Final answer:
In a scale model of the solar system, the Earth would be much smaller than the Sun.
Step-by-step explanation:
In a scale model of the solar system with a scale factor of 1 billion, if the sun is represented by a ball with a diameter of 8 inches, the Earth would be about the size of a grape, with a diameter of 1.3 centimeters. At this scale, the Moon would be represented by a pea orbiting the Earth at a distance of 40 centimeters or a little over a foot away. So, in the scale model, the Earth would be much smaller than the Sun.