From the Hubble Space Telescope

Hubble Meet Hubble

Edwin P. Hubble, 1889-1953

As a child, Edwin Powell Hubble wandered the Kentucky countryside, observing the habits of birds and animals. As an adult, he scrutinized the stars and galaxies. Although Hubble was always interested in science, he didn't settle on a career in astronomy immediately. He received an undergraduate degree from the University of Chicago in 1910, where he also lettered in basketball and almost became a professional boxer. He studied law under a Rhodes scholarship at Oxford University, in England, passed the bar exam, and practiced law briefly and halfheartedly. He "chucked the law for astronomyÉ I knew that even if I were second-rate or third-rate, it was astronomy that mattered." Hubble completed graduate studies at the Yerkes Observatory of the University of Chicago, where he began his examination of spiral nebulae. He earned his doctorate in 1917 and was invited to join the Mount Wilson Observatory in Pasadena, California. But Hubble didn't yet begin the studies which made him famous. Answering the call to World War 1, he enlisted in the infantry, telegraphing observatory personnel, "Regret cannot accept your invitation. Am off to the war."

Two years later he finally began working with the instrument that would enable him to make his greatest discoveries-the 100-inch reflector at Mount Wilson, at the time the largest telescope in the world. Except for four years of service in World War ll, Hubble was devoted to astronomy until his death in 1953.

Hubble's patient, painstaking observations revealed a much larger universe than anyone had imagined. He was enchanted by dim, foggy patches called "nebulae," the Latin word for cloud. One called Andromeda was the most spectacular nebula observed during the early decades of the century, but telescopes weren't powerful enough to see if it harbored any stars like the vast stellar populations of the Milky Way. Since the 18th century, scientists had argued about whether these areas were "island universes," separate galaxies, or simply clouds in our galaxy. Was the Milky Way the only galaxy? Was it the center of the universe?

In 1924, Hubble ended the debate when he reported stars in the outskirts of Andromeda, and found a special kind of star, known as a Cepheid variable, which reveals its distance by the way its light regularly brightens and dims. Careful observations of the Cepheids enabled him to measure the distance to Andromeda, far too many light-years away to be in our galaxy. He moved on to classify the galaxies, grouping them by size and shape, and established that many other nebulae were also galaxies, even more distant than Andromeda. Hubble measured the depths of space out to 500 million light years, distances far greater than any previous surveys.

As he continued to study galaxies, he concluded that they were moving away from Earth at velocities proportional to their distance. This supported the concept that the universe originated in a cosmic explosion, and that all the matter in the universe was expanding from an initial Big Bang. The galactic survey resulted in "Hubble's law": the more distant the galaxy from Earth, the faster it moves away. Of course, if all the galaxies originated from one explosion, residents of other galaxies would see the same thing: a universe of fleeing galaxies with the more distant ones moving more rapidly. Hubble found that the ratio of the velocity of receding galaxies to their distance from Earth is constant -the "Hubble constant"- a significant astrophysical number still not calculated with certainty today. Current estimates of the "Hubble constant," and thus the rate of expansion of the universe, differ by a factor of two. Still more powerful telescopes are needed to make more precise measurements and determine whether the universe will expand forever, or halt and perhaps reverse.

The Hubble Space Telescope builds on Hubble's research, measuring distances with greater accuracy than ever before possible, and returning beautiful and instructive images of galaxies which Edwin Powell Hubble would have loved to see. It is altogether fitting and proper that this premier space observatory is named for the American astronomer whose work revolutionized modern astronomy. Hubble's research proved that larger, more powerful telescopes are needed to see more of the universe. He assisted in the design of the 200-inch Hale telescope at Mount Palomar near San Diego, and made the first observations with it. When asked what he expected to find with the new telescope, he said, "We hope to find something we hadn't expected." With the Hubble Space Telescope, this quest continues.

Adapted, with thanks, from Exploring the Universe with the Hubble Space Telescop e. edited by Valerie Neal,
NASA, NP-126, p. 18

The Hubble Space Telescope, 1990-20??

The Hubble Space Telescope (HST) is a cooperative program of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) to operate a long-lived space-based observatory for the benefit of the international space community. An observatory in space was first dreamt of in the 1940's, long before being designed and eventually built in the 1970's and 1980's and becoming operational in the 1990's. HST is a 2.4 meter reflecting telescope encased in a protective shell housing cameras and other instruments, solar panels for power and communications antennae. It's the size of a school- bus, 13.1 meters long, 4.27 meters in diameter, and weighing some 11,000 kilograms when launched. HST was delivered into low-Earth orbit (600 kilometers) by the crew of the space shuttle Discovery (STS-31) on April 25, 1990. To counteract the telescope's gradual fall from orbit (the result of the solar wind) and to protect the spacecraft against instrument and equipment failures, NASA planned regular servicing missions, for which Hubble has special grapple fixtures and 76 handholds. The first servicing mission by STS- 61 (Endeavour) in December 1993 was an enormous success. During extensive and carefully-rehearsed space-walks, astronauts added corrective optics to fix a problem with the HST's main mirror, which had been mistakenly manufactured 2 microns too flat at the edge, resulting in less than optimal focus for many observations. Future servicing missions are tentatively planned for early 1997, mid-1999, and mid-2002.

Responsibility for conducting and coordinating the science operations of the Hubble Space Telescope rests with the Space Telescope Science Institute (STScI), situated on the Johns Hopkins University Homewood Campus in Baltimore, Maryland. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc. (AURA). HST's current complement of science instruments includes two cameras, two spectrographs, and fine guidance sensors (primarily used to point the telescope precisely, and for astrometric observations). [Editor's note: for the Live from... observations, we'll be using both camera systems: WF/PC2, the Wide Field and Planetary Camera (pronounced "wiff-pik," and built by NASA's Jet Propulsion Laboratory) for Neptune; and the FOC, Faint Object Camera (built by ESA) for Pluto.]

Although HST operates around the clock, not all of its time can be spent observing. Each orbit lasts about 95 minutes, with time allocated for housekeeping functions and for observations. "Housekeeping" functions includes turning the telescope to acquire a new target, avoiding the Sun or Moon, switching communications antennae and data transmission modes, receiving command loads and downlinking data, calibrating and similar tasks. (see Activities 2C and 2D, pp. 22-24, for further background.)

When STScI completes its master observing plan, the schedule is forwarded to Goddard's Space Telescope Operations Control Center (STOCC), where the science and housekeeping plans are merged into a detailed operations schedule. Each event is translated into a series of commands to be sent to the on-board computers. Computer loads are uplinked several times a day to keep the telescope operating efficiently. Some limited real-time commanding for target acquisition or filter-changing is performed, if the observation program has been set up to allow for it. Spontaneous control is not possible.

Engineering and scientific data from HST, as well as uplinked operational commands, are transmitted through the Tracking Data Relay Satellite (TDRS) system and its companion ground station at White Sands, New Mexico. Up to 24 hours of commands can be stored in the on-board computers. Data can be broadcast from HST to the ground stations immediately or stored on tape and downlinked later.

The observer on the ground can examine the "raw" images and other data within a few minutes for a quick-look analysis (which is what we'll see happening, live, during LHST Program 2.) Within 24 hours, GSFC formats the data for delivery to the STScI. STScI is responsible for data processing (calibration, editing, distribution, and maintenance of the data for the scientific community). Competition is keen for HST observing time. Only one of every ten proposals is accepted. This unique space-based observatory is operated as an international research center and as a resource for astronomers world-wide.

Joseph D. Exline, Ph.D., Executive Secretary, Council of State Science Supervisors, former head, V-QUEST (VA)

At the national and state levels, standards have been developed in an attempt to make science education more relevant for ALL students. Guidelines, such as the National Science Standards (National Academy of Sciences/National Research Council), Benchmarks for Scientific Literacy (AAAS/Project 2061) and the California Science Framework have been promulgated to help direct local efforts. Central to these efforts is the argument that science taught as a kind of history course ("this is what your learned predecessors have found out") or lecture series ("this is what we experts already know for sure") is not as relevant, nor as effective, nor as exciting for most students as other approaches. Instead, science presented as "these are ways YOU can join with others to find out about the Universe we all inhabit" helps students understand the present and shape the personal and social future. An added benefit is that this approach even appeals to those who won't find their career in research. To make science as relevant "For All Americans" (in the words of one AAAS publication) as are reading and writing, students must become more involved in the "finding out" aspect, i.e. turning science into a process of "scienc-ing."

To help science reform succeed, efforts like those undertaken by the NSF-NASA funded Passport to Knowledge project (PTK) and its Live from the Hubble Space Telescope "Module" can become an integral and ongoing part of classroom learning. I believe that PTK activities help teachers address many of the objectives outlined in the National Science Standards and the Benchmarks. PTK certainly provides ways to make the classroom a place for active student learning and suggests relevant, flexible, immediate and practical ways to use new and emerging technologies. The use of free, broadcast tv and open access via the Internet also helps support the National Science Foundation's state, urban, and rural systemic initiatives, designed to reach otherwise under-served populations.

Passport to Knowledge and Science Reform

The philosophy of the National Science Standards and Benchmarks advocates using important and relevant science content to develop real-world connections, problem-solving skills and to nurture reasoning abilities. PTK parallels these national trends by involving students as active learners, and serves as a model for how to make science connect beyond the classroom, showing how science literacy may also apply to resolving non-scientific issues in modern society.

The second important way that PTK embodies the spirit of the new standards is by demonstrating the use of cutting-edge technology and demonstrating in specific ways how increasingly "school will be just one of the many places where learning will occur." Technology can make the whole world a classroom. Resources for learning are no longer confined to one school and to an isolated teacher working alone. The ability to interact with real scientists at remote locations, and to collaborate with other educators and students in the doing of real science, is well illustrated by Live from the Hubble Space Telescope. Too often modern telecommunications delivers merely "distance teaching": PTK, however, illustrates true "distance learning."

During the "Great Planet Debate," for example, students from around the world were interacting with scientists to help select which planets to study. During the remainder of the project they have the opportunity to interact "live" with astronomers and other working researchers as data is gathered and interpreted, and so can be part of the process of making new scientific discoveries.

Live from the Hubble Space Telescope: addressing the Standards

These four elements are:

• conceptual themes or connectors which put isolated information into a meaningful context
• process skills which are necessary to observe, collect and analyze valid data
• habits of mind which encourage the validation and testing of the reasonableness of information
• the specific content of the discipline

All four of these elements are essential and must be an integral part of all learning in order to develop scientific literacy. These elements also lead to the development of the attributes necessary for life-long learning in subjects other than science. Through skills in problem solving and scientific reasoning, learners can understand the content under study. More importantly, they can use these same abilities to understand new and different content they encounter later. The method or approach is the key to successful and meaningful learning. Science education is important for the learner to the extent that it enables him or her to understand, in an active way, how the natural world is organized and interrelates changes and interacts with the human-designed world. PTK is modeling this integration of process, content and active learning by having scientists, teachers, and students do scientific investigations in ways that have both personal and societal applications.

The following examples show how these four elements are an integral part of the design of Passport to Knowledge and the development of scientific literacy.

* Conceptual Themes or Understandings are broad and interdisciplinary in nature in order to have cross-content application. They can be subdivided into more science-related themes such as evolution and energy. Themes are used to put the smaller details of information into a more meaningful context, such as learning how the natural and social worlds are organized, interrelated, and changed. PTK uses themes to organize information as follows:

• The interrelationship of the planets' essential characteristics, atmospheres and weather systems.
• How conditions on the outer planets relate to conditions we experience here on Earth

*Skills of Problem-Solving are developed when the learner becomes actively involved and takes more responsibility for his/her learning. These skills are important tools for future learning and make science as relevant as reading and writing. PTK's programs help develop these skills as illustrated by the following:

• Experimenting with color filters, and generating rules for how colors appear
• Figuring out how to measure the speed and scale of storms on Jupiter, Uranus and Earth

* Scientific Values are attributes which predispose learners to take action (curiosity) and to test the judgment (respect for data) of their decisions. PTK's on-line and on camera scientists model these attributes as illustrated by the following questions they'll be seen to ask:

• How do we know the atmospheres differ? (Respect for Data)
• What conclusions do the data support? (Demand for Verification)
• Should we devote resources to study other planets? (Consideration of Consequences)

* Relevant and Important Content is essential in itself but it is much enriched if it serves as a means to an end in developing conceptual understandings and skills of problem solving, and nurtures scientific reasoning. Passport to Knowledge stresses important and relevant content as illustrated by the following:

• Latest findings on characteristics of the planets being studied
• Characteristics and unique advantages of using the Hubble Space Telescope

* Conclusion

PTK sees itself as a member of a larger learning community. The project evolves as the development team learns new things along with you. You'll see some changes from the design and format of our earlier Modules and this will continue. However, to keep our project of high quality both from a scientific and an educational perspective, we subscribe to certain Guiding Principles for design and implementation. (See sidebar below) We hope you'll agree that Passport to Knowledge can help you and your students do science.

While LHST is not intended as a plug-in replacement for sections of your existing course of instruction, we do believe this 3-5 week project can be justified in terms of at least three criteria: (1) what content your students know after participating which they might not have known before; (2) what positive attitudes they develop towards what they now know; and (3) what research and technical skills they gain and practice (see also pp. 10-11 for thoughts on PTK and science reform, and, of course, the Teacher and Student Evaluation pages.) Each individual Activity also states a specific Instructional Objective in clear-cut performance or behavioral terms.

We hope these project objectives and program overviews also provide you with tools to create an "anticipatory set" for your students, so that they approach each Activity or viewing experience as active learners rather than passive consumers.

Activity 1A: Planet Tours, Inc.

Project Objectives

After Program 1 and Activities 1A-1C, students will be able to:

• describe the scale and structure of the solar system in terms of distances between the planets, compare/contrast their relative sizes and distinctive characteristics, and differentiate between "terrestrial" and gaseous bodies.
• develop collaborative learning and research skills to create multimedia reports illustrating the complexity and diversity of our solar system.

• describe the Hubble Space Telescope as both a spacecraft AND a telescope, and compare and contrast the importance of each role.
• describe the extensive network of people, places and processes needed to design, deploy and operate the HST.
• summarize current knowledge about Neptune, Pluto and Jupiter, and explain what might be learned about these planets through the use of HST during the Passport to Knowledge observations.
• identify the main parts of the electromagnetic spectrum, and compare and contrast the use of various wavelengths to study the planets.
• compare/contrast HST with other telescopes, and describe how its unique advantages are being used during the Passport to Knowledge observations.
• describe how HST observes the "moving targets" of the planets of our solar system, and how the data is routed down to Earth for analysis.

After Program 3 and Activities 3A-3D, students will be able to:

• understand how images are constructed from digital data, and the process by which black and white images become color pictures.
• understand how the use of different color filters, time exposures and image processing techniques reveal different aspects of the same image.
• compare/contrast weather patterns on the HST target planets to storms on Earth, in terms of scale, speed of motion, vertical structure and duration.
• describe how scientists gather data, interpret it, test hypotheses, come to preliminary conclusions and publish results for review by peers.

After Closing Activities 4A-4C, students will be able to:

• synthesize and articulate, in media of their own choice, the individual learning they have experienced during Live from the Hubble Space Telescope.
• discuss/debate the value to society of such "Big Science" projects as HST.
• describe and evaluate the effects of advanced technology on the process of contemporary scientific research.
• demonstrate a greater interest in the study of astronomy, and a more positive attitude towards scientific research and/or high-tech employment as a possible career.

Objective

Ask students to describe their favorite summer vacation. Take out a map of your state, America or another country, and have students place pins to show where they've traveled. Ask them what made their adventure special, and what features of the location they most remember. Ask them where they'd like to go if they could go anywhere in the world. Ask them where they'd like to go if they could go anywhere in the solar system!

Explain to students that for this Activity, they are going to imagine that it's not 1996 but rather far in the future. Tourist travel to the planets is just becoming possible and they are working for the first interplanetary travel agency, "Planet Tours, Inc." Their task is to research the wonders of the solar system (especially those of the LHST target planets) and create a series of brochures or travel posters designed to attract the first space tourists.

Materials:

• Advertisements from Sunday newspapers or travel magazines, and/or brochures and posters collected from area travel agencies
• appropriate art supplies, texts, back issues of astronomy and science magazines with space imagery, or computers with scanners and graphics software

Procedure: Divide the class into conveniently-sized teams, who will each work on a different solar system destination. Have students collect brochures, travel posters and other material advertising exotic destinations. Challenge them to create similar brochures and travel posters for the most exotic ports of call in the solar system. What wonders of Mercury or Mars do they feel would be most appealing? What adventures for the well- equipped adventurer-ballooning on Jupiter? Sulfur-surfing on Io? What creature comforts required to tame the chill of Mars, the heat of Venus? What incredible sights on Neptune or Pluto, Triton or Charon?

Have student teams discuss what factors make some posters and brochures more compelling than others. How is the writing they find in a travel brochure different from what they find in a book, the front page of a newspaper, or a magazine? Have students develop a list of "rules" for a successful travel poster or brochure

Turn students' attention skyward. Help students research the necessary factual information about our neighboring worlds and obtain the pictures they need from books, magazines, CD-ROMs or the Internet.

(Check our A note from Jan Wee, Education Outreach Coordinator, Passport to Knowledge)

Dear Educators,

Welcome to Passport to Knowledge! One of my top priorities is to provide support to all educators as you integrate our projects into your learning environment. My background of 18 years as science teacher, computer support services (especially in the area of Internet- based resources), library media director, and Passport to Knowledge team member gives me a broad perspective.

Please feel free to call, no matter your question (608-786-2767), or fax (608-786-1819), or e-mail (janw@quest.arc.nasa.gov), or write (Jan Wee, 431 North Youlon Street, West Salem, WI 54669).

Looking forward to assisting your efforts to make this experience an exceptional and successful one!

Program 1:

This 30 minute program introduced the entire project, and announced the on-line discussion which led to a December 1995 consensus decision about which planets to observe. The four astronomers who served as "Planet Advocates" for the on-line debate (Reta Beebe for Jupiter, Marc Buie for Pluto, Heidi Hammel for Neptune and Carolyn Porco for Uranus) each presented reasons for using three HST orbits for "their" planet, and summarized key scientific goals which could be achieved. Presenter Bill Gutsch reviewed the history of Space Telescope (launch, servicing mission, most revealing and amazing images, current capabilities). Gutsch provided a project timeline, Internet addresses for on-line updates and encouraged participation in an unprecedented experiment in science education and outreach. Web page for links to some great on-line resources. See Activity 4B for tips on how to make slides from books or computer screen.) Challenge them to find the most exciting sites and sights offered by their chosen planet or its moons-from Valles Marineris, a Grand Canyon on Mars that would stretch across the entire United States, to sheer cliffs of ice on Uranus' satellite, Miranda, 8 miles high. What resort attractions might 21st century technology bring? A golf course on the moon? Snow machines creating a long downhill ski run from a mighty Martian volcano?

Have students make rough sketches of their posters or brochures. Through team discussion, encourage them to edit and refine. Have them compose the finished product before making an oral presentation to the entire class-and come prepared to respond to charges of false advertising or bad science!

Lead a class discussion about what might some day be feasible, and what are likely to remain fantasies. (Be somewhat cautious about skepticism: in the late 19th century, eminent scientists were still saying heavier-than-air flight was utterly impossible.)

Give students an overall advertising budget for "Planet Tours, Inc." for a one month advertising campaign, and challenge students to develop a marketing plan. If a student has a relative who's a travel or advertising professional, they might be invited to give a talk before the class.

Have them make their presentations to another class (perhaps a lower grade, who can then also ask questions, turning your students into teachers) who will vote on their favorite planetary vacation destination.