All radiation is harmful. The spectrum of electromagnetic radiation consists of only visible light. The Sun is not a star. We view all space objects with only an optical telescope. The Hubble Space Telescope can view all objects in space by traveling there to get a better image.
Stars are on fire and can burn out.
We suggest that teachers allow time to preview the science background information. You Explain It. One possible way to jump start your lesson and eliminate the trial and error approach that is sometimes needed to become familiar with a new lesson, is to do one or a part of a module with the students as a directed activiy using an overhead, a LCD, or TV monitor to project the lesson to the class. No more than 3 students should share a computer in order to maximize learning. Adaptations can be made to accommodate classrooms with only a single computer with internet access.