IF THE SUN DISAPPEARS?

If the sun were to disappear, the immediate effect would be darkness as light takes time to travel. After about 8 minutes, we would notice the absence of the sun's light and warmth. The Earth would then be plunged into a deep freeze, and the lack of sunlight would halt photosynthesis, eventually leading to the extinction of plant and animal life as we know it. Earth would also leave its orbit and drift into space. 

Here's a more detailed breakdown: 

Darkness:
Light from the sun takes about 8 minutes to reach Earth, so we wouldn't notice the sun's disappearance for that long. After that, the sky would turn completely dark, as the moon also relies on the sun's light for illumination. 

Loss of Gravity:
The sun's gravity holds the Earth in orbit. Without it, Earth would begin to move in a straight line away from where the sun used to be.

Rapid Cooling:
Without the sun's heat, Earth's temperature would drop drastically. Within a week, the average temperature would be below freezing, and within a year, it could drop to -100°C (-148°F), according to some estimates. 

End of Photosynthesis:
The sun's energy fuels photosynthesis, the process by which plants convert sunlight into food. Without sunlight, plants would die, and with them, all life forms that depend on plants for food. 

Extinction of Life:
The combination of darkness, cold, and lack of food would lead to the extinction of most life on Earth, including humans. 

Gravitational Chaos:
While Earth would initially drift in a straight line, other planets and celestial bodies in the solar system would also be affected by the loss of the sun's gravity, potentially leading to collisions or other unpredictable movements.