Cursor Understanding About Investigating Ice T Worlds in the Outer Plan- O

Home , Charon (moon)

Exploring Ice I MAIN MENU IN THE SOLAR SYSTEM N V

SCIENCE & LITERATURE 2 L E CONCEPT OVERVIEW 3 S

PRE K–GRADE 2 CONCEPTS 3 T

GRADE 3–GRADE 5 CONCEPTS 3 I G LESSON SUMMARY & OBJECTIVES 4 A

STANDARDS 5 E T

ESSENTIAL QUESTION 6 I

ACTIVITY QUESTION 6 N

BACKGROUND 7 G

ACT OUT THE SCIENCE 10 I

MATERIALS 14 C S

DEMONSTRATION 15 E

PRE K–GRADE 2 15 W GRADE 3–GRADE 5 16

MAIN ACTIVITY 18 O R

PREPARATION 18 S

TEACHING TIPS 19 L D WARM-UP AND PRE-ASSESSMENT 20 S PROCEDURES 20 DISCUSSION AND REFLECTION 25

CURRICULUM CONNECTIONS 25 O ASSESSMENT CRITERIA 26 RESOURCES 27

PHOTO GALLERY N D I R E This lesson develops pre- C cursor understanding about investigating ice T worlds in the outer plan- O

etary regions that can R

help us explain more Y about the Solar System. Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

SCIENCE & LITERATURE

“Life beneath the ice-covered oceans of “Today, most of Pluto’s long-held secrets Jupiter’s moon Europa will appear remain secrets—guarded by the depths increasingly likely and before the century of distance between us and that ancient, is half way through, large marine creatures icy little world. Hubble delivered a will be discovered when the ﬁrst robot glimpse of the pinkish little ice-ball probes drill through Europa’s ice, ornament to us, temptingly close now, revealing an entire new biota.” but still too maddeningly far.

— Sir Arthur C. Clarke, To see the Solar System’s ninth sister as “2099…The Beginning of History” she really is, we must go to her. And in Greetings, Carbon-Based Bipeds! PRINT amazingly, our species has developed the will, and the way, to do just that. “All these worlds are yours—except EUROPA. Attempt no landings there.” So guard your secrets while you can, — Sir Arthur C. Clarke, Pluto! We are coming.” — Alan Stern, and Jacqueline Mitton, 2010: Odyssey Two Pluto and Charon: Ice Worlds on the Ragged Edge of the Solar System

2 Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

CONCEPT OVERVIEW This lesson develops precursor PRE K–GRADE 2 CONCEPTS understanding about investigating ■ There are many small icy, rocky worlds ice worlds in the outer planetary in the outer Solar System, such as regions that can help us explain more Pluto/Charon. about the Solar System. ■ Jupiter’s moon Europa is covered with Concepts: ice and is thought to have an ocean of water beneath its icy surface. ■ Outer planets

■ Ice worlds GRADE 3–5 CONCEPTS ■ Photometry ■ There are many small icy, rocky worlds in the outer Solar System, such as This lesson provides concrete Pluto/Charon, Neptune’s moon, Triton, experiences of: and the Kuiper Belt Objects. ■ Enacting stories that connects literature to ■ science related to ice worlds. Small icy worlds in the outer system are remnants of the formation of the Solar ■ Viewing and interpreting space-based System. images of ice worlds. ■ Scientists familiar with ice on Earth notice ■ Investigating ice on outer planetary many similarities to the appearance of sea ice worlds. ice on Europa—suggesting that an ocean exists beneath its icy surface.

■ The appearance of the surface of an icy world provides clues to interior processes. PRINT ■ In addition to water ice (frozen H2O), there are other ices on the surface of outer planetary worlds.

3 Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

LESSON SUMMARY & OBJECTIVES Once thought to be scarce, water ice appears Objective 1: Notice that the outer Solar in abundance as a constituent of ancient ice System is the home of many ice worlds. worlds that populate the outer region of the Neptune’s moon Triton, the planet Pluto Solar System, the region of Pluto/Charon and and its moon Charon, and the Kuiper Belt the Kuiper Belt Objects orbiting at distances objects beyond are small icy, rocky worlds of 50 to 100 AU from the Sun. The large and short-period comets. outer planets have captured ice worlds that may have formed early in the history of the Objective 2: Notice that the surface Solar System, notably Neptune’s Triton and features of ice worlds are indicators of Jupiter’s Europa. active processes, both on the surface and in the interior. Scientists are alert to surface activity by examining reﬂected light at various wavelengths. Europa is especially interesting because of the very strong evidence for an ocean beneath the icy surface. Images of Europa’s surface returned by the Galileo spacecraft have given clues to the interior workings of Europa.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

STANDARDS BENCHMARKS: NSES: 4A The Physical Setting: The Universe Content Standard E Science and GRADES 3–5, PAGE 63 Technology: Understanding about science ■ Telescopes magnify the appearance of and technology some distant objects in the sky, including GRADES K–4, PAGE 138 the Moon and the planets. The number of ■ Tools help scientist make better stars that can be seen through telescopes observations, measurements, and is dramatically greater than can be seen by equipment for investigations. They the unaided eye. help scientists see, measure, and do things that they could not otherwise see, measure, and do.

5 Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

ESSENTIAL QUESTION ACTIVITY QUESTION What is the importance of outer What do the surface features of ice worlds planetary ice worlds? tell us about active processes? How does the abundance of ice worlds affect What can we learn about the Solar System scientist’s view of the Solar System? How by considering the formation of ices on does the presence of ice and sub-surface outer planetary worlds? What observations oceans on a world like Europa affect our about water ice and other ices on ancient thinking about where to look for life in the worlds in the outer Solar System can we Solar System? record? What can we say, draw, or write about outer planetary ice worlds?

6 Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

BACKGROUND Our understanding of distant ice worlds Scientists are studying the patterns of light in the outer Solar System is based on reflected by Pluto/Charon to determine observation through ground-based and whether its tenuous atmosphere indicates space-based telescopes as well as spacecraft. active change processes. So far, data These objects are so distant that even the suggests minimal activity. best images are still very dim, even when observed through the Hubble Space Telescope. Nevertheless, unlocking the mystery of these primeval icy worlds may tell us more about the story of how the Solar System formed. How do space scientists know the composition of dim and distant objects in the Solar System? Planetary objects such as Europa, Triton, Neptune’s moon Triton is another interesting Pluto, and the Kuiper Belt Objects are small, ice world. Ground-based photometry data dim, and distant from the Earth. None of from Triton does indicate active processes, these objects are visible to the naked eye. indicating changes in the atmosphere that Even through high-powered telescopes, suggest some kind of seasonal change. these objects appear as tiny points of light, without features. So how do astronomers Photometry and Spectroscopy: and planetary scientists figure out what these The Information in the Light Photometry is the art and science of worlds look like and are made of? Basically, extracting information from light. All of they look at these objects using ever more PRINT these small outer planetary worlds receive light-sensitive instruments to analyze the the incident light of the Sun. Each object information contained in the reflected light. absorbs some of the light and reflects the Pluto and Charon can be considered as a rest. The measurement of the ratio of the binary system. amount of reflected light compared to the sunlight is called albedo. For example, Earth has an albedo of 0.38, which means that Earth reflects 38% of the sunlight back out into space.

7 Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

Radar telescopes act like light flash Occultations: Readings of Filtered Starlight attachments on a camera. Just as a flash Occasionally, Pluto and Charon pass directly illuminates the object to be imaged, a radio in front of a star. This is called an occultation, telescope beams radio waves that bounce off a hiding of the star behind the planetary planetary objects and the reflected radar object. By comparing the unobstructed bounces back. Radar albedo is the ratio of the starlight signal with the light that filters amount of reflected radar compared to the through the tenuous atmospheres of beamed radar. Pluto/Charon, we have learned that Pluto Spectroscopy looks at patterns of emissivity has water, ammonia and methane ices and and reflectivity of different elements and that Charon is mostly water ice. Pluto is still compounds. Stars emit light; planetary an object for ground-based exploration: objects reflect light. By comparing patterns even students can observe Pluto/Charon and of reflected light with objects of known take photometric data. In early 2006, NASA composition, scientists can infer what an launched a mission called New Horizons to object is made of, at least at the surface. explore Pluto/Charon and the Kuiper Belt Sensitive digital instruments called objects beyond. charge-coupled devices (CCD) can be used Europa to observe objects in greater detail, limited Europa is one of Jupiter’s four largest by the resolution available, by changing the moons. The astronomer Galileo first saw photon measurements into charged signals Europa through his telescope back in 1610. that read as pixels. These pixels are the At first the public was skeptical. They photometric data that scientists examine to thought Galileo’s moons were mere bubbles infer what the surface looks like and what in the flawed lenses. But as telescopes the object is made of. advanced in quality, the four Galilean moons PRINT were consistently observed, showing Jupiter and its moons to be a kind of miniature Solar System. In fact, Galileo’s discovery helped persuade the European public to accept that the Earth went around the Sun.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

Back in the 1970s, Earth-based telescopic Europa’s rosy glow might be explained by photometric data showed that Europa was the presence of bacteria. covered with ice. Essentially, this was done Eventually, planetary scientists would like to with long-distance radar astronomy. By return to Europa for a closer look. The next sending out a radio signal and letting it step would be to send an orbiter back to bounce back, investigators retrieved basic Europa equipped with a radar sounder. spectral signatures that identified the Radar is electromagnetic energy that has surface as composed of nearly pure long wavelengths that go through ice, but frozen water: ice! are reflected by water. The orbiter would In 1979, NASA’s Voyager spacecraft sent identify locations where we might be able back the first views of surface features to melt through to explore beneath the ice. showing Europa’s smooth icy surface, Then we could select places where we crisscrossed by fracture-like features might send a Lander, perhaps a Cryobot to hundreds of miles long. melt through the ice—or a Hydrobot, a submarine robotic explorer to see what the From 1995 to 2003, the Galileo spacecraft sent back spectacular close-up images and oceans of Europa might reveal. other readings that gave us a detailed look at a surface that resembles ice-covered areas on Earth. Analysis has revealed evidence for movement of ice floes, absence of massive cratering (suggesting a relatively young surface no older that 30 million years), a tenuous oxygen atmosphere (perhaps a product of interaction with Jupiter’s intense PRINT magnetosphere), and remnants of salts consistent with ocean-water evaporation (perhaps ice volcanoes, geysers, or cratering could explain such salt slicks). The most exciting implication is the high probability that an ocean lies beneath the icy surface—surface features most resemble features of sea ice on Earth. Europa is a candidate for astrobiological exploration, exploring for the possibility of past or present life. Some scientists suggest that

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

ACT OUT THE SCIENCE STORY Narration and mime activity: Move- ment Integration Mediating Experience Based on accounts drawn from various versions of Ovid’s Metamorphoses, this story of Europa moves from the Roman myth to the contemporary science. From classic Greek myth, the Roman poet Ovid retold how Jupiter appeared in the form of a bull to sweep Europa off her feet, then taking her to the island of Crete to found the Minoan dynasty.

The Story of Europa Retold by Richard Shope

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

Narrative Movement Concept

From his balustrade on Mt. Leaning, looking out over Link the mythical power of Olympus, Jupiter looked out the distance the Roman God Jupiter, to over the world. the gravitational power of the planet Jupiter

He noticed a group of young Select three or four girls and These characters will people picking ﬂowers and boys, as those who pick transform later to become gathering wood in a pasture ﬂowers and gather wood, Europa’s ice surface, ocean on a hillside near the shore, and invite three or four boys and rocky mantle later on… as they watched over their and girls to become the cattle that were grazing cattle (humorously) upon the green grass.

Jupiter noticed the beautiful Invite an outgoing girl to play Europa in their midst and he the part, invent gestures to got an idea. convey her beauty (humor is ﬁne)

Jupiter sent his messenger, Fleet-footed messenger, Later becomes a Europa Mercury, to coax the cattle running in slow motion, then orbiter down from the hillside, gestures toward the cattle to closer to the shore, so that move them toward the Europa and her friends “sea,” then stands to the side would be sure to follow.

Then mischievously, Jupiter The character of Jupiter PRINT transformed himself into a transforms himself, taking handsome bull, with magniﬁ- on the movements of a cent horns and a gentle face. handsome bull

Europa and her friends Garlands are crowns and noticed the bull and began necklaces of ﬂowers strung to place garlands around together his neck.

Soon Europa and the bull The two mimewalk together were walking hand in hoof along the shore.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

Narrative Movement Concept

Europa decided to ride the Europa stands a foot or so bull. The bull waded out into behind Jupiter the Bull as if the sea, then started to to ride. swim out far from the shore.

Europa became alarmed. Europa grabs as if there With one hand she grabbed were reins a horn and with the other As Jupiter and Europa Europa waved back to her “swim” away from the friends who were now shore, friends and cattle clambering over the rocky motion wildly shore calling out to her.

Too late now to swim back, Jupiter and Europa “swim” Europa was taken all the away out into the audience, way to Crete, a rocky island and then return to where surrounded by the sea. they began. Transforming to reveal his Jupiter turns back into himself, true form, Jupiter then returns to Mt. Olympus; returned to Mt. Olympus. Europa gestures like a queen Though far from home, of the people (in the audience) Europa became a greatly loved leader of the Minoan people who lived there.

Just as the mythical Europa Around Europa, the cattle This image is to resemble a PRINT became the inner strength gather to become the rocky cutaway view of Europa the of the Minoan culture, on a mantle surrounding her. moon. rocky island surrounded by Some of the friends become the sea, so Jupiter’s moon the ocean with arms moving Europa’s rocky inner core is like waves and others use the surrounded by a great ocean hands like a ﬂat wall to show beneath it icy surface. the icy surface.

Jupiter stands away, but uses his arms to suggest a powerful gravity.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

Narrative Movement Concept

And just as Europa’s father “Mercury” becomes a Projects an image of future Cadmus launched ships in spacecraft beaming radar, exploration search of her, so scientists searching for Europa’s urge NASA now to launch ocean. spacecraft to investigate the ice world, Europa.

Small Group Mime Activity: Movement Integration Mediating Experience Invite students to form small groups (about three to ﬁve students), look at pictures of features on ice worlds and create their own mime and narrated story about how they formed. Encourage students to act out a sequence that results in drawing science questions from the story.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

MATERIALS For all activities, to record reﬂections, Space phenomena observations, calculations, etc. Gallery of images selected from NASA ■ Science Notebooks: writing and drawing collections utensils ■ Ground-based and Hubble images of Pluto Occultation Demonstration and Triton ■ Construction paper ■ Galileo images of Europa

■ Colored transparencies ■ Images of ice on Earth from space

■ Flat wooden sticks to be used as handles (for example, paint stirrers)

Photometry Activity ■ Several shallow platters in which to freeze ice to model surfaces of an ice world (cookie sheets, cake pans, plastic platters)

■ A selection of objects with varying degrees of reﬂectivity, such as:

■ Ice cubes, loose

■ Ice cubes, refrozen loosely in an ice platter

■ Crushed ice, loose on a platter

■ Crushed ice, refrozen on a platter

■ Icy water PRINT ■ Ice with dirt, ﬂour, or cake mix sprinkled on top

■ Ice with sand sprinkled on top

■ Various light sources of different intensities (ﬂashlights, bright lamp, sunlight)

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

DEMONSTRATION This demonstration seeks to communicate Explanation of occultation sequence one of the ways planetary scientists extract A circle of black construction paper repre- information from light about the appearance sents an ice world. A surrounding circle and composition of planetary objects. of transparent colored plastic represents It introduces precursor understanding the tenuous planetary atmosphere, gases of photometry. sublimating from the surface ices.

PRE K–2 Here is one way we get information about a b c d ice worlds from light: Occultation Demonstration a. Ice world about to cross in front of star. 1. Construct the occultation model out b. Starlight passes through atmosphere. of circular cutouts of construction paper c. Star is hidden behind ice world. and sheets of colored transparencies. d. Ice world reveals star; starlight passes (Optional: fashion a handle for ease through atmosphere again. of holding.) As the combined circles pass in front of a 2. Have one student volunteer hold the bright light source (a flashlight, for example), “ice world” and be ready to move along the “atmosphere” acts as a filter, so we see an “orbital path.” a difference between the “star” by itself 3. Have another student volunteer hold a and the starlight passing through the atmos- flashlight, in the role of the “star.” phere. From that difference, scientists can use spectroscopy to tell what the atmosphere 4. Use your own words to talk through the is made of, and infer what the surface occultation sequence. is made of. PRINT

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

3–5 We are Paolo and Francesca, who once This activity uses one of the most well-known walked side by side into a beautiful garden. [link to Magniﬁed Ice] passages of Dante’s Divine Comedy (Canto V, We sat down on a bench beneath a tree, Inferno) to build an understanding about how where we read a story together. This was Pluto and Charon move through space and no ordinary story. It was the tale of Sir how scientists learn more about Pluto/ Lancelot in love with Queen Guinevere, Charon by observing during an occultation, who was married to Sir Lancelot’s best the passing of a planetary object in front of friend, King Arthur, just as I, Francesca was a distant star. married to Paolo’s jealous brother.

Adapt the telling to the audience. Parts Well, as we read on, we were drawn into this famous love story tend to produce the story. Just as Sir Lancelot looked into some giggling among this age group. Queen Guinevere’s eyes, just so our eyes Have fun with it, keep it light, and use lifted from the pages of the book, and the their fun with it to draw them toward book seemed to float away. We looked into the science point of the telling it. each other’s eyes. We drew closer, and nearly kissed. But it was never to be. Just at In Dante’s time in the 1300s, they did that moment, Paolo’s jealous brother came not know of the planet Pluto, which was into the garden and saw us, thinking the discovered by Clyde Tombaugh in 1930. Had worst. He raised his sword and slew the Dante known, he most probably would have two of us. seen the connection between his story of Paolo Our spirits released, we floated toward the and Francesca and the science story of the underworld. As we approached the River occultation of Pluto and Charon. Styx, where the boatman Charon ferries As Dante was guided by the poet Virgil spirits from the world of the living to the PRINT through the first realm of the underworld, world of the dead, we entered Pluto’s realm. he saw two spirits spinning slowly in space, Our fate is to swirl eternally in the darkened with arms outstretched toward each other, sky. We always face one another. We always but not quite touching. Dante was moved circle about each other at an arm’s length. by their expressions, so seemingly in love. Yet we are never able to give comfort to At last Dante spoke to his Guide: “Poet, I each other in the cold darkness so far from should be glad to speak a word with those the Sun. And so we are very sad. two swept together so lightly on the wind and still be so sad.” The two spirits, a young man and a young woman, approached to tell their story.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

But every once in a while, the light from a After telling the story, invite two volunteers distant star passes through our outstretched (a boy and a girl as Pluto and Charon) to arms, and in this occulted light we can see demonstrate the occultation sequence. our icy breath, and sense the perfume of Instruct students as follows: our radiant love. Reach out your arms toward each other without And just so, the Poet thought, the planet Pluto quite touching at the fingertips.Very slowly, still and its moon Charon circle about each other facing each other, move together so that you in their tilted orbit around the Sun. And just slowly whirl about each other. This is Pluto so, now one, then the other, occasionally and Charon. passes before a star whose starlight filters Invite another student to stand behind Pluto through to reveal their frosty breath, the and Charon with a flashlight, ready to shine sublimation of ices from their surfaces: water, toward the line of sight of the rest of the ammonia, and methane ices from Pluto, and class. Position them so that as Pluto and water ice from Charon. Charon whirl, they each occult, or hide, Dante writes: “Through a round aperture I the “star” so that the light of the star saw appear some of the beautiful things that appears and disappears. Talk through the Heaven bears, where we came forth, and once occultation sequence (see page 15) in terms more saw the stars.” of the student volunteers. (Closing lines of the Inferno, from Robert Pinsky’s translation)

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

MAIN ACTIVITY This activity models photometric PREPARATION techniques and results that lead to Devise several exploratory zones: understanding about outer planetary ■ Material for occultation sequence ice worlds. ■ Set out a variety of examples of surface ice features along with a variety of light sources (for example, ﬂashlights of various intensities)

■ Select a gallery of dramatic Europa and outer planetary images.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

TEACHING TIPS Discuss Explore Lead a discussion guided by questions such Guide students to focus on the idea of as: How do scientists investigate outer how the way light reﬂects off icy surfaces planetary ice worlds? Observation of these provides useful information. Encourage dimly lit worlds is a challenge. What are the students to notice how light strikes the ice big science questions scientists are asking? at different angles and that each angle Use shows different features. Guide students Suggest that students apply new understandings toward making a connection between the about reﬂection of light to drawing, taking light and ice exploration and the selection photos, and to better interpret space images. of images of ice worlds

Diagnose In the midst of the exploration, listen to student ideas about light and what happens when it strikes the different samples of ice. How capable are students in connecting the classroom activity with the images of ice worlds? Ask questions that guide students toward recognizing connections.

Design Invite students to devise ways to use the light sources to create different effects. If digital cameras or videos are available, have students PRINT imagine them as spacecraft obtaining images. Have students work in collaborative teams to devise ways to explore questions that arise from the exploratory zones.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

WARM-UP AND PRE-ASSESSMENT PROCEDURES Assure that students have an understanding PART 1. about light sources Three Ways to Obtain Photometric Data [create link to ED3U Science Hold up one of the ice platters, tilted forward 1. Occultation Zone: Place the materials Model and Inquiry Wheel Game] slightly so that everyone can see it. Ask that and explanation used for the occultation students imagine that the ice platter is the demonstration in an exploratory zone so surface of an ice world in the viewfinder of a the students can enact the occultation telescope. You might have students cup their sequence for themselves, in small groups. hands together as if they were looking 2. Sunlight Zone: Invite small groups of through a telescope. Ask students why the students to view the ice platters in ice platter is visible: Where is the light source? the naturally available light. Have In the Solar System, where does the light them generate and record drawings, come from? observations, and questions about Demonstrate radar astronomy by using the what they notice. analogy of a camera flash that illuminates the 3. Flash Zone: Invite small groups of students surface for a quick moment—use a flashlight to use light sources, such as flashlights of to show the action. Remind students that varying intensities to illuminate the ice there are wavelengths of light that our eyes platters. Have them generate and record cannot see, such as infrared, ultraviolet, drawings, observations, and questions x-rays, and radio waves, but that we can still about what they notice. take advantage of with special instruments. 4. Lead a discussion about the different kinds Some of the images in the exploratory zones of information each technique yields. use false colors to represent features Invite students to write/draw about their revealed by those wavelengths. PRINT photometry and ice experience.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

PART 2. ■ Explore online about NASA’s exploration View images and photometry data of of Quaoar and other icy worlds in the outer planetary ice worlds. Kuiper Belt: http://hubblesite.org/ 1. Triton, Pluto and the Kuiper Belt Objects newscenter/newsdesk/archive/releases/ (KBOs) such as Quaoar. category/solar%20system/minor%20body/ kuiper%20belt%20object/

PRINT Hubble Telescope photometric view alongside Artist’s View of Quaoar, newly discovered icy world in the Kuiper Belt.

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This table guides understanding of gallery images of Triton, Pluto, and KBOs.

Photometrics Observations/Questions Possible Explanations

■ Ground-based observations through ■ Active seasonal processes, in cycles of powerful telescopes show active changes sublimation, cloud-forming, and snowing in albedo on Saturn’s moon Triton. of its ammonia, methane, and water ices

■ Occultation data indicates that Pluto has ■ When Pluto is in closer (35-40 AU) a very thin atmosphere of ammonia, to the Sun, ices sublimate to form its methane, and water tenuous atmosphere

■ Occultation and radar data indicate ■ Pluto and Charon have different origins; Charon is composed of water ice: perhaps the two are together as a result What does this tell us? of an impact or close call; or that Charon is a captured comet

■ Telescopic photometry of Kuiper Belt ■ As a group Kuiper Belt Objects are small Objects has revealed a variety of ices. comets and icy rocky worlds What are they?

■ These objects probably formed at ■ Debris from formation of the Solar System the beginning of the history of the Solar informs us of early Solar System conditions System. What can we learn from exploring them?

■ Scientists speculate that short-period ■ Jupiter perturbations cannot explain all comets might reside in the Kuiper Belt. the short-period comets PRINT Why? ■ Observations tend to conﬁrm the presence of water ice

■ Ice detected on Europa.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

Europa This table guides viewing of historical Europa images . Europa Phenomenon Photometric Measurements

■ Features on Europa: Europa explored ■ Originally detected through ground-based by Galileo Mission, radar telescopes

■ Conﬁrmed by Voyager

Optical data reveal:

■ Ridges

■ Fractures: linear, arcuate, wavy, cycloidal

■ Craters ■ Comparison to Sea Ice on Earth, similarities led to conclusion that a liquid ■ Ice volcanism ocean exists beneath Europa’s icy surface ■ Chaotic areas

■ Earth-observing spacecraft reveal large-scale structure

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

Explore online about NASA’s exploration of PART 3. Europa with the Galileo spacecraft at the Optional Follow-Up: Investigate Ice Galileo web site: Worlds with Planetary Scientists http://www.jpl.nasa.gov/galileo/ Invite students to work in small groups to view the collection of materials and to generate questions to guide their investigation of ice worlds in greater detail. Have students utilize the Planetary Photojournal: http://photojournal.jpl.nasa.gov Encourage students to prepare a focused interview, based on specific questions, that they would ask a planetary scientist working in the field. Contact an expert in the field (start with Science or Education teams associated with NASA missions exploring ice worlds) to create access for students in a collaborative science learning relationship, via email or live speakerphone hook-up for class participation.

Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

DISCUSSION & REFLECTION CURRICULUM CONNECTIONS How much of our knowledge of space This lesson connects to the visual arts. relates to our understanding of light? Awareness of the effects of lighting Perhaps all of it! Through telescopes, enhances our capabilities to draw, take ground-based as well as space-based, we photographs, and interpret images. The view the electromagnetic signals emitted activities can be springboards to observing directly by stars and starlight reflected off the play of light in terms of: lightness and interstellar clouds of dust and gas and off darkness, brightness and dullness, color, planetary objects. We have learned to contours, shadows, relief, and intensity. correlate emission, absorption, and reflection Compare and contrast how we think about wavelengths of electromagnetic radiation with the effects of lighting in art, when the specific elements and compounds. Science purpose is aesthetic to how think about the instruments on spacecraft provide information effects of electromagnetic radiation when about planets and other planetary objects the purpose is scientific inquiry in the form of electromagnetic waves communicated back to Earth via radio waves. The spacecraft carries sensors that are like nerve endings; the radio waves are like the central nervous systems with its the multiple pathways; the complex of receivers are like the synapses that activate awareness once the signal arrives. Then it is the human mind that interprets what it all means. To the extent that we each piece together for ourselves the PRINT information gained through astronomy and space exploration, we participate in the construction of new knowledge of the universe around us. We each create our own vision of space and our own feelings about it. Through this encounter with light, and the information it contains, space exploration extends humanity’s senses into the vast distances of the Solar System and beyond.

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ASSESSMENT CRITERIA Exemplary Emerging ■ Students write and illustrate a ■ Students write and illustrate a description photometry and ice experience and of outer planetary worlds sharing it with share it dynamically with both a small both a small group and the whole group. group and the whole group. ■ Students pose basic science questions ■ Students display drawings, constructions, drawn from their observations and and dynamic kinesthetic models drawn research of Pluto/Charon, Europa, and from their science notebooks and other outer planetary worlds. web-based research. ■ Students observe examples of icy outer ■ Students identify and extend science planetary objects. questions drawn from research about the ■ Students display results using a variety of outer planets. ways to represent examples of ■ Students explore a rich range of Pluto/Charon and Europa. observations about outer planetary ■ Students ask a rich range of questions icy objects and relate it to prior about the origin, structure and composition shared experiences. of outer planetary worlds. ■ Students ask a rich and extensive range of ■ Students make speculations about possible questions about outer planetary objects: explanations for how they formed. composition, formation, orbits, and history of observation. Formative ■ Students recognize features of icy, rocky, ■ Students extend learning by considering implications of the view that these icy, rocky outer planetary worlds and describe outer planetary worlds may be the remnants where they come from. PRINT of the formation of the Solar System. ■ Students identify characteristics of the structure of an icy, rocky outer ■ Students relate ideas to the whole context of exploring ice in the Solar System. planetary world. ■ Students pose science questions drawn out of the context of observing and researching icy rocky, outer planetary worlds.

26 Exploring Ice LESSON 11 DIRECTORY MAIN MENU IN THE SOLAR SYSTEM INVESTIGATING ICE WORLDS

RESOURCES Pluto Europa Pluto: Ninth Planet or Not! Nine Models http://www.jpl.nasa.gov/galileo of Teaching! Nine Lessons! The Galileo web site By Richard Shope Charles White comparing ice on Earth http://pluto.jhuapl.edu and Europa The mission to Pluto/Charon and the Frank Carsey discussing the inferences Kuiper Belt about Europa from the point http://www.plutoportal.net of view of knowing about sea ice Alan Stern and Jacqueline Mitton Images Pluto and Charon: Ice Worlds on the Ragged Link to image gallery Edge of the Solar System