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Period: 300 to
Gravity
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340
Aristotle (BC)
objects with different weights fall at different speeds; rocks fall to center/fire rises -
400
Ptolemy (140 AD)
accredited with geocentric theory; theory that earth is the center of the universe; because the earth was seemingly at rest, other objects must orbit around it -
Galileo Galilei
Galileo formulated the equation for a falling body or an object moving in uniform acceleration: d=1/2gt2; dropped objects from leaning tower of Pisa to prove all objects, no matter mass, fall at same rate -
Isaac Newton
any two objects in the Universe exert gravitational attraction on each other, with the force having a universal form; thought upon after seeing apple fall; Newton's orbital cannon proved that if cannon was fired horizontally from mountain, it would either fall or orbit, depending on velocity. -
Henry Cavendish
measured the value of G in the equation for the law of universal gravitation; used this to discover the mass of the sun; obtained using the torsion balance technique: When two heavy attracting bodies are placed on opposite sides of a dumbbell, the dumbbell twists by a very small amount. the magnitude of the twists gives us G. -
Albert Einstein
gravity was part of general theory of relativity; said gravity was not a force, but a curve in space-time; based on a idea that due to gravity, objects moving on straight parallel line will intersect because there paths become spherical.
