Parallel Worlds Read Online Free PDF
Author: Michio Kaku
instilling awe and fear
throughout Europe. Everyone, it seemed, from peasants to kings, was mesmerized
by this unexpected celestial visitor which swept across the heavens. Where did
the comet come from? Where was it going, and what did it mean?
One wealthy
gentleman, Edmund Halley, an amateur astronomer, was so intrigued by the comet
that he sought out the opinions of one of the greatest scientists of the day,
Isaac Newton. When he asked Newton what force might possibly control the motion
of the comet, Newton calmly replied that the comet was moving in an ellipse as
a consequence of an inverse square force law (that is, the force on the comet
diminished with the square of its distance from the sun). In fact, said Newton,
he had been tracking the comet with a telescope that he had invented (the
reflecting telescope used today by astronomers around the world) and its path
was following his law of gravitation that he had developed twenty years
earlier.
Halley was
shocked beyond belief. "How do you know?" demanded Halley.
"Why, I have calculated it," replied Newton. Never in his wildest
dreams did Halley expect to hear that the secret of the celestial bodies, which
had mystified humanity since the first humans gazed at the heavens, could be
explained by a new law of gravity.
Staggered by the
significance of this monumental breakthrough, Halley generously offered to pay
for the publication of this new theory. In 1687, with Halley's encouragement
and funding, Newton published his epic work Philosophiae Naturalis Principia Mathematica (Mathematical Principles of
Natural Philosophy). It has been hailed as one of the most important works ever
published. In a single stroke, scientists who were ignorant of the larger laws
of the solar system were suddenly able to predict, with pinpoint precision, the
motion of heavenly bodies.
So great was the
impact of Principia in the salons
and courts of Europe that the poet Alexander Pope wrote:
Nature and
nature's laws lay hid in the night,
God said, Let Newton Be! and all was
light.
(Halley realized
that if the comet's orbit was an ellipse, one might be able to calculate when
it might sail over London again. Searching old records, he found that the
comets of 1531, 1607, and 1682 were indeed the same comet. The comet that was
so pivotal to the creation of modern England in 1066 was seen by people throughout
recorded history, including Julius Caesar. Halley predicted that the comet
would return in 1758, long after Newton and Halley had passed away. When the
comet did indeed return on Christmas Day that year, on schedule, it was
christened Halley's comet.)
Newton had
discovered the universal law of gravity twenty years earlier, when the black
plague shut down Cambridge University and he was forced to retreat to his country
estate at Woolsthorpe. He fondly recalled that while walking around his estate,
he saw an apple fall. Then he asked himself a question that would eventually
change the course of human history: if an apple falls, does the moon also fall?
In a brilliant stroke of genius, Newton realized that apples, the moon, and the
planets all obeyed the same law of gravitation, that they were all falling
under an inverse square law. When Newton found that the mathematics of the
seventeenth century were too primitive to solve this force law, he invented a
new branch of mathematics, the calculus, to determine the motion of falling apples
and moons.
In Principia, Newton had also written down the laws of mechanics, the
laws of motion that determine the trajectories of all terrestrial and
celestial bodies. These laws laid the basis for designing machines, harnessing
steam power, and creating locomotives, which in turn helped pave the way for
the Industrial Revolution and modern civilization. Today, every skyscraper,
every bridge, and every rocket is constructed using Newton's laws of motion.
Newton not only
gave us the eternal laws of motion; he also overturned our worldview, giving
us a
throughout Europe. Everyone, it seemed, from peasants to kings, was mesmerized
by this unexpected celestial visitor which swept across the heavens. Where did
the comet come from? Where was it going, and what did it mean?
One wealthy
gentleman, Edmund Halley, an amateur astronomer, was so intrigued by the comet
that he sought out the opinions of one of the greatest scientists of the day,
Isaac Newton. When he asked Newton what force might possibly control the motion
of the comet, Newton calmly replied that the comet was moving in an ellipse as
a consequence of an inverse square force law (that is, the force on the comet
diminished with the square of its distance from the sun). In fact, said Newton,
he had been tracking the comet with a telescope that he had invented (the
reflecting telescope used today by astronomers around the world) and its path
was following his law of gravitation that he had developed twenty years
earlier.
Halley was
shocked beyond belief. "How do you know?" demanded Halley.
"Why, I have calculated it," replied Newton. Never in his wildest
dreams did Halley expect to hear that the secret of the celestial bodies, which
had mystified humanity since the first humans gazed at the heavens, could be
explained by a new law of gravity.
Staggered by the
significance of this monumental breakthrough, Halley generously offered to pay
for the publication of this new theory. In 1687, with Halley's encouragement
and funding, Newton published his epic work Philosophiae Naturalis Principia Mathematica (Mathematical Principles of
Natural Philosophy). It has been hailed as one of the most important works ever
published. In a single stroke, scientists who were ignorant of the larger laws
of the solar system were suddenly able to predict, with pinpoint precision, the
motion of heavenly bodies.
So great was the
impact of Principia in the salons
and courts of Europe that the poet Alexander Pope wrote:
Nature and
nature's laws lay hid in the night,
God said, Let Newton Be! and all was
light.
(Halley realized
that if the comet's orbit was an ellipse, one might be able to calculate when
it might sail over London again. Searching old records, he found that the
comets of 1531, 1607, and 1682 were indeed the same comet. The comet that was
so pivotal to the creation of modern England in 1066 was seen by people throughout
recorded history, including Julius Caesar. Halley predicted that the comet
would return in 1758, long after Newton and Halley had passed away. When the
comet did indeed return on Christmas Day that year, on schedule, it was
christened Halley's comet.)
Newton had
discovered the universal law of gravity twenty years earlier, when the black
plague shut down Cambridge University and he was forced to retreat to his country
estate at Woolsthorpe. He fondly recalled that while walking around his estate,
he saw an apple fall. Then he asked himself a question that would eventually
change the course of human history: if an apple falls, does the moon also fall?
In a brilliant stroke of genius, Newton realized that apples, the moon, and the
planets all obeyed the same law of gravitation, that they were all falling
under an inverse square law. When Newton found that the mathematics of the
seventeenth century were too primitive to solve this force law, he invented a
new branch of mathematics, the calculus, to determine the motion of falling apples
and moons.
In Principia, Newton had also written down the laws of mechanics, the
laws of motion that determine the trajectories of all terrestrial and
celestial bodies. These laws laid the basis for designing machines, harnessing
steam power, and creating locomotives, which in turn helped pave the way for
the Industrial Revolution and modern civilization. Today, every skyscraper,
every bridge, and every rocket is constructed using Newton's laws of motion.
Newton not only
gave us the eternal laws of motion; he also overturned our worldview, giving
us a