The Birth of Modern The Birth of Modern AstronomyAstronomy

Renaissance: From the Renaissance: From the ancients and beyondancients and beyond

RenaissanceRenaissance• The Renaissance is marked by the The Renaissance is marked by the

rediscovery of the knowledge of the rediscovery of the knowledge of the ancient Greeks and Romans as well ancient Greeks and Romans as well as continuation of the progress of as continuation of the progress of scientific discovery.scientific discovery.

• However, it is also a time turbulence However, it is also a time turbulence in the religious sphere. Freedom of in the religious sphere. Freedom of expression is strongly curbed at expression is strongly curbed at times.times.

RenaissanceRenaissance• Great ExcitementGreat Excitement

• Columbus sails in 1492Columbus sails in 1492

• Da Vinci and MichelangeloDa Vinci and Michelangelo

• The Catholic church is questioned by The Catholic church is questioned by Martin Luther and the beginning of Martin Luther and the beginning of ProtestantismProtestantism

• The nature of the world came into The nature of the world came into question.question.

Nicolas Copernicus

Nicolas Copernicus• 1473 to 1543• He was a canon in

the Catholic Church• Good mathematician• Physician• Well Educated• In Rome for the 1500

Jubilee

Nicolas CopernicusHe wrote a book in1514 outlining his basic arguments for the Heliocentric universe.He only allowedfriends to read it anddid not put his nameon it.

Copernicus’ Axioms1. There is no one center in the universe.2. The Earth’s center is not the center of the universe.3. The center of the universe is near the Sun.4. The distance from the Earth to the Sun is

imperceptible compared with the distance to the stars.

5. The rotation of the Earth accounts for the apparent daily rotation of the stars.

6. The apparent annual cycle of movements of the Sun is caused by the Earth revolving around it.

7. The apparent retrograde motion of the planets is caused by the motion of the Earth from which one observes.

Nicolas CopernicusPtolemy Copernicus

Copernicus still believed inPerfect circular orbits

Copernicus• Since he knew that

his book De Revoltionibus would be considered heresy, Copernicus had it published by a friend after his death.

• He also pointed out gaps in Ptolemy’s model .

Copernicus• Despite the improvement

in the model of the

universe, he still believed

in the idea of perfect

circular orbits.• This made his predictions no more accurate than

Ptolemy’s and led to doubts about his theory.• Although the Church condemned the book, the

damage was already done and the world was opened to new was of thinking about the world.

Christopher Clavius• 1538 to 1612• Astronomer for Pope Leo X.• Clavius determined that the

Julian Calendar was adding 3 days too many over a period of 385 years.

• This caused the date of Easter to slip against the calendar.

• That’s a bad thing!!

Christopher Clavius• Clavius made (2) proposals:

1. The day following Wednesday October 4th 1582 should be called Thursday October 15th 1582

2. Leap years occur in all years divisible by 4 but in years ending in “00” must be divisible by 400 to called a leap year.

– 1600, 2000 yes– 1700, 1800, 1900, 2100 No

Pope Gregory X is credited for instituting the newCalendar and today it is known as the

Gregorian Calendar.

Tycho Brahe• 1546 to 1601• Tycho studied medicine, law,

mathematics, astronomy, and politics.

• A supernova seen in 1572 turned his attentions toward astronomy permanently.

• He constructed observatories at Hven

• After closing Hven due to the political environment, he became the Imperial Mathematician to the Holy Roman Empire in Prague.

Tycho Brahe• Tycho was a great maker

of astronomical instruments.

• He was able to measure the positions of hundreds of stars to within 4’.

• Because he found great errors in the Alphonsine tables he decided to create his own Rudolphine Tables

• He measured the positions of the planets to within 2’.

Tycho Brahe• Tycho had devised

his own unique model of the universe where the moon and the sun revolved around the Earth but all of the planets went around the Sun.

• He hoped to use his data tables to prove his hypothesis

Tycho Brahe• Kepler applied to work at

Tycho’s observatory.• Tycho recognized his

talents quickly and set him to work on the Rudolphine tables with the purpose of finding the laws of planetary motion.

• Unfortunately Tycho died less than two years later, before Kepler worked out his first two laws. (1601)

Giordono Bruno• 1548 to 1600• He was an ordained priest

by the Catholic Church.• He believed in many

heretical ideas.• Here are just a few:

– He believed that there was no center to our universe

– the universe was infinite.– He believed other stars

were suns– He believed in atoms

Giordono Bruno• He believed in atoms• Because of his views, he

was persecuted by many different churches and peoples.

• Ultimately he went back to face trial in the Vatican.

• The trial lasted 7 years before he was found guilty and sentenced

Giordono Bruno

Giordono Bruno

Giordano Bruno

• Giordano Bruno was publicly burned at the stake on Feb 17th, 1600.

• This was the year of the Jubilee celebration.

• Bruno was easily 200 years ahead of his time.

Galileo Galilei• 1564 to 1642• Very talented

mathematician• Excellent

experimenter and astronomer

• Originally trained in medicine but never completed the degree

Galileo Galilei

Galileo Galilei• Strong believer in the

Copernican system.• Understood that an object

that is dropped will fall straight down, not left behind because of the Earth’s rotation!

• Used a telescope to look at the heavens and made improvements in quality and magnification.

Galileo GalileiDiscoveries

• Venus has phases that shows it orbits the Sun.• The Moon is covered with mountains, valleys, and

craters (Imperfect).• The Sun is covered with spots (Imperfect) that come

and go and the rotation is measured.• Jupiter has moons that clearly do not orbit the Earth.• He also found that the innermost moon was fastest

and they moved slower as they became farther away (just as Copernicus’ system)

• Saturn is not round (rings)• The Milky Way is the result of a larger number of stars

that are too faint too be seen by the eye.

Galileo Galilei• Galileo wrote a book

in Italian about the new evidence for the Copernican system.

• He ultimately faced the Inquisition and was force to renounce the Copernican system

Galileo Galilei• He was sentenced to

house arrest for the last ten years of his life.

• During that time he wrote his most complete argument for the Copernican system.

Johannes Kepler• 1571 to 1630• Kepler showed great

mathematical talent as a youth

• Studied at the University of Tubingen (in modern Germany)

• Became a professor at Graz

Johannes Kepler• Kepler was a member

of the Lutheran Orthodox church and even considered being ordained as a priest until his astronomy teacher convinced him to become a professor of mathematics

• Kepler had issues with his church much like Galileo.

Johannes Kepler• Kepler’s open minded

beliefs caused doubts among the clergy

• In 1612 he was excommunicated despite his position as the Imperial Mathematician (he replaced Tycho Brahae

• The ban was never lifted

Johannes Kepler• Kepler’s first

cosmological model was based on solid geometric shapes and met with good agreement of the orbits. 1596

• When Tycho Brahae received Kepler’s book Mysterium Cosmographicum he immediately hired Kepler!

Johannes Kepler• Tycho set Kepler on

the task of solving Mars’ orbit.

• Kepler used Tycho’s massive amount of planetary data to work out the three Laws of Planetary motion.

• The first two laws came quickly but the third took almost 10 years to complete

Johannes Kepler• At the core of Kepler’s

work is the undying belief in the Copernican Helio- centric system

• Kepler’s 1st Law – The orbits of the

planets are ellipse with the sun at one foci of the ellipse

Johannes Kepler

Johannes Kepler• Kepler’s 2nd Law• Planets sweep out

an equal area in equal time.

• This address the issue of planets moving at different speeds depending on what part of their orbit they were in and the systematic change in brightness

Johannes Kepler• Kepler’s 3rd Law• The square of the period

of a planet is proportional to the cube of its average distance from the Sun.

• T2 = k·r3

• This law took almost ten years to formulate and allows near perfect predictions of planet locations

Johannes Kepler• Kepler’s other scientific

contributions include error analysis, optics, Algorithms proof, early steps toward calculus, astronomical tables, astrology.

• He defended his mother in a witchcraft trial where she was later acquitted

Isaac Newton• 1643 to 1727• Born and raised on a

farm, Newton was relatively useless as a farm hand.

• He showed great promise in school and later attended Trinity college in London where he graduated with a degree in math in 1665

Isaac Newton• The college was shut

down for two years due to the plague so Newton returned home to the farm.

• Here he formulated some of his greatest achievements.

• These include:

Isaac Newton• The Law of Universal

Gravitation• Invention of Calculus• 3 Laws of Motion• Optical

advancements• Nature of light and the

spectrum

Isaac Newton• 3 Laws of Motion

1. All objects resist changes in their state of motion unless acted on by an outside net force (law of inertia)

Isaac Newton• 3 Laws of Motion

2. If an object is acted on by an outside net force, it will accelerate according to the following formula

a=F/m

Isaac Newton• 3 Laws of Motion

3. For every force there exists an equal and opposite force

often called

action-reaction law

Isaac Newton• Law of Universal

Gravitation• Newton’s great

revelation was that the same force that pulls an apple toward the surface of the Earth is the same force that holds the moon in orbit

Isaac NewtonGM1M2

F = ----------------- r2

Newton imagined a cannon fired from high mountain.With enough speed the falling cannon ball would match the curve of the earth and remain at the same height above the surface, returning to the cannon from the other side

Isaac Newton• After returning to

Cambridge University as a professor, He became the Lucasian Professor of Mathematics. 1669

• This position is held by Steven Hawking today

Isaac Newton• Newton was later hired

as the head of the British mint.

• He was in charge of finding and prosecuting counterfeiters

• He often went undercover and ultimately convicted more than 10 counter-feiters who were executed

Isaac Newton• Newton conducted hundreds of

experiments on light and discovered the origin of the spectrum created by prisms

• Newton also

invented the

reflecting

telescope

Isaac Newton• Much of Newton’s life was

filled with controversy.• He fought with many other

scientists and mathematicians over who was the discoverer of various ideas.

• These included Leibnitz (calculus) and Hooke (optics) and several others.

Isaac Newton• Newton is often credited as

the greatest scientist of all time.

• He impacted more areas of science and even invented an entire branch of mathematics called calculus.

• He was knighted among his many honors and served as president of the Royal Society (a scientific watchdog)

• He was ill for the last two years of his life and was buried in Westminster Abbey after his death.

Isaac NewtonFamous Quotes

“If I have seen further it is by standing on the shoulders of giants”

“I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing

on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell

than ordinary, whilst the great ocean of truth lay all undiscovered before me”