Isaac Newton’s groundbreaking insights stem from his understanding of gravity as a universal force. He observed that both the falling apple and the moon’s orbit around Earth could be explained by the same force acting upon them—gravity. Newton formulated the law of universal gravitation, which posited that every mass attracts every other mass. To draw his conclusion, he considered the following:
- Experiments with Falling Objects: Newton’s studies of falling objects, such as an apple, led him to question what caused them to fall towards the Earth. He recognized that a force—that we now call gravitational force—was acting upon the apple, pulling it downwards.
- Observation of Celestial Bodies: Newton also studied the motion of celestial bodies, such as the moon. He observed that the moon’s orbit could be explained by a gravitational force exerted by the Earth. The moon was not merely falling toward the Earth, but instead was in a constant state of free-fall, creating a curved trajectory.
- Mathematical Formulation: Using mathematics, Newton formulated equations that described both terrestrial and celestial motions. His law of gravitation quantified how the strength of the gravitational force decreases with distance, allowing him to relate the acceleration of falling apples to the moon’s orbit.
Through these observations and formulations, Newton concluded that the force responsible for the apple falling from the tree was indeed the same force that governed the moon’s motion around the Earth. This profound realization laid the groundwork for classical mechanics and changed the way we understand motion in our universe.