Whether you are a parent or teacher, the total lunar eclipse coming Saturday evening can serve as a great launch pad for teaching some simple things about how the solar system works. A little advance reading will also make the event a richer experience for you.
START BY LEARNING and then explaining the basics. A lunar eclipse is just Earth’s shadow falling on the moon, and one can occur only during a full moon. Why? Because that’s when the Sun, Earth and Moon are lined up. Show your child or student the graphic presentation at the top of this page.
So why isn’t there an eclipse at every full moon? Because the moon’s plane of orbit around the Earth is a bit tilted compared to Earth’s path around the sun. Think of it as an imaginary dinner plate (the moon’s orbital plane) that sits both above and below the kitchen table (Earth’s orbital plane). Sometimes the moon is above or below the shadow that Earth casts into space.
You might also discuss the phases of the moon, so your aspiring astronomers will know where it goes when it’s not full and obvious in the night sky. And don’t miss the chance to explain how the moon was probably made. The leading theory is that it formed when a Mars-sized object slammed into Earth — that’ll get their attention!
Arm you students with some specific information about the eclipse, such as when it occurs and that they need a clear view of the horizon. Then on the evening of the event, tell them to ponder all these things as they watch the moon be “eaten,” which is how many ancient cultures (who didn’t know anything about orbital mechanics) viewed lunar eclipses. Perhaps give them a printable map of the moon so they can identify a few major features — visible with the naked eye — while they watch the eclipse unfold.
And if your child or student is interested in other fields of science, try this out: Most scientists figure the moon served a crucial role in the initial habitability of Earth and the evolution of life here.
Importantly, an eclipse requires no special equipment. Just tell the kids to dress warm and bring their eyes and imaginations.
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