Re: what are objects that give off u.v.(ultraviolet rays)

Ultraviolet light needs more energy than visible light to be produced in similar amounts. Therefore sources of UV light in Nature are very hot or energetic objects. Stars produce some amount of UV light, but stars with temperature higher than 30000 degrees produce as much UV light as visible light. Our Sun, at 5800 degrees, produces little UV light if we compare it with its visible light. In spite of this, the Sun is the main source of natural UV light on Earth.

The Earth's atmosphere also produces natural UV light. When very energetic particles from the Sun strike the air molecules, they produce UV light. The result is that the Earth's atmosphere, or portions of it, glows in UV light. Solar particles can also make the air produce visible light, which is what we call an aurora.

UV light can be produced artifically with special lamps that are filled with some gas like xenon. When an electric current passes through the gas, it makes it produce UV light. What happens is that electrons in the current strike the gas atoms and make them produce UV light.

Vladimir Escalante Ramirez