Which waves cause sunburn

Melanin absorbs UV light and dissipates it as heat. When the body senses sun damage, it sends melanin into surrounding cells and tries to protect them from sustaining more damage. The pigment causes the skin to darken. However, continued exposure to UV radiation can overwhelm the body's defenses.

When this happens, a toxic reaction occurs, resulting in sunburn. UV rays can damage the DNA in the body's cells. The body senses this destruction and floods the area with blood to help with the healing process.

Painful inflammation occurs as well. Usually within half a day of overindulging in the sun, the characteristic red-lobster look of a sunburn begins to make itself known, and felt. Sometimes the cells with DNA mutated by the sun's rays turn into problem cells that don't die but keep proliferating as cancers.

The result is skin cancer, the most common form of cancer in the United States. People who get sunburned repeatedly are at much higher risk. The risk for the deadliest form of skin cancer , called melanoma , doubles for someone who has received five or more sunburns, according to the Skin Cancer Foundation.

A number of artificial sources have been devised for producing UV radiation. According to the Health Physics Society , "Artificial sources include tanning booths, black lights, curing lamps, germicidal lamps, mercury vapor lamps, halogen lights, high-intensity discharge lamps, fluorescent and incandescent sources, and some types of lasers.

One of the most common ways of producing UV light is passing an electric current through vaporized mercury or some other gas. This type of lamp is commonly used in tanning booths and for disinfecting surfaces.

The lamps are also used in black lights that cause fluorescent paints and dyes to glow. Light-emitting diodes LEDs , lasers and arc lamps are also available as UV sources with various wavelengths for industrial, medical and research applications. Many substances — including minerals, plants, fungi and microbes, as well as organic and inorganic chemicals — can absorb UV radiation.

The Sun sends lots of energy toward us all the time. There are a few different kinds of energy. There is infrared radiation , which is heat. There is visible light , which is what our eyes can see.

There is also ultraviolet light. And it can burn our skin. Infrared radiation, visible light, and ultraviolet light are all types of waves in the electromagnetic spectrum. Some have more energy than others. Infrared waves have less energy than visible light waves. Infrared waves are longer with more space between each high and low.

Many of them only detect a small portion of UV light. For example, the Hubble Space Telescope observes stars and galaxies mostly in near ultraviolet light. The International Ultraviolet Explorer IUE satellite has observed in the far and near ultraviolet regions for over 17 years.

What does Ultraviolet light show us? We can study stars and galaxies by studying the UV light they give off - but did you know we can even study the Earth? Below is an unusual image - it is a picture of Earth taken from a lunar observatory! This false-color picture shows how the Earth glows in ultraviolet UV light.

The part of the Earth facing the Sun reflects much UV light. Even more interesting is the side facing away from the Sun. Here, bands of UV emission are also apparent. These bands are the result of aurora caused by charged particles given off by the Sun. They spiral towards the Earth along Earth's magnetic field lines.