Pencil sketches by Leonardo da Vinci from the early 16th century suggest that he understood gravity long before the English mathematician Isaac Newton, who is credited with discovering it in the late 17th century.
Researchers at the California Institute of Technology reanalyzed da Vinci’s notebooks and found the famous Italian experiments designed to show that gravity is a form of acceleration.
And he modeled the gravitational constant with an accuracy of 97 percent.
The team believes the only thing that prevented da Vinci’s experiments from definitively explaining gravity were the limited tools at his disposal – he lacked a means of accurately measuring time while objects fell.
The sketches show experiments showing that gravity is a form of acceleration. And Leonardo da Vinci modeled the gravitational constant with an accuracy of about 97 percent
Da Vinci, who lived from 1452 to 1519, was way ahead of the curve in exploring these concepts—so it’s perhaps no surprise that the famous polymath caught the idea of gravity.
However, it was not until 1604 that Galileo Galilei proposed that the distance traveled by a falling object was proportional to the square of the elapsed time.
And then, in the late 17th century, Newton extended this to develop a law of universal gravitation that describes how objects are attracted to one another.
The story goes that the apple fell on Newton’s head as he sat under the tree.
He then had a “eureka” moment developing his theory of gravity after watching the fruit fall in the summer of 1666.
Newton theorized that when an apple falls from a tree, gravity could extend even further—possibly into space.
Mory Gharib first discovered da Vinci’s experiments in the Codex Arundel, a collection of articles written by da Vinci dealing with science, art, and personal subjects.
“What caught my eye was when he wrote ‘Equatione di Moti’ over the hypotenuse of one of his sketched triangles – the one that was an isosceles right triangle,” Gharib, lead author of the paper, said in a statement.
“I was interested in what Leonardo meant by this sentence.”
Leonardo d Vinci was way ahead of his time in exploring these concepts – so it’s perhaps no surprise that the famous polymath caught the idea of gravity. Recent work suggests da Vinci understood gravity long before Isaac Newton (right), who is accredited for the discovery
Researchers at the California Institute of Technology have reanalyzed da Vinci’s notebooks
The sketches show a water pitcher moving along a straight line parallel to the ground, pouring out water or sand.
Da Vinci’s notes make it clear that when dumped, the contents would not fall at a constant rate, but would accelerate.
He also wrote that the horizontal acceleration of the contents would stop because the jug was no longer affecting them — the “acceleration is purely downward due to gravity,” according to the researchers.
“If the pitcher is moving at a constant speed, the line created by falling material is vertical, so a triangle does not form,” the researchers further explained.
“As the pitcher accelerates at a constant rate, the line created by the accumulation of falling material forms a straight but sloping line, which then forms a triangle.
Da Vinci attempted to describe this acceleration mathematically, which can be seen in the sketches, but he didn’t quite hit the mark.
Researchers used computer models to conduct his water vase experiment and figured out where da Vinci went wrong
“And, as da Vinci pointed out in a key diagram, if the pitcher’s motion is accelerated at the same rate that gravity accelerates the falling material, an equilateral triangle is formed.”
This was what Gharib first noticed, which da Vinci had emphasized with the note “Equatione di Moti” or “Equality (equivalence) of movements”.
Da Vinci attempted to describe this acceleration mathematically, which can be seen in the sketches, but he didn’t quite hit the mark.
Researchers used computer models to conduct his water vase experiment and figured out where da Vinci went wrong.
Chris Roh, who was a postdoc at Caltech at the time of the research, said: “What we saw is that Leonardo struggled with that, but he modeled it so that the distance of the falling object was proportional to 2 to the power of t [with t representing time] instead proportional to t squared.’
“It’s wrong, but we found out later that he used that kind of wrong equation in the right way.” In his notes, da Vinci illustrated an object falling for up to four time intervals—a period in which graphs of both types of equations are closely aligned.
“We don’t know if da Vinci conducted further experiments or investigated this question in more depth,” says Gharib. “But the fact that he dealt with this problem in this way in the early 15th century shows how far ahead he was in his thinking.”