Download - Chapter 4 Copernican Revolution
Chapter 4
Copernican
Revolution
1. Greek Astronomer Ptolemy
2. Dawn of Modern Astronomy
3. Copernicus
4. Bruno
5. Tycho
6. Kepler
7. Galileo
8. Newton
Outline
Ptolemaic UniversePtolemy’s Universe
• The Earth is at the center of the
cosmos.
• The Earth is a sphere.
• The Earth does not move.
• Planets revolve around the
Earth
• The celestial realm is spherical,
and moves in circular orbits.
• The planets move in epicycles,
circles within circles.
Middle AgesMiddle Ages
Unfortunately, during the next thousand-odd years a vast majority
of this information was lost, ignored, or “misplaced.” This was
largely due to two factors:
1. the violent nature of these times, and
2. a heavy religious influence on ruling bodies.
Up to this point, it was still 'common-knowledge' that the Earth was
the centre of the universe.
Early Classical Astronomers
Nicolaus Copernicus 1473-1543, Polish
Tycho Brahe 1546-1601, Danish
Thomas Digges 1546-1595, English
Giordano Bruno 1548-1600, Italian
Edmond Halley 1656-1742, English
Galileo Galilei 1564-1642, Italian
Johannes Kepler 1571-1630, German
John Babtist Riccioli 1598-1671, Italian
Giovanni Cassini 1625-1712, Italian-born French
Christiaan Huygens 1629-1695, Dutch
Sir Isaac Newton 1643-1727, English
Nicolaus Copernicus 1473-1543, Polish
Tycho Brahe 1546-1601, Danish
Thomas Digges 1546-1595, English
Giordano Bruno 1548-1600, Italian
Edmond Halley 1656-1742, English
Galileo Galilei 1564-1642, Italian
Johannes Kepler 1571-1630, German
John Babtist Riccioli 1598-1671, Italian
Giovanni Cassini 1625-1712, Italian-born French
Christiaan Huygens 1629-1695, Dutch
Sir Isaac Newton 1643-1727, English
Copernican Revolution
The Copernican Revolution refers to the paradigm
shift away from the Ptolemaic model of the heavens,
which postulated the Earth at the center of the
universe, towards the heliocentric model with the Sun
at the center of our Solar System.
It was one of the starting points of the Scientific
Revolution of the 16th Century.
Paradigm - generally accepted model of how ideas relate to one
another
Copernican Revolution
Nicolaus Copernicus
• (19 February 1473 – 24 May
1543) was a Polish doctor,
Diocesan Administrator (official
of the Catholic Church), and
amateur astronomer.
• He studied the Ptolemaic model
and found it convoluted and
inaccurate.
Nicolaus Copernicus
• Copernicus' epochal book, De revolutionibus orbium
coelestium (On the Revolutions of the Celestial Spheres),
published just before his death in 1543.
• It is often regarded as the starting point of modern astronomy
and the defining epiphany that began the scientific revolution.
Nicolaus CopernicusCopernicus' heliocentric theory is based upon some of the
following assumptions:
•The Earth is not the center of
the universe, but only of the
lunar sphere.
•The sun is the center of the
universe.
•The planets orbit the Sun in
perfectly circular orbits.
•Whatever motion appears in
the celestial sphere , arises
from the Earth's motion.
Nicolaus CopernicusCopernicus' heliocentric theory is based upon some of the
following assumptions:
•The apparent retrograde and direct motion of the planets
arises not from their motion but from the Earth's.
•The planets move at different speeds.
•Thus a planet seems to go into reverse when the Earth
passes by it in its orbit.
Nicolaus Copernicus
Nicolaus Copernicus
The ideas of Copernicus made astronomy much simpler, but
more evidence was needed for astronomers to accept his ideas.
This evidence was first provided by Galileo.
Copernicus' heliocentric theory is based upon some of the
following assumptions:
Nicolaus Copernicus
Archaeologists reported they have identified the remains of
Nicolaus Copernicus.
Copernicus died at age 70 in 1543.
A Polish archaeologist told a news conference forensic
reconstruction of the skull his team found in 2005 buried in a
cathedral in Frombork, Poland, bears striking resemblance to
portraits of the 16th century astronomer.
The reconstruction shows a broken nose and other features that
resemble a self-portrait of Copernicus, and the skull bears a cut
mark above the left eye that corresponds to a scar in the painting.
Giordano Bruno
Giordano Bruno (1548 – February 17, 1600), born Filippo
Bruno, was an Italian Dominican friar, philosopher,
mathematician and astronomer.
In astronomy he is best
known as a proponent of
the infinity of the universe.
His cosmological theory
identified the Sun as just
one of an infinite number
of independently moving
heavenly bodies.
Giordano Bruno
• He is the first European
to have conceptualized
the universe as a
continuum.
• The stars we see at
night are identical in
nature to the Sun.
• He had no scientific
data to support his
claim.
Giordano Bruno
In the 19th and early 20th centuries, commentators
focusing on his astronomical beliefs regarded him as a
martyr for free thought and modern scientific ideas.
Giordano Bruno
Charges brought against Bruno by the Inquisition:
• Holding opinions contrary to the Catholic Faith and
speaking against it and its ministers.
• Holding erroneous opinions about the Trinity.
• Holding erroneous opinions about Christ's divinity and
Incarnation.
• Holding erroneous opinions about the Mass.
• Claiming the existence of a plurality of worlds and their
eternity.
• Believing in reincarnation of the human soul into animals.
• Dealing in magic and divination.
• Denying the Virginity of Mary.
Giordano Bruno
After being found guilty of heresy in 1600 by the Roman
Inquisition, he was burned at the stake.
Giordano Bruno
• Recent assessments suggest
that his ideas about the
universe played a small role in
his conviction before the
Inquisition.
• Bruno was a martyr for magic
and hermetic philosophy, and
not for free thinking and support
of the Copernican System.
Tycho Brahe
Tycho Brahe
(14 December 1546 – 24 October 1601),
born Tyge Ottesen Brahe de Knudstrup,
was a Danish nobleman known
for his accurate and
comprehensive astronomical
and planetary observations.
The Man with the Golden Nose.
Tycho Brahe
•It had been maintained since antiquity that the world
beyond the Moon's orbit was eternally unchangeable.
• On 11 November 1572, Tycho observed a NEW very
bright star in the constellation Cassiopeia.
Tycho Brahe
•Tycho’s star was a
Supernova.
•Now named SN 1572
(Supernova of 1572).
•The appearance of the
supernova caused
considerable concerns
by the general public.
This is an image of the remnant of
Tycho’s Supernova.
Tycho Brahe
•Through his observations, Tycho
was able to prove that the new
celestial body was a fixed star in
the stellar sphere beyond all the
planets.
•In 1573 he published a small
book, De nova stella thereby
coining the term nova for a "new"
star.
•We now classify this star as a
supernova and we know that it is
7500 light-years from Earth.
Tycho Brahe
•This discovery was
decisive for his choice of
astronomy as a profession.
•Tycho was strongly critical
of those who dismissed the
implications of the
astronomical appearance.
•In the preface to De nova
stella, he wrote, “Oh thick
wits. Oh blind watchers of
the sky".
Tycho Brahe
• Tycho's observations of stellar and planetary
positions were noteworthy both for their
accuracy and quantity.
• Before his time, the accuracy was on the
order of 12 arc minutes.
Tycho Brahe
• He aspired to a level of accuracy in his
estimated positions of celestial bodies of
being consistently within 1 arcminute of their
real celestial locations.
• In reality, his accuracy was very close –
approximately 1.5 arcminutes (1' 30”).
Tycho Brahe
Tycho's observations of
stellar and planetary
positions were noteworthy
both for their accuracy and
quantity.
He achieved this high level of
accuracy by his very keen
eye sight and his superior
instruments.
Tycho Brahe
Images of
Tycho’s
sextants.
Sextants for
astronomical
observations
were used
primarily for
measuring
the positions
of stars.
Tycho BraheSextants for astronomical observations were used
primarily for measuring the positions of stars.
Tycho Brahe
Tycho’s Quadrant is
a rectangular division
of the celestial sphere
that is used for
constellation
navigation.
Tycho Brahe
An armillary sphere
(as spherical
astrolabe) is a
model of the
portions of the
celestial sphere.
Tycho Brahe
Tycho’s
Celestial Globe
Tycho Brahe
Tycho’s Great
Equatorial
Armillary
Tycho Brahe
Tycho’s Wall
Quadrant at
Hevn
Tycho Brahe
Tycho advocated an
alternative to the Ptolemaic
geocentric system, a geo-
heliocentric system now
known as the Tychonic
system.
In this system, the five known
planets orbit the Sun.
The Sun (and the 5 planets)
orbit the Earth.
Tycho's model of the Earth
does not rotate daily, but is
static.
Tycho Brahe
Tycho Brahe
In this system, the five known planets orbit the Sun.
The Sun (and the 5 planets) orbit the Earth.
Tycho's model of the Earth does not rotate daily, but is static.
Tycho Brahe
King Frederick II of Denmark gave Tycho the island of
Hven.
An
island of
about 3
square
miles
Tycho Brahe
On Hven,
Tycho built
Uraniborg in
1576.
Uraniborg was
a palatial home
and
observatory.
Tycho Brahe
The building
was dedicated
to Urania, the
Muse of
Astronomy and
named
Uraninborg,
"The Castle of
Urania.”
Tycho Brahe
•The wind caused instruments in the upper floors of
Uraniborg to twist.
•To combat this, Tycho built Stjerneborg in 1581.
•Stjerneborg “castle of the stars”
•Stjerneborg is an series of underground observatories
with removable roofs.
Tycho Brahe
•The wind caused
instruments in the
upper floors of
Uraniborg to twist.
•To combat this,
Tycho built
Stjerneborg in 1581.
•Stjerneborg is an
series of
underground
observatories with
removable roofs.
Tycho Brahe
•The wind caused
instruments in the
upper floors of
Uraniborg to twist.
•To combat this,
Tycho built
Stjerneborg in 1581.
•Stjerneborg is an
series of
underground
observatories with
removable roofs.
Tycho Brahe
•The wind caused
instruments in the
upper floors of
Uraniborg to twist.
•To combat this,
Tycho built
Stjerneborg in 1581.
•Stjerneborg is an
series of
underground
observatories with
removable roofs.
Tycho Brahe
•The wind caused
instruments in the
upper floors of
Uraniborg to twist.
•To combat this,
Tycho built
Stjerneborg in 1581.
•Stjerneborg is an
series of
underground
observatories with
removable roofs.
Tycho Brahe
•The wind caused
instruments in the
upper floors of
Uraniborg to twist.
•To combat this,
Tycho built
Stjerneborg in 1581.
•Stjerneborg is an
series of
underground
observatories with
removable roofs.
Tycho Brahe
However, with the death
of his sponsor, King
Frederick, Tycho fell from
favor in the Danish Royal
Court. Tycho was forced
to leave Uraniborg.
Tycho Brahe
• On February 4, 1600, Tycho
gained an assistant of sorts,
the talented mathematician
Johannes Kepler.
• Kepler was not as skilled as
Tycho when it came to making
observations on the sky. He
had poor eye sight.
Tycho Brahe
Kepler was remarkably gifted at geometry and was
ideally suited to making sense out of the observations
Tycho had recorded.
Tycho Brahe• Tycho suddenly contracted a bladder ailment after
attending a royal banquet in Prague.
• He died eleven days later, on 24 October 1601.
•• According to
Kepler's first hand
account, Tycho had
refused to leave the
banquet to relieve
himself because it
would have been a
breach of etiquette.
• Before dying, he
urged Kepler to
adopt the Tychonic
planetary system.
Tycho Brahe
• It has been long believed that
Tycho died from kidney failure
or a ruptured bladder.
• In 1901 scientists opened his
grave and claimed to have
discovered mercury in his
remains.
• This presents the possibility
that Tycho was murdered.
• The primary suspect would
have been
Johannes Kepler.
Tycho Brahe
• In 2010 Tycho’s remains were exhumed to study.
• A chemical analysis of the corpse indicated that
mercury poisoning did not kill Tycho.
• Additionally, the Golden Nose was probably made of
brass.
Tycho Brahe
Johannes Kepler
Johannes Kepler
(December 27, 1571 –
November 15, 1630)
was a German
mathematician,
astronomer and
astrologer.
He was a key figure in
the 17th century
scientific revolution.
Johannes Kepler
Unlike his master, Tycho, Kepler was a Copernican.
Tycho’s family was very reluctant in supplying Kepler
with the data he desired to prove the Copernican
system.
So, Kepler had only one choice (at least in his mind):
Kepler stole the data.
Johannes Kepler
Kepler claimed to have had an epiphany on July 19,
1595.
He reasoned that there might be a geometric basis of
the universe and attempted to find a relation between
the five extraterrestrial planets known at that time and
the five Platonic solids.
All the sides of a Platonic solid are congruent.
Johannes Kepler
In the same year (1596),
Kepler published his
theory in Mysterium
Cosmographicum (The
Cosmographic Mystery),
was the first published
defense of the
Copernican system.
Johannes Kepler
•In Mysterium
Cosmographicum,
Kepler laid out a model
of the solar system in
which the five solids
were set inside one
another.
•The solids were
separated by a series
of spheres.
•Each sphere
represented a planet’s
orbit.
Johannes Kepler
Kepler’s CosmologyPlanet Name Platonic Solid
Number of sides
Mercury Inside the Octahedron
8
Venus Octahedron 8
Earth Icosahedron 20
Mars Dodecahedron 12
Jupiter Tetrahedron 4
Saturn Cube 6
The six spheres each corresponded to one of the planets
(Mercury, Venus, Earth, Mars, Jupiter, and Saturn).
Johannes Kepler
After working with Tycho’s data, Kepler reluctantly
concluded that his geometric scheme was wrong and
had to be abandoned.
Johannes Kepler
• In 1609 Kepler
published
Astronomia nova
(New Astronomy).
• It contains the
results of his ten-
year long
investigation of the
motion of Mars.
Johannes Kepler
Kepler bases his investigations upon the observations of
Danish astronomer Tycho Brahe.
Astronomia nova is divided into 5 parts:
Part I Tycho Brahe's data is vigorously investigated for embedded
errors.
Part II The errors of previous models of the universe is discussed.
Part III Kepler’s discussion of gravitation.
Part IV Kepler discovers that the orbit of Mars cannot be circular.
Part V Kepler's conjecture that the Sun follows some orbit across
the stars.
Johannes KeplerIn Astronomia nova Kepler records the discovery of the
first two of the three principles known today as Kepler's
Laws of Planetary Motion, which are:
The First Law: That the planets move in elliptical orbits
with the sun at one focus.
Johannes Kepler
An ellipse is a distorted circle. Has a center and
two foci.
Johannes Kepler
The orbits of the planets are ellipses with the Sun
at one focus.
Eccentricity e = c/a
c
Johannes Kepler
The orbital eccentricity of an astronomical body is the
amount by which its orbit deviates from a perfect
circle, where 0 is perfectly circular.
c
a
Orbits of planets are virtually indistinguishable
from circles:
Johannes Kepler
Planet Eccentricity
Mercury 0.21
Venus 0.01
Earth 0.02
Mars 0.09
Jupiter 0.05
Saturn 0.06
Uranus 0.05
Neptune 0.01
Pluto 0.25
Mars
Johannes KeplerThe Red circular line is Mars’ orbit. The Blue circle is a
perfect circle.
Kepler could not make Mars’ orbit fit the requirements
of a circular path.
However, the green ellipses fits Mars’ the orbit
perfectly.
Johannes KeplerThe Second Law: The orbital speed changes as the
planet moves through its orbit. As the planet
approaches the sun, its speed increases. As the
planet retreats from the sun, its speed decreases.
Johannes KeplerThe Second Law can also stated as:
That the speed of the planet changes at each
moment such that the time between two positions is
always proportional to the area swept out on the orbit
between these positions.
Johannes Kepler
•However, Kepler's "area-time principle" was very
difficult to use.
•A planet’s position could not be accurately
determined because the planet’s speed was
constantly changing.
•This paradox, referred to as the "Kepler Problem,"
could only be solved after the development of
calculus.
Johannes Kepler
Kepler discovered his third law
and published the findings in
the 1619 book, Harmonices
Mundi (The Harmony of the
World).
Johannes Kepler
The Third Law: In its simplest form, if you know how
far a planet is from the sun, you know how long its
year is.
The square of the time of 1 year of a planet is directly
proportional to the cube of the radius of its orbit."
Symbolically:
P2 ≈ a3
where P is the time of orbit period (in years) and a is
the radius of the orbit (in AU).
Johannes Kepler
Name
Orbital
radius
(AU)a3
Orbital
period
(years)P2
Mercury 0.387 0.06 0.24 0.06
Venus 0.723 0.38 0.62 0.38
Earth 1 1.00 1 1.00
Mars 1.52 3.5 1.88 3.5
Jupiter 5.2 140.6 11.859 140.6
Saturn 9.54 868 29.46 868
Uranus 19.229 7110 84.32 7110
Neptune 30.061 27165 164.79 27156
Johannes Kepler•While medieval philosophers spoke metaphorically
of the "music of the spheres", Kepler discovered
physical harmonies in planetary motion.
•He found that the difference between the maximum
and minimum angular speeds of a planet in its orbit
approximates a harmonic proportion.
Johannes Kepler
• Kepler was envious that Tycho had discovered a new
star (supernova).
• In 1604, Kepler observed a new star.
Johannes Kepler
• He recorded the finding
in De Stella nova in
pede Serpentarii (On
the New Star in
Ophiuchus's foot)
• It is the last supernova
to explode in our galaxy.
This is an image of the remnant of
Kepler’s Supernova.
Galileo Galilei
Galileo Galilei
(15 February 1564 –
8 January 1642)
Galileo was an Italian
physicist,
mathematician,
astronomer and
philosopher.
He played a major role
in the Scientific
Revolution.
Galileo GalileiAt the same time Kepler was making his
groundbreaking discoveries, Galileo was single-
handedly bringing on the downfall of naked-eye
astronomy, using a new invention called the
telescope.
Galileo Galilei
Galileo has been called:
The Father of Modern
Observational Astronomy
The Father of Modern Physics
The Father of Science
The Father of Modern Science.
Galileo GalileiGalileo did not invent the telescope, but in 1609 he
became the first person to use the telescope for
astronomy.
Galileo Galilei
Hans Lippershey, also known
as Johann Lippershey or
Lipperhey, was a German-
Dutch lensmaker commonly
associated with the invention
of the telescope, although it
is unclear if he was the first
to build one
Galileo Galilei
Galileo made a
number of
discoveries with the
telescope. In 1610,
Galileo published
these findings in a
book called
Sidereus Nuncius
(The Sidereal
Messenger).
Galileo GalileiHe discovered moons orbiting Jupiter. This showed
that the Earth is not the center of all motion.
These are Galileo’s
records of his
observations.
This is
probably
what he
saw.
This is
what we
see today.
Galileo Galilei• Draft of a letter to
Leonardo Donato, Doge
of Venice, August, 1609,
and Notes on the Moons
of Jupiter, January 1610.
• It reflects a pivotal
moment in Galileo's life
that helped to change
our understanding of the
universe.
Galileo Galilei
•The four moons (Io,
Europa, Ganymede, and
Callisto) are called the
Galilean Moons.
•Originally, Galileo
wanted to name them
after Medici brothers
(Cosimo, Francesco,
Carlo, and Lorenzo).
•Cosimo dé Medici was
the Grand Duke of
Florence.
Galileo Galilei
He observed mountains,
craters, and what looked like
oceans on the Moon.
He saw that the Moon was a
world of hills, valleys,
mountains and planes, not a
perfect, heavenly light.
Galileo Galilei•He also discovered Saturn’s Rings. Although he
initially thought that the rings were "handles" or large
moons on either side of the planet.
•He said "I have observed the highest planet [Saturn] to
be tripled-bodied.”
Galileo Galilei
Galileo in Art• Painted in 1636 (shortly after
Galileo’s trial and
recantation), Peter Paul
Rubens created “Saturn
Devours His Son.”
• In the background, Rubens
included Galileo’s discovery
that “the star of Saturn is not
a single star, but is a
composite of three.”
Galileo Galilei• In 1612 Galileo was astounded when he
found that the rings he first observed a
couple of years earlier had now
disappeared.
• The rings were, in fact, edge-on from
Earth's perspective.
• Galileo inadvertently became the first
person to observe Saturn’s rings on-edge.
Galileo GalileiHe observed the phases of Venus. This was predicted
by the heliocentric model, but not the geocentric model.
These are Galileo’s
records his
observations.
Phases as Galileo may
have seen them.
Galileo Galilei
The Ptolemaic View only allows for the New or
Crescent phases of Venus.
Galileo GalileiHe also found imperfections on the supposedly perfect
body of the Sun. He discovered sunspots, and found
that the Sun rotated, like an ordinary, material object.
Galileo Galilei
He resolved the
Milky Way into a
multitude of stars,
showing that stars
were more distant
than had been
imagined, and that
some of them
were not visible to
the human eye.
Galileo Galilei
These findings were strong evidence
supporting heliocentrism (Sun-centered
universe) which was, at the time, against
the teachings of the Bible and the
Catholic Church.
Galileo was then warned by the church
not to teach heliocentrism as fact, only as
a theory.
Galileo Galilei
•The climax of Galileo's
publishing was the book,
Dialogo sopra i due
massimi sistemi del
mondo, tolemaico
copernicano (Dialogue
Concerning the Two Chief
World Systems, Ptolemaic
and Copernican).
•Published in 1632, it
compares the Copernican
system with the traditional
Ptolemaic system.
Galileo Galilei
The book is presented as a
series of discussions, over a
span of four days, among two
philosophers and a layman:
•Salviati argues for the
Copernican position and
presents some of Galileo's
views directly.
•Sagredo is an intelligent
layman who is initially
neutral.
•Simplicio, a dedicated
follower of Ptolemy and
Aristotle, presents the
traditional views and the
arguments against the
Copernican position. This engraving contains the images of
Aristotle, Ptolemy, and Copernicus.
Galileo Galilei
Biblical references Psalm 93:1, Psalm 96:10, and
1 Chronicles 16:30 include text (depending on the
translation) stating that "the world is firmly
established, it cannot be moved."
In the same manner, Psalm 104:5 says, "the Lord
set the Earth on its foundations; it can never be
moved."
Further, Ecclesiastes 1:5 states that "And the Sun
rises and sets and returns to its place".
One of the main reasons for Galileo's
condemnation in 1633 was his attack on the
Aristotelian doctrine of matter rather than his
defense of Copernicanism.
Galileo Galilei
Galileo was called to Rome in 1633 to face the Roman
Inquisition.
On 22 June 1633 Galileo, having been found guilty of
“vehemently suspect of heresy” and was forced to make a
“confession” to the Cardinals of the Holy Office of the Church.
Galileo Galilei
The sentence of the Roman Inquisition was in three essential
parts:
1. Galileo was required to "abjure, curse and detest" the
opinions that the universe was heliocentric.
Galileo Galilei
The sentence of the Roman Inquisition was in three essential
parts:
2. He was sentenced to formal imprisonment at the pleasure of
the Inquisition. On the following day this was commuted to
house arrest, which he remained under for the rest of his life.
Galileo Galilei
The sentence of the Roman Inquisition was in three essential
parts:
3. His offending Dialogue was banned, and publication of any
of his works was forbidden.
Galileo Galilei
• According to popular legend,
after recanting his theory,
Galileo allegedly muttered the
rebellious phrase Eppur si
muove (And yet it moves).
However, there is no evidence
that he actually said this or
anything similar.
• The first account of the legend
dates to a century after his
death.
Galileo Galilei
In 1835, 202 years after it was banned,
Galileo's Dialogue Concerning the Two
Chief World Systems is removed from the
Vatican's list of banned books.
Galileo Galilei
357 years later.
Thanks to his intuition as a brilliant physicist and by relying on
different arguments, Galileo, who practically invented the
experimental method, understood why only the sun could function
as the centre of the world, as it was then known, that is to say, as
a planetary system. The error of the theologians of the time, when
they maintained the centrality of the Earth, was to think that our
understanding of the physical world's structure was, in some way,
imposed by the literal sense of Sacred Scripture....
– Pope John Paul II - November 4, 1992
Sir Isaac Newton
Sir Isaac Newton
4 January 1643 –
31 March 1727
[Old Calendar System]
25 December 1642 –
20 March 1726
He was an English
physicist, mathematician,
astronomer, natural
philosopher, alchemist,
and theologian.
Sir Isaac Newton
Isaac Newton is
considered by many
scholars to be one of the
most influential people in
human history.
Sir Isaac Newton
In this work, Newton stated the three universal laws of
motion that were not to be improved upon for more than
200 years.
He used the Latin word gravitas (weight) for the effect
that would become known as gravity, and defined the
law of universal gravitation.
Sir Isaac NewtonIn the same work, Newton presented a calculus-like
method of geometrical analysis and gave the first
analytical determination of
• inferred the oblateness of the Earth (slightly
flattened sphere).
• accounted for the precession of the equinoxes as a
result of the Moon's gravitational attraction on the
Earth
• initiated the gravitational study of the irregularities in
the motion of the moon
• and much more
Note: We will spend an entire chapter exploring
Newton’s Law of Universal Gravitation and its
implications in astronomy.
TermsNicolaus Copernicus
On the Revolutions of the
Celestial Spheres
heliocentric theory
Retrograde motion
Giordano Bruno
plurality of worlds
Tycho Brahe
SN 1572
De nova stella
Sextants
Quadrant
armillary sphere
Wall Quadrant
Tychonic System
Uraniborg
Stjerneborg
Johannes Kepler
Platonic solids
The Cosmographic Mystery
New Astronomy
Kepler’s 1ST Law of Planetary Motion
Ellipse
Eccentricity
Kepler’s 2ND Law of Planetary Motion
Kepler’s 3RD Law of Planetary Motion
The Harmony of the World
SN 1604
Galileo Galilei
Telescope
Galileo’s planetary/lunar/solar discoveries
The Sidereal Messenger
Dialogue Concerning the Two Chief World
Systems, Ptolemaic and Copernican
Roman Inquisition
Isaac Newton
The Principia
Copernican Revolution
The End