If the sun suddenly disappeared, there would be an 8-minute delay before any effects are noticed on Earth because light and gravity from the sun take about 8 minutes and 20 seconds to reach us. After that time, Earth would plunge into complete darkness as no sunlight would reach the surface. The moon would no longer be illuminated, and temperatures would rapidly drop, falling to around 0°F (-18°C) within a week and potentially reaching -100°F (-73°C) within a year. Photosynthesis would cease immediately, causing plants to die and collapsing the food chain, severely affecting all life forms. Gravitationally, without the sun's pull, Earth and other planets would stop orbiting and move in straight lines through space at their current velocities. This would destabilize the entire solar system with planets, asteroids, and comets wandering off, possibly colliding unpredictably. The moon would likely drift away from Earth, adding to the chaos. The loss of the sun would also remove the protective heliosphere, exposing Earth to cosmic radiation. In summary, Earth would become a dark, freezing, lifeless world drifting aimlessly through space without the sun's light, warmth, and gravitational anchor, ending life as we know it and dismantling the solar system's structure.