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Hunt for Alien Worlds

Viewing Ideas

Before Watching

1. It's nearly impossible to actually see planets next to distant stars. However, there are indirect ways to collect evidence that can be used to infer their existence. Discuss with students the difference between evidence and inference. Ask them to provide examples of inference. For example, you can't see wind, but if you look out the window and see a tree moving, you can infer wind is the cause. Ask students to identify other things that can be inferred by their effect on something else. As they watch the program, have students look for ways scientists infer the existence of planets.

After Watching

1. Ask students to consider the pros and cons of searching for and finding planets outside our solar system. What reasons might there be for conducting such a search? What kinds of questions or concerns might be raised? How might the discovery of an Earth-like planet affect us?

Scientists believe the following stars may have orbiting planets:

RA, or Right Ascension, tells your how far away an object is east or west from a fixed meridian in the sky. Dec, or Declination, tells you how far above or below the celestial equator an object is. Positive Dec numbers are in the Northern Hemisphere.