Green Flash

Sometimes at sunset, when the atmosphere is calm, and we have an expansive view, there could be some colorful sparks (green or blue) right before sunset. These beautiful colors appear right above the sun. It lasts only one er two seconds.

The reason for this phenomenon is the diversity of refraction in different wavelengths. When we are looking at the sunset, actually, the sun has set. We can still see the sun because the beams are bent by the atmosphere and move towards our eyes. The blue light bends the most (green light is in the second place), so it is the last light color which disappears from our sight.