1. Light Bending:
* When sunlight enters the Earth's atmosphere, it passes through layers of air with varying densities.
* Denser air bends light more than less dense air. This bending is called refraction.
* As light travels from the less dense upper atmosphere to the denser lower atmosphere, it bends downwards.
2. Apparent Position of the Sun:
* Since light bends downwards, the sun appears higher in the sky than its actual position.
* When the sun is near the horizon, the bending is most pronounced. This means the sun appears above the horizon even when it's actually slightly below it.
3. Lengthened Day:
* Because the sun appears to rise earlier and set later due to refraction, the day is effectively lengthened.
* This effect is most noticeable at sunrise and sunset. The amount of time the sun appears to be above the horizon is increased by several minutes each day.
Example:
* If the sun is actually setting below the horizon, but atmospheric refraction makes it appear above the horizon for a few minutes, you'll be able to see it even though it's technically "gone."
In summary: Atmospheric refraction bends sunlight downwards, making the sun appear higher in the sky than it actually is. This apparent elevation of the sun extends the time it appears to be above the horizon, effectively lengthening the day.
