1. Distance: The Sun is *much* closer to Earth than Rigel. The Sun is about 93 million miles away, while Rigel is about 860 light-years away. This means that the light from Rigel has to travel a far greater distance to reach our eyes, resulting in a significantly dimmer appearance.

2. Intrinsic Luminosity: While Rigel is a much larger and hotter star than the Sun, it's not *infinitely* brighter. Rigel is about 40,000 times more luminous than the Sun, meaning it emits 40,000 times more energy. However, due to its immense distance, this vast energy output appears much fainter to us.

3. Apparent Magnitude: The brightness of a star as we perceive it is called its *apparent magnitude*. The Sun has an apparent magnitude of -26.7, while Rigel's apparent magnitude is 0.12. This means the Sun appears much brighter because its light is concentrated on a smaller area of the sky.

4. Atmospheric Scattering: The Earth's atmosphere scatters sunlight, making it appear brighter during the day. Rigel, being so far away, is not affected by this scattering.

In essence, the Sun appears brighter than Rigel because of its proximity to Earth and the way we perceive light.