Here's why:
* Galileo's Experiments: Galileo is famous for his thought experiments and observations, particularly the famous Leaning Tower of Pisa experiment (though it's debated whether he actually performed it). He argued that, in the absence of air resistance, all objects would fall at the same rate. He used inclined planes to study motion and supported his claims through careful observations and calculations.
* Air Resistance: Galileo's work was largely theoretical, as he couldn't fully eliminate air resistance. In reality, air resistance plays a significant role, especially for objects with different shapes and sizes.
* Newton's Universal Gravitation: Isaac Newton later formulated the Law of Universal Gravitation, which mathematically explained why objects fall at the same rate regardless of their mass. This law states that every particle in the universe attracts every other particle with a force proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
* Real-World Demonstrations: In a vacuum, where air resistance is eliminated, objects of different masses do indeed fall at the same rate. This was dramatically demonstrated in 1971 by Apollo 15 astronaut David Scott, who dropped a hammer and a feather on the moon, showing they landed simultaneously.
Therefore, while Galileo laid the groundwork, it was Newton who mathematically proved the concept of objects falling at the same rate in a vacuum, based on the universal law of gravitation.
