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Seeds - Foundations of Astronomy 14/e (Homework)

James Finch

Astronomy, section 1, Fall 2019

Instructor: Dr. Friendly

Current Score : 20 / 31

Due : Monday, January 28, 2030 00:00 EST

Last Saved : n/a Saving...  ()

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  • Instructions

    In this Sample Assignment, you will see several of the question types found in Foundations of Astronomy, 14th ed., by Michael A. Seeds and Dana Backman and published by Cengage Learning.

    Many of these question types provide scaffolding to build skills and confidence in the use of simple algebra, geometry, and proportional reasoning to solve astronomy problems. Many provide targeted feedback to address specific student errors. Finally, the Virtual Astronomy Laboratories provide rich interaction elementssamples from two different VALs appear at the end of this sample assignment.

    Question 1 is an Animation Tutorial (AT). Animation Tutorials present rich concepts using animations, interactive figures, or other multimedia elements, and then assess student learning with a variety of item types.

    Questions 2 & 3 are Optimized Problems (OP). Optimized Problems offer randomized parameters and provide targeted feedback to students who have incorrectly answered any part of the problem.

    Question 4 is a Problem (P). Problems appear in the back of textbook chapters, though numbers and contextual details may be randomized for a customized learning experience.

    Question 5 is a General Problem (GP). General Problems are multiple-select (MS) items, in which several choices may be correct. They invite students to synthesize descriptive knowledge about a particular topic.

    Question 6 is a Tutorial (Tut). Tutorials coach the student through every step of the most essential astronomical problems. These highly structured, scaffolded learning activities give strong support to the student with emerging or dormant quantitative-reasoning skills.

    Questions 7 & 8 are Review Questions (RQ). Generally adapted from the textbook, Review Questions provide opportunities for test prep and formative assessment.

    Questions 9 & 10 are sections of two Virtual Astronomy Laboratories (VAL). Each can be assigned as a standalone activity or as part of a larger learning experience. VAL incorporates real astronomical data, simulations, and other interactive elements, offering students the opportunity to experience astronomy as a scientist. Targeted feedback guides students in revising any incorrect answers. This demo assignment allows many submissions and allows you to try another version of the same question for practice wherever the problem has randomized values.

Assignment Submission

For this assignment, you submit answers by question parts. The number of submissions remaining for each question part only changes if you submit or change the answer.

Assignment Scoring

Your last submission is used for your score.

1. 3/3 points  |  Previous Answers SeedsFoundations14 17.AT.001. My Notes
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Raisin Bread

Choose a raisin as your vantage point. As the bread bakes, how do the movements of the nearest and farthest raisins compare?
     Correct: Your answer is correct.

Yes, because of how the bread expands.
How is the raisin bread analogy like the expansion of the universe?
     Correct: Your answer is correct.

Yes! Galaxies move apart as space expands.
The farther a raisin is from the selected raisin, the faster it moves away.
     Correct: Your answer is correct.

Right. The distance to the farthest raisin keeps increasing more than the distance to nearer raisins.
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2. 2/3 points  |  Previous Answers SeedsFoundations14 17.OP.003. My Notes
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Calculate the wavelength shifts, Δλ (in nm), of the ionized calcium H line (λ0 = 393.5 nm) in the spectra of the Ursa Major cluster and the Hydra cluster.
Images of five galaxy clusters are labeled with their speed, distance, and the name of the constellation containing that cluster. Each cluster is arranged next to an image of its spectrum. Two vertical lines show the unshifted position of calcium lines for each spectrum, and an arrow is drawn horizontally to the right from this position to the actual position of the calcium, showing redshift. The five image pairs are arranged vertically, starting with the smallest shift at the top to the largest shift at the bottom.
  • A cluster in Virgo, at a distance of 17 Mpc, moves at 1200 km/s.
  • A cluster in Ursa Major, at a distance of 215 Mpc, moves at 15,000 km/s.
  • A cluster in Corona Borealis, at a distance of 310 Mpc, moves at 22,000 km/s.
  • A cluster in Boötes, at a distance of 550 Mpc, moves at 39,000 km/s.
  • A cluster in Hydra, at a distance of 860 Mpc, moves at 61,000 km/s.
Ursa Major Incorrect: Your answer is incorrect. seenKey

19.7
Use the Doppler shift formula to solve for the wavelength shift. nm Hydra Correct: Your answer is correct. seenKey

80

 nm
How are velocity, wavelength shift, and distance related?
     Correct: Your answer is correct.
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3. 0/1 points  |  Previous Answers SeedsFoundations14 18.OP.017. My Notes
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What diameter telescope would a lifeform need to resolve the Sun-Jupiter separation (d = 5.2 AU) at 550 nm when viewed from the orbit of Barnard's Star, 1.8 pc away? (Give your answer in m.)
Incorrect: Your answer is incorrect. seenKey

0.0392
Use the small angle formula to solve for the angular separation of the Sun and Jupiter from this distance. Then use the telescope resolution equation to determine the diameter needed to resolve this separation. m
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4. 1/1 points  |  Previous Answers SeedsFoundations14 9.P.009. My Notes
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1/1
 
If a main-sequence star has a luminosity of 8000 Lalchemist sun symbol, what is its spectral type?
An H-R diagram is shown with the names of specific stars plotted. This diagram has 4 axis labels, one on each side of the plot.
  • The bottom horizontal axis is labeled Temperature (K) and it begins at 40,000 K on the left to 1000 K on the right.
  • The top horizontal axis is labeled "Spectral type" and is sectioned at certain intervals. The region between 40,000 kelvin and around 30,000 kelvin is labeled O. The region between 30,000 kelvin and 10,000 kelvin is labeled B. The region between 10,000 kelvin and 8000 kelvin is labeled A. The region between 8000 kelvin and 6000 kelvin is labeled F. The region between 6000 kelvin and 4500 kelvin is labeled G. The region between 4500 kelvin and 3500 kelvin is labeled K. The region between 3500 kelvin and 1000 kelvin is labeled M.
  • The vertical axis on the left is labeled Luminosity in L/LSun. It ranges from 10−5 at the bottom and ends at 106 at the top.
  • The vertical axis on the right is labeled Absolute Magnitude in MV and it ranges from 15 at the bottom to −10 at the top.
  • The luminosity classes of stars, which are based on the appearance of absorption lines in the spectra of stars, are shown as lines that go across the H-R diagram. Luminosity class Ia is a line that begins at around 20,000 K at a luminosity of a little over 105 L/LSun and it moves to the right nearly horizontally until it gets to about 3000 K. This line indicates that bright supergiants are the most luminous stars. Luminosity class Ib is a curve that begins at around 32,000 K, moves down and to the right, and reaches a minimum at around 5000 K and a luminosity of 5 ✕ 103 L/LSun, where it begins to curve up and to the right and ends at about 3000 K and luminosity of 8 ✕ 104 L/LSun. Luminosity class II begins at about 20,000 K and luminosity of 5 ✕ 103 L/LSun, curves slightly down and to the right, and reaches a minimum at approximately 8000 K and luminosity of 103 L/LSun, whereupon the line remains nearly horizontal before it ends at about 3000 K. Luminosity class III begins at about 11,000 K and luminosity of 103 L/LSun, moves down and to the right, and reaches a minimum at about 5500 K and luminosity 30 L/LSun, whereupon it curves up and to the right to end at 3000 K and luminosity of 103 L/LSun. Luminosity class IV begins at about 11,000 K and luminosity of 500 L/LSun, moves down and to the right, and reaches a minimum at around 5000 K and luminosity of 80 L/LSun, whereupon it remains nearly horizontal until it ends at about 3000 K. Main sequence stars, including the Sun, are luminosity class V stars. This line begins at around 30,000 K and 3 ✕ 104 L/LSun and moves down and to the right in a straight line until about 3000 K and luminosity of 0.5 L/LSun. The Sun is noted to be at 5500 K and 1 L/LSun.
     Correct: Your answer is correct.
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5. 1/1 points  |  Previous Answers SeedsFoundations14 9.GP.004. My Notes
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This is a General Problem. General Problems are multiple-select items, in which several choices may be correct. They invite students to synthesize descriptive knowledge about a particular topic.

Based on what you know about the masses of stars, select all of the correct statements from the following list.
Correct: Your answer is correct.

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6. 3/9 points  |  Previous Answers SeedsFoundations14 18.Tut.002. My Notes
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Tutorial
What is the angular separation of the Sun and Jupiter if observed from Proxima Centauri at a distance of 1.3 pc. (Assume Jupiter is located 5.2 AU from the Sun.)
arc seconds
What diameter telescope would you need to resolve the separation between the Sun and Jupiter at a wavelength of 550 nm?
m
What would the apparent magnitude of the Sun be from this distance
(M = 4.8)?
A horizontal coordinate line labeled "Apparent magnitude (mV)" ranges from −30 on the left to 30 on the right. Arrows indicate that values to the left are brighter and values to the right are fainter. The following points are labeled on the line:
  • Sun at −27
  • Full moon at −12
  • Venus at brightest at −4
  • Sirius at −1
  • Polaris at 2
  • Naked eye limit at 6
  • Hubble Space Telescope limit at 30
Is the Sun visible with the naked eye at this distance?
    
Part 1 of 3
To calculate the angular size, we use the small angle formula:
θ
2.06 ✕ 105
 = 
d
D
We first need to convert the distance between the Sun and Jupiter into parsecs.
dpc
 =
dAU 
1 pc
2.06 ✕ 105 AU
dpc
 = (No Response) seenKey

2.52e-05

 pc
Now solving the small angle formula for the angular separation:
θ =
2.06 ✕ 105
dpc
Dpc
 θ = (No Response) seenKey

4

 arc seconds
Part 2 of 3
We use the telescope resolution formula to determine the diameter.
α = 2.06 ✕ 105
λ
diameter
Solving for diameter:
diameter =
2.06 ✕ 105
λm
α
 diameter = (No Response) seenKey

0.0283

 m
Part 3 of 3
We can use the magnitude-distance formula to determine the apparent magnitude of the Sun from this distance.
mV − MV = −5 + 5 log(D) mV = −5 + 5 log(D) + MV mV =
Using the figure below, we see that the naked eye limit is around 6 magnitudes.
A horizontal coordinate line labeled "Apparent magnitude (mV)" ranges from −30 on the left to 30 on the right. Arrows indicate that values to the left are brighter and values to the right are fainter. The following points are labeled on the line:
  • Sun at −27
  • Full moon at −12
  • Venus at brightest at −4
  • Sirius at −1
  • Polaris at 2
  • Naked eye limit at 6
  • Hubble Space Telescope limit at 30
Is the Sun visible with the naked eye from this distance?
    


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7. 1/1 points  |  Previous Answers SeedsFoundations14 3.RQ.003. My Notes
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You are located in St. Louis, MO, United States. Your friend is located in Buenos Aires, Argentina. You see a waning gibbous in your clear night sky. What phase, if any, will your friend see if the night sky in Buenos Aires is also clear?
     Correct: Your answer is correct.
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If you looked back at Earth from the Moon, what phase would Earth have when the Moon is in the following phases?
An photograph of the Earth, as seen from the Moon. The Earth is in the gibbous phase.
(a) full
Correct: Your answer is correct. seenKey

new

(b) new
Correct: Your answer is correct. seenKey

full

(c) first quarter
Correct: Your answer is correct. seenKey

third quarter

(d) waxing crescent
Correct: Your answer is correct. seenKey

waning gibbous
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Welcome to Lab 5: Planetary Geology

Even though the planets in our solar system have different physical properties in terms of radius, mass, and density, they often have similar characteristics with respect to planetary geology. By thoroughly studying the geology of Earth, we can leverage that knowledge to understand conditions on other planets.
Images of the four terrestrial planets side by side:
  • Mercury,
  • Venus,
  • Earth,
  • and Mars.
This lab will focus on the geology of Earth, since this is the planet that we know the most about. We will study the techniques that are used to learn about Earth's inner structure, and the processes that have caused Earth to evolve since it formed. While studying the terrestrial planets, our approach will utilize comparative planetology, noting the similarities and differences of these planets.
  • After conducting this Virtual Astronomy Laboratory, the learner will be able to …
    1. LO5.1 … explain how the surface of Earth gives clues to the structure of the interior.
    2. LO5.2 … describe the different regions of the interior of Earth.
    3. LO5.3 … list the lines of evidence (on Earth) favoring the theory of plate tectonics.
    4. LO5.4 … compare and contrast the surfaces and interiors of the other terrestrial planets with those of Earth.
  • Waves generated by earthquakes travel through Earth and carry information about the interior to the surface.
    We can learn about the interior of Earth by studying the transmission of seismic waves through Earth. These waves are most often produced by earthquakes, but can also be caused by impacts or explosions.
    Seismologists identify two different types of relevant seismic waves:
    • P waves (pressure or compression waves) are longitudinal waves. This means that the medium through which the wave travels moves back and forth in the same direction the wave itself is traveling. (Sound waves are longitudinal waves.)
    • S waves (shear waves) are transverse waves, meaning that the medium moves at right angles to the wave's direction of propagation. (Radio waves are transverse waves; so is the wriggle that you make when you and a friend hold opposite ends of a rope and one of you shakes it up and down.)
    Generate and observe each type of wave using the simulator below.
    When an earthquake occurs, both P waves and S waves propagate through Earth. Both types of waves may undergo reflection and refraction at the boundaries of layers that have different densities. Both waves also refract (or bend) as they travel through Earth; this is due to the increase in density with depth.
    In general, P waves move faster than S waves. Another difference between the two is that pressure (compression) waves can travel through either solid or liquid material, whereas shear waves cannot propagate through liquids.
    Seismograms are collected from all over the world when earthquakes occur. They allow us to study whether or not both types of waves have been detected. They also reveal the relative arrival times of the two types.
  • The interior of Earth is divided into four concentric layers: the crustThe outermost solid shell of a rocky planet or planetoid, the mantleThe layer of dense rock and metal oxides that lies between the molten core and the surface of Earth, the outer (or liquid) coreThe fluid layer of dense metals inside Earth, below the mantle and above the solid core, and inner (or solid) coreSolid metallic material at the very center of Earth.
    From P and S wave measurements and other data, seismologists can identify four distinct regions of Earth's interior. From the center outward, they are:
    • Solid (Inner) Core: a hot region, largely composed of nickel and iron, that extends from the center of Earth to a radius of about 1,200 km.
    • Liquid (Outer) Core: a liquid nickel- and iron-rich region that extends from a radius of 1,200 km to about 3,500 km.
    • Mantle: a lower-temperature region primarily composed of silicates, which are less dense than nickel and iron. The mantle extends halfway through Earth, almost to Earth's surface.
    • Crust: the brittle, low-density outer layer of Earth, 20 to 70 km thick (depending on location). The crust also is composed mainly of silicates.
    Region Percent Mass Temperature Density
    Crust 0.5% 500 K 2.5 g/cm3
    Mantle 67.0% 3,000 K 4.5 g/cm3
    Outer Core 30.8% 5,200 K 10.9 g/cm3
    Inner Core 1.7% 5,700 K 12.9 g/cm3
    Four layers of Earth are shown as concentric filled circles. From outside in the layers are:
    1. crust,
    2. mantle,
    3. outer core,
    4. and inner core.
  • This simulation allows you to measure seismic waves on an unexplored planet in order to determine the structure of the interior.
    To use it, click on each of the three probes and place them at different distances from the "top" of the planet. Note that a vertical bar appears on the graph whenever you move one of the probes. This shows how far the probe lies from the planet's "north pole," in units of degrees of arc (180° is the "south pole" at the "bottom" of the globe).
    Next, click the Make Waves button to create a burst of seismic waves from the top of the planet.
    As the probes detect the S waves from this burst, their arrival times will appear as functions of delta, the angular distance from the pole.
    Move the probes to three new delta values and repeat the process. Do this a few more times, until you have probed at least 12 different positions ranging from delta = 0 to delta = 180.
    If no data point appears at a delta value where a probe is located, that doesn't necessarily mean you've made an error. Rather, the seismic wave may have failed to reach that position. (Based on what you read under the heading Seismic Waves above, can you guess why?)
    Once you have completed the graph, click on the Next Page button (→) to interpret your data. Instructions continue below.
    Once you have turned to Page 2 of the Unknown Planet Interior activity, note the Core Radius and S Wave Velocity sliders; your data (+ symbols); and a red line, tilting upward—the predictions of a mathematical model for wave propagation through the unknown planet.
    Adjust the Core Radius slider until you mark off the area where you were unable to detect seismic waves. The existence of this shadow zone implies that a liquid core exists at the center of the planet, and the size of this zone determines the radius of this fluid zone.
    Now adjust the S Wave Velocity slider until the red curve lies as close as possible to your data points. The S wave velocity that gives the best fit is your measurement of the wave speed within the planet's solid portion. Wave speeds can help planetary geologists determine the density of the solid material.
    (a)
    The Core Radius that best fits my data is km.
    (b)
    The S Wave Velocity that best fits my data is km/s.
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10. 5/6 points  |  Previous Answers SeedsFoundations14 VAL.4.002. My Notes
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The Earth's Magnetic Field

The photo below shows an auroral display seen from Landmannarlaugar, Iceland. Many aurora-seekers travel to Iceland because the island nation is so close to the Earth's north magnetic pole. Magnetic-field lines converge there, concentrating the flow of charged particles and boosting the odds of seeing the Northern Lights.
But that's not the only benefit of Earth having a strong, well-ordered magnetic field. Because magnetic fields exert forces upon moving charges, we on Earth are largely shielded from the solar wind—especially intense during solar storms—and from rare but high-powered cosmic rays: atomic nuclei hurtling across space from sources such as supernova explosions and black holes. This shielding greatly reduces the risks of radiation damage and mutation in terrestrial life forms.
In this section we'll learn about the forces that allow magnetic fields to shape the aurorae while shielding the Earth from hazardous particles.
A photograph of an auroral display seen from Landmannarlaugar, Iceland.
  • The Earth's magnetic field exerts forces on moving charged particles, and this shields nearly all of the Earth's surface from the solar wind and from cosmic rays.
    The Earth has a powerful magnetic field because currents of iron-nickel alloy are circulating in its liquid core. When the electrically charged particles of the solar wind encounter the Earth's magnetic field, they experience a force called the Lorentz force.
    In a nutshell, charged particles in a magnetic field experience a force that is perpendicular to both the direction of the field and the direction of the particles' motion.
    The strength of the force depends on the amount of electric charge, how fast the charges are moving, and the strength of the magnetic field. Particles that have no charge do not experience this force. Nor do particles that are stationary, regardless of whether or not they are charged.
    The following activity allows us to explore the nature of this unusual but essential force—a force that operates in toys, cars, power tools, and anything else with an electric motor.
    An illustration of the magnetic field of the Earth. Field lines emanate from the south magnetic pole and converge at the north magnetic pole.
    This conceptual illustration shows selected magnetic-field lines emanating from one magnetic pole and converging on the other. This dipole field pattern is similar to that of a simple bar magnet.

  • Magnetic Forces

    The Magnetic Forces simulation allows us to explore the effects that magnetic fields have on moving charged particles. Note that you can change the direction of the magnetic field and the type of particles entering the magnetized region, both by using radio buttons near the bottom of the frame. in addition, sliders allow you to modify the magnetic field strength and the particle energy (related to speed). Note that you can adjust the sliders by using your keyboard's left and right arrow keys, but first you must click on the dot at the end of the slider you wish to manipulate.
    Take a minute to familiarize yourself with the functions of the simulation. Then conduct the exercises that appear below.
    Use the Magnetic Force simulation to complete the table below. For Particle Deflection Direction, indicate whether the particles move left, right, or neither (undeflected). Feel free to adjust the magnetic field strength or particle energy to make the effects easier to study. (For example, electrons feel magnetic forces much more strongly than do protons, since they have equal amounts of charge—sign aside—but very different masses.)
    Particle Type Magnetic Field
    Direction     		Particle Deflection
    Direction
    Protons Into Screen
    Out of Screen Correct: Your answer is correct. seenKey

    Right
    Electrons Into Screen Correct: Your answer is correct. seenKey

    Right
    Out of Screen Correct: Your answer is correct. seenKey

    Left
    Neutrons Into Screen Correct: Your answer is correct. seenKey

    Undeflected
    Out of Screen Correct: Your answer is correct. seenKey

    Undeflected
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