Ptolemy and the Geocentric Model

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Early Astronomy

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Part: 1 of2

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Ptolemy’s Universe

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Many ancient cultures

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Many ancient cultures have taken a keen interest…

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…in the changing

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…in the changing night sky.

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Many artifacts havesurvived

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Many artifacts havesurvived until the present time…

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…which make thatfact

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…which make thatfact more than abundantly clear.

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Artifacts

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Artifacts from Antiquity

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The Quadrant

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The Quadrant

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The Quadrant

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The Quadrant One ofthe earliest tools

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The Quadrant One ofthe earliest tools for astronomical observation…

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The Quadrant

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The Quadrant …wasan instrument

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The Quadrant …was aninstrument known as the quadrant.

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The Quadrant

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The Quadrant The quadrantwould divide the sky

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The Quadrant The quadrantwould divide the sky into (4) segments of 6-hour arcs

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The Quadrant

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The Quadrant It couldthen calculate a star’s latitude

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The Quadrant It couldthen calculate a star’s latitude above the Earth’s surface.

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The Astrolabe

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The Astrolabe

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The Astrolabe

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The Astrolabe The ancientPersian Astrolabe

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The Astrolabe The ancientPersian Astrolabe was another useful tool in Astronomy.

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The Astrolabe

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The Astrolabe The astrolabewas similar

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The Astrolabe The astrolabewas similar to an early version of a star-chart,...

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The Astrolabe

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The Astrolabe …and wasuseful in predicting the positions

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The Astrolabe …and was useful in predicting the positions of the Sun, Moon, planets,

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Stonehenge

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Stonehenge

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Stonehenge

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Stonehenge One of thebest examples

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Stonehenge One of thebest examples of an early interest in

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Stonehenge

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Stonehenge …is found inthe ancient stone monolith

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Stonehenge …is found inthe ancient stone monolith known as “Stone Henge”.

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Stonehenge

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Stonehenge Built between 2,000-3,000B.C.

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Stonehenge Built between 2,000-3,000B.C. in southern England,

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Stonehenge

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Stonehenge …Stone Henge stillstands today

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Stonehenge …Stone Henge stillstands today as a popular tourist attraction.

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Stonehenge

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Stonehenge

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Stonehenge

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Stonehenge

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Stonehenge The positions ofthe great rocks

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Stonehenge The positions ofthe great rocks of Stone Henge…

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Stonehenge

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Stonehenge …were used tomark the important events

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Stonehenge …were used tomark the important events during the celestial calendar.

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Stonehenge

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Stonehenge The risings ofthe Moon and the Sun,

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Stonehenge The risings ofthe Moon and the Sun, for example,…

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Stonehenge

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Stonehenge …can be seenin the photos above

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Stonehenge …can be seenin the photos above during the

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Artwork

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Artwork

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Artwork

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Artwork

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Artwork Throughout the history

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Artwork Throughout the history of mankind,…

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Artwork

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Artwork …Astronomy has playeda prominent role

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Artwork …Astronomy has playeda prominent role in various forms of artwork.

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Artwork

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Artwork Shown above areseveral examples

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Artwork Shown above areseveral examples of paintings featuring Astronomy

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Artwork

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Artwork Van Gogh’s famous“Starry Night”

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Artwork Van Gogh’s famous“Starry Night” is the painting shown on

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Artwork Starry Night VanGogh’s famous “Starry Night” is the painting shown on

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Artwork Starry Night VanGogh’s famous “Starry Night” is the painting shown on

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The Pyramids

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The Pyramids

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The Pyramids

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The Pyramids The pyramidsof the Sun and the Moon

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The Pyramids The pyramidsof the Sun and the Moon can be found near Mexico City, Mexico.

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The Pyramids

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The Pyramids Built bythe ancient Aztec civilization

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The Pyramids Built bythe ancient Aztec civilization around 100 A.D.,…

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The Pyramids

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The Pyramids …they arestill a popular tourist attraction

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The Pyramids …they arestill a popular tourist attraction even 2,000 years later.

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…and there aremany, more examples

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…and there aremany, more examples of the ancients’ interest in Astronomy

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…and there aremany, more examples of the ancients’ interest in Astronomy from the periods of antiquity.

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But unlike today,

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But unlike today, the need to understand Astronomy

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But unlike today, the need to understand Astronomy was neither scientific nor religious.

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The ancients instead

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The ancients instead had more practical reasons

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The ancients instead had more practical reasons to study the Heavens.

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Navigation

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Navigation

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Navigation

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Navigation The ancient seafarers,

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Navigation The ancient seafarers, for example,…

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Navigation

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Navigation …needed to understandthe stars

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Navigation …needed to understandthe stars in order to navigate their vessels by

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Farming

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Farming

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Farming

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Farming Additionally, farmers neededto know

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Farming Additionally, farmers neededto know how to predict the seasons…

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Farming

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Farming …in order toknow on which dates

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Farming …in order toknow on which dates to plant and to harvest their crops.

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Cosmetology

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Cosmetology VS

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Cosmetology VS Cosmology

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Cosmetology

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Cosmetology If you wantedto study

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Cosmetology Ifyou wanted to study the field of cosmetology,…

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Cosmetology

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Cosmetology …thenone day

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Cosmetology …then one day you might want to work here.

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Cosmetology …then one day you might want to work here.

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Cosmology

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Cosmology However, if youwould rather study

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Cosmology However, if youwould rather study the field of cosmology,…

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Cosmology

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Cosmology …then you mightprefer to work

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Cosmology …then you mightprefer to work in an observatory like this

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Cosmology

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Cosmology –

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Cosmology – Thescientific study

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Cosmology – Thescientific study of the structure and evolution

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Cosmology – Thescientific study of the structure and evolution of the Universe.

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The Sun

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The Sun

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The Sun The Planets

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The Sun The Planets

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The Sun The Planets The Earth

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The Sun The Planets The Earth

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The Moon The Sun The Planets The Earth

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The Moon The Sun The Planets The Earth The Universe,

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The Moon The Sun The Planets The Earth The Universe, to the ancient Greeks,…

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The Moon The Sun The Planets The Earth

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The Moon The Sun The Planets The Earth …was basically

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The Moon The Sun The Planets The Earth …was basically just the Solar System.

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Perseus Galaxy Cluster

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Perseus Galaxy Cluster Today’sview of the Universe, however,

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Perseus Galaxy Cluster Today’sview of the Universe, however, is quite a bit different.

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Perseus Galaxy Cluster Cosmologyentails looking at the Universe

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Perseus Galaxy Cluster Cosmologyentails looking at the Universe on scales so large today…

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Perseus Galaxy Cluster …thateven entire galaxies only appear

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Perseus Galaxy Cluster …thateven entire galaxies only appear as mere pinpoints of light in

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Perseus Galaxy Cluster Shownabove is the Perseus Galaxy Cluster

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Perseus Galaxy Cluster Shownabove is the Perseus Galaxy Cluster located 300 million LYs away from Earth.

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Perseus Galaxy Cluster And each pinpoint of light

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Perseus Galaxy Cluster Andeach pinpoint of light is a galaxy,…

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Perseus Galaxy Cluster …representing 100 billion

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Perseus Galaxy Cluster …representing100 billion or more stars.

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Perseus Galaxy Cluster Imagine the total number of planets

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Perseus Galaxy Cluster Imaginethe total number of planets contained in all of these galaxies.

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Ptolemy and the

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Ptolemy and the GeocentricModel

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Claudius Ptolemy

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Claudius Ptolemy 83 A.D. – 165 A.D.

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Claudius Ptolemy

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Claudius Ptolemy The ancientGreek astronomer,

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Claudius Ptolemy The ancientGreek astronomer, Claudius Ptolemy,…

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Claudius Ptolemy

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Claudius Ptolemy …devised theGeocentric Model

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Claudius Ptolemy …devised theGeocentric Model of the Universe.

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The Geocentric Model

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The Geocentric Model In the geocentric model

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The Geocentric Model Inthe geocentric model of the Universe,…

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The Geocentric Model …the Earth lay at the center

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The Geocentric Model …theEarth lay at the center of all creation.

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The Geocentric Model Everything else in the Heavens

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The Geocentric Model Everythingelse in the Heavens then orbited the stationary Earth.

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The Geocentric Model But unlike

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The Geocentric Model Butunlike the Sun, Moon, and stars,…

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The Geocentric Model …theancients noticed that the planets

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The Geocentric Model …theancients noticed that the planets would wander across the night sky.

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Prograde Motion

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If you watchthe motions of the planets

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If you watchthe motions of the planets over many months,…

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…you’ll notice thatthey drift eastward

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…you’ll notice thatthey drift eastward across the night sky.

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March …you’ll noticethat they drift eastward across the night sky.

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April …you’ll notice thatthey drift eastward across the night sky.

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May …you’ll notice thatthey drift eastward across the night sky.

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June …you’ll notice thatthey drift eastward across the night sky.

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July …you’ll notice thatthey drift eastward across the night sky.

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Aug …you’ll notice thatthey drift eastward across the night sky.

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Sept …you’ll notice thatthey drift eastward across the night sky.

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Oct …you’ll notice thatthey drift eastward across the night sky.

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Nov …you’ll notice thatthey drift eastward across the night sky.

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Nov Oct Sept Aug July June May April March …you’ll notice that they drift eastward across the night sky.

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ar d Nov e as t w Oct Sept Aug July June May April March …you’ll notice that they drift eastward across the night sky.

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ar d Nov e as t w Oct Sept Aug July June May April March

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ar d Nov e as t w Oct Sept Aug July June May April March This forward and eastward drift

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ar d Nov e as t w Oct Sept Aug July June May April March This forward and eastward drift is called “prograde

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ar d Nov e as t w Oct Sept Aug July June May April March This forward and eastward drift is called “prograde

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Nov Oct Sept Aug July June May April March This forward and eastward drift is called “prograde

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t i on mo Nov a de pr ogr Oct Sept Aug July June May April March This forward and eastward drift is called “prograde

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t i on mo Nov a de pr ogr Oct Sept Aug July June May April March

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t i on mo Nov a de pr ogr Oct Sept Aug July June May April March …and prograde motion is caused

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t i on mo Nov a de pr ogr Oct Sept Aug July June May April March …and prograde motion is caused by the planets’ orbits around the

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Retrograde Motion

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Nov Oct Sept Aug July June May April March

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Nov Oct Sept Aug July June May April March If you watch a planet’s motion

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Nov Oct Sept Aug July June May April March If you watch a planet’s motion more closely, however,…

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Nov Oct Sept Aug July June May April March …you’ll notice that the planet

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Nov Oct Sept Aug July June May April March …you’ll notice that the planet does something interesting over time.

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Nov Oct Sept Aug July June May April March After the planet moves forward

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Nov Oct Sept Aug July June May April March After the planet moves forward in the eastward direction for a while,…

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d t war eas Nov Oct Sept Aug July June May April March After the planet moves forward in the eastward direction for a while,…

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d t war eas Nov Oct Sept Aug July June May April March

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d t war eas Nov Oct Sept Aug July June May April March …it then stops,

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d t war eas Nov Oct Sept Aug July June May April March …it then stops, backs up,

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d t war eas Nov Oct Sept Aug July June May April March …it then stops, backs up, and goes westward for a while.

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d t war eas Nov Oct Sept Aug July June May April March …it then stops, backs up, and goes westward for a while.

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ard ard eastw westw Nov Oct Sept Aug July June May April March …it then stops, backs up, and goes westward for a while.

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ard ard eastw westw Nov Oct Sept Aug July June May April March

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ard ard eastw westw Nov Oct Sept Aug July June May April March But then it stops,

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ard ard eastw westw Nov Oct Sept Aug July June May April March But then it stops, turns around,

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ard ard eastw westw Nov Oct Sept Aug July June May April March But then it stops, turns around, and moves in the eastward direction again.

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ard ard eastw westw Nov Oct Sept Aug July June May April March But then it stops, turns around, and moves in the eastward direction again.

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ard ard ard tw stw eas we eastw Nov Oct Sept Aug July June May April March But then it stops, turns around, and moves in the eastward direction again.

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ard ard ard tw stw eas we eastw Nov Oct Sept Aug July June May April March

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ard ard ard tw stw eas we eastw Nov Oct Sept Aug July June May April March While the forward and eastward motion

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ard ard ard tw stw eas we eastw Nov Oct Sept Aug July June May April March While the forward and eastward motion was called “prograde

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ard ard ard tw stw eas we eastw Nov Oct Sept Aug July June May April March While the forward and eastward motion was called “prograde

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ard westw Nov Oct Sept Aug July June May April March While the forward and eastward motion was called “prograde

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otion rd otion m a a de stw em pr ogr we grad Nov pro Oct Sept Aug July June May April March While the forward and eastward motion was called “prograde

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otion rd otion m a a de stw em pr ogr we grad Nov pro Oct Sept Aug July June May April March

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otion rd otion m a a de stw em pr ogr we grad Nov pro Oct Sept Aug July June May April March …this backward and westward motion

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otion rd otion m a a de stw em pr ogr we grad Nov pro Oct Sept Aug July June May April March …this backward and westward motion is called “retrograde

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otion rd otion m a a de stw em pr ogr we grad Nov pro Oct Sept Aug July June May April March …this backward and westward motion is called “retrograde

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tion tion e mo mo grad rad e pro pro g Nov Oct Sept Aug July June May April March …this backward and westward motion is called “retrograde

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ot ion tion tion m mo o a de r ade em ogr rog rad pr ret pro g Nov Oct Sept Aug July June May April March …this backward and westward motion is called “retrograde

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Now watch theplanet Mars

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Now watch theplanet Mars as it demonstrates this motion.

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As the planetmoves eastward,

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As the planetmoves eastward, it demonstrates the prograde

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prograde motion As theplanet moves eastward, it demonstrates the prograde

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prograde motion March Asthe planet moves eastward, it demonstrates the prograde

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prograde motion April As the planet moves eastward, it demonstrates the prograde

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prograde motion May As the planet moves eastward, it demonstrates the prograde

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prograde motion June As the planet moves eastward, it demonstrates the prograde

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prograde motion July As the planet moves eastward, it demonstrates the prograde

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prograde motion Aug As the planet moves eastward, it demonstrates the prograde

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prograde motion Aug As the planet moves eastward, it demonstrates the prograde

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prograde motion tion e mo grad pro Aug As the planet moves eastward, it demonstrates the prograde

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tion e mo grad pro Aug

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tion e mo grad pro Aug But then it stops,

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tion e mo grad pro Aug But then it stops, turns around,

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tion e mo grad pro Aug But then it stops, turns around, and shows westward retrograde motion.

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retrograde motion tion e mo grad pro Aug But then it stops, turns around, and shows westward retrograde motion.

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retrograde motion tion e mo grad pro Sept But then it stops, turns around, and shows westward retrograde motion.

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retrograde motion tion e mo grad pro Oct But then it stops, turns around, and shows westward retrograde motion.

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retrograde motion tion e mo grad pro Nov But then it stops, turns around, and shows westward retrograde motion.

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retrograde motion tion e mo grad pro Nov But then it stops, turns around, and shows westward retrograde motion.

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retrograde motion t ion tion mo e mo r ade rad prog retrog Nov But then it stops, turns around, and shows westward retrograde motion.

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t ion tion mo e mo r ade rad prog retrog Nov

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t ion tion mo e mo r ade rad prog retrog Nov And finally it stops,

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t ion tion mo e mo r ade rad prog retrog Nov And finally it stops, turns around again,

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t ion tion mo e mo r ade rad prog retrog Nov And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion t ion tion mo e mo r ade rad prog retrog Nov And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion t ion tion mo e mo r ade rad prog retrog Dec And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion t ion tion mo e mo r ade rad prog retrog Jan And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion t ion tion mo e mo r ade rad prog retrog Feb And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion t ion tion mo e mo r ade rad prog retrog March And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion t ion tion mo e mo r ade rad prog retrog April And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion t ion tion mo e mo r ade rad prog retrog May And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion t ion tion mo e mo r ade rad prog retrog May And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion ot ion tion tion m mo o a de r ade em ogr rog rad pr ret pro g May And finally it stops, turns around again, and shows the prograde motion again.

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prograde motion ot ion tion tion m mo o a de r ade em ogr rog rad pr ret pro g May

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prograde motion ot ion tion tion m mo o a de r ade em ogr rog rad pr ret pro g May While it requires many months of observation,

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prograde motion ot ion tion tion m mo o a de r ade em ogr rog rad pr ret pro g May While it requires many months of observation, to witness the retrograde motion of Mars,

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prograde motion ot ion tion tion m mo o a de r ade em ogr rog rad pr ret pro g May

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prograde motion ot ion tion tion m mo o a de r ade em ogr rog rad pr ret pro g May …it was nevertheless a phenomenon

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prograde motion ot ion tion tion m mo o a de r ade em ogr rog rad pr ret pro g May …it was nevertheless a phenomenon the ancients did not fail to notice.

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The entire retrogrademotion sequence

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The entire retrogrademotion sequence can be seen in this photo collage.

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Can you explainwhy

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Can you explainwhy this phenomenon is happening?

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This slide showsan animation

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This slide showsan animation of the retrograde

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This slide showsan animation of the retrograde

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Ptolemy Explains

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Ptolemy Explains Retrograde Motion

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The Geocentric Model Inthe Geocentric Model

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The Geocentric Model Inthe Geocentric Model of the Universe,…

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The Geocentric Model …Ptolemyhad to explain this phenomenon

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The Geocentric Model …Ptolemyhad to explain this phenomenon of the retrograde motion of the planets.

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The Geocentric Model Ptolemyexplained that when Mars

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The Geocentric Model Ptolemyexplained that when Mars orbited the Earth,…

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The Geocentric Model …that it did so

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The Geocentric Model …thatit did so using (2) pivot arms.

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The Geocentric Model The larger of the (2) arms

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The Geocentric Model Thelarger of the (2) arms makes a loop called a “deferent”,…

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The Geocentric Model deferent The larger of the (2) arms makes a loop called a “deferent”,…

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The Geocentric Model deferent

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The Geocentric Model deferent …whilethe smaller of the (2) arms

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The Geocentric Model deferent …while the smaller of the (2) arms makes a loop called an “epicycle”.

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The Geocentric Model epicycle deferent …while the smaller of the (2) arms makes a loop called an “epicycle”.

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The Geocentric Model When both of the pivot arms

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The Geocentric Model Whenboth of the pivot arms are moving in circles,…

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The Geocentric Model …thenthe planet exhibits prograde motion

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The Geocentric Model …thenthe planet exhibits prograde motion throughout most of its orbit.

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The Geocentric Model Butsometimes, however,

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The Geocentric Model Butsometimes, however, Mars also appears to

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The Geocentric Model …andwhen this happens,

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The Geocentric Model …andwhen this happens, the planet exhibits retorgrade

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The Geocentric Model Like this…

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The Geocentric Model Like this…

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The Geocentric Model WhilePtolemy did not correctly explain

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The Geocentric Model WhilePtolemy did not correctly explain the retrograde motion of

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The Geocentric Model …his explanation nevertheless sounded

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The Geocentric Model …his explanation nevertheless sounded both credible and plausible.

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The Geocentric Model But Ptolemy’s explanation

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The Geocentric Model ButPtolemy’s explanation for the retrograde motion of Mars,…

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The Geocentric Model …did not alone prove

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The Geocentric Model …didnot alone prove that the Geocentric Model was correct.

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The Geocentric Model The ancients also offered

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The Geocentric Model Theancients also offered (4) other arguments,…

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The Geocentric Model …indefense of the Earth’s position

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The Geocentric Model …indefense of the Earth’s position at the center of the Universe.

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4 Arguments forthe

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4 Arguments forthe Geocentric Model

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1) We Can’tDetect Earth’s Motion

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1) We Can’tDetect Earth’s Motion The first argument given,

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1) We Can’tDetect Earth’s Motion The first argument given, to support the Geocentric Model,…

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1) We Can’tDetect Earth’s Motion …was that if the Earth revolved the Sun,

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1) We Can’tDetect Earth’s Motion …was that if the Earth revolved the Sun, then we would feel the Earth’s motion.

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1) We Can’tDetect Earth’s Motion But since the Earth’s motion,

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1) We Can’tDetect Earth’s Motion But since the Earth’s motion, could not be detected,…

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1) We Can’tDetect Earth’s Motion …then the Earth, they thought,

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1) We Can’tDetect Earth’s Motion …then the Earth, they thought, could not possibly be moving.

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1) We Can’tDetect Earth’s Motion But there are actually (5) ways

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1) We Can’tDetect Earth’s Motion But there are actually (5) ways in which the Earth does in fact move.

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1) We Can’tDetect Earth’s Motion 1)

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1) We Can’tDetect Earth’s Motion 1) The Earth is rotating

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1) We Can’tDetect Earth’s Motion 1) The Earth is rotating on its imaginary axis.

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1) We Can’tDetect Earth’s Motion 2) The Earth is revolving

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1) We Can’tDetect Earth’s Motion 2) The Earth is revolving around the Sun.

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1) We Can’tDetect Earth’s Motion 3) The Earth is “precessing”,

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1) We Can’tDetect Earth’s Motion 3) The Earth is “precessing”, or wobbling, on its axis.

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1) We Can’tDetect Earth’s Motion 4) The Sun is revolving

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1) We Can’tDetect Earth’s Motion 4) The Sun is around the center of the Milky Way. revolving

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1) We Can’tDetect Earth’s Motion 5) The galaxies are moving apart,

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1) We Can’tDetect Earth’s Motion 5) The galaxies are moving apart, as a result of the Big Bang.

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1) We Can’tDetect Earth’s Motion separating 5) The galaxies are moving apart, as a result of the Big Bang.

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1) We Can’tDetect Earth’s Motion separating

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1) We Can’tDetect Earth’s Motion separating But none of these motions

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1) We Can’tDetect Earth’s Motion separating But none of these motions could be felt by the ancients.

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1) We Can’tDetect Earth’s Motion separating And since none of these motions

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1) We Can’tDetect Earth’s Motion separating And since none of these motions were detectable,…

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1) We Can’tDetect Earth’s Motion separating …then the ancients incorrectly concluded

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1) We Can’tDetect Earth’s Motion separating …then the ancients incorrectly concluded that the Earth could not

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1) We Can’tDetect Earth’s Motion separating Of course, the real reason

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1) We Can’tDetect Earth’s Motion separating Of course, the real reason why the Earth’s motion was not

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1) We Can’tDetect Earth’s Motion separating …is because motion is relative

527.
1) We Can’tDetect Earth’s Motion separating …is because motion is relative and cannot be detected.

528.

529.
1) We Can’tDetect Earth’s Motion separating But until Albert Einstein came along,

530.
1) We Can’tDetect Earth’s Motion separating But until Albert Einstein came along, 19 centuries later,…

531.

532.
1) We Can’tDetect Earth’s Motion separating …the dynamics of relative motion

533.
1) We Can’tDetect Earth’s Motion separating …the dynamics of relative motion would not be fully understood.

534.
1) We Can’tDetect Earth’s Motion separating …the dynamics of relative motion would not be fully understood.

538.
2) We Don’tObserve Stellar Parallax

539.
2) We Don’tObserve Stellar Parallax A second argument given

540.
2) We Don’tObserve Stellar Parallax A second argument given in support of the Geocentric Model,

541.

542.
2) We Don’tObserve Stellar Parallax …had to do with the failure of the ancients

543.
2) We Don’tObserve Stellar Parallax …had to do with the failure of the ancients to observe parallax among the stars.

544.

545.
2) We Don’tObserve Stellar Parallax If the Earth were truly in motion,

546.
2) We Don’tObserve Stellar Parallax If the Earth were truly in motion, the thinking went,…

547.

548.
2) We Don’tObserve Stellar Parallax …then a star would appear to shift positions

549.
2) We Don’tObserve Stellar Parallax …then a star would appear to shift positions as the Earth orbited the Sun.

550.

551.
2) We Don’tObserve Stellar Parallax A star would appear in one position,

552.
2) We Don’tObserve Stellar Parallax A star would appear in one position, in June for example,…

553.

554.

555.
2) We Don’tObserve Stellar Parallax June A star would appear in one position, in June for example,…

556.

557.

558.

559.
2) We Don’tObserve Stellar Parallax June

560.
2) We Don’tObserve Stellar Parallax June …and then appear in different position

561.
2) We Don’tObserve Stellar Parallax June …and then appear in different position (6) months later.

562.

563.

564.
2) We Don’tObserve Stellar Parallax June December …and then appear in different position (6) months later.

565.

566.

567.

568.
2) We Don’tObserve Stellar Parallax June December

569.
2) We Don’tObserve Stellar Parallax June December And as the Earth

570.
2) We Don’tObserve Stellar Parallax June December And as the Earth revolved around the Sun,…

571.
2) We Don’tObserve Stellar Parallax June December

572.
2) We Don’tObserve Stellar Parallax June December …the star would then seem to demonstrate

573.
2) We Don’tObserve Stellar Parallax June December …the star would then seem to demonstrate a certain amount of parallactic shift.

574.

575.

576.

577.

578.

579.

580.

581.
2) We Don’tObserve Stellar Parallax parallactic shift June December …the star would then seem to demonstrate a certain amount of parallactic shift.

582.
2) We Don’tObserve Stellar Parallax parallactic shift June December

583.
2) We Don’tObserve Stellar Parallax parallactic shift June December But since stellar parallax

584.
2) We Don’tObserve Stellar Parallax parallactic shift June December But since stellar parallax was not observed by the ancients,

585.

586.
2) We Don’tObserve Stellar Parallax parallactic shift June December …then they thought that the Earth

587.
2) We Don’tObserve Stellar Parallax parallactic shift June December …then they thought that the Earth could not possibly be revolving the Sun.

588.

589.

590.

591.
2) We Don’tObserve Stellar Parallax parallactic shift June December Of course, the real reason

592.
2) We Don’tObserve Stellar Parallax parallactic shift June December Of course, the real reason why the ancients never observed

593.

594.
2) We Don’tObserve Stellar Parallax parallactic shift June December …is because stars are too far away

595.
2) We Don’tObserve Stellar Parallax parallactic shift June December …is because stars are too far away to observe parallax with the naked eye.

596.
2) We Don’tObserve Stellar Parallax parallactic shift June December …is because stars are too far away to observe parallax with the naked eye.

603.
Heliocentric Model

604.
3) The MoonCould Not Keep Up Heliocentric Model

605.
3) The MoonCould Not Keep Up Heliocentric Model The third argument given

606.
3) The MoonCould Not Keep Up Heliocentric Model The third argument given in support of the Geocentric Model,

607.

608.
3) The MoonCould Not Keep Up Heliocentric Model …was that if the Earth orbited the Sun,

609.
3) The MoonCould Not Keep Up Heliocentric Model …was that if the Earth orbited the Sun, that the Moon would lag behind.

610.

611.
3) The MoonCould Not Keep Up Heliocentric Model Since there is no tether

612.
3) The MoonCould Not Keep Up Heliocentric Model Since there is no tether to pull the Moon along,…

613.

614.
3) The MoonCould Not Keep Up Heliocentric Model …then the Moon would be unable

615.
3) The MoonCould Not Keep Up Heliocentric Model …then the Moon would be unable to keep up with the Earth’s motion.

616.

617.

618.

619.

620.

621.

622.

623.

624.

625.

626.

627.

628.

629.

630.

631.

632.

633.

634.

635.

636.

637.

638.

639.

640.

641.

642.

643.

644.

645.

646.

647.

648.

649.

650.

651.

652.

653.

654.

655.

656.

657.

658.

659.

660.

661.

662.

663.

664.

665.

666.

667.

668.

669.

670.
3) The MoonCould Not Keep Up Heliocentric Model The flaw in the ancients’ thinking,

671.
3) The MoonCould Not Keep Up Heliocentric Model The flaw in the ancients’ thinking, however,…

672.

673.
3) The MoonCould Not Keep Up Heliocentric Model …lay in the their failure to properly understand

674.
3) The MoonCould Not Keep Up Heliocentric Model …lay in the their failure to properly understand Newton’s first law of motion.

675.

676.
3) The MoonCould Not Keep Up Heliocentric Model All objects move through space

677.
3) The MoonCould Not Keep Up Heliocentric Model All objects move through space because they have inertia.

678.

679.
3) The MoonCould Not Keep Up Heliocentric Model And since the Moon and the Earth

680.
3) The MoonCould Not Keep Up Heliocentric Model And since the Moon and the Earth were already in motion together,…

681.

682.
3) The MoonCould Not Keep Up Heliocentric Model …then the Moon has no problem at all

683.
3) The MoonCould Not Keep Up Heliocentric Model …then the Moon has no problem at all keeping up with the moving Earth.

684.

685.

686.

687.

688.

689.

690.

691.

692.

693.

694.

695.

696.

697.

698.

699.

700.

701.

702.

703.

704.

705.

706.

707.

708.

709.

710.

711.

712.

713.

714.

715.
3) The MoonCould Not Keep Up Heliocentric Model But since the ancients

716.
3) The MoonCould Not Keep Up Heliocentric Model But since the ancients knew nothing at all about inertia,…

717.

718.
3) The MoonCould Not Keep Up Heliocentric Model …then they incorrectly believed

719.
3) The MoonCould Not Keep Up Heliocentric Model …then they incorrectly believed that the Earth could not possibly be in

720.

721.

722.

723.
3) The MoonCould Not Keep Up Heliocentric Model They therefore incorrectly concluded,

724.
3) The MoonCould Not Keep Up Heliocentric Model They therefore incorrectly concluded, that the Earth must remain

725.

726.
3) The MoonCould Not Keep Up Heliocentric Model …and that the Geocentric Model

727.
3) The MoonCould Not Keep Up Heliocentric Model …and that the Geocentric Model must be correct.

728.
3) The MoonCould Not Keep Up Heliocentric Model …and that the Geocentric Model must be correct.

731.
4) Objects WouldFly Off Earth

732.
4) Objects WouldFly Off Earth The fourth argument given

733.
4) Objects WouldFly Off Earth The fourth argument given in support of the Geocentric

734.

735.
4) Objects WouldFly Off Earth …had to do with the Earth’s rotation

736.
4) Objects WouldFly Off Earth …had to do with the Earth’s rotation on its axis.

737.

738.
4) Objects WouldFly Off Earth If the Earth were to rotate on its axis,

739.
4) Objects WouldFly Off Earth If the Earth were to rotate on its axis, the ancients believed,…

740.

741.
4) Objects WouldFly Off Earth …then anything not nailed down

742.
4) Objects WouldFly Off Earth …then anything not nailed down would fly off into space.

743.

744.

745.

746.

747.

748.

749.

750.

751.

752.

753.

754.

755.

756.

757.

758.

759.

760.

761.

762.
4) Objects WouldFly Off Earth Since the ancients failed to observe

763.
4) Objects WouldFly Off Earth Since the ancients failed to observe objects flying off into space,…

764.

765.
4) Objects WouldFly Off Earth …then they incorrectly concluded

766.
4) Objects WouldFly Off Earth …then they incorrectly concluded that the Earth must not be rotating.

767.

768.

769.

770.
4) Objects WouldFly Off Earth Of course, the real reason

771.
4) Objects WouldFly Off Earth Of course, the real reason why objects do not fly off into space,…

772.

773.
4) Objects WouldFly Off Earth …is because the Earth

774.
4) Objects WouldFly Off Earth …is because the Earth is not spinning fast enough.

775.

776.
4) Objects WouldFly Off Earth If the Earth were to spin

777.
4) Objects WouldFly Off Earth If the Earth were to spin 17x as fast as it currently spins,…

778.

779.
4) Objects WouldFly Off Earth …then everything not nailed down

780.
4) Objects WouldFly Off Earth …then everything not nailed down would suddenly go airborne.

781.
4) Objects WouldFly Off Earth …then everything not nailed down would suddenly go airborne.

785.

786.
The Geocentric Model Since none of these questions

787.
The Geocentric Model Sincenone of these questions could be answered,…

788.

789.
The Geocentric Model …thenPtolemy and the Geocentric Model

790.
The Geocentric Model …thenPtolemy and the Geocentric Model remained unchallenged for 14 centuries.

792.
End of Part1

793.
A Note fromthe Author~ If you liked my presentation, please email me at AstronomyTeacehr@aol.com and tell me why you liked it. I have made a powerpoint as thorough as this one for each Astronomy subject. I placed this one online just to see if it is getting any response and usage. I am an Astronomy teacher in northern Virginia, age 50. I have taught Astronomy to the students of northern VA for 24 years. Tom March 24, 2012

Ptolemy and the Geocentric Model

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