Unit 5: Galileo Galilei

What were Galileo’s birth & death dates?

1564 & 1642

What is Galileo’s birthplace?

Pisa, Italy

True or False: Galileo invented the telescope.

False: Galileo popularized the telescope.

What was the telescope’s invention date?

1608

What date did Galileo hear about the telescope?

1609

What are the word origins of “telescope?”

• telo: far

• scopos: to see

What does “refraction” mean?

• light bending as it passes from 1 medium to other medium

What is the telescope’s method of using refraction?

Galilean Refractor

What was the Galilean Refractor?

• light shines in all directions

• convex primary lens converges light

• concave eyepiece bends light back to parallel angle

What is the reason for the concave eyepiece?

eyes only focus on distant light if parallel

What was the 1st improved telescope’s method of using refraction?

Keplerian Refractor

What was the reason for the 1st improved telescope?

lost outer regions

What was the Keplerian Refractor?

• convex eyepiece

• placed beyond spot where converging rays intersect

What is the largest refracting telescope size?

1 meter wide

What is the reason for the largest refracting telescope size?

if larger single glass, it warps due to weight under gravity

True or False: All big telescopes today are reflecting telescopes.

True.

True or False: Galileo publicly believed in heliocentrism.

False: Galileo privately believed in heliocentrism, exchanging letters with Kepler after he published the Cosmographic Mystery.

What was Galileo’s reason for publicly believing in heliocentrism?

• telescope

What was 1 event in 1600 that possibly explained Galileo’s initial private support?

Giordano Bruno was burned at stake for heresy

• Copernican

What did Galileo do in 1610?

published “Sidereus Nuncias”

What is the translation of “Sidereus Nuncias?”

“Starry Messenger”

True or False: “Starry Messenger” is the 1st published telescope observation book.

True.

What did Aristotle believe about the Moon?

• terrestrial dust layer

What did Galileo believe about the Moon in “Starry Messenger?”

• chasms

• prominences

  • along terminator

• Maria / convolution

What does “chasm” mean?

• crater

What does “terminator” mean?

• day & night line

What does “prominence” mean?

• mountain range

What does “convolution” mean?

• big dark patch

What does “Maria” mean?

• big convolution

  • dry lava plane

What are the word origins for “Maria?”

seas

• Latin

What are the Moon prominence sizes?

as high as 7 kilometres

What are the Moon Maria sizes?

few hundred kilometres

What did Galileo realize from the Moon?

celestial body ≠ perfect unblemished sphere

What did Greece believe about the Milky Way?

• Hera’s spilled milk

What are the word origins of “galaxy?”

Hera’s spilled milk → “galaxias”

• Greek

What did Aristotle believe about the Milky Way?

• atmospheric / territorial

What did Galileo believe about the Milky Way in “Starry Messenger?”

• region packed with stars creating cloudy appearance

What did Galileo believe about stars?

• point shape

• if farther away, explains lack of stellar parallax

What did Galileo believe about Jupiter?

• embedded with 4 “stars”

• but “stars” moved west → east

• “stars” = brightest moons

What was the 1st time in human history that 1 individual discovered new Solar System member?

Jupiter’s 4 moons

What did Galileo’s beliefs about Jupiter prove about heliocentrism?

if Jupiter can move with moons, so can Earth

What are the Galilean satellites / moons?

• Callisto

• Ganymede

  • largest Solar system moon

• Europa

• Io

What are the word origins of the Galilean satellites / moons?

• Roman god’s lovers

What was Galileo’s launch date?

October 18, 1989

What was the 1st discovered asteroid with a moon?

Ida

What did the Galileo spacecraft realize about Europa?

• large amount of cracks

• ice surface

What is the reason for ice cracks?

• ice floats on water ocean

What did Galileo believe about Venus?

• gibbous Venus is only possible if Venus orbits Sun

• gibbous Venus appears smaller than crescent Venus

so

• Venus orbits Sun

What would Venus phases look like in the Ptolemaic model?

• new

• crescent

True or False: Mercury does not share Venus’ phases.

False: Mercury shares Venus’ phases.

What do outer planet phases look like?

• full

• gibbous

What is the reason for outer planet phases?

• never between Earth & Sun

True or False: Galileo didn’t notice outer planet phases.

True.

True or False: Galileo noticing outer planet phases would’ve helped heliocentrism.

False: Galileo noticing outer planet phases wouldn’t have helped heliocentrism, as the Copernican & Ptolemaic models predict the same.

What did “Starry Messenger” prove about the Ptolemaic Model?

debunked

What did Galileo initially believe about Saturn?

• 1610: saw 2 moons

What did Galileo subsequently believe about Saturn?

• 1612: 2 moons disappeared

so

• ≠ moons

What did Galileo finally believe about Saturn?

• 1616: 2 half ellipses with 2 dark triangles in middle

  • “handle”

  • “lobe”

  • “ear”

What was the identity of the person that realized Saturn’s rings in 1665?

Christiaan Huygens

• Dutch

What did Huygens believe about Saturn?

• thin flat ring touching nowhere inclined to ecliptic

What did Galileo believe about the Sun?

• sunspots get closer together near edge

What is 1 way to observe sunspots?

pinhole camera

What did Aristotle believe about sunspots?

• dust cloud between Earth & Sun

What method did Galileo use to prove his beliefs of the Sun?

• 1612: published projected & sketched images on paper

• calculated Sun curvature

What is the growing realization towards heliocentrism as a result of Galileo’s observations?

if Earth isn’t unique, why does it have to be at centre?

What was Galileo’s new job?

Grand Duke of Tuscany’s personal scientist

What were some examples of geocentric Bible interpretations?

• Joshua requests to stop the Sun

• David’s son says the Sun rises & does down & hurries to place where it rises

• Psalms say Lord set Earth on foundations

What was Galileo’s response to warnings that his statements weren’t appreciated?

• circulated letter to employer’s wife

  • mistranslation

What was the Church’s response to Galileo’s response?

• criminalized heliocentrism

• Pope requested review

• 1616: St. Robert Bellarmine did review

  • lacked physical proof

  • Galileo proved by tides

• Galileo didn’t rule out fixed Earth

so

• concluded geocentrism

What change happened in the 1620s?

Pope change

• Urban VIII

What did Pope Urban VIII encourage Galileo to do?

publish unbiased heliocentrism & geocentrism analysis

What famous text did Galileo publish in 1632?

“Dialogue on Two Great World Systems”

What was Galileo’s method of writing his famous text in 1632?

play

• 3 main characters

  • Salviati

    • rational heliocentrist

  • Simplicio

    • foolish geocentrist

  • neutral

What is the translation of “Simplicio?”

“The simple one”

What did Galileo believe about tides?

• when boat speed changed, water sloshed from one end to other end

so

• Earth water sloshed back & forth causing rising ocean level

What was the reason that Galileo’s beliefs of tides were an offence?

• Pope rejected

  • if God wanted tides, God created tides

• Pope’s response was said by Simplicio

What happened to Galileo in 1633?

formally charged by Church

• punishments

  • public recant

  • forbid “Dialogue on Two Great World Systems” & creation of heliocentrist work

  • house arrest for life

What did Galileo do in his final years?

published physics book

What happened related to Galileo in 1992?

Pope John Paul II formally apologized