Can the Sun be dangerous?

Never look directly at the Sun, even with sunglasses. The human eye is not made to look at an object that bright. It is so bright it could easily blind you in just a few seconds. 

Have you ever looked at a bright light bulb and then had to look away after a short time? Well, the Sun is about a million times brighter than a household light bulb. This is why you can injure your eyes: if you look directly at the Sun, the inside of your eyes can burn severely and may never heal again. You could lose your sight permanently. In order to study the Sun, scientists look directly at the Sun only with the aid of special instruments that are made to tolerate the extreme brightness.    

The Sun also emits harmful ultraviolet (UV) radiation, which can damage your skin and eyes. In fact, any tan is a sign of damage to your skin! A sunburn may hurt for a while, but damaging your skin over many years can cause many problems, including skin cancer. That is why you should always wear sunscreen of SPF 15 or higher when you will be out in the Sun for more than a few minutes. This applies even for cloudy days -- though not as bright as sunny days, much of the harmful UV light still comes through. Note that having a tan is little protection from skin damage, providing an SPF of only about 2.

To help protect your eyes, use sunglasses that filter 100% of UV light. When you buy glasses, check for labels that say 100% UV Protection. People who don't protect their eyes when they are young run the risk of loss of sight when older, including getting cataracts.