Gravity Timeline
Category: Other
Updated: 28 Feb 2020
Contributors
Created byRon Berglund
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Events
Newton Publishes His Book (1687)
The book outlines the universal
law of gravity, and finally made
accurate predictions of planetary motion.Pseudo-Planet (1859)
Urbain Le Verrier observed the strange orbit
of Mercury. He proposed that a planet
called "Vulcan" must exist, and would
account for the oddities of Mercury's orbit.
No such planet would ever be observed,
but rather Einstein's theories would later explain
the observations.Early Concepts of Gravity (4th Century BCE)
Very early Greek/Indian concepts
from philosophers such as
Aristotle described gravity as
some intrinsic property of
heavy bodies (Earth) versus light bodies (fire).
Heavy objects were also believed to fall faster.
These beliefs were held for nearly 2000 years.Galileo Galilei (1600s)
Gelileo found that all objects
accelerate equally towards Earth
in free fall; regardless of their weight.Theory of Relativity (1905-1915)
Albert Einstein would redefine physics;
he proposes mass and energy are equivalent.
Gravity is the result of the warping of spacetime,
predicts gravitational waves, & black holes.
This theory was strengthened when it predicted
Mercury's orbit, as previously mentioned.Gravitational Lensing (1919)
Einstein's theory would indicate that
large enough bodies would bend light.
This was confirmed when in 1919, during
the total solar eclipse, stars near the sun were
apparently out of position. The sun's large
mass would account for the light bending.Hawking Radiation (1974)
Einstein's theory conflicted with quantum physics.
The boundary of a black hole couldn't exist
in the smooth spacetime, if the black hole is composed of
granular energy required by quantum physics.
Hawking solved this with Hawking Radiation:
black holes are emitting energy.
Quantum Gravity is still a working concept.Gravitational Wave False Alarm (1969)
Joseph Weber claimed he had detected gravitational waves.
These waves were predicted in Einstein's Theory
of General Relativity,but Weber's results could
not be reproduced.Muslim Scientists (1000s)
Muslim physicists, mathematicians, & astronomers began advancing
parts of physics.
Al-Biruni argued that all heavenly
bodies have mass & gravity like Earth, criticizing
Aristotle and previous Muslim Scholars.
Ibn Bajjah proposed a very early version of the
third law of motion
(every action has an equal & opposite reaction).
However, Bajjah, like Galileo, would attempt to
explain planetary orbits without gravity.
These ideas wouldn't be widely accepted until later.Gravitational Waves Confirmed (2016)
After rigorous checks, the LIGO team confirmed
that they had detected gravitational waves.
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