Eclipses: Shadow and Light

Which of the Following is True? 1. An eclipse of the sun occurs when an invisible dragon eats the sun. 2. During eclipses, poisons drop from the sky 3. An eclipse is a sign that the world is coming to an end. 4. None of thee above.

Answer None of thee above. People from cultures all over the world created these and other stories to explain the mysterious disappearance of the sun and moon from the sky.

Solar Eclipse A solar eclipse occurs when the Moon comes directly between Earth and the Sun. The key word is directly, because the moon orbits the Earth every month, and every month the moon casts a shadow.

Solar Eclipses During a solar eclipse, the darkest part of the Moon’s shadow cone, called the “umbra” is often only 250 kilometers in diameter. As the earth spins, different parts of it fall within the umbra. People who happen to be in the umbra can see a total blocking of the Sun, or a total solar eclipse.

Outside the Umbra The moon blocks only part of the Sun and creates a partial Solar Eclipse. A shadow is cast, but it isn’t as dark as the umbra. This lighter part of the shadow cone is called the “preumbria.”

Lunar Eclipse In a Lunar Eclipse, Earth comes directly between the Sun and Moon - placing the Moon in Earth’s shadow. When the entire full moon falls within the center of Earth’s umbra, we have a total lunar eclipse. Everyone on the night side of the Moon can see the eclipse!

More on Lunar Eclipses Depending on how much dust and how many clouds are in Earth’s atmosphere, the moon will appear dark brown, red, orange, or yellow.

Partial Lunar Eclipse A partial lunar eclipse occurs when only part of the Moon passes through the Earth’s umbra. A penumrial lunar eclipse occurs when the moon passes through only the lighter part of Earth’s shadow cone. Neither of these eclipses is as colorful as a lunar eclipse.

Safe Way to View a Solar Eclipse NEVER look through a telescope or binoculars, or any optical aide or device that magnifies an image, at the Sun or a Solar Eclipse; this would cause PERMANENT BLINDNESS INSTANTLY !

Safety! NO filtering device, sunglasses, photographic film or negatives, or darkened or "smoked" glass or plastic, is safe for looking at the Sun or a Solar Eclipse, unless it is SPECIFICALLY DESIGNED FOR SOLAR ECLIPSE OBSERVING and UNDAMAGED (i.e. includes no pinholes or holes of any size) !

Safety! To safely view a Solar Eclipse, prepare a box as shown, with a pinhole (perhaps in aluminum foil covering a larger hole in the box) at one end and a white sheet of paper at the other end, inside. as shown as shown Standing, with your back to the Sun and your head inside the box, allow the Sun's light to shine through the pinhole and observe a small image of the Solar Eclipse on the white sheet of paper.

Alternatives If you cannot find a box, you can also use two pieces of cardboard. Place a pinhole in one piece of cardboard. Standing with your back to the Sun, allow the light from the eclipse to shine through the pinhole and project onto the second piece of cardboard, where you will see a small image of the solar eclipse. Again, NEVER look through the pinhole at the Sun or a Solar Eclipse; this could cause MAJOR EYE DAMAGE and POSSIBLE BLINDNESS !

Safety tips found at: andrewcarnegie.tripod.com/solflyer2.htm