How light Travels Through Space
Light acts like particles little balls of objects that stream from the source. This explains how a shadow works. Light also acts as waves, ripples in space. This explains how rainbows works. In fact, light is both. This is one of the most confusing and hard to understand particle in the universe but it also the most interesting. Isaac Newton is the most famous for his invention into 'the nature of light'. He discovered that white is made up off all colours at once. Spectral lines demonstrate that every element has a particular frequency associated with it. When a photon hits an element's atom, the light is absorbed. This creates dark bands in the spectrum at those frequency's. From colours you can tell the chemical compositions of the stars. When light passes through a prism it separates into colours that make it up. White light changes to a swath of colours. Scientists build special instruments to separate light, usually worth gratings. These instruments are called spectrograms. When light of a star passes through a spectrogram a spectrum of the star is seen. The spectrum looks like a regular rainbow or colours, except that there are dark lines. Visible light is the only type of electromagnetic wave that is visible to the human eye. Visable light produce different colours depending on their wave length.