The Renaissance
During the Renaissance, great advances
occurred
in
geography,
astronomy,
chemistry,
physics,
mathematics,
manufacturing, and engineering. The
rediscovery of ancient scientific texts was
accelerated after the Fall of Constantinople
in 1453, and the invention of printing which
would democratize learning and allow a
faster propagation of new ideas. But, some
see the Renaissance as one of scientific
backwardness. Humanists favored humancentered subjects like politics and history
over study of natural philosophy or applied
mathematics. Others have focused on the
positive influence of the Renaissance,
pointing to factors like the rediscovery of lost
or obscure texts and the increased emphasis
on the study of language and the correct
reading of texts.
Scientific Revolution
In the history of science, the Scientific Revolution was a period
when new ideas in physics, astronomy, biology, human
anatomy, chemistry, and other sciences led to a rejection of
doctrines that had prevailed starting in Ancient Greece and
continuing through the Middle Ages, and laid the foundation of
modern science. According to most accounts, the scientific
revolution began in Europe towards the end of the Renaissance
era and continued through the late 18th century, the latter period
known as The Enlightenment. It was sparked by the publication
(1543) of two works that changed the course of science:
Nicolaus Copernicus's De revolutionibus orbium coelestium (On
the Revolutions of the Heavenly Spheres) and Andreas
Vesalius's De humani corporis fabrica (On the Fabric of the
Human body).
State of the World
Spain and Portugal explored the world's seas and opened worldwide oceanic trade routes. Large parts of the New World
became Spanish and Portuguese colonies, and while the
Portuguese became the masters of Asia's and Africa's Indian
Ocean trade, the Spanish opened trade across the Pacific
Ocean, linking the Americas with Asia.
In Europe, the Protestant Reformation gave a major blow to the
authority of the Papacy and the Roman Catholic Church.
European politics became dominated by religious conflicts, with
the groundwork for the epochal Thirty Years' War being laid
towards the end of the century.
State of the World
In the Middle East, the Ottoman Empire continued to expand, with
the Sultan taking the title of Caliph, while dealing with a
resurgent Persia. Iran and Iraq were caught by major popularity
of the once-obscure Shiite sect of Islam under the rule of the
Safavid dynasty of warrior-mystics, providing grounds for a
Persia independent of the majority-Sunni Muslim world.
China evacuated the coastal areas, because of Japanese piracy.
Japan was suffering under a severe civil war at the time.
Mughal Emperor Akbar the Great tried to reconcile the major
religions by founding a new religion, Din-i-Ilahi. Akbar was
convinced that no religion has the absolute truth.
Pythagorean Paradigm
1. The planets, Sun, Moon and stars move in perfectly circular
orbits;
2. The speed of the planets, Sun, Moon and stars in their
circular orbits is perfectly uniform;
3. The Earth is at the exact center of the motion of the
celestial bodies.
Plato was teaching this geocentric view of the universe.
Only Aristarchus, one of his students, dared to oppose this
view putting the Sun at the center of the universe, but his view
was not accepted by the Greeks.
Plato’s Reasoning:
1. The Earth is not part of the heavens.
2. The celestial objects are bright points of
light while the Earth is an immense,
nonluminous sphere of mud and rock.
3. The Greeks saw little change in the
heavens---the stars are the same night
after night. In contrast to this, they saw the
Earth as the home of birth, change, and
destruction.
4. Finally, our senses show that the Earth
appears to be stationary! Air, clouds, birds,
and other things unattached to the ground
are not left behind as they would be if the
Earth was moving. There should be a
strong wind if the Earth were spinning as
suggested by some radicals.
Retrograde motion
Ordinarily, planets will wander eastwards among the stars.
But sometimes they slow down, stop and start to move westwards.
Then they stop, start to move eastward again.
And when this happens, the planets appear brighter.
This retrograde motion has been one of the biggest mysteries of antiquity.
Epicycles
Aristotle’s model:
geocentric universe
planets moving around the
Earth on crystalline spheres.
Ptolemy:
Refined Aristotle’s model with
the addition of epicycles.
Almagest – 13 volume set of
astronomy
Stood for 1500 years
Ockham’s Razor
By the 16th century the following paradigm had developed: Man is
God's special creation of the physical universe; the Earth is the
center of a mathematically-planned universe and we are given the
gift of reading this harmony.
Scientists use a guiding principle called Ockham's Razor to choose
between two or models that accurately explain the observations.
the best model is the simplest one---the one requiring the fewest
assumptions and modifications in order to fit the observations.
Guided by Ockham's Razor some scientists began to have serious
doubts about Ptolemy's geocentric model in the early days of the
Renaissance.
Copernicus
He lived between 1473-1543 C.E.
Ptolemaic model was un-Godlike.
Life-giving force should be at the
center of the universe  Sun gives
life, so Sun must be at the center
Inner planets are faster, outer planets
are slower  explains the retrograde
motion of the planets
Giardano Bruno
Bruno (1548 – February 17, 1600), was
an Italian Dominican friar, philosopher,
mathematician and astronomer, who is
best known as a proponent of the infinity
of the universe. His cosmological
theories went beyond the Copernican
model in identifying the Sun as just one
of an infinite number of independently
moving heavenly bodies: he is the first
European to have conceptualized the
universe as a continuum where the stars
we see at night are identical in nature to
the Sun. He was burned at the stake by
civil authorities in 1600 after the Roman
Inquisition found him guilty of heresy and
turned him over to the state, which at
that time considered heresy illegal.
Tycho Brahe
Tycho Brahe (lived 1546--1601 C.E.)
revived Heroclides' model that had the
all of the planets, except the stationary
Earth, revolving around the Sun. Brahe
believed that the Sun, Moon, and stars
revolved around the Earth. Tycho's
model was mathematically equivalent
to Copernicus' model but did not
violate Scripture and common sense.
Stars must be at least 700 times more
distant than Saturn.
Made his observations on Uraniborg,
small island in Denmark.
In 1600, Kepler became his assistant.
Johannes Kepler
Kepler (lived 1571--1630 C.E.) was
hired by Tycho to work on the
geocentric theory.
After the death of Tycho, he started
working as the court matematician to
Bavaria.
He had all of Tycho’s data to work
with.
In 20 years he developed three laws,
simple and obvious for us, but a
major revolution for his time.
Kepler’s Laws
Both Copernican and Ptolemaic theories agreed on one major point:
God was perfect  God created the universe  the universe must be
perfect
The circle is the perfect shape  whatever was rotating around
whatever else, the orbit must be a circle.
Kepler’s First Law: Planetary orbits
are ellipses with the Sun at one focus.
Kepler’s Laws II
Kepler’s Second Law:
a line between the planet
and the Sun sweeps out
equal areas in equal times
A planet’s speed changes
with it’s distance from the
Sun.
Kepler’s Third Law:
(a planet's period of rotation
in years)2 = (semimajor axis
of its orbit in A.U.)3.
Galileo Galilei
Galileo Galilei (1564 – 1642) was an Italian physicist, mathematician,
astronomer and philosopher who played a major role in the Scientific
Revolution. His achievements include improvements to the telescope
and consequent astronomical observations, and support for
Copernicanism.
Galileo Galilei
Controversy with Father Orazio Grassi over the nature of the comets
Observed the craters on the Moon  Moon was not perfect.
Observed Jupiter’s moons  Jupiter also had moons.
Venus had phases just like the moon  Ptolemaic theory did not allow
this.
Galileo Galilei
Galileo's championing of Copernicanism was controversial within his
lifetime, when a large majority of philosophers and astronomers still
subscribed to the geocentric view. After 1610, when he began publicly
supporting the heliocentric view, he met with bitter opposition from some
philosophers and clerics, and two of the latter eventually denounced him
to the Roman Inquisition early in 1615. In February 1616, although he
had been cleared of any offence, the Catholic Church nevertheless
condemned heliocentrism as "false and contrary to Scripture", and
Galileo was warned to abandon his support for it—which he promised to
do. When he later defended his views in his most famous work, Dialogue
Concerning the Two Chief World Systems, published in 1632, he was
tried by the Inquisition, found "vehemently suspect of heresy", forced to
recant, and spent the rest of his life under house arrest.
Newton's Laws
Newton’s 1st Law: A body at rest remains at
rest, and one moving in a straight line
maintains a constant speed and same
direction unless it is deflected by a “net force”.
Newton’s 2nd Law: The force applied = mass
of an object × acceleration
F = ma
Newton’s 3rd Law: For every action force ON
an object, there is an equal but opposite force
BY the object .
Newton’s Law of Gravitation
Centripetal force:
F = Mmv2/D
Gravitational force: F = GMeMm/D2
Gravitational Force = Centripetal Force and
v = 2D/P  Me = v2Rm/G = (42/G)(D3/P2)