Arizona State University
AST 113 Lab10
Lab 10
Question 1
1 out of 1 points
Lab 10 Figure 1 - Click Image to Enlarge
Finding Saturn
We will start this lab by finding the planet Saturn. In this lab, you will use
...
Arizona State University
AST 113 Lab10
Lab 10
Question 1
1 out of 1 points
Lab 10 Figure 1 - Click Image to Enlarge
Finding Saturn
We will start this lab by finding the planet Saturn. In this lab, you will use
the Starry Night software to learn about and answer Questions related to
Saturn and its moons. You should have a general familiarity with Starry
Night before attempting this portion of the lab. To become more familiar
withStarry Night, access the tutorial exercise within the software.
Begin this activity in Phoenix, Arizona, at sunset on June 1, 2014. To do this,
select Phoenix, United States from the Viewing Location drop-down
menu. Then enter the date in the Time and Date field and click
the Sunset button. Look toward the west by clicking the W viewing direction
button located on the button bar across the top of your screen or by pressing
the W key on your keyboard. The screen will pan toward the west. Select a
playing speed of 300 times normal time by selecting 300x from the Time
Flow Rate drop-down menu. Click the Stop time mode button when the sun
has set, the stars have come out, and the dusk is almost over. Finally, click
the Constellations button to show the constellations.
After you have had a chance to explore.Lab 10 Figure 2 - Click Image to Enlarge
Finding Saturn (cont.)
Click the Find tab on the left side pane. A list of planets should appear. Those
that are highlighted are currently up in your evening sky. Those that are not
highlighted are not up in the sky at this time. We want to find the planet
Saturn. Double-click or right-click Saturn (Control-click for Mac) and
select Centre. This action pans the screen and centers Saturn. You can now
zoom in on Saturn either by using the Zoom control at the far right of the
control panel or by right-clicking (Control-clicking for Mac) Saturn on
the Find tab and selecting Magnify.
Click the information icon (i) next to Saturn on the Find tab to read a short
description of the planet Saturn. Then select the Info tab on the left side pane
and click the plus sign (+) icon (a gray arrow for Mac) to expand each of the
information categories. Use the information on the Info tab to answer the
Questions.
After you have had a chance to explore, use the Starry Night software
to answer these Questions.
What is the radius of Saturn?
km Question 2
1 out of 1 points
Given that Earth’s radius is 6378 km, what percentage of Earth’s
radius is Saturn’s radius?
Question 3
1 out of 1 points
What is the mass of Saturn in relation to Jupiter?
Question 4
1 out of 1 points
What is the angular size of Saturn as seen from Earth?
Selected
Answer: 19.0
arcseconds
Correct
Answer: 19.0
arcseconds
Question 5
1 out of 1 points
What is Saturn’s orbit size?
Question 6
1 out of 1 points
What is the length of a sidereal day for Saturn?
Question 7
1 out of 1 points
What is the length of a solar day for Saturn?
Selected
Question 8
1 out of 1 points
How long is a year on Saturn?
Question 9
1 out of 1 points
In which constellation is Saturn on June 1, 2014?
Question 10
1 out of 1 points
What is Saturn’s current apparent magnitude?
Question 11
1 out of 1 points
How far is Saturn currently from Earth?
Question 12
1 out of 1 points
For a superior planet, the distance at opposition is calculated by subtracting the Earth’s
distance from the Sun (1 au) from the planet’s orbit size. What is the distance at
opposition?
Question 131 out of 1 points
The distance at conjunction is calculated by adding the planet’s
orbit size to Earth’s distance from the Sun (1 au). What is Saturn’s
distance at conjunction?
Question 14
1 out of 1 points
Lab 10 Figure 3 - Click Image to Enlarge
Saturn's Moons
For the next section of the lab, we will use the Starry Night software to learn
about Saturn's moons. We will look at Saturn's largest moon—Titan—and at a
small but interesting moon—Mimas. Titan has a methane atmosphere that
obscures its surface. The organic molecules on this moon might indicate
conditions suitable for life. Mimas is interesting because of a very large impact
crater a quarter of the diameter of the moon itself. This is one of the largest
crater-to-moon size ratios in the solar system and could have shattered Mimas
into pieces.
Click the plus sign (+) icon (a gray arrow for Mac) next to Saturn in
the Find side pane. This action lists Saturn's moons. Click the first checkbox
forTitan; click the plus sign (+) next to Smaller Moons and then click the
first checkbox for Mimas. This action labels the moons on your screen. To seeboth the planet and the moons, you might have to pan out by using the Zoom
control buttons at the far right of the control panel. Keep in mind that the
moons might be out of sight behind the planet itself. In that case, use
the 3000x time speed setting on the control panel to move time forward so
that both moons are clearly visible. Remember that as you move time forward,
you might have to click the Horizon and Daylight buttons on the button
bar as needed.
Let's take a closer look at Titan and Mimas. Double-click Titan in the list. This
action centers Titan on your screen. Use the Zoom control buttons to get a
close-up view. Click the information icon (i) in the left side pane to read a short
description of this moon. Then select the Info tab on the left side pane and
click the plus sign (+) (a gray arrow for Mac) to expand the different
information categories. Repeat these steps to view Mimas. Try to see the
exceptionally large impact crater for which Mimas is so famous.
Note how small the ratio of Titan's mass is when compared to the mass of
Saturn itself. Although Titan is the second largest moon in the solar system, its
mass ratio is very small and has little gravitational effect on Saturn. In
contrast, Earth's moon-to-planet mass ratio is one of the largest in the solar
system at 0.0123 (or 1.23%).
Note how Saturn's rings do not extend beyond a few multiples of Saturn's
radius. Compare this with our own Moon, whose distance from Earth is over 60
times Earth's radius. When a large moon is too close to its parent planet, the
tidal forces are so great that they try to rip the moon apart. The critical
distance, known as the Roche limit, is the closest distance a large moon can
exist in orbit around a planet without being ripped to shreds. Moons are thus
generally found outside the Roche limit; ring systems are usually found within
the Roche limit.
The origin of Saturn's rings is still under debate. The particles from which they
are made might either have tried to come together over the ages to form a
moon, but have been unable to do so because they are within the Roche limit.
A large moon, meteoroid, or comet might have entered the Roche limit and
been ripped to shreds, scattering the debris that currently comprises today's
ring system. Statistically, Saturn's original ring system should have dissipated
by now, and people Question how the rings are being maintained or
rejuvenated.
After you have had a chance to explore, use the Starry Night software
to answer these Questions.
What is the radius of Titan?
Question 15
1 out of 1 points
Given Earth’s Moon’s radius of 1737 km, what is Titan’s radius in
multiples of Earth’s Moon’s radius (divide Titan’s radius by Earth’s
Moon’s radius)?
Question 16
1 out of 1 points
Question 17
1 out of 1 points
Given that the mass of Earth’s Moon is 0.0123 Earth masses,
what is the mass of Titan in multiples of Earth’s Moon mass?
Question 18
1 out of 1 points
What is the orbit size of Titan in astronomical units?
Question 19
1 out of 1 points
What is the orbit size of Titan in kilometers (where 1 au= 1.5 x
108 km)?
Question 20
1 out of 1 points
How long is a sidereal day on Titan?
Question 21
1 out of 1 points
How long is a solar day on Titan?
Question 22
1 out of 1 points
What is the radius of Mimas?
Question 23
1 out of 1 points
Given Earth’s Moon’s radius of 1737 km, what is Mimas’s radius
in multiples of Earth’s Moon’s radius (divide Mimas’s radius by
Earth’s Moon’s radius).
Question 24
1 out of 1 points
What is the mass of Mimas?
Question 251 out of 1 points
Given that the mass of Saturn is 5.68 x 1026 kg, what is the mass
of Mimas as a ratio of Saturn’s mass?
Question 26
1 out of 1 points
What is the orbit size of Mimas?
Question 27
1 out of 1 points
What is the orbit size of Mimas in astronomical units (where 1
au= 1.5 x 108 km)?
Question 28
1 out of 1 points
How long is a sidereal day on Mimas?
Question 29
1 out of 1 points
How long is a solar day on Mimas?
Question 30
1 out of 1 points
Lab 10 Figure 4 - Click Image to Enlarge
Saturn's Satellite Orbital Characteristics
For the next section of the lab, we will use the Starry Night software to observe
some of Saturn's satellite orbital characteristics.
Zoom back out so that you can see Saturn and its moons. Click
the Labels button on the button bar to see the names of other moons. DoubleclickSaturn in the Find side pane to center on Saturn; zoom in and out a bit to
see how many moons you can observe. Select the 3000x time speed on the
control panel and watch the moons orbit Saturn. Click
the Daylight and Horizon buttons as needed. For best results (so that the
smaller moons will be displayed), Saturn should cover about a third of your
screen. Watch the moons orbit Saturn for a bit. The tilting is a result of ourlocal perspective. You can remove this effect by selecting View/Ecliptic
guides and then choosing The Ecliptic. Why do the moons move from side to
side rather than in circles around Saturn? This also has to do with perspective.
Because Saturn's satellite orbital plane lies along the ecliptic (the plane of our
solar system), we can observe Saturn only from the side.
Let's take a closer look at satellite orbits. To better visualize the satellite orbital
motion, click both the first and second set of checkboxes in the Findside pane
for Titan, Mimas, and a few other moons of your choosing; this action labels
and traces their respective orbits around Saturn. Again, you might have to
adjust the Zoom control to better view the orbital plane. To get a feel for how
fast these moons move around in their orbits, slowly move time forward using
the 300x or 3000x time speeds and observe the orbital motion as it would
appear as seen from Earth.
To see some different viewing perspectives of the moons, right-click (Controlclick for Mac) Saturn and select Graph Elongation of Moons. The graph
shows the angular separation between numerous moons and Saturn. Titan is
graphed, but Mimas is not. To add Mimas to the graph, right-click (Control-click
for Mac) Mimas either in the Find side pane or on the screen and select Start
Graphing. Similarly, you can remove moons from the graph by right-clicking
(Control-clicking for Mac) them and selecting Stop Graphing.
To calculate maximum elongation, turn on the Angular Separation tool by
selecting it from the cursor tool drop-down menu. Center your pointer
onSaturn and then click and drag to the farthest extent of the moon's orbit
(make sure that the orbit trace is on). The angular separation will be displayed.
You can move time forward with the time speed controls on the control panel,
or you can simply grab the graph and drag to the left or right. You can expand
the horizontal resolution of the graph by clicking the plus and minus indicators
at the top left of the graph. To increase the vertical resolution, grab the bottom
of the graph and pull down. By moving the graph back and forth to look for
different alignments, you can answer the following Questions.
After you have had a chance to explore, use the Starry Night software
to answer these Questions.
What is the amount of time it takes for a complete cycle of Titan?
days Question 31
1 out of 1 points
What is the maximum elongation of Titan?
Question 32
1 out of 1 points
What is the amount of time it takes for a complete cycle of
Mimas?
Question 33
1 out of 1 points
What is the maximum elongation of Mimas?
Question 34
1 out of 1 pointsLab 10 Figure 5 - Click Image to Enlarge
Saturn's Orbital Characteristics
We will use the Starry Night software to observe the characteristics of Saturn's
orbit. Hide the graph from the top of the screen by dragging its lower border
up until the graph disappears. Return to using the Adaptive cursor by
selecting it from the drop-down cursor tool menu.
Use the Zoom control at the far right of the control panel to zoom back out to
full-scale view. Right-click (Control-click for Mac) Saturn and selectOrbit. This
action shows Saturn's orbital path as seen from Earth. Notice that you can see
only a portion of Saturn's orbit because part of it is blocked by the horizon.
Click the Horizon button on the button bar to hide Earth's horizon for a
complete view of Saturn's orbit. Also click the Daylight button to turn off
daylight. You should still be locked on to Saturn. If not, right-click (Control-click
for Mac) the planet Saturn and select Centre. To maintain the proper
perspective, select Ecliptic Guides from the View menu and then select The
Ecliptic.
Enter June 1, 2014 in the Time and Date field and click the Sunset button.
Note the constellation that Saturn is in on this date. Select 1 days from
the Time Flow Rate drop-down list and click the Play time mode button. If
you need to slow down or speed up, adjust the Time Flow Rate field as
needed.
You should see Saturn locked in the center of your field of view as it moves
across the starry background. The planet should complete a full revolution in
less than a minute. Click the Stop time mode button when Saturn returns to
the original constellation and note the date of this event. Use this information
to answer the Questions.
After you have had a chance to explore, use the Starry Night software to
answer these Questions.In what constellation is Saturn on June 1, 2014?
Question 35
1 out of 1 points
In what constellation is Saturn on January 22, 2015?
Question 36
1 out of 1 points
On what date does Saturn return to the constellation it was in on
June 1, 2014?
Question 37
1 out of 1 pointsLab 10 Figure 6 - Click Image to Enlarge
Flying to Saturn
In this final section of this lab, we will explore from Saturn's surface. Let's see
what a day (technically referred to as a solar day) would be like on Saturn. The
easiest way to experience a solar day is by watching a sunset, taking note of
the date and time, then watching another consecutive sunset, and calculating
the time difference between the two events. For the purposes of this exercise,
make sure that the date is set to June 1, 2014, click the Sunrise button, and
turn off planet labels and elliptical tracks. If Sunrise is in the afternoon, this is
the wrong sunrise - there are two of them on this date. Manually set the time
to 7 am and click the sunrise button again. You should get something in the
morning.
Right-click (Control-click for Mac) on Saturn and select Go There from the
menu. Note: You can animate the journey by first deselecting the Only
animate intra planet changes checkbox
under File/Preferences/Responsiveness. Be sure that your horizon is turned
on so that you see the photorealistic surface panorama.
View from the surface of Saturn by selecting Other from the Viewing
Location drop-down menu and then selecting The Surface of, Saturn from
the View From drop-down menu. Click the W viewing direction button on the
button bar or press the W key on the keyboard. Next, select 1 minutefrom
the Time Flow Rate drop-down list and click the Play time mode button.
When the Sun is near setting, click the Stop button. Use the Step
Forward and Step Backward time mode buttons until you see the Sun just
starting to set. You might have to select a smaller unit of time until the Sun is
just touching the horizon. Note the date and time of this event. Continue on to
the next sunset, note the time, and calculate the time difference between the
two events. This difference is the length of a solar day on Saturn. Record this
information (you will need it to answer the Questions).If you are unable to see the Sun to the west during sunset, first click
the Sunset button; click the checkbox to the left of the Sun in the Find side
paneto label the Sun; then pan to the left (SW) or right (NW) until you see the
Sun. If you still have trouble locating the Sun, right-click (Control-click for Mac)
the Sun in the Find side pane and select Centre. You will have to unlock the
Sun before continuing with this activity. The easiest way to unlock is to simply
grab the sky (click and hold the left mouse button) and then move the mouse a
little bit in any direction.
The solar day is not the same as the sidereal rotation period of a planet. This is
because the solar day takes into account both the rotation of the planet and
the revolution of the planet around the Sun. Your calculation of a solar day can
now be compared to the length of a sidereal day found in the Info side pane
earlier in this activity.
To determine the revolutionary period, or a planet's "year," we will return to
the solar system view. From the Favourites menu on the left side of the
screen (not the favourites menu on the top), select C-The Planets/Outer
Planets/Outer Solar System. Select 1 Days from the Time Flow Ratedropdown list (or something slightly slower), click the Play time mode button, and
note the time it takes for the planet to return to its original position (you might
have to increase the number of days depending on the speed of your
computer). You might find it easiest to align the planet to the furthest left or
right before starting. Write down your observation (you will need it to answer
the Questions). Or just mark the position of saturn with your finger, and play
the animation until it comes back to your finger.
(Note: If you used the Favourites Menu on the top of the screen, you will have to set
up the solar system view manually. To see the solar system view manually, remember
to 1) Go to the surface of the sun; 2) set your latitude to 89.9 degrees; 3) select
statioinary view (or else you will spin with the sun and get the wrong answer); 4)
increase your elevation above the sun until you are about 50 AU above the north pole
of the sun. )
After you have had a chance to explore, use the Starry Night software
to answer these Questions.
When did the first sunset take place (make sure that your date and time were
set at the first sunrise on June 1, 2014 about 7 am)?
Question 38
1 out of 1 points
When did the second sunset take place (make sure that your date
and time were originally set at sunrise on June 1, 2014)?
Question 39
1 out of 1 points
What is the length of a solar day on Saturn based on the date and
times you observed for the sunsets?
Question 40
1 out of 1 points
Assuming a start date of June 1, 2014, in what month does Saturn
complete its first full revolution?
Question 41
1 out of 1 pointsAbout how long is a year on Saturn?
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