Sun refraction is the bending of sunlight as it passes through Earth's atmosphere.
Understanding Sun Refraction
Sun refraction occurs because light changes speed as it moves from one medium to another. In the case of sunlight reaching Earth, the light travels from the vacuum of space into the denser medium of our atmosphere.
Key aspects of sun refraction:
- Change in Medium: Sunlight travels from the vacuum of space into Earth's atmosphere.
- Bending of Light: Sunlight refracts as it enters the atmosphere.
- Downward Bend: As its wavefronts graze the upper atmosphere, light bends downward.
- Apparent Position: This downward bending causes us to see the Sun higher in the sky than it actually is.
Why Does Sunlight Bend?
Light travels fastest in a vacuum. When it enters a medium like air, which is denser than a vacuum, its speed decreases. This change in speed causes the light rays to bend, following the principles of refraction described by Snell's Law.
Practical Effects
The most noticeable effect of sun refraction is the apparent position of the Sun in the sky. Because the atmosphere bends the light downwards towards an observer on Earth:
- The Sun appears higher in the sky than its true geometric position.
- This effect is most pronounced when the Sun is near the horizon (during sunrise and sunset), making the day seem slightly longer than it would without an atmosphere.
In summary: Sun refraction is the atmospheric phenomenon where light from the Sun bends as it enters Earth's atmosphere, altering its apparent position in the sky.
