Light travels at a high speed. It could travel around the earth 8 times in a second! They behave like waves and also have the character of the particles. Basically it behaves like waves. At this speed it is very high when compared to the speed of sound. In vacuum light travels at a speed of 300 thousand kilometers per second or 186 thousand miles per second. Isn?t that pretty fast? When light travels in a denser medium its speed is reduced based on the medium in which travels. Hence light travels comparatively slowly in glass or in our planet?s atmosphere. What you see is usually visible light and there are other forms of light that are not visible to human naked eyes. The invisible lights are called the electromagnetic spectrum. It is the wavelength of the light that makes the difference in visibility. Different lights like visible lights and x-rays differ in their wavelengths.
[tags]Light Year, Speed of Light, Wave Length[/tags]