Today’s Wonder of the Day was inspired by Thomas . Thomas Wonders, “Why do people get temporarily blinded by the sun? ” Thanks for WONDERing with us, Thomas !
Have you noticed that solar eclipses are kind of a big deal? This astronomical phenomenon, during which the moon blocks out most or all of the sun for a brief period of time, doesn't happen very often.
When it does occur, it's all over the news. People spend weeks, if not months, preparing for it. And why not? It's an incredibly rare and unique event to see the Sun go dark during the middle of the day. Who wouldn't want to see that?
Of course, there's one little problem. You're not supposed to look directly at the sun…especially during a solar eclipse! What's the deal with that? People get so excited to see a solar eclipse and then all the experts tell you not to look at it. What's going on here?
While this may seem like a bit of a conundrum, it's actually very good advice. It's never a good idea to stare directly at the sun. If you've ever looked directly at the sun, you've probably looked away very quickly when your eyes began to hurt.
The ultraviolet light from the sun is quite powerful. If you've ever experienced a bad sunburn, you know what sunlight can do to your skin in just a short time if left unprotected. Your skin is much tougher than your eyes, and the delicate parts of your eyes can be damaged by the sun much more quickly. That's why it's a natural reaction to divert your eyes in bright sunlight.
So why is it even more dangerous to look at the sun during an eclipse? As the Sun darkens during an eclipse, your eyes think it's getting dark. Therefore, your pupils dilate to let in more light just like they do every evening. Since it's getting darker out, your eyes' natural protective defenses, such as pupil contraction and blinking, also don't kick in.
However, during an eclipse — except at the moment of totality when the sun's disk is completely covered by the moon — there is still sunlight entering your eyes. This sunlight can flood your retinas, overstimulating the rods and cones that sense light and causing them to release chemicals that can damage the retinas.
This condition is known as solar retinopathy, and it can cause permanent eye damage. Since there are no pain receptors in the retina, you won't know it's happening until it's too late. Although permanent blindness is rare, serious eye damage can occur that has lasting effects.
If you can't look at the sun during a solar eclipse then, are you just out of luck? Not necessarily! With a little preparation, you can take steps to view a solar eclipse safely. According to NASA, the safest way to view a solar eclipse is through special sun filters that block out the harmful ultraviolet radiation. You can find glasses with these filters online or at specialty stores.
Unfortunately, regular sunglasses do not provide the necessary protection to view a solar eclipse. If you know a welder, though, you may be in luck. Specialty No. 14 welder's glasses have sufficient filters to protect your eyes from the sun's harmful rays during a solar eclipse. You can find these glasses at specialty stores that sell welding supplies.
If you want to incorporate a fun science project into your eclipse viewing, you can also make a pinhole viewer to view a solar eclipse safely. This simple device allows you to view the eclipse indirectly by casting a shadow of the sun onto another surface.