Why can't I look at the sun for a long time?
For grown-ups: the science
The sun's strong light can hurt the back of your eye, so you shouldn't stare at it for a long time.
Sunlight contains very strong visible light along with infrared and ultraviolet rays. Looking directly at the sun focuses that light energy on the retina, the part of the eye that receives images, and even a short exposure can sometimes lead to damage like solar retinopathy. Looking through clouds or during an eclipse isn't necessarily safe either. To observe the sun, use a proper solar filter made for that purpose, and never use sunglasses, dark plastic sheets, or smoked glass.
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Transcript
The sun shines so bright up in the sky—why can't we look right at it for a long time?
The sun gives off very strong light, and a child shades their eyes with a hand. If too much of that light gets into your eyes, it can sometimes hurt the back of your eye.
Deep inside your eye is an important spot that catches everything you see. If that spot gets hurt, it can become hard to see.
Even behind thin clouds, sunlight can still be strong. And during a solar eclipse, you should never look without special safe gear.
The sun sends light that's too strong for our eyes. So when we look at the sky, we look away from the sun.