Which of the following is not a proof to show that the earth is spherical in shape?

The option that is not a proof to show that the Earth is spherical in shape is "twilight and dawn." Twilight and dawn occur when the sun is just below the horizon, and the Earth's atmosphere refracts or bends the sunlight. This bending of light makes the sun appear higher in the sky than it actually is, creating an illusion that the Earth's surface is flat. However, this phenomenon can occur on any curved surface, not just a sphere. On the other hand, sunrise and sunset, aerial photographs, and lunar eclipses all provide evidence that the Earth is spherical. During a sunrise or sunset, the sun appears to rise or set on the horizon, and the shape of the shadow cast by the Earth on the moon during a lunar eclipse is curved. Aerial photographs of the Earth also reveal its curvature, as the horizon appears to curve away from the observer's viewpoint. These observations provide evidence that the Earth is not flat, but rather, it is curved in shape.