What is the cause of advanced sunrise and delayed sunset?
What is the cause of advanced sunrise and delayed sunset?
It is due to atmospheric refraction of sunlight. Imagine the journey of light rays from the sun. At first, the journey of light is through vacuum and then through the atmosphere of the earth and then it is finally seen by us. At first, vacuum will act as a rarer medium and the earth’s atmosphere with all its temperature changes, winds, different gases, will be a denser medium in comparison to that.
During sunrise, the light rays bend due to our atmosphere and we see the sun early even though the sun is just below the horizon. Similarly, at sunset, due to the same bending of light rays, we see the apparent position of the sun, not the actual position.
To sum up, due to refraction we see the sun rise about two minutes before it’s actually there and during sunset we see it for around two minutes more, even though it has already moved from that position
Imagine the journey of light rays from the sun. At first, the journey of light is through vacuum and then through the atmosphere of the earth and then it is finally seen by us. At first, vacuum will act as a rarer medium and the earth’s atmosphere with all its temperature changes, winds, different gases, will be a denser medium in comparison to that.
During sunrise, the light rays bend due to our atmosphere and we see the sun early even though the sun is just below the horizon. Similarly, at sunset, due to the same bending of light rays, we see the apparent position of the sun, not the actual position.
To sum up, due to refraction we see the sun rise about two minutes before it’s actually there and during sunset we see it for around two minutes more, even though it has already moved from that position
