how can sun be bad for humans?

Answer 1

Besides the cancer risks other have mentioned, constant tanning leads to many wrinkles, dry skin, leathery skin as one ages. I know that thinking about 35 or 40 when you are only 10 or 15 is difficult, but the day will come. There is also the risk of eye damage. Frequent sun tanning without proper eye protections encourages the development of cataracts --the clouding of the lens of they eye. Lots and lots of people in their 60's and 70's have to have cataract surgery that they might have avoided if they had just worn good quality sun glasses when outside in the sun.

HTH

Charles

Answer 2

All good things are bad when you get too much of them, aren't they?

A glass of wine a day is a good thing - a bottle a day is bad.

Nobody was ever meant to lay in the sun, so most of the sun humans would naturally get would not be fully on the body, except when the sun is low, in which case its rays are less fierce.

I lived in Middle east for a long time and noted that people born into hot sunny places know to keep out of it, while all the white expats (including me at the time) cooked themselves like lobsters.

There's no understanding human folly.

Answer 3

People who spend time in the sun are at a greater risk of developing skin cancer. Risk factors for melanoma include:
· Family history of melanoma
· Dysplastic nevi (non-cancerous, but unusual looking moles)
· Previous melanoma
· Weakened immune system
· Many nevi (moles): more than 50
· Severe, blistering sunburns, particularly if this occurred as a child or teenager
· Many freckles
· Fair skin and light eyes
· Frequent visits to tanning salons

Answer 4

Light is electro-magnetic radiation. It just happens to be at a frequency we can see. Other frequencies we can't see, but they have other effects on us. Below the red end of the spectrum, the radiation feels like heat. Above the violet end of the spectrum is a radiation frequency that reacts with our skin cells. The cells react by producing melanin, a pigment that produces a suntan. but if there is too much radiation at once, the cells are damaged and you get a sunburn. Even if you tan slowly and cerefully, the ultraviolet radiation bombarding the cells slowly damages them. If there is enough damage, the cells forget how to properly divide and reproduce and you get skin cancer.

Have you ever looked at an old sheet of plastic that has been out in the sun for a few years? It's brittle and flakey because it's been worn out by solar radiation. Even photo-voltaic cells can wear out after years of exposure to the sun.

Consider other frequencies. At the slower end, below infrared, are microwaves, which can cook things. At the faster end, above ultraviolet, are x-rays, which can pass completely, but not perfectly, through your body. the ones that don't make it through are absorbed by tissue in the body. Enough x-ray exposure and you can kill cancer cells (actually, any cells, it's just aimed carefully). But enough x-ray exposure in general and you can get new cancers because of cell damage.

Radiation at different frequencies has different effects on different materials. Just because you can't see it doesn't mean nothing's happening. The damage occurs when rays and particles collide directly with the molecules in our cells, changing them. It happens rarely but often enough to have an effect. The more time you spend exposed to sunlight, the greater your chances of being damaged by it.

Answer 5

Too much sun, specifically UV irradiation, can cause skin cancer and destroy folic acid, a vitamin needed to prevent birth defects.

Answer 6

Ultraviolet rays are high energy radiation that can do cellular and molecular damage resulting in cancer or genetic defects.

Answer 7

Because if you get too close you can melt

Answer 8

to much can cause skin cancer.