibbous set?
Optional: A friend claims that the Moon spends more time above the horizon at night than during the day. Explain why they are wrong. Why is that a common misconception?
Part 2:
Optional space for notes on example: What is the angular size of the Sun as seen from Earth? What is, on average, the angular size of the Moon as seen from Earth?
(OP3) The Moon’s orbit is not perfectly circular. What is the angular size of the Moon when it is closest to Earth (at perigee), when it is 3.63 x 108 m from Earth?
(OP4) What is the angular size of the Moon when it is furthest from Earth (at apogee), when it is 4.06 x 108 m from Earth?
(OP5) The textbook states that there are two types of solar eclipses: total, where the full Sun is blocked, and annular, where an outer ring of the Sun is still visible. Based on your answers above, if a solar eclipse happened when the Moon was at perigee, what type of eclipse would it be? What type of solar eclipse would happen when the Moon was at apogee? Why?
(Chapters 5.1, 5.2, 5.3) Electromagnetic Spectrum
Worksheet Topics: electromagnetic spectrum, frequency & wavelength, inverse square law
Chapters: 5.1, 5.2, 5.3
Lesson Learning Objectives:
Describe the relationship between wavelength, frequency, and speed of light
Explain how and why the amount of light we see from an object depends upon its distance
Understand the bands of the electromagnetic spectrum and how they differ from one another
Understand how each part of the spectrum interacts with Earth’s atmosphere
Explain how and why the light emitted by an object depends on its temperature
Describe the properties of light
Explain how astronomers learn the composition of a gas by examining its spectral lines*
Discuss the various types of spectra*
*in reading but discussed following class after exam
In-Class Worksheet: Class 7 - Electromagnetic Spectrum
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 2 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Tuesday, June 6.
Guidance: The equation for frequency and wavelength of a light wave is: c = f x λ, where c is the speed of light (3x108m/s), f is frequency (with units of inverse time, usually Hertz, or s-1), and the symbol lambda, λ, is the wavelength of light (with unit of distance).
The inverse square law, meaning the amount of light received (flux, Φ) from an object is proportional to the intrinsic brightness (luminosity, L) of the object and inversely proportional to the object’s distance squared (d2): Φ = L ÷ (4πd2) ∝ L ÷ d2.
Step 1:
(5.41) What is the wavelength of the carrier wave of a campus radio station, broadcasting at a frequency of 97.2 MHz (million cycles per second or million hertz)?
(5.42) What is the frequency of a red laser beam, with a wavelength of 670 nm?
(5.43) You go to a dance club to forget how hard your astronomy midterm was. What is the frequency of a wave of ultraviolet light coming from a blacklight in the club, if its wavelength is 150 nm?
OP1: How bright is the Sun relative to Earth at different locations in our solar system? Recall, 1 AU is the average distance between Earth and the Sun.
At Mercury (d = 0.387 AU)
At Mars (d = 1.524 AU)
At Saturn (d = 9.54 AU)
At Pluto (d = 39.48 AU)
OP2: Star A is half as luminous but twice as close as Star B. Which star appears brighter at Earth and by how much?
Optional: An old-school classroom television emitted sound waves with frequencies around 20,000 Hz, and wavelengths of about 0.0172 meters. What is the speed of sound?
Optional: Test your knowledge (or practice for an exam) by filling in the blanks with arbitrary values: Star A has ______ the luminosity of Star B. Star A has a distance from Earth that is _____ the distance of Star B. (Example values: twice, a third, five times, etc..)
Part 2:
(5.45) If the emitted infrared radiation from Pluto has a wavelength of maximum intensity at 75,000 nm, what is the temperature of Pluto assuming it follows Wien’s law?
(OP3) A star has a surface temperature of 4000 Kelvin, at what wavelength will it emit the most light?
(OP4) Star A has a surface temperature of 4000 Kelvin and Star B has a surface temperature of 6000 Kelvin. Which star emits more light in the infrared part of the spectrum?
Optional: Humans have a temperature of about 310 Kelvin. If we were perfect blackbody emitters, what wavelength would we emit light in? What part of the spectrum is that in?
Optional: Why do humans and other animals appear as bright shapes when using infrared “night vision” goggles?
(Chapters 5.4, 5.5, 5.6) Learning from Spectra
Worksheet Topics: spectra, energy levels, photon energy, frequency & wavelength, Doppler effect
Chapters: 5.4, 5.5, 5.6
Lesson Learning Objectives:
Explain the behavior of electrons within atoms and how electrons interact with light to move among energy levels
Explain how emission line spectra and absorption line spectra are formed
Identify the various types of spectra
Describe what ions are and how they are formed
Explain why the spectral lines of photons we observe from an object will change as a result of the object’s motion toward or away from us
Describe how we can use the Doppler effect to deduce how fast astronomical objects are moving through space
In-Class Worksheet: Class 9 - Learning from Spectra
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 2 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Wednesday, June 7.
Guidance: The equation for frequency and wavelength of a light wave is: c = f x λ, where c is the speed of light (3x108m/s), f is frequency (with units of inverse time, usually Hertz, or s-1), and the symbol lambda, λ, is the wavelength of light (with unit of distance).
The equation that relates a photon’s energy, E, to its frequency, f, is E=h x f, where h is called Planck’s constant, where h=6.626x10-34 Joule-seconds.
The energy levels of a hydrogen atom:
Part 1: Energy Levels and Photons
(OP1) a. If an electron in a hydrogen atom moves from energy level n=1 to level n=3, did the atom absorb or emit a photon?
(OP1) b. What is the difference in energy between levels n=3 and n=1?
(OP1) c. What is the frequency of a photon with the energy in part b?
(OP1) d. What is the wavelength of that photon? What part of the spectrum is that photon in?
(OP3) A hydrogen atom is excited with a photon in energy level n=3. What energy photon would be required to ionize that atom?
(OP2) Complete the following table by finding the difference in energy, whether a photon would have been absorbed or emitted for the change to occur, and what the wavelength of that photon would be.
Original level | Resultant level | Energy difference | Photon absorbed or emitted? | Photon wavelength |
n=5 | n=1 | |||
n=3 | n=5 | |||
n=1 | n=3 | |||
n=4 | n=3 |
Optional: Identify all the photon energies and wavelengths for the Lyman and Paschen series of transitions. Which parts of the spectrum do the Lyman and Paschen series affect?
Part 2: Doppler effect
(OP4) In Hydrogen, the transition from level 3 to level 2 emits a photon with a rest wavelength 652.6 nm. Identify the speed and direction of motion for stars where this line is observed at a wavelength of:
651.2 nm
653.4 nm
For each star above, is the light being redshifted or blueshifted?
(OP5) You just missed a green line train and now it is moving away from you. From astronomy class, you know that light from an object moving away from you should be redshifted, but the cars still look green. The train is moving at the average speed of trains on the B-branch, 3.17 m/s. Assume light reflected from the green part of the train is 550 nm.
What wavelength does the green light get shifted to?
What color is this wavelength?
Why don’t humans notice the Doppler effect on light in everyday situations?
(OP6) Astronomers observe a cloud of hydrogen gas and notice an emission line at a wavelength of 659.2 nm. They know that in a laboratory, that wavelength is measured at 652.6 nm.
Is the cloud of gas moving toward or away from Earth?
Is the cloud of gas redshifted or blueshifted?
How fast is the cloud moving along the line of sight to Earth?
If time allows: From measuring other lines in a Hydrogen cloud’s spectrum, an astronomer has found that the cloud is moving at 400 km/s away from Earth. They ask you if you can look at the spectrum and find if the cloud has an emission line at the wavelength of a photon emitted from the n=4 to n=1 transition. At what wavelength should you look? (Note, this is a multi-step problem.)
(Chapters 16.1, 16.2 [abbr.], 16.3) Power from the Sun
*Part 1 adapted from University of Indiana activity
Worksheet Topics: solar energy and lifetime, fusion energy, hydrostatic equilibrium
Chapters: 16.1, 16.2 (abbreviated), 16.3
Lesson Learning Objectives:
Identify different forms of energy
Understand the law of conservation of energy
Explain ways that energy can be transformed
Explain how matter can be converted into energy
Summarize the key nuclear reaction in the solar interior
Describe the state of equilibrium of the Sun
Understand the energy balance of the Sun
Explain how energy moves outward through the Sun
In-Class Worksheet: Class 10 - Power from the Sun
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 2 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Thursday, June 8.
Part 1:
Calculating the lifetime of the Sun (Adapted from University of Indiana activity)
The Sun begins with a “full tank” of hydrogen, and reaches its end when only half the hydrogen is converted to helium. To estimate the lifetime of the Sun we need to figure out how much fuel the Sun has, and the rate it is burning that fuel.
HINT: For estimates, use simple math and round off numbers. You may use a calculator, but should not need to. This is an “order of magnitude” calculation. Use scientific notation.
A. How much fuel does the Sun have?
The mass of the Sun is 2 x 1033 grams. Each gram contains about 6 x 1023 hydrogen nuclei. The Sun’s energy is produced by nuclear reactions in the core of the Sun, from the conversion of four hydrogen nuclei into helium. For each helium nucleus created,
5 x 10 -12 joules of energy are produced. (For purposes of an estimate, assume the Sun starts made entirely of hydrogen.)
How many joules of energy can the Sun produce in its lifetime? Remember that the Sun can only use half of its hydrogen, and that four hydrogen atoms are used to create each helium atom.
B. How much energy does the Sun produce each second?
The average amount of energy falling on the Earth each second from the Sun corresponds to the energy output of fourteen 100-watt light bulbs for each square meter at the Earth’s equator at noon. At the distance of the Earth, the energy from the Sun is 1400 watts per square meter or 1400 joules of energy per second per square meter (a watt is a unit of energy per second, a joule is a unit of energy).
This much energy flows outward from the Sun in each square meter of the surface of a sphere with a radius equal to the distance of the Earth from the Sun (1 AU, 1.5 x 108 km or 1.5 x 1011 meters). How much total energy does the Sun produce each second?
Compute the surface area of a sphere with a radius of the Earth’s orbit. The formula for the surface area of a sphere is A=4 π r2.
Multiply the area of the sphere in square meters by the energy per square meter per second (watts per square meter) that falls on the Earth, to compute the total energy output of the Sun each second.
C. Estimate how long it will take the Sun to run out of fuel. Divide the total energy the Sun can produce in its lifetime by the amount of energy it radiates each second to determine the number of seconds the Sun will shine.
Convert the length of time in from seconds to years (one year contains approximately
3 x 107 seconds).
In fact, the Sun will shine less than this amount of time, because it will burn hydrogen at a somewhat faster rate as it ages.
Part 2: Hydrostatic equilibrium and more fusion practice
(16.19) Earth’s atmosphere is in hydrostatic equilibrium. What this means is that the pressure at any point in the atmosphere must be high enough to support the weight of air above it. How would you expect the pressure on Mt. Everest to differ from the pressure in your classroom? Explain why.
(16.20) Explain what it means when we say that Earth’s oceans are in hydrostatic equilibrium. Now suppose you are a scuba diver. Would you expect the pressure to increase or decrease as you dive below the surface to a depth of 200 feet? Why?
(16.29) Estimate the amount of mass that is converted to energy when a proton (m = 1.67x10-27 kg) combines with a deuterium nucleus (m = 3.3435 x 10-27 kg) to form 3He.
(16.30) How much energy is released when a proton combines with a deuterium nucleus to produce 3He? (Hint: You found the mass converted in 16.29)
Optional: Suppose all of the matter in your body were suddenly converted into energy according to E=mc2. How much energy would be released? You can estimate a mass of about 75 kg. Compare this to the energy released by a 1-megaton H-bomb (4x1015 J).
Optional CHALLENGE (not on test): The pressure of the air is equal to the weight of a column of air above a unit area on the land surface. If the pressure on the surface of Earth is 10,332 kg/m2, what is the total mass of Earth’s atmosphere? (Hint: Use unit analysis. You will also need to know the radius of Earth, 6378 km, and the equation for the surface area of a sphere: SA=4πr2.)
(Chapter 15) The Sun and Solar Storms
*Adapted from Sun | NOVA Labs | PBS, makes use of NASA helioviewer tool, requires computers
Worksheet Topics: Sunspots, solar activity
Chapters: All of 15
Lesson Learning Objectives:
Explain how the composition of the Sun differs from that of Earth
Describe the various layers of the Sun and their functions
Explain what happens in the different parts of the Sun’s atmosphere
Describe the sunspot cycle and, more generally, the solar cycle
Describe the various ways in which the solar activity cycle manifests itself, including flares, coronal mass ejections, prominences, and plages
Explain what space weather is and how it affects Earth
In-Class Worksheet: Class 11 - The Sun and Solar Storms
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 2 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Monday, June 12.
Sun Lab from PBS Nova Labs
This activity will make use of an excellent tool from Nova Labs to look at images of sunspots on the Sun - including one from today! On your own time, you may want to explore some of the other resources available on this site for learning about the Sun.
Step 1: Visit: https://www.pbs.org/wgbh/nova/labs/lab/sun/ and click “CHALLENGE” to get started. Then select the first option: “Solar Cycle”
Step 2: The website will walk you through instructions for counting spots. You will be counting both individual sunspots and groups of sunspots.
Step 3: Count the number of spots and groups in the image. Record your answer here before going to the next step:
Groups _________ Spots ________
Step 4: Turns out counting can be hard! How did your results compare? Did you over or under count?
Step 5: Now do the next five images. Record your values for R
Image 1 | Image 2 | Image 3 | Image 4 | Image 5 |
Are your counts under or over the official (averaged) estimates? Why do you think this is?
Optional: Compare your counts with other members of your group.
Step 6: Answer: What makes counting sunspots difficult? Why is the official sunspot number an average from multiple scientists?
(OP) Step 7: Now select “open investigation” at the bottom left. (A better version of the same tool can be found here: https://student.helioviewer.org/) This will bring up near real-time solar data. On the top left, select “Sun spots” under “Make an observation.” How many groups and spots can you count today? (If you have events turned on, you can count more than just those flagged.)
Groups _________ Spots ________
(OP) Step 8: Now we will compare different types of observations of the Sun in the same area. Pick a sunspot group and keep track of that spot on the image. Switch to the “magnetic field” observation. Disturbances from the “typical” magnetic field are shown as white or black. Is there a disturbance in the magnetic field observation where you observed sun spots?
Now switch to the “Flares and active regions” observation. More active regions are brighter (whiter). Are there active regions in the area you observed sunspots?
Switching between the observation of sunspots and the observation of active regions, are regions where sunspots are present more or less active than regions without sunspots?
(OP) Step 9: Switch back to the “sunspots” observation. Just above the “make an observation” field is a field for “time step”. Select 1 year as the time step. Click through at least 11 years of sunspot observations on this day. Is there a notable difference in the number of sunspots in each of the observations taken over the last 11 years?
Optional/if time allows: Explore different types of observations of the Sun during the last few days, or over the last few years. Use this space to write down any observations.
(Chapters 8.1, 8.3, 8.4, 8.5) Climate Change
*Entirely original questions
Worksheet Topics: climate change, CO2 cycle, solar cycle, interpreting graphs
Chapters: 8.1, 8.3, 8.4, 8.5
Lesson Learning Objectives:
Specify the origin and effect of Earth’s magnetic field
Describe the chemical composition and possible origins of our atmosphere
Explain the difference between weather and climate
Explain the ways that life and geological activity have influenced the evolution of the atmosphere
Describe the causes and effects of the atmospheric greenhouse effect and global warming
Describe the impact of human activity on our planet’s atmosphere
Describe the evidence for recent impacts on Earth
Describe how impacts have influenced the evolution of life on Earth
Discuss the search for objects that could potentially collide with our planet
Outline the origins and subsequent diversity of life on Earth
Explain the scarcity of impact craters on Earth compared with other planets and moons
In-Class Worksheet: Class 12 - The Earth
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 2 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Tuesday, June 13.
Part 1: Climate Change
Figure 1: Based on air bubbles trapped in ice that froze at different points in the Earth’s history, scientists can measure the historic concentration of carbon dioxide in Earth’s atmosphere. Today, these measurements are taken directly.
What feature(s) do you notice in this plot?
The CO2 cycle can regulate CO2 levels in Earth’s atmosphere over time. Do you see evidence of this in Figure 1? Explain.
Figure 2: In blue, the levels of CO2 in the atmosphere (the same measure as in Figure 1). In gray is the amount of CO2 that humans have been emitting.
Compare the timescales (range on the x-axis) between Figure 1 and Figure 2. What is different about Figure 2?
What feature(s) do you notice in Figure 2?
Is there a trend between the total amount of atmospheric CO2 and the total amount of CO2 emissions?
Why did CO2 emissions start increasing in the mid-1800s?
Figure 3: This plot shows the total amount of power received by the Earth from the Sun in yellow. The average temperature on the surface of Earth is shown in red. The darker lines show an 11-year average while the thinner lines show the year-to-year variation.
What feature(s) do you notice in this plot?
Do you see evidence for the 11-year solar cycle in this plot? (Hint: look at the thin yellow lines.)
Is there a trend between the total solar irradiance and average temperature for at least some years? Which years?
Based on Figures 1, 2, and 3, what can you conclude about the cause of the rising temperatures over the last few decades?
Based on Figures 1, 2, and 3, what actions should humans take to not cause further climate change?
(If time allows) On the next page are some arguments made by people who don’t want to believe in climate change. Using evidence from the plots, how could you respond to these points?
The amount of CO2 in the atmosphere and the global temperature have always changed over time. Now is no different.
This is the coldest winter in years, that shows that global warming is a lie!
We’re probably just getting more light from the Sun than usual.
Even if the climate is changing, it’s not the fault of human activity.
(Chapters 14.3, 21.3, 21.4, 21.5, 21.6) Solar System Formation and Exoplanets
*Final activity makes use of Planet Hunters citizen science project, requires computer
Worksheet Topics: solar system formation, frost line, exoplanet orbits and transits, Planet Hunters
Chapters: 14.3, 21.3, 21.4, 21.5, 21.6 (only section on habitable exoplanets)
Lesson Learning Objectives:
Describe the motion, chemical, and age constraints that must be met by any theory of solar system formation
Explain the formation process of the terrestrial and giant planets
Trace the evolution of dust surrounding a protostar, leading to the development of rocky planets and gas giants
Evaluate evidence for planets around forming stars based on the structures seen in images of the circumstellar dust disks
Compare the indirect and direct observational techniques for exoplanet detection
Explain what we have learned from our discovery of exoplanets
Discuss the kinds of planetary systems we are finding around other stars
In-Class Worksheet: Class 13 - S.S. Formation and Exoplanets
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 2 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Wednesday, June 14.
Part 1: Solar System Formation
There are two main reasons why planets in the outer solar system grew to be larger and less dense than planets in the inner solar system. Let’s explore both:
Types of Material
This table will help you answer the following questions:
Material Type | Examples | Temperature below which material will condense | Relative abundance (by mass) | Rough estimate for density when solid |
Hydrogen and Helium gas | Hydrogen, helium | Very low, did not condense in nebula | 98% | N/A |
Hydrogen compounds | Water (H2O), methane (CH4), ammonia (NH3) | 150 K | 1.4% | 1 g/cm3 |
Rocks | Various minerals | 500-1300 K | 0.4% | 2.5 g/cm3 |
Metals | Iron, nickel, aluminum | 1000 - 1600 K | 0.2% | 7.9 g/cm3 |
(OP) What are hydrogen compounds? (Hint: Look at the molecular formula in the examples above.)
(OP) The “frost line” (also called the “ice” or “snow” line) occurs where the temperature of the solar nebula dips below 150 K. Why do scientists call this point the frost/ice/snow line?
(OP) Earth and the other terrestrial planets formed inside the frost line, where it was too hot for hydrogen compounds to condense but cool enough for rocks and metals to condense. What percentage of the solar nebula (by mass) was able to condense and be accreted within the frost line?
(OP) What percentage of the solar nebula (by mass) was able to condense and be accreted outside the frost line (where it was cold enough for hydrogen compounds to condense)?
(OP) How massive could Earth have become if it had been able to accrete hydrogen compounds in addition to rocks and metals? (Hint: Use equal ratios - % availableMEarth)
(OP) Why are the planets formed in the outer solar system less dense on average than planets formed in the inner solar system?
Amount of Material
Planets grew by accreting material along the path of their orbit about the Sun. Let’s calculate the length of that path for Earth and Saturn.
Guidance: The circumference of a path is C=2πR, where R is the radius. In the case of planets, the radius of its orbit would be the average distance, or semi-major axis, a. The semi-major axis in units of AU is related to the period, P, of the planet around Sun-like stars in units of years by: P2=a3.
What is the length of the path Earth follows around the Sun in units of AU? Recall, the period of Earth’s orbit around the Sun is 1 year.
What is the length of the path Saturn follows around the Sun in units of AU? The period of Saturn’s orbit around the Sun is 29 years.
Summary: Consider your answers to the previous sets of questions to answer:
Why did planets that formed in the outer solar system grow to be more massive than planets formed in the inner solar system? Base your answer on what you found above.
Part 2: Exoplanet orbits and transits
Guidance: The “depth” of a transit is the fraction of light from the star that is blocked by a transiting planet. The depth will be equal to the square of the ratio of the planet’s radius to a star’s radius: depth = (Rplanet/Rstar)2.
When measuring transits, we can identify the period of a planet based on the time between two transits. When the planet is orbiting a star that does not have the same mass as the Sun, we have to modify Kepler’s third law as: P2=a3/M, where P is the period in years, a is the semi-major axis in AU, and M is the mass of the star in units of solar masses. A solar mass, or M☉, is the mass of the Sun, and a useful unit for measuring masses of stars. So the mass of our Sun is 1M☉ and a star twice as massive as the Sun would be 2M☉. When using M☉ in P2=a3/M, you DO NOT plug in the mass of the Sun in kg, just like you don’t plug in the number of seconds in a year.
(21.25) Calculate the transit depth for an M dwarf star that is 0.3 times the radius of the Sun with a gas giant planet the size of Jupiter.
(OP) The M dwarf star has a mass that is 0.22 times the mass of the Sun. The Jupiter-like planet causes a transit to occur every 292 days. What is the semi-major axis of the Jupiter-like planet’s orbit?
(21.26) If a transit depth of 0.00001 can be detected with the Kepler spacecraft, what is the smallest planet that could be detected around a 0.3 Rsun M dwarf star?
(OP) Based on variations in the timing of an observed exoplanet transit around a star with a mass of 2 M☉, scientists predict that another planet should be present and orbiting at a distance of 2 AU. How frequent should transits from this second planet be? (Hint: transit frequency will be the period of this planet)
Optional - More practice:
(Remember: in the equation above, P should be in years.)
Mass of Star in M☉ | Period | Semi-major axis |
10 | 563 days | |
8 | 0.86 AU | |
3 | 250 days | |
0.5 | 3 AU | |
0.25 | 78 days |
Planet Hunters
Visit: https://www.zooniverse.org/projects/nora-dot-eisner/planet-hunters-tess (link on Blackboard)
(Optional) Make an account if you would like to keep track of work, or potentially get credit for helping find a new planet!
Complete the short tutorial.
Start looking for transits! Click and drag to indicate a potential transit.
After doing a few, you will hit a simulated light curve. You will know it’s a simulated curve if you get a pop-up after telling you how you did.
How did you do at spotting the transits in a simulated light curve?
(Chapter 30) Are we alone? (Drake equation)
*Inspired by The Drake Equation – What are the Chances of Extraterrestrial Life? — Information is Beautiful, from which numbers are sourced
Worksheet Topics: Drake equation
Chapters: 30.1, 30.2, 30.3, 30.4
Lesson Learning Objectives:
Discuss the assumption underlying the Copernican principle and outline its implications for modern-day astronomers
Understand the questions underlying the Fermi paradox
Describe the characteristics of a habitable environment
Identify where in the solar system life is most likely sustainable and why
Describe some key missions and their findings in our search for life beyond our solar system
Explain the use of biomarkers in the search for evidence of life beyond our solar system
Understand the various SETI programs scientists are undertaking
Describe the chemical and environmental conditions that make Earth hospitable to life
List efforts by humankind to communicate with other civilizations via messages on spacecraft
Describe some of the extreme conditions on Earth, and explain how certain organisms have adapted to these conditions
In-Class Worksheet: Class 14 - Are we alone?
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 2 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Wednesday, June 14.
Guidance: The Drake equation is: N = R* x fP x ne x fl x fi x fc x L. These variables are explained in the table below. Calculate your estimate (est.) for the number of communicating civilizations in the Milky Way by picking reasonable values (generally somewhere between the optimistic and skeptical estimates) for these variables.
Meaning | Open questions | Drake est. | Skeptic est. | Opti-mist est. | Your est. | |
R* | mean rate of star formation | Star formation rate varies as a galaxy ages so hard to tell what the current value is | 10 yr-1 | 7 yr-1 | 7 yr-1 | |
fP | fraction of stars that have planets | Will have a better estimate as we continue finding exoplanets Can all types of stars host planets? | 0.5 = 50% | 0.22 = 22% | 0.9 = 90% | |
ne | mean number of planets that could support life per star with planets (aka number of habitable planets per star) | Can all types of stars host habitable planets? What does habitable mean? How common are insulating atmospheres? Does life require water? Can life survive in environments that would seem impossible even for Earth extremophiles? Study of exoplanets will help us get better estimate | 2 | 0.01 | 0.3 | |
fl | fraction of life-supporting planets that develop life | What chance events are necessary for life to occur and how rare are they? How did life develop on Earth? How many planets with the right conditions won’t form life for whatever reason? Complete guess | 1 = 100% | 0.001 = 0.1% | 0.1 = 10% | |
fi | fraction of planets with life where life develops intelligence | What does intelligence mean? Is intelligence the natural outcome of evolutionary processes? Are there unknown barriers to developing intelligence? What are the odds of life developing past single-cell organisms? Complete guess | 0.01 = 1% | 0.001 = 0.1% | 0.01 = 1% | |
fc | fraction of intelligent civilizations that develop communication | Do they develop radio communication? Do they have a desire for wide communication? Is there a different way to communicate that we haven’t yet discovered? Complete guess | 0.01 = 1% | 0.01 = 1% | 0.01 = 1% | |
L | mean length of time that civilizations can communicate | How long, if ever, do intelligent civilizations broadcast advertising that they are out there? How frequent do they broadcast? (Earth has no current program to broadcast “we are here” despite having radio communications for 125 years). Complete guess | 104 years | 104 years | 107 years |
(OP1) Calculate the value of N, the number of communicating civilizations in the galaxy, for the skeptical, optimistic, and your estimates by multiplying each number together in the respective column. Make sure to use the fractional representation, and not the percentages. For example, the original Drake estimate would be:
N = 10 x 0.5 x 2 x 1 x 0.01 x 0.01 x 10,000 = 10
Meaning | Open questions | Drake est. | Skeptic est. | Optimist est. | Your est. | |
N | Number of communicating civilizations in galaxy | All open questions for each part of the equation | 10 |
(OP2) Based on your estimate, is it surprising that we have not found evidence of a communicating civilization yet?
(Chapter 7) The Solar System
Worksheet Topics: surface-area-to-volume ratio, radioactive dating (simple)
Chapters: 7.1, 7.2, 7.3 (optional: 7.4 for review of solar system formation)
Lesson Learning Objectives:
Describe how the objects in our solar system are identified, explored, and characterized
Describe the types of small bodies in our solar system, their locations, and how they formed
Model the solar system with distances from everyday life to better comprehend distances in space
Describe the characteristics of the giant planets, terrestrial planets, and small bodies in the solar system
Explain what influences the temperature of a planet’s surface
Explain why there is geological activity on some planets and not on others
Explain how astronomers can tell whether a planetary surface is geologically young or old (lab)
Describe different methods for dating planets
In-Class Worksheet: Class 15 - The Solar System
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 3 may include similar questions; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Wednesday, June 21.
Guidance:
Surface area of a sphere: A = 4 π R2
Volume of a sphere: V = 4/3 π R3
For radioactive dating: after one half life, half of the original, parent isotope will remain. The amount that decayed will be converted to the daughter isotope. Construct a simple table to track how much will have decayed over a few half-lives. If you prefer, you can also use an equation:
Surface area to volume ratio:
(OP) What is the surface area to volume ratio of Mars (radius = 3397 km)?
(OP) What is the ratio of the surface-area-to-volume ratios of Mars to Earth?
(OP) Which planet, Mars or Earth, will cool faster? How much faster?
(OP) Would you expect Mars to have more or less geological activity than Earth? Why?
Radioactive Dating:
(OP) A rock sample from Earth contains 2 grams of the radioactive parent isotope, Potassium-40 and 14 grams of the daughter isotope, Argon-40. The half-life of Potassium-40 is 1.31 billion years. How old is the rock sample?
(CP8.50b) [Carbon-14 Dating]
(OP) How many half-lives of Carbon-14 (5,730 years) have passed since the formation of Earth (4.5x109 years)?
(OP) What percent of Carbon-14 would remain in a rock that solidified around the time the Earth formed? (Use (½)(# of half-lives) to get the fractional value)
(OP) Can Earth’s age be established with Carbon-14 dating? Why or why not?
Optional: If 50 grams of Carbon-14 are originally present in a sample, how much will be left after 5 half-lives?
Optional: A rock sample from Earth contains 0.5 grams of the radioactive parent isotope, Potassium-40 and 1.5 grams of the daughter isotope, Argon-40. The half-life of Potassium-40 is 1.31 billion years. How old is the rock sample?
Optional: (7.36) A radioactive nucleus has a half-life of 5×108 years. Assuming that a sample of rock (say, in an asteroid) solidified right after the solar system formed, approximately what fraction of the radioactive element should be left in the rock today?
(Chapter 9) The Moon and Mercury
*Part 1 adapted from GEOLOGIC MAPPING OF THE MOON
Worksheet Topics: lunar and Mercurian geological features
Chapters: 9.1, 9.2, 9.3, 9.4, 9.5
Lesson Learning Objectives:
Discuss what has been learned from both manned and robotic lunar exploration
Describe the composition and structure of the Moon
Differentiate between the major surface features of the Moon
Describe the history of the lunar surface
Describe the properties of the lunar “soil”
Explain the process of impact crater formation
Discuss the use of crater counts to determine relative ages of lunar landforms
Summarize the current “giant impact” concept of how the Moon formed
Describe Mercury’s structure and composition
Explain the relationship between Mercury’s orbit and rotation
Describe the topography and features of Mercury’s surface
Summarize our ideas about the origin and evolution of Mercury
In-Class Worksheet: Class 17 - The Moon and Mercury
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 3 may include similar questions or concepts; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Thursday, June 22.
Part 1: Geological Mapping of the Moon
Adapted from LPI Education/Public Outreach Science Activities
Apollo 15 Landing Site:
Examine this image and use it to answer the following questions.
There are a number of indicators of whether one unit is superposed (on top of) on another unit. One of these indicators is called an embayment relation. This occurs when a unit is deposited in fluid form, for instance as lava flows or as sediment that settled out of water. In this case the younger unit embays the older unit, or in other words, it fills in low spots of the older unit at the contact. When one feature embays another it often looks like the water of a bay flowing around land features, and this is where the term embay comes from. Look carefully at the contact between the mare and terra for an embayment relation. On this basis, which unit (mare or terra) is younger? Why?
Now look at the number of craters on each of the two units. Do the crater densities show the same relative ages of the mare and highlands as you just determined? If not, can you think of possible reasons why?
The major structure in this photograph is the curvy trough, called Hadley Rille. What would you call this structure? (Hint: Look over the definitions in the glossary)
What are the relative ages of the mare and Hadley Rille? What principle did you use to recognize this age relation?
Look at the large, round impact crater alongside Hadley Rille. This is Hadley crater. What are the relative ages of Hadley crater and Hadley Rille? Why?
Now, reconstruct the geologic history of the area surrounding Hadley Rille by numbering the following units and structures in the order in which they formed (unit 1 formed first).
______ Hadley Crater
______ Mare
______ Highlands
______ Hadley Rille
Based on everything you’ve learned about the mare, what kind of rock do you think it might be (lava flows, sediments, coal, etc.). What is necessary for you to know for sure?
Look at the slightly brighter region of mare away from the contact with the highlands (terra). This region contains an abundance of very small craters with noncircular shapes. Compare and contrast their appearance (their size, shape, and relief) with that of Hadley crater, by listing their similarities and differences.
Are these unusual craters older or younger than the mare? Why?
How might the origin of the unusual craters have differed from the origin of Hadley crater? Can you think of a process that could have formed them?
Optional: Can you make a list of things that would be different if Earth had no Moon? Don’t restrict your answer to astronomy and geology. Think about our calendars and moonlit romantic strolls, for example.
Part 2: Mercury
(OP) Why does the presence of a magnetic field suggest some part of Mercury’s core is still molten?
Take a look at images of “scarps” or cliffs on Mercury:
(OP) Indicate the direction to the Sun on the image on both images.
(OP) Were the scarps formed before or after the impacts that caused most of the craters on Mercury’s surface? Why?
(OP) The Moon has too little iron, Mercury too much. How can both of these anomalies be the result of giant impacts? Explain how the same process can yield such apparently contradictory results. (More room to write on next page)
Glossary
Geologic unit - A group of rocks/ an area with the same definite characteristics.
Contact - The boundary between different geologic units.
Structures - Physical features that affect the shapes of geologic units, such as channels and faults.
Channel - A narrow, winding depression generally carved by flowing liquid like water or lava.
Fault - A large break in a planet's crust, across which the crust has moved.
Relative age - The age of a geologic unit or structure relative to another geologic unit or structure. The unit or structure is "older than" or "younger than" another one.
Geologic history - The basic history of how the geologic units in an area were formed and what happened over time. Scientists use two principles to decode the geologic history of an area from an overhead photograph or a geologic map:
Principle of superposition - Whatever unit lies on top of, or superposes, other units is the youngest unit. The bottom unit had to be there first in order for a younger unit to form on top.
Principle of cross-cutting relations - Structures such as faults and channels which disrupt geologic units, are younger than the units they disrupt, or cross-cut.
Studying geology using pictures is called photogeology. It is different from studying geology on the ground, because all the observations are made from a distance.
Impact craters are circular, raised-rimmed depressions formed by explosions that occur when comets and asteroids collide with the Moon. Impact craters provide an important tool for determining the relative ages of different units: Older units have more impact craters on them. and younger units have fewer impact craters. The number of craters in an area of specified size is called crater density; thus, older units have a higher crater density than younger units.
(Chapter 10) Venus and Mars
*This activity refers to the CORGI tool, which received mixed feedback when used in class, so I included the activity in the worksheet format instead
Worksheet Topics: atmospheric weight (Venus and Mars), water on Mars
Chapters: Chapter 10.1, starting at “Rotation of the Planets”, 10.3-10.5; Overview | Venus – NASA Solar System Exploration (subbed for the longer 10.2)
Lesson Learning Objectives:
Compare the basic physical properties of Earth, Mars, and Venus, including their orbits
Describe the general features of the surface of Venus
Explain why the surface of Venus is inhospitable to human life
Describe the general composition and structure of the atmosphere on Venus
Explain how the greenhouse effect has led to high temperatures on Venus
Discuss the main missions that have explored Mars
Compare the volcanoes and canyons on Mars with those of Earth
Describe the general conditions on the surface of Mars
Describe the general composition of the atmosphere on Mars
Explain what we know about the polar ice caps on Mars and how we know it
Describe the evidence for the presence of water in the past history of Mars
In-Class Worksheet: Class 18 - Venus and Mars
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 3 may include similar questions or concepts; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Friday, June 23.
Guidance: A Pascal is a unit of pressure that is equal to 1 Newton of force per square meter. Recall that force = mass x acceleration. The acceleration in this case is that due to gravity on a planet: a=GM/R2. See Blackboard for full example using Earth.
Part 1: Atmospheric Weight
The atmospheric surface pressure on Venus is estimated to be about 9.2x106 Pa. Venus has a radius of 6,052 km and a mass of 4.9x1024 kg. The following parts will walk you through computing the total mass of the atmosphere.
What is the acceleration due to gravity at Venus’ surface?
What is the total mass of the atmosphere per square meter?
What is the total surface area of Venus?
What is the total mass of the atmosphere of Venus?
How does this compare to the mass of Earth’s atmosphere (about 5x1018kg)? (Use a ratio.)
Repeat the same steps as in 1., but for Mars. Mars has an average atmospheric surface pressure of just 600 Pa. Mars has a radius of 3,390 km and a mass of 6.39x1023 kg. What is the total mass of the atmosphere of Mars?
(optional, practice for exam) Why has Venus experienced a runaway greenhouse effect, but not Earth?
(optional, practice for exam) In what way is the high surface temperature of Venus relevant to concerns about global warming on Earth today?
Part 2: Claim, Evidence, and Reasoning: Liquid water on Mars
The claim is that Mars, now mostly dry and geologically dead, once had liquid water on its surface.
Various missions, both orbiters and landers/rovers, have uncovered evidence that supports this claim. Use reliable sources on the Internet (e.g., your textbook, NASA, ESA, other space agencies, Scientific American, Science.org, The Planetary Society, etc.) to identify at least three distinct pieces of evidence that liquid water once existed on Mars. Explain why that piece of evidence supports the claim. Be sure to cite both where you got the information and where the original source (which rover/lander/orbiter). You may complete this activity with a CORGI guide, or on the following pages. If done as a Corgi guide, submit the link on Blackboard.
Evidence #1:
Reasoning (how does this evidence support the claim?):
Source:
Evidence #2:
Reasoning:
Source:
Evidence #3:
Reasoning:
Source:
Optional - Other supporting evidence:
Conclusion: Does the evidence support the claim that there was once liquid water on Mars? Explain.
(Chapter 11) The Giant Planets
Worksheet Topics: storms, wind speeds, rate of change
Chapters: 11.1, 11.2, 11.3
Lesson Learning Objectives:
Provide an overview of the composition of the giant planets
Chronicle the robotic exploration of the outer solar system
Summarize the missions sent to orbit the gas giants
Describe the basic physical characteristics, general appearance, and rotation of the giant planets
Describe the composition and structure of Jupiter, Saturn, Uranus, and Neptune
Compare and contrast the internal heat sources of the giant planets
Describe the discovery and characteristics of the giant planets’ magnetic fields
Discuss the atmospheric composition of the giant planets
Describe the cloud formation and atmospheric structure of the gas giants
Characterize the giant planets’ wind and weather patterns
Understand the scale and longevity of storms on the giant planets
In-Class Worksheet: Class 19 - The Giant Planets
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 3 may include similar questions or concepts; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Monday, June 26.
Guidance: Wind speed is given by: speed = distance/time. The distance will be the circumference of the storm at the distance where you are calculating the speed. Circumference of a circle is C=2πR, where R is the radius.
Rate of change is given by: rate = change/time.
(11.27) Calculate the wind speed at the edge of Neptune’s Great Dark Spot, which was 10,000 km in diameter and rotated in 17 d.
(OP) Example 11.1 gives the answer for the wind speed at the edge of Jupiter’s Great Red Spot. The Great Red Spot rotates once every 6 days and has a radius of 10,000 km. What is the wind speed halfway between the edge and the center of the spot (5,000 km from the center)?
(OP) According to the book, in 1979 the Great Red Spot had a diameter of 25,000 km and in 2000 had a diameter of 20,000km. Assuming the rate of shrinkage remains the same, in what year will the Great Red Spot have a diameter equal to Earth? In what year will the Great Red Spot disappear? Do you think a constant rate of shrinkage is a good assumption?
(CP 11.52) [Disappearing Moon]
(a)
(b)
(Chapter 12) Rings, Moons, Dwarf Planets
Worksheet Topics: jovian moons, orbital resonance, dwarf planets
Chapters: 12.1, 12.2, 12.3, 12.4, 12.5
Lesson Learning Objectives:
Briefly describe the system of moons around each of the jovian planets
Describe key characteristics of the Galilean Moons, Titan, Triton and Charon
Explain how tidal forces generate the geological activity we see on Europa and Io and the tidal locking of Pluto and Charon
Compare the orbital characteristics of Pluto with those of the planets
Describe information about Pluto’s surface deduced from the New Horizons images
Describe the two theories of planetary ring formation
Explain how the rings of Uranus and Neptune differ in composition and appearance from the rings of Saturn
Describe how ring structure is affected by the presence of moons
In-Class Worksheet: Class 20 - Moons, Rings, Pluto
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 3 may include similar questions or concepts; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Tuesday, June 27.
Guidance: An orbital resonance is when two orbits have periods that are perfect fractions (e.g. ½). Kepler’s third law for objects orbiting a different mass than the Sun is: P2=a3/M, where P is in years, a is in AU, and M is in solar masses.
Part 1: Orbits and Resonances
(12.26) The average distance of Enceladus from Saturn is 238,000 km; the average distance of Titan from Saturn is 1,222,000 km. How much longer does it take Titan to orbit Saturn compared to Enceladus? Is there a resonance?
(OP) Is there an orbital resonance relationship between Saturn’s moon Titan (period = 15.945 days) and Hyperion (period = 21.277 days)? What is it?
(Optional, 12.24) Saturn’s A, B, and C Rings extend 75,000 to 137,000 km from the center of the planet. Use Kepler’s third law to calculate the difference between how long a particle at the inner edge and a particle at the outer edge of the three-ring system would take to revolve about the planet.
(Optional, OP) The following table provides information about the density of the Galilean moons and their orbital distance.
Moon | Orbital Distance (km) | Density (g/cm3) |
Io | 4.21x105 | 3.57 |
Europa | 6.71x105 | 2.97 |
Ganymede | 1.07x106 | 1.94 |
Callisto | 1.88x106 | 1.86 |
Is there a trend between the orbital distance of a Galilean moon and its density?
What might explain the cause of this trend?
Part 2: Dwarf Planets
4. (OP) Choose one of the recognized dwarf planets (besides Pluto) and use credible sources to find out how and when it was discovered, how it was named, and anything interesting about it. The recognized dwarf planets, not including Pluto, are: Ceres, Haumea, Eris, and Makemake.
(Chapter 13) Asteroids and Comets
Worksheet Topics: mass of asteroids & Kuiper belt, comets
Chapters: 13.1, 13.2, 13.3, 13.4
Lesson Learning Objectives:
Describe the composition, classification, and orbits of the various types of asteroids
Discuss what was learned from spacecraft missions to several asteroids
Recognize the threat that near-Earth objects represent for Earth and possible defensive strategies
Characterize the general physical appearance of comets
Explain the range of cometary orbits
Describe the size and composition of a typical comet’s nucleus
Discuss the atmospheres of comets
Explain the proposed fate of comets that enter the inner solar system
Describe the composition of the Oort cloud and Kuiper Belt
In-Class Worksheet: Class 21 - Asteroids and Comets
Instructions: Work with your classmates to understand the problems and write your answers below. Exam 3 may include similar questions or concepts; write your steps or notes on this worksheet so it can serve as a study guide.
Due: You may turn this worksheet in to your instructor at the end of class, electronically via Blackboard, or at the beginning of next class. This worksheet will be considered late after 9:00AM on Wednesday, June 28.
Guidance: The volume of a sphere is given by: V = 4/3 π R3. Density is: density=mass/volume.
(13.26) The mass of the asteroids is found mostly in the larger asteroids, so to estimate the total mass we need to consider only the larger objects. Suppose the three largest asteroids—Ceres (1000 km in diameter), Pallas (500 km in diameter), and Vesta (500 km in diameter)—account for half the total mass. Assume that each of these three asteroids has a density of 3 × 103 kg/m3 and calculate their total mass. Multiply your result by 2 to obtain an estimate for the mass of the total asteroid belt. How does this compare with the mass of the Oort cloud (~1027 kg from Example 13.1)?
(13.27) Make a similar estimate for the mass of the Kuiper belt. The three largest objects are Pluto, Eris, and Makemake (each roughly 2000 km). In addition, assume there are eight objects (including Haumea, Orcus, Quaoar, Ixion, Varuna, and Charon, and objects that have not been named yet) with diameters of about 1000 km. Assume that all objects have Pluto’s density of 2 × 103 kg/m3. Calculate twice the mass of the largest 11 objects and compare it to the mass of the main asteroid belt.
(OP) Label each part of the diagram below:
(OP) Using the numbers on the diagram on the previous page, describe what each component is and how it forms.
(Optional) Describe, in order, the changes that happen to a comet as it gets closer to the Sun.
(Optional) Make a Venn diagram or otherwise compare and contrast the similarities and differences between asteroids and comets.
(Optional, CP 12.47) [Adding up asteroids]