Here's why:
* Gravity as a Centripetal Force: The Sun's gravity is the force that keeps the planets in their orbits. It acts as a centripetal force, constantly pulling the planets towards the Sun, preventing them from flying off in a straight line.
* Inertia: Planets have inertia, which is their tendency to resist changes in motion. When the Sun's gravity disappears, there's no longer a force to counteract this inertia.
* Tangential Velocity: Planets are also constantly moving in a direction perpendicular to the Sun (tangential velocity). This tangential velocity is what keeps them in orbit. When gravity disappears, the planets would continue moving in the direction they were traveling when the Sun's pull stopped.
Imagine a ball tied to a string being swung in a circle. The string acts like gravity. If you let go of the string, the ball would no longer move in a circle. Instead, it would fly off in a straight line, tangent to the circle at the point where you let go. The planets would do the same if the Sun's gravity disappeared.
Important Note: This scenario is highly hypothetical. It's impossible for the Sun's gravity to suddenly cease to exist.
