What are the harmful effects of looking directly into an eclipse?
If you ever want to view an eclipse, the first thing you must know is this: NEVER VIEW THE SUN WITH THE NAKED EYE OR WITH ANY OPTICAL DEVICE, SUCH AS BINOCULARS OR A TELESCOPE! This is more than advice. Why? Did you ever take a magnifying glass out into the sun and burn leaves? If so, you probably remember that when the focused sunlight coming through the lens was refracted and concentrated to a small spot, the energy available there was truly remarkable. Guess what? You have a lens just like that in your eye. If you look at the sun, your eye-lens will concentrate the sun’s light and focus it to a very small spot on the back of your retina. This can cause permanent eye damage or blindness. Additionally, there are no pain sensors back there so you won’t even know it happening! For more information on how to view an eclipse, go to: http://www.exploratorium.edu/eclipse/how.
