* Atmospheric Refraction: When sunlight passes through the Earth's atmosphere, it bends due to the varying density of air at different altitudes. The denser air near the horizon causes the light to refract (bend) more than the air higher up.
* Apparent Shape: As the sun rises, its light travels through a greater thickness of atmosphere near the horizon. This bending of light makes the sun appear elongated vertically, giving it an oval or flattened shape.
* Optical Illusion: This effect is strongest at sunrise and sunset when the sun is low on the horizon. The apparent flattening is an illusion, as the sun itself remains a perfect sphere.
In summary, the sun doesn't actually flatten, but the way its light bends through the atmosphere creates the illusion of a flattened shape at sunrise and sunset.
