Question

How does atmospheric refraction affect sunrise and sunset?

Answer 1

Hint: We need to know that atmospheric refraction is the refraction of light by the earth’s atmosphere that is when an object transmits light ray in the atmosphere the light rays passes through the atmosphere having differ air layers of different density due to which it get refracted by the atmosphere and now using this concept only we can write the solution to this problem.

Complete answer:
Sunrise and sunset are two instants when the upper edge of the sun appears and disappears over the horizon respectively which is the result of Earth’s rotation. This condition is also affected by the atmospheric refraction when the sunlight passes through the atmosphere.

As the density of our atmosphere is not evenly made and this density will decrease with increase in altitude. This results, when sunlight passes through the atmosphere there will be successive refraction occurs and this results in a bend of sunlight towards the ground. And at this time if we look towards the sun the altitude of the observed Sun’s image will be higher than that of the actual location of the sun.

Hence this is the reason that the sunrise occurs before the actual time that the sun reaches the horizon and at the same time the sun truly appears below the horizon before the actual sunset happens.

Note: Here we used the word observed sun image, remember that this is the apparent position of the sun. Keep in mind that there are other various effects of the atmospheric refraction like the twinkling of the stars, apparent position of the celestial bodies etc. Note that the atmospheric reaction near the ground produces mirages.