Transcript:
Have you laid on your back looking up towards the sky, noticed how blue the sky is, and wondered why the sky is blue? Most of us wondered the same thing! If you remember, visible light is a form of electromagnetic waves and the colors within the visible spectrum are determined by wavelength, or distance between each successive wave. Violet light has the shortest wavelength, green light has the medium wavelength, and red light has the longest wavelength.
When light travels through space from the sun and enters the atmosphere, the light particles begin to collide with atmospheric particles or gas molecules like Oxygen and Nitrogen. The molecules will absorb the photon, then shoot them out in a random direction. This process is also known as scattering and these scattered photons are the colors we see. Red, orange and yellow photons, or light particles, have longer wavelengths, which means they have less chance of intersecting with a particle. As a result, they scatter less. Green, blue and purple photons, however, have shorter wavelengths and have higher chance of intersecting with a particle, which make them scatter more easily. The blue light is scattered the most – this is why we see the sky as blue.
What about the sun setting over the horizon with its spectacular display of red, orange and yellow colors? Remember, the distance between the sun and your eyes during daytime is shorter than the distance between the sun and your eyes during sunsets. During sunsets, photons have to travel a long path through the atmosphere before they reach our eyes. Green, blue and purple are mostly scattered out of the way in the beginning and little to none of these photons reach our eyes. Red, orange, and yellow photons are partially scattered and these remaining photons travel and reach our eyes. As a result, we see mainly these colors in the sunset.
When you watch a beautiful sunset, are you seeing the sun as you see it instantly? No, the photons reaching your eyes from the sun are actually eight minutes old because it takes that long for the light to reach the Earth and subsequently, our eyes!
