# Sketches Hint Leonardo da Vinci Grasped Gravity a Century Ahead of Newton

A new study reveals that Leonardo da Vinci recognized some fundamental aspects of gravity more than a century before Isaac Newton formulated his theory. Although Newton is typically credited with first formulating a theory of gravity in the latter half of the 17th century, Leonardo’s notebooks provide evidence that he understood the concept of gravity as a kind of acceleration.

The study analyzed sketches of triangles in Leonardo’s now-digitized notebooks, which show the relationship between natural motion, directed motion, and the equalization of motion. This recognition of gravity’s pull was not as fully developed as Newton’s laws, but it was still an important early insight into the workings of the universe.

“About 500 years ago, Leonardo da Vinci tried to uncover the mystery of gravity and its connection to acceleration through a series of ingenious experiments guided only by his imagination and masterful experimental techniques,” write the researchers in their published paper.

In one example of Leonardo’s thinking about gravity, he considered the motion of sand pouring from a jar. He realized that if the jar was pulled along a horizontal plane at the same speed as the force pulling down the grains, the sand would form the hypotenuse of a triangle. This insight into the change in speed that a falling object undergoes over time was a crucial step toward finding the gravitational constant on Earth, which would later be used by Newton to define his laws of motion, including gravity, and by Albert Einstein in his theory of general relativity. Although Leonardo knew he had found something important, he wasn’t certain quite what it was.

One reason for his uncertainty was his adherence to Aristotle’s idea of continuous force known as impetus, which fills projectiles and provides them with a drive to move against gravity. The principle of inertia, where objects simply continue to travel in a direction until they’re met with an opposing force, had not yet been established in the science of the time.

Despite his lack of access to modern tools and technologies, Leonardo’s algorithms calculated the elusive gravitational constant to 97% accuracy when his experiments were recreated in the lab. The researchers who conducted the study were particularly impressed with Leonardo’s methods and the way he used geometry and the resources available to him to investigate the unknown. They suggest that this same kind of innovative thinking and problem-solving can still be applied to scientific inquiry today.

“By developing a geometrical equivalency approach to demonstrate the laws of motion, Leonardo showed remarkable insight into the dynamics of falling objects by avoiding the need to know the exact value of ‘g’, as long as we assume that ‘g’ represents the rate of change of velocity or acceleration,” write the researchers.

“If he conducted the experiment that he depicted in his manuscript, then he could have been the first human who knowingly generated a ‘g’ force effect without being in a free-fall condition.”

It’s worth noting that Newton did not arrive at his law of universal gravitation on his own. Galileo had recognized the relationship between free fall motion and time as early as 1604, and Newton himself credits the findings of Bullialdus and Borelli in informing his theories. Leonardo da Vinci was also on the right track with his early insights into the patterns of falling objects, which would later be used to explain the movements of stars and planets, and even to predict the existence of Neptune.

Overall, the study of Leonardo’s contributions to the development of our understanding of gravity highlights the importance of ongoing scientific inquiry and the value of open-minded exploration of the unknown.

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