1 . Five Great Men
There are five men who are principally responsible for wresting our view of the Cosmos from the province of myth and/or religion. They are Nicolaus Copernicus, Tycho Brahe, Galileo Galilei, Johann Kepler, and Sir Isaac Newton. Individual writers tend to focus on one or another of these men, such as Carl Sagan focusing primarily on Kepler and not even mentioning Galileo. But there is no doubt that the great idea which began with the view of Copernicus that the Sun was the true center of the solar system and ended with Newton's formulation of the laws of gravity could not have been achieved without the great contributions of each man. Let us take a moment to assess them.
a. Nicolaus Copernicus (1473-1543)
The six volume set
which comprised his life's work was finally published at about the same
time he died. While he formulated the basic ideas in it no later than
1514, the work was considered so controversial, because of its Sun
centered universe as opposed to the accepted Earth centered universe,
that he still hesitated to publish it in spite of an "official"
invitation to do so from the pope, issued in 1536.
The work was intended as a mathematical reinterpretation of Ptolemy.74
His stated motivation was to increase the accuracy of calendars, a goal
which was seen as an acceptable one. In his books, he correctly
describes such phenomena as the precession of the equinoxes being
caused by the gyration of the axis of rotation of the Earth. But sadly,
he clung to the erroneous idea that the orbits of the planets around
the Sun had to be circular, and this caused him to devise complicated
distortions, of roughly the same complexity as those of Ptolemy which
he sought to supplant, to account for the observed phenomena, such as
the retrograde motion of the planets.75
The views of Copernicus, that
the Sun was the center of the solar system, had some other implications
for our overall world view. If the Earth was not the fixed center of
the universe, then the universe had to be much larger to account for
the observed fixed positions of the stars. Also, the view that things
"naturally" fell towards the center of the Earth (which was the center
of the universe) could no longer be unquestioningly accepted, and this
led eventually to Newton's laws of gravitation.
b. Galileo Galilei (1564-1642)
Galileo was born
two decades after the death of Copernicus, and by the time he began his
studies, his mind was ready to wholeheartedly accept the Sun centered
view of the universe which Copernicus had proposed. However, a 1597
letter to Kepler discloses that he feared to advocate the theory of
Copernicus.
Galileo did not actually
invent the telescope, but as a trained astronomer, he was the first to
put this invention to the obvious use of studying the stars in a
methodical way. What Galileo actually invented was a method for
checking the curvature of the lenses, and this manufacturing technique
resulted in a great demand for telescopes of his. From late in 1609,
Galileo announced a series of discoveries about the Sun, the Moon, and
the stars which would eventually revolutionize our understanding of the
universe.
The controversy begun by these
observations of Galileo, taken in combination with the book of
Copernicus, led to a decree issued on March 5, 1616 which declared the
book of Copernicus to be "false and erroneous" as a matter of religious
faith.76
Accordingly, Galileo was careful to obtain prior approval of his 1632
book which discussed at length the two contrasting world views of
Copernicus and the ancients. But thorough readers of the book noted
that the conclusion he reached, that the classical system was
"correct," seemed so artificial and contrived that the book would
actually enhance the position of Copernicus and thereby undermine the
authority of the pope and his decree. Thus, in spite of his prior
license to publish, Galileo was prosecuted by the Inquisition in 1633
(many believe the principal evidence against Galileo was a forgery),
forced to recant, and sentenced to house arrest for the remainder of
his life. In spite of this, Galileo continued to work and correspond
with other scientists right up until his death in 1642.
c. Tycho Brahe (1546-1601)
Tycho Brahe, born
three years after the death of Copernicus, was also easily able to
accept the radical ideas of the Polish astronomer. In 1576, Brahe
established a great observatory under the patronage of King Frederick
II of Denmark. Surrounded by scholars, and visited by learned travelers
from all over Europe, Brahe and his assistants collected a series of
astronomical observations which corrected nearly every known prior
record of the paths of various bodies through the heavens.
The death of Frederick in
1588, and the subsequent disputes with his heir over the funds to be
allocated to his use, led eventually to his departure in 1597, and his
later appointment to the court of the Holy Roman Emperor, Rudolf II, in
Prague during 1599. In 1600, he was joined by Johann Kepler, who
carried on his work after Brahe died the next year.
Brahe was in no way a
theoretician. His great body of observations would find no practical
use until Kepler would be forced by them to once again alter our view
of how things worked. His contributions can be measured as three-fold:
1) the concept that man could carefully construct scientific
instruments to observe natural phenomena; 2) the concept that a
group of scholars could work cooperatively to produce a large body of
scientific knowledge simply for the sake of having it; and 3) the
concept that knowledge had a quality which was related to the precision
of the scientific observations and the care with which those
observations were recorded for posterity, a quality which Brahe tried
to demonstrate as well by having the finest craftsmen used to print and
bind the books in which his accumulated knowledge was distributed.
d. Johann Kepler (1571-1630)
Kepler started his
education with the idea of becoming a Lutheran minister, but this idea
was sidetracked by those who quickly recognized the greatness of his
mind. He tried to teach, but the principal result of his teaching was a
vision, totally erroneous, of a relationship between the six known
planets and the six so-called "perfect" solids.77
This vision was to haunt Kepler all of his life, because he could never
make it work out. But it motivated Kepler to pursue a career as an
astronomer and astrologer.
In 1600, Kepler joined the
staff of Tycho Brahe in Prague, and when Brahe died the next year,
Kepler was promptly appointed to replace him. In 1602, Kepler published
his first book at Prague, which supported the prevailing view that the
stars guide the lives of men. As a highly skilled mathematician, his
horoscopes were in great demand. We tend to overlook this aspect of his
life, but it is the principal factor which allowed him to survive in
the harsh world of seventeenth century Europe.
Using decades of observations
accumulated by Brahe and his assistants, Kepler derived the first two
of his three laws of planetary motion, which he published in 1609. But
before he could correctly interpret the observed results, he first had
to amend our understanding of optics. His 1604 book provided the
foundation for all of the advances in our understanding of the workings
of the human eye, including the actual reason that eyeglasses work
(even though they had been made for roughly three centuries before).
Kepler took the concept of a
Sun centered solar system from Copernicus, but was forced by the
accumulated effect of the observations of Brahe and his associates to
discard the circular orbits which Copernicus refused to abandon.
Instead, Kepler was led to an accurate description of planetary orbits
as an ellipse, with the Sun at one focus of the ellipse. But an
elliptical orbit was incompatible with a theory of uniform motion,
which required the planets to always move at the same velocity. So, the
second law of Kepler held that, instead of traversing an equal arc in
an equal amount of time (uniform velocity), the planets would cover an
arc which would describe an equal area as related to the focus at which
lay the Sun. This requires the planets to slightly speed up and slow
down as they traverse their orbits. Ten years later, in 1619, he
published his third law of planetary motion, holding that the cube of
the planet's average distance from the Sun was at a constant ratio to
the square of the time required for the planet to complete its orbit.
Each of the above laws was
derived by using the fundamentals of scientific method: carefully
recorded observations; carefully calculated mathematical formulas; and
a willingness to accept an answer which these two forces demanded.
However, Kepler was tragically
affected by the upheavals occurring during his life. In 1620, he was
forced to rush to the defense of his mother, who had been accused of
witchcraft. Because of the Thirty Years' War, and various consequences
thereof, he was unable to publish his final collection of his thoughts
about his life's work until 1627. On his way to collect interest due to
him so he could continue working, he fell ill and died on November 15,
1630. If the location of his grave was in any way recorded, the Thirty
Years' War obliterated that record.
While Kepler was quick to
acknowledge his debt to Galileo, who actually survived Kepler, it
appears that Galileo did not return the favor and acknowledge the
contributions of Kepler. Like Copernicus, Galileo was stuck on the idea
of perfect circular orbits, and that myopic view even prevented Galileo
from producing an even greater contribution with his final work in the
field of inertia. Thus it was left to another to tie it all together.
e. Sir Isaac Newton (1643-1727)78
Sir Isaac Newton
is arguably one of the greatest geniuses which mankind has ever
produced. He invented whole new fields of mathematics because he needed
tools which would allow him to solve the great scientific questions of
his time. It was left to Newton to finally draw together the
fundamental principals of our modern view of the Cosmos.
Newton was born just months
after the death of Galileo, but had a very troubled childhood which
contributed an erratic nature to his interactions with other people. It
is believed he was a virgin at the time of his death, having never
developed a love for any person which would draw him away from his
scientific studies.
When Newton arrived at
Cambridge in 1661 to attend Trinity College, the schools were still
mired in teaching the Earth centered universe of Aristotle and Ptolemy,
even though it had been about 118 years since Copernicus had published
his great work. But the rebellious students of that time, including
Newton, found plenty of time and motive to study the writings of the
new breed of scientists. Newton wrote: "Plato is my friend, Aristotle
is my friend, but my best friend is truth." This philosophy launched
Newton on his path to scientific greatness.
Beginning from the natural
philosophy and geometry of René Descartes, Newton formed the
foundations of the mathematics of infinite series, which we now call
Calculus, and in 1669 he wrote down his first thoughts on this subject.
A revised version issued two years later established Newton as the
leading mathematician of Europe, in spite of the fact that his work was
known to only a few savants.
As if his contributions to
mathematics were not enough, while forced to sit idly at home during
the plague years of 1665-1667 he developed his inverse square law79
and an essay on Color. The essay was eventually expanded to a
university course in optics, which he taught from 1670-1672. His work
on refractive analysis led him to believe that lenses would always
distort the colors passing through them, so he designed the first
reflecting telescope based upon a large curved mirror. This telescope
came to the attention of the Royal Society of London in 1671, and by
1672, Newton had been elected as a member and had presented his first
paper on optics to that society. However, less than a year later, the
irrational rage grew within Newton, who could not take any criticism of
his work from anyone, and beginning in 1672, Newton withdrew into
virtual isolation. By 1678, Newton had apparently suffered a complete
nervous breakdown, and he would only most grudgingly return answers to
correspondence directed to him.
Nonetheless, during this
period of isolation, Newton continued to think about the subject of the
orbital dynamics of planetary motion. After a 1684 visit from Edmund
Halley, Newton wrote a short piece titled "On Motion." While working on
a revision to that piece, Newton finally embraced the idea of inertia
which had eluded Galileo, and this led to his first two laws of motion:
1) a body at rest remains at rest unless compelled to change by an
outside force; and 2) when a force acts on a body, the change in
the motion (meaning velocity times mass) of the body is proportional to
the force impressed on the body. Eventually, the third law of motion
was added: 3) to every action, there is an equal and opposite
reaction. Analyzing these three laws in light of Kepler's third law and
the known facts about the moons of Jupiter and our own moon eventually
led Newton to the law of universal gravitation: every particle of
matter in the universe attracts every other particle of matter in the
universe with a force which is proportional to the product of their
masses and inversely proportional to the square of the distances
between their centers. This all grew into the culminating work of his
life, Mathematical Principles of Natural Philosophy, first published in 1687.
After the publication of the
first edition of his greatest work, Newton became involved with the
Protestant resistance to the attempt of King James II to restore the
Roman Catholic faith in England. This involved him with politics, and
exposed him to the excitement of life in a big city, London. No longer
content with the quiet of an academic cloister, in 1696 Newton obtained
an appointment as warden and then master of the mint, a position which
gave him a considerable income of up to £2,000 per year. With his move
to London secure, his creative years were essentially at an end. But he
began to receive recognition for his accomplishments, including a
knighthood bestowed by Queen Anne in 1705. He continued to revise and
publish new editions of his scientific works until his death. However,
if there was any intellectual passion remaining in him, he devoted that
to studies of religion. In fear of persecution as an unbeliever, he
refused to allow any of his religious writings to be published until
after his death. But it must be seen that this attempt to apply the
rules of scientific inquiry to a study of the bible, its origins, and
its chronology would have far reaching implications for Western
Civilization, implications which we have not yet fully digested to this
day.
74 Very little is known of the life of Ptolemy. Working backwards from modern mathematical models of the universe, it is possible to date his observations to the second century, a. d. A contemporary wrote that Ptolemy was actively working at the library in Alexandria during 127 a. d. through 145 a. d., with possible activity as late as 151 a. d. (see Encyclopaedia Britannica.) His thirteen volume work of astronomical observations and the mathematical description of his Earth centered universe was of such great value to three civilizations, Classical, Arabian, and Western, that it survives to this day. In fact, the Christian church was so enamored of the erroneous Earth centered universe that it used all its power to suppress opposing points of view, thereby contributing mightily to roughly fourteen centuries of no progress in the sciences.
75 The word "planet" comes from the Greek word meaning "wanderer." The planets were "stars" which appeared to "wander" through the heavens. An observer on the Earth will see a planet moving along gradually in the night sky, proceeding from one constellation to another. Retrograde motion occurs when the Earth, as it moves through its own orbit, overtakes the current position of another planet, causing the other planet to make an apparent "loop the loop" through the constellations. This looping action, now well understood, was quite disturbing to ancient thinkers.
76 The "false and erroneous" declaration was due to the challenge to Aristotle and Ptolemy and their Earth centered universe, not due to the errors which modern science can show.
77 The six solids are the sphere, the tetrahedron, the cube, the octahedron, the dodecahedron, and the icosahedron. The sphere has no sides, and each of the other has all of its edges as exactly the same length. Given that constraint, no other solids are possible.
78 Remember, a stated motivation for Kepler was to produce a more accurate calendar. In 1582, Pope Gregory XIII promulgated the calendar still in use today, but it was not adopted in England or its colonies until the eighteenth century. Nonetheless, I have given the "new style" date of birth here.
79 The inverse square law holds that any force acting radially on a planet decreases with the square of the distance of the planet from the Sun. This law was the first step in the development of his law of universal gravitation.
