1643 – 1727
Sir Isaac Newton
"Nature and nature's laws lay hid in night; God said 'Let Newton be' and all was light."
— Alexander Pope
laws that moved the world
Lex I
Law of inertia: Every body perseveres in its state of rest, or of uniform motion in a right line, unless compelled to change by forces impressed.
— Philosophiæ Naturalis Principia Mathematica
Lex II
F = m·a The change of motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed.
— the second law, 1687
Lex III
Actioni contraria To every action there is always opposed an equal reaction; or the mutual actions of two bodies upon each other are always equal.
— action = –reaction
I have not as yet been able to discover the reason for these properties of gravity from phenomena, and I do not feign hypotheses.
The apple & gravity
Legend says Newton, watching an apple fall, began contemplating gravity. Click the apple to see what thought struck him.
An apple falls straight down ...
fluxions → calculus
prism & optics