From the Hubble Space Telescope
Activity 1B: Painting Planets
ObjectiveStudents will research and construct accurately-scaled models of the planets, reflecting each planet's currently-known physical characteristics and appearance.
Ask your students to close their eyes. Have several students describe the planets of our solar system. Challenge them to recall as much detail as possible. Ask other students to describe the sizes of the various planets relative to each other.
/Explain that you are going to explore our solar system by creating visually-accurate scale models of all the planets, depicting currently known features. Materials
Procedure Divide the class into teams of 2-3 students, and have each team choose a planet to create. Copy and distribute Table 1B-1 as a reference for the actual sizes of the planets and to corresponding sizes (in inches or cm). Help students determine the relative size of their planet so that everyone is working on the same scale. If they are going to show the ring systems, supply Table 1B-2. Once students agree on the planets' sizes, assign each team the task of acquiring an object of the right dimension.
Have students research the appearance of each of the planets using books, magazines, CD-ROMs, Internet pages or other sources (see Resources for suggestions.) Challenge students to identify the most important surface or atmospheric characteristics of each planet, and to think about ways in which these features can be represented on their models. As they research their planet, have them list its special characteristics, as an Artist's Think Pad, recording its color or colors, surface or atmospheric features, whether it has rings and, if so, whether they are light or dark? Have students use this as a guide to decide what coloring or painting techniques they'll need to use to create their model. How will they construct and assemble the giant planets' ring systems? (Remember Neptune's strange ring arcs: for more, see LHST Program 1.) If you're not sure about colors and textures, consult with an art teacher or art supply store.
Consider whether larger planets need more student artists and let the painting begin. When all the models have been painted, discuss where they can be displayed: the ceiling of the classroom, a school hallway or the auditorium. A special assembly, with students reporting on the completed Live from the Hubble Space Telescope project could be scheduled. Have students make a sign for each planet listing its name, size and other key data (see Activity 1C).
If you want to add the Sun to your solar system model, how big a ball would you use? (The Sun is 865,000 miles [1,392,000 kilometers] in diameter, about 109 times the diameter of Earth.) Have students research whether there's a ball or sphere around your school that's large enough. Could they paint a picture of the Sun this large to go with their planets? How big would it be? Where would you place it?
As a math activity, using ratios and proportions, have older students calculate the planets' relative sizes, defining Jupiter (instead of Earth, as in the table below) as 1 inch, and all other planets scaled accordingly.
If resources permit, (and the drama department or tech crew has some stage lighting to loan!) students may wish to light their planet models dramatically in a darkened room and video tape "close encounters" with their planet, as if their video camera were a spacecraft like the twin Voyagers, or Galileo, slowly flying past. (See LHST Program 1, "The Great Planet Debate" for JPL's great computer graphics representations of the Voyagers' encounters with Jupiter, Neptune and Uranus. Remember Galileo will be orbiting Jupiter and its moons for the next 2 years.) Students may later wish to edit these sequences into a multimedia presentation as described in Activity 4B, p. 39.
As another math expansion, challenge students to calculate how far apart the planets would have to be from each other given the size scale of the planets that they adopted. Use the table of distances provided in Activity 1C, p. 16 Whether you use that Activity or not, they'll soon see that our solar system is a very large and empty place!
At the conclusion of Live from the Hubble Space Telescope, have students revisit their models of the planets we'll be studying (Neptune, Pluto and Jupiter) and see what "new" information they now have. As a writing activity, how would they update the textbooks or other sources they consulted? Perhaps you might even submit their reports to your text publisher as input for their next revision! (see also Activites 4B and 4C pp. 39-40) Have students keep a journal as they create their model. What did they do, and discover, each day? What were the easiest, most fun parts of the project? What parts were more difficult or challenging? If another class were going to do this same project next year, what pointers would they give them? Consider keeping a photo-journal or video diary of their progress. Taking a picture of their model each day would provide a timelapse record of how it gradually changed into a planet. Paste such pictures into their journal entries for each day: think how in years to come, you'll also be able to paste video into your students' Web pages!
Dr. Marc Buie on Pluto
Lowell Observatory, Flagstaff, AZ,
In 1988, Pluto passed perihelion, which is the point at which it's closest to the Sun, and it's going to begin its 125 year voyage to its most distant place in its orbit. And over this time Pluto is going to receive less and less sunlight, and cool off, so we now have an opportunity to study Pluto when it is at its warmest. If we don't take the opportunity now to make these observations we'll have to wait another 240 years to repeat the experiment. Pluto is sort of the last "astronomers' planet." We haven't yet had a close-up view with a spacecraft. We have an opportunity here to see the development of a science and a knowledge-base about Pluto in our lifetimes. And certainly the past ten years have been exciting, watching what we learned about Pluto. I am certain we are going to learn a great deal more, but this is sort of the special epoch in human history where we are learning for the first time what this planet is all about.
Prof Heidi Hammel, on Neptune
Massachusetts Institute of Technology
What I like best about the planet Neptune is that every time you look at it, it's different. So Neptune can be your planetÉNo one else will have seen the clouds that you see and they'll probably never be seen again. And so that means that the pictures of Neptune your students take will be absolutely unique...
One of the biggest surprises when the Voyager spacecraft flew by Neptune was a huge dark spot on the planet. We called it the "Great Dark Spot." We weren't able to see it from Earth because Neptune is the most distant planet from us right now. When we looked with the Hubble Space Telescope last year that Great Dark Spot was gone! It had simply disappeared, it wasn't there anymore, which was a big surprise but when we looked very, very carefully, we saw a different big, dark spot on the planet, in the northern part of the planet- the other one was in the South-so that means Neptune's atmosphere just turned upside down!
When we look at Neptune this time we don't know what we are going to see. There might be a whole, new dark spot and that dark spot would belong to this (PTK) group. They would have discovered it!
Activity 1C: The Great Student Solar System Model
ObjectiveStudents will demonstrate the ability to convert distance data into a large-scale model of the solar system (using the "Astronomical Unit" as a yardstick) with students representing the planets.
Ask students to describe how the previous activity helped them understand the relative sizes of the planets. Tell them they haven't seen anything yet. Now they are going to calculate and show just how far apart they are.
/Tell students that they are going to measure distances to the various planets, and that some of them will "become" the planets, in an accurately-scaled representation of their correct distance from the Sun. Pass out copies of Table 1C, but cover the numbers in the last column before making copies. Point out the distances in miles or kilometers: ask them if they have their walking shoes ready!
Procedure Explain that to build this model, the class will have to scale down the distances involved, to numbers that can be dealt with easily. Look at Table 1C with them. Point out that if we try to deal with distances to planets in either miles and kilometers, we have to work with huge numbers. (Ask them if we could talk about distances to major cities around the world in inches? Ask them why we don't.) With this in mind, introduce them to a useful new unit of distance, the Astronomical Unit, which is the distance of the Earth from the Sun, just under 93 million miles or 150 million kilometers. This will become our new "yardstick." As a math exercise, have them calculate the distances from the Sun to all the planets in A.U.s, and then confirm their answers with the right-hand column of numbers in the table. Next, have them calculate the distance in A.U.s of each planet from its neighbor. Point out that now, when representing the solar system, instead of dealing with numbers in the hundreds of millions, we only have to worry about numbers up to about 40, at most.
Brainstorm where the class will create its Great Student Solar System. (Hint: Pick a space long enough to be impressive, and fun like a playground or athletic field.) Next, choose a reasonable length for the A.U. in your model. (Hint: Pre-measure the total length of the area likely to be selected for the model and divide this length by 40. This will mean that if the Sun is at one end of the space, Pluto will just neatly fit at the other, with all the other planets spaced out [sic] in between.)
Let students choose to be the different planets and the Sun. If you are preparing this Activity one day and making the model the next, suggest that they wear clothing appropriately-colored for their celestial object. (Mars is a nice, fashionable, rust-color, but Jupiter might require something tie-dyed.)
Discuss having more than one student be each planet, with the number of students indicating the relative size of the planet (see Activity 1B) Have students make posters with the names of their celestial object in large letters, with a picture, created by them, or found in a magazine (being sure only to use ones that are ok to cannibalize!)
To construct your model, go to the designated place with students, posters, and the piece of brightly-colored yarn cut to the length of A.U. chosen for your model. Start at the Sun and place that student in position. Select two or three students as Official Solar System Measurers (OSSMs). With A.U. yarn in hand, have them measure off the correct distance to each planet, using the numbers they have calculated. As the OSSMs reach the right position for each planet, have the student who will represent that planet take their place until the whole solar system is complete. Then, take a few pictures of your Great Human Solar System Model and return to class for discussion. (Live from the Stratosphere, Program 5, contains a similar Activity, presented by HST Guide author Bill Gutsch, done live on-camera at NASA Ames in an aircraft hangar: it might help to review that tape if you have it.)
See also Carl Sagan's Pale Blue Dot for a discussion of how when Voyager left our solar system, beyond the orbit of Neptune, it turned to take a farewell snapshot which emphasized just how small our Earth was against the huge dimensions of our solar system: think about doing something rather similar, looking out from the Sun to distant Pluto, and vice versa.
When the students reassemble, discuss what they discovered about how the planets were spaced. Most will probably be surprised to see how relatively close together the first four planets are, crowded around the Sun. Beyond Mars, however, the planets are vastly spread out.
Ask the students who represented each planet to work with a small team of other students to figure out how large each of their planets would be, if the actual solar system were really as small as the model you just created. Use Table 1B-1, and help them make scale cross-references as necessary. As follow-up to Activity 1B, ask them to figure out the distance their planet would be from the Sun if you used planets of that size in your model. As a math and social studies activity, using local maps, have them figure out where in your community their models would need to be, if they used this larger scale, and the planets were properly distanced from your school, which would represent the Sun. See if, as a "Science Expo," project wrap-up, or year-end activity, you could distribute planet models made by the students around your town, at the right distances in public buildings for everyone to see. Invite the press, district administration, and parents to see math, astronomy, science and art in cooperative action!
"Moving Targets"The position of any object on Earth can be plotted on a map using that object's unique longitude and latitude. In the same way, celestial objects can be plotted on maps of the sky using a similar set of coordinates. Declination (Dec.) takes the place of latitude and is measured in degrees and minutes of arc north (+) or south (-) of a line in the sky called the "celestial equator," which lies directly above the equator on Earth. Astronomers use Right Ascension (R.A.) in place of longitude. Just as longitude is measured from a line on Earth called the prime meridian, so Right Ascension is measured from a line that passes through a point in the sky called the "vernal equinox." Right Ascension keeps track of how the sky overhead rotates over time during the day and night, and so Right Ascension is measured in units of time (hours and minutes). The Right Ascension and Declination of stars don't change significantly on the time scales we need to worry about for contemporary astronomy. But the planets are all moving around the Sun at different speeds in different orbits so their Right Ascensions and Declinations are always changing along with that of the Sun (since the Earth, too, is moving). It's important for HST mission planners to keep track of the ever-changing positions of the Sun and planets in planning observing times for astronomers because for safety reasons, the HST is usually not pointed within about 45 degrees of the Sun (although sometimes with the Earth acting as a kind of shield, it can - with great care - be pointed closer). In Activity 2C, students will act as Mission Planners for the HST. They'll be asked to plot the position of the planets and the Sun, for a series of dates, and to determine which planets are safe to view on those dates, and which will appear too close to the Sun to observe safely.
The Gallery of the Sky
What is this gallery of the sky? Images placed there by the gods, like a pattern, A pattern of diamonds spread on a table, A pattern of pins stuck in black cloth, Memories, Memories of forgotten heroes, Memories of forgotten times, An art book of love, that soothes the soul, An art book of hope, to help us through it all. A gallery, A gallery of everything and nothing at all