The history
From Aristotle's 'everything needs a pusher' to a hammer and a feather falling side by side on the Moon: 2,300 years of working out why things move.
For about two thousand years, most thinkers followed Aristotle: a moving thing keeps moving only while something pushes it. A few doubters, from Alexandria to Persia to Paris, wondered what kept a thrown stone flying. Galileo, Descartes and Huygens cracked the puzzle open, Newton wrote three short laws in 1687, and later scientists turned them into equations, found where they stop working, and used them to fly to the Moon and Mars.
Early 500s
Thrown objects carry their own force
John Philoponus, Egypt
1644
Law of inertia stated in print
René Descartes, France
1656
Correct rules for elastic collisions
Christiaan Huygens, Netherlands
1687
Three laws of motion together
Isaac Newton, England
1750
F = ma in general form
Leonhard Euler, Switzerland
1903
Rocket equation applied to spaceflight
Konstantin Tsiolkovsky, Russia
1948
Unit of force named the newton
9th CGPM, France
1971
Hammer and feather dropped on the Moon
David Scott, USA
350 BCE – 1400
Aristotle says every motion needs a mover. Philoponus, Ibn Sina and Buridan argue that a thrown object carries its push along with it.
350 BCE
c. 350 BCE
Aristotle taught that a stone falls because it is heading for its natural place, and that anything pushed sideways moves only while something keeps pushing it. To explain why an arrow keeps flying, he said the air behind it pushes it on. He also thought heavier things fall faster.
Why it mattered. His ideas ruled for about two thousand years, and every later step was an argument with them.
515
Early 500s
In his commentary on Aristotle's Physics, Philoponus said air cannot keep a thrown stone moving. Instead, the thrower gives the stone a force of its own. He also said that if you drop a heavy and a light weight together, they land at almost the same time.
Why it mattered. It was the first clear break with Aristotle's idea that air does the pushing.
1020
c. 1014–1020
In The Book of Healing, Ibn Sina described a 'mayl', an inclination given to a thrown object. He argued that it is used up only by things like air resistance, so in a vacuum a moving object would never stop.
Why it mattered. It came remarkably close to the idea of inertia, six centuries before Galileo.
1600 – 1680
Galileo rolls balls down ramps, Descartes states the law of inertia, and Huygens works out what happens when things collide.
1638
Galileo timed balls rolling down gentle ramps using a water clock, and showed that falling things speed up steadily. He saw that a ball rolling on a level surface would keep going if nothing slowed it. The famous story of him dropping balls from the Leaning Tower of Pisa is probably a legend.
Why it mattered. His book Two New Sciences replaced arguments about motion with measurements.
1644
In his Principles of Philosophy, Descartes wrote down laws of nature. A thing stays at rest or keeps moving until something changes it, and on its own it moves in a straight line.
Why it mattered. It was the law of inertia stated in print, and Newton made it his first law.
1656
1656 (shared 1669, printed 1703)
Huygens worked out the correct rules for bouncy collisions in 1656 and told the Royal Society about them in 1669. His full book on collisions was printed only in 1703, after his death. In 1659 he also found the formula for the outward pull you feel going round a curve.
Why it mattered. His collision rules are the ideas behind Newton's third law and momentum.
1684 – 1759
A question from Halley leads to Newton's three laws, and du Châtelet brings them to French readers.
1684
August–November 1684
Halley visited Newton to ask what path a planet would follow if the Sun's pull weakened with distance. Newton said he had already worked it out. In November he sent Halley a short paper, De motu corporum in gyrum, which grew into a whole book.
Why it mattered. Without Halley's question, the Principia might never have been written.
1687
5 July 1687
Newton's Principia opened with three laws of motion, written in Latin: inertia, force changing motion, and every action having an equal and opposite reaction. Halley edited the book and paid for the printing himself. The same laws explained falling apples, tides and planets.
Why it mattered. For the first time one set of rules covered motion on Earth and in the sky.
1759
1756 (partial), 1759 (complete)
Du Châtelet translated the Principia into French and added her own commentary, finishing just before she died in 1749. It was published in part in 1756 and in full in 1759.
Why it mattered. It helped Newton's ideas win over Europe, and it is still the standard French translation.
1750 – 1948
Euler, Lagrange and Hamilton turn the laws into powerful equations. Einstein and quantum physics find where they stop working, and the unit of force gets Newton's name.
1750
1750 (printed 1752)
Newton wrote his second law in words and geometry. In a paper for the Berlin Academy, Euler wrote it as equations, one for each direction, and showed they work for every tiny piece of any object, even a spinning one.
Why it mattered. This is the first appearance of F = ma in the general form students use today.
1788
Lagrange's Mécanique analytique rebuilt Newton's mechanics using energy and pure algebra. He proudly said the book had no diagrams at all.
Why it mattered. His method makes hard problems, like a swinging chain of pendulums, much easier to solve.
1833
1833–1835
Hamilton found another way to write mechanics, based on positions and momenta instead of forces. It gives exactly the same answers as Newton's laws.
Why it mattered. His form of mechanics later became the starting point for quantum physics.
1903
Tsiolkovsky, a schoolteacher, used Newton's laws to work out how fast a rocket can go by throwing its fuel out of the back. He showed rockets could reach the speeds needed for spaceflight. A British mathematician, William Moore, had found the same formula back in 1810 to 1813.
Why it mattered. Every space launch is planned with his equation, which is Newton's third law put to work.
1905
26 September 1905
While working at the patent office, Einstein published special relativity. Near the speed of light, Newton's laws give the wrong answers: an object's momentum grows without limit, so it can never reach light speed.
Why it mattered. It showed Newton's laws are a superb approximation for everyday speeds, not the final word.
1925
1925–1926
Inside atoms, electrons do not follow neat Newtonian paths. Heisenberg in 1925 and Schrödinger in 1926 found new rules, quantum mechanics, for the very small.
Why it mattered. It marked the second border of Newton's world, the size of atoms.
1957 – today
Satellites, Moon landings and Mars missions put Newton's laws to the ultimate test.
1957
4 October 1957
A rocket pushed hot gas backwards and was pushed forwards in return, lifting Sputnik 1 into orbit. From then on, the satellite kept falling towards Earth but moved sideways fast enough to keep missing it.
Why it mattered. It was the first human-made object to orbit Earth, steered entirely by Newton's laws.
1971
2 August 1971
Standing on the Moon, where there is no air, Scott dropped a 1.32 kg hammer and a 0.03 kg falcon feather at the same moment. They hit the ground together, live on television.
Why it mattered. It proved on another world what Galileo and Newton said: without air, gravity speeds up everything equally.
2014
24 September 2014
India's PSLV rocket was too small to fling the spacecraft straight to Mars. So it circled Earth, firing its engine seven times to stretch its orbit, then set off on a 298-day coast to Mars.
Why it mattered. It made India the first Asian nation to reach Mars orbit, using Newton's laws to save fuel.
Did you know?
Newton wrote the Principia in Latin, and its laws section is headed 'Axiomata, sive Leges Motus': axioms, or laws of motion.
Edmond Halley, not the Royal Society, paid for the Principia to be printed.
Only about 500 copies of the first Principia were probably printed.
One newton is about the weight of a 102 g mass on Earth, roughly a small apple.
Lagrange boasted that his great book on mechanics contained not a single diagram.
The feather David Scott dropped on the Moon was a falcon feather, a nod to Apollo 15's lunar module, which was named Falcon.
India's Mangalyaan cost about ₹450 crore. Prime Minister Narendra Modi pointed out that, at about ₹7 a kilometre, the trip to Mars cost less per kilometre than an auto-rickshaw ride.
The people
384 – 322 BCE · Philosopher · Greece
Taught that every motion needs a mover, an idea that lasted two thousand years.
c. 490 – c. 570 · Philosopher · Alexandria, Egypt
Argued that a thrower gives a stone its own force, not the air.
1564 – 1642 · Physicist and astronomer · Italy
Measured falling motion with ramps and water clocks, and saw that motion continues unless something stops it.
1596 – 1650 · Philosopher and mathematician · France
First printed the rule that things keep moving in a straight line.
1629 – 1695 · Physicist and mathematician · Netherlands
Solved collisions and the pull of circular motion before Newton.
1643 – 1727 · Mathematician and physicist · England
Wrote the three laws of motion and the law of gravity in the Principia.
1656 – 1742 · Astronomer · England
Asked the question that started the Principia, then edited it and paid to print it.
1706 – 1749 · Mathematician and physicist · France
Translated the Principia into French with her own commentary.
1707 – 1783 · Mathematician · Switzerland
Turned Newton's second law into the equations used today.
1857 – 1935 · Schoolteacher and rocket pioneer · Russia
Showed with Newton's laws that rockets could reach space.
Where it happened
Sources
Dates marked “c.” are approximate, and historians sometimes disagree about who was first. If you spot a mistake, tell us.
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