Is it safe to look in the direction of the sun when it's overcast?

Question

On an overcast day I've wondered if it is dangerous to be looking directly where the sun is as opposed to other patches of the sky. Is UV light evenly distributed like visible light is it (or other electromagnetic waves) coming much more strongly from the sun's direction?

Answer 1

yes, that's why people developed eye cataract!

Answer 2

Only the solar eclips is really dangerous, other wise you could, but if you look at the sun too long, or many times, its painful, if you feel pain in your eyes, you have to stop

Answer 3

It's only a solar eclipse that is particularly risky.

On an overcast day, less light (or most of the electromagnetic radiation EMR spectrum) comes straight from the sun to our eyes because it is dispersed by cloud, with a large proportion of the light being reflected back into space.

During an eclipse, with the sun a reasonable amount above the horizon, our eyes pupils expand to let in more of the available light.  Were we to then look directly at the sun, the pupils won't have contracted quickly enough to cut out as much light as possible for a split-second or two.

The colours of sunrise and sunset are caused by diffraction.  Red light bends more than blue, so IR bends more than UV.

In an eclipse, the light coming to the eye has more UV by proportion than visible light because it is dispersed (split up) less than red at the edge of the moon crossing over the sun, so deviates less.

Geoff G - claim your expertise or don't criticise others who do (List your sources - includes your personal expertise).

BTW - "is it safe to look in the direction of the sun ...?" does not mean stare at the sun.  Staring at is hard to do, and obviously increases the risks when there is no cloud.

Answer 4

It is dangerous to look at the Sun under any cicumstances.

Answer 5

It is better to be safe than sorry.  Many people can get a sunburn on an overcast day because UV radiation has very short energetic wavelengths (X-rays are even shorter and more energetic).  The Iris of an eye adjusts in diameter (area) to control the amount of light entering the eye and likely will not adjust to keep out UV but will open wider because it is overcast.  The lens of the eye will focus light from any object in the line of sight (the sun?) onto the fovea (the most sensitive part of the eye that sees details and colors).  The fovea has no blood vessels to carry away the heat and may burn like a leaf held under a lens on a sunny day.  The question is how long would you stare at the sun and how overcast is it really?  Even skiers can go snowblind from too much reflection of UV.  Why take a chance.

Answer 6

Clouds may block the visible rays of sunlight, but allow the damaging infrared rays to pass, so it is better not to look in the Sun's direction under any circumstances.

To those who answered about danger only during eclipses, that is nonsense! Please don't guess at answers when you don't know the truth! Looking at the Sun is dangerous at ANY time. The main danger during the partial phases of an eclipse is that enough of the Sun may be covered so that our reflexes to avoid looking at the Sun may not kick in, and damage may result. But the Sun is no more dangerous during an eclipse than at any other time: it's ALWAYS dangerous to look at the Sun without proper protection. Proper protection includes only filters expressly designed for solar observation or #14 welder's glass (not the #12 commonly available).

Answer 7

yes