1. Journey through the Universe
How common are planetary systems around other stars (besides the sun), which might support life. Is there life beyond our solar system?

Begin your journey and answer the questions above by following the recommended links below. Discover how common planetary systems are around other stars (besides the sun), which might support life.

Consider This Before Answering the Questions
If you had the opportunity (and the financial resources), would you like to take a journey through the universe? It might be exciting for some, frightening for others, and for just about everyone here on Earth way beyond our means at this moment in time. But let's try a safer, less expensive alternative.

• Go to http://www.nineplanets.org which offers a Multimedia Tour of the Solar System. Although going through the entire tour wouldn't quite take a light year, for the sake of this exercise let's try a more abbreviated trip.
• Begin by clicking on either the solar system you see on the right side of the page or the "Overview of the Solar System" link. Either of these will take you to the sun and its nine planets (together with their satellites).
• We'll end with a brief stop at the "Small Bodies," although you may choose to stop at that introduction (without going through the comets, asteroids, meteors, etc.).
• To travel from one site to the next, just click on the appropriate link at the bottom of each section (from Overview you'll click on the Sun link, from the Sun you'll click on Mercury, etc.). Feel free to take any side trips that seem interesting and/or fun.
• As you move through the planets, compare them in terms of size (diameter and mass), temperature, number of satellites, distance from the sun, orbit, classification (e.g., terrestrial, rocky, Jovian, gas, etc.), and other names (what do those names mean?).
• What else have you learned about each of these planets? Which solar bodies have been "visited" by humans? For those that have, who was first to get there? In what other ways have we "visited" these solar bodies? Which ones have been explored in any way, and what are some of the things we've learned about them?
• Then consider some of the "Big Questions" about such things as: the origin of the solar system; how common planetary systems are around other stars (besides the sun); which might support life and how we would know that-and, if not, why Earth would be special; whether there is life ("intelligent" or otherwise) beyond our solar system; and whether life is rare and unusual in the evolution of the universe or if it is common and widespread.
• Some answers to the Big Questions are offered at the end of the Overview, some will undoubtedly not be answered for many years-for those, you'll have to consider what you've learned and put that together with your own imagination.

After You Answer the Questions
Are you intrigued? If you want to know more about the history of solar system discovery go the following link on the web site you've just surfed http://www.nineplanets.org/history.html

2. The Search for Terrestrial Planets
Visit the recommended links at below and join NASA and the Kepler Mission on their search for habitable planets. What are the science objectives of the Kepler Mission? How are planets detected? Why do we care if life exists elsewhere in the universe? What difference might it make to our own lives here on the Earth?

Consider This Before Answering the Questions
One of the Big Questions presented in the previous exercise is whether other life forms exist in the universe. For life to exist elsewhere, the planets must be habitable-and NASA is actively searching.

• To understand the basics of this search, go to the NASA web site that talks about the Kepler Mission, http://www.kepler.arc.nasa.gov/, and first read what the mission is and how extrasolar terrestrial planets can be detected.
• Then scroll down toward the bottom of the site and click on the little hand that points to "Go to the First Topic." As you traverse through this overview, try to anticipate and answer questions as you go-for example, "What is the importance of planet detection?"; "What are the science objectives of the Kepler Mission?"; and "What hypotheses do you think would be tested?"
• Come up with other questions yourself, such as, "How would we be able to detect life if it's different from our own?" and any others that may come to mind for you. As you move through the site, write down the answers to these questions as you encounter them.
• Describe the overview of the Kepler Mission, how it searches space, and the hypotheses it is designed to test. What are the minimum parameters for detecting planet size? What are the expected results of this mission? What laboratory tests have already been performed, and what did they demonstrate?
• Toward the end of the Mission Characteristics http://www.kepler.arc.nasa.gov/summary.html#anchor427556 link to the Discovery-class Mission: What is the program's prime objective? Why do we care if life exists elsewhere in the universe? What difference might it make to our own lives here on Earth? Take a major leap here (well, for some of you it's a major leap, for others not) and assume that there is life somewhere else in the universe-what would you personally want to know about that life? What would be important in terms of the way we exist on Earth? Why is this an important issue?

After You Answer the Questions
Do you want to read on about NASA's ten chosen discovery missions? Go to http://discovery.nasa.gov/mission.html