Return to SSI Education Modules Page"Galileo Calling Earth"
Teacher Notes
Answers to Review Questions:
Figure 3. What do you see as the result? What type of landform might this be?
A cone-shaped mountain. Ask your students what kind of mountain might be represented. The cone shape is typical of some types of volcanoes.
Figure 4. Now what do you see? Do you see anything that you were unable to detect in the first picture?
A cone-shaped mountain with a gray cloud above it. Shadows on the mountain and the cloud appear to be oriented toward the right from the summit. Now ask your students to consider the possible origin for the mountain and the cloud. This feature could be an actively erupting volcano, with the wind blowing from the left to the right.
How many shades of gray does this represent?
28 = 2x2x2x2x2x2x2x2 = 256 shades of gray.
Figure 5. Now what are you able to see in the picture?
More shading gives detail on the mountain and in the cloud. In particular, there is a dark zone with a central bright stripe down the flank of the mountain. This image suggests not only that the inferred volcano is 'smoking' (active), but that lava is erupting from the summit and flowing down its flank into the foreground.
Ask your students to think about this last image as being taken of some unknown planet or moon. What could be deduced from this picture about the planetary object?
a. The surface is made of some material strong enough to form a mountain; this could be rock or frozen water; thus it would be similar to the terrestrial ('Earthlike') planets such as Mars or Earth's Moon, or similar to the moons of the outer planets. Eliminated would be the gas giant planets, such as Jupiter, because they lack solid surfaces.
b. The object must have an internal heat source, such as radioactive elements or internal tides, producing enough heat to lend to volcanism. In addition, it is volcanically active today. Only Earth, Io (a moon of Jupiter), and Triton (a moon of Neptune) are known to have active volcanoes.
c. The object has an atmosphere and active winds. Venus, Earth, Mars, Triton, and Titan (a moon of Saturn) are the only known solid-surface objects that have significant atmospheres and winds.
Extension Question Answer:
1. Bit rate describes the speed at which data can be transmitted. Currently, the low-gain antenna is able to transmit to Earth at 10 bits/sec. This figure is lower than expected because of the failure of the high-gain antenna to unfold.
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Top Level "Bringing Jupiter to Earth"
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This module was written by Brian Exton (National Optical Astronomy Observatories, Tucson AZ).
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Galileo Solid State Imaging Team Leader: Dr. Michael J. S. Belton
The SSI Education and Public Outreach webpages were originally created and managed by Matthew Fishburn and Elizabeth Alvarez with significant assistance from Kelly Bender, Ross Beyer, Detrick Branston, Stephanie Lyons, Eileen Ryan, and Nalin Samarasinha.
Last updated: September 17, 1999, by Matthew Fishburn
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