History of History of AstronomyAstronomyAncients - Ancients - AntiquityAntiquityAmy NelsonAmy Nelson

PHY3901PHY3901

September 13, 2004September 13, 2004

Chinese AstronomyChinese Astronomy

Mankind’s first Mankind’s first astronomical records astronomical records ~3000BC~3000BC

First recorded solar eclipse First recorded solar eclipse -2136BC-2136BC

Ahead of their time Ahead of their time designs for astronomical designs for astronomical instrumentsinstruments

Forecasting solar eclipsesForecasting solar eclipses Devised calendarDevised calendar

12 lunar months12 lunar months 365.25 days365.25 days

The Ecliptic Armillary SphereQing Dynasty

Egyptian AstronomyEgyptian Astronomy In order to maintain power, In order to maintain power,

pharaohs and priests used pharaohs and priests used astronomy to predict the astronomy to predict the annual flooding of the Nileannual flooding of the Nile

This yearly flooding was This yearly flooding was imperative to survival in the imperative to survival in the dry African desertdry African desert

Early astronomers discovered Early astronomers discovered the flooding coincided with the flooding coincided with the rise of Siriusthe rise of Sirius

25 days after the summer 25 days after the summer solsticesolstice

Egyptian AstronomyEgyptian Astronomy

2000BC Amenhotep wrote a 2000BC Amenhotep wrote a catalog of starscatalog of stars

5 constellations recorded along 5 constellations recorded along with 36 decans.with 36 decans.

Decans were a method of telling Decans were a method of telling time at nighttime at night

Each decan rises 40 minutes later Each decan rises 40 minutes later every nightevery night

18 of these decans are used for 18 of these decans are used for telling time at nighttelling time at night

Only 12 are visible due to dusk and Only 12 are visible due to dusk and dawn lightsdawn lights

Egyptians believed that many Egyptians believed that many of the stars and planets were of the stars and planets were actually the gods and actually the gods and goddesses they worshippedgoddesses they worshipped

Ra- the sun god traveled in his Ra- the sun god traveled in his chariot across the sky each chariot across the sky each dayday

Nut- the sky goddess was the Nut- the sky goddess was the actual sky and all the stars actual sky and all the stars were her children. were her children.

Pyramids were aligned Pyramids were aligned precisely with Ursa Major and precisely with Ursa Major and Orion.Orion.

These were believed to be the These were believed to be the most holy of starsmost holy of stars

In order for the deceased to In order for the deceased to be reincarnated, they had to be reincarnated, they had to reach this destination from reach this destination from their place of burial. their place of burial.

Elaborate ceremonies were Elaborate ceremonies were held called Pedj Shes or the held called Pedj Shes or the “stretching of the cord” before “stretching of the cord” before each pyramid was built each pyramid was built

Egyptian AstronomyEgyptian Astronomy

Babylonian AstronomyBabylonian Astronomy

One of the first cultures to base astronomy on One of the first cultures to base astronomy on mathematical theorymathematical theory

Development of astronomy as a science due Development of astronomy as a science due to inconsistency of lunar months with solar to inconsistency of lunar months with solar yearsyears New calendar evenly distributed the months so New calendar evenly distributed the months so

there were not days left over at the end of the there were not days left over at the end of the yearyear

Earliest records date back to ~ 1800BCEarliest records date back to ~ 1800BC Had names for several constellationsHad names for several constellations

Many of today’s constellations are simply Greek Many of today’s constellations are simply Greek and Latin translations of the Babylonian namesand Latin translations of the Babylonian names

Babylonian AstronomyBabylonian Astronomy

Eclipses recorded onto a tablet circa 518 and 465 BCEclipses recorded onto a tablet circa 518 and 465 BCMentions the death of King XerxesMentions the death of King Xerxes

Greek and Roman AstronomyGreek and Roman Astronomy

Became a scienceBecame a science Based on geometry and mathematics, not Based on geometry and mathematics, not

physicsphysics Many new theories emerged from some Many new theories emerged from some

rather famous namesrather famous names

Greek and Roman AstronomyGreek and Roman Astronomy

PythagorasPythagoras ~500BC~500BC Recognized the earth Recognized the earth

was sphericalwas spherical Found that the moon Found that the moon

was inclined to the was inclined to the EquatorEquator

Discovered Venus is Discovered Venus is both the morning and both the morning and the evening starthe evening star

Most famous for his Most famous for his theorem theorem

c²= a²+b²c²= a²+b²This theorem became This theorem became

an integral tool for an integral tool for the measurement of the measurement of starsstars

Greek and Roman AstronomyGreek and Roman Astronomy

EuxodusEuxodus ~370BC~370BC Developed Developed

mechanical system mechanical system to explain the to explain the motion of the motion of the planetsplanets

AristotleAristotle ~300BC~300BC Geocentric theoryGeocentric theory

HipparchusHipparchus ~140BC~140BC Divided stars into Divided stars into

groups of apparent groups of apparent brightnessbrightness

This system of This system of magnitude of magnitude of brightness is still used brightness is still used todaytoday

Greek and Roman AstronomyGreek and Roman Astronomy

PtolemyPtolemy ~127-41AD~127-41AD EpicyclesEpicycles

Small circular motion in a Small circular motion in a larger circular motion, or larger circular motion, or deferentdeferent

Explained retrogradeExplained retrograde AlmagestAlmagest

Source of all Greek and Source of all Greek and Roman advances of the timeRoman advances of the time

Geocentric believerGeocentric believer Ptolemaic theory stood Ptolemaic theory stood

for 1500 years, the for 1500 years, the Renaissance (you’ll have Renaissance (you’ll have to wait till next time for to wait till next time for the exciting heliocentric the exciting heliocentric theory!)theory!)

Greek and Roman AstronomyGreek and Roman Astronomy

Greek and Roman AstronomyGreek and Roman Astronomy

Aries- Roman god of WarAries- Roman god of War

Andromeda- daughter of Andromeda- daughter of Cepheus and Cassiopeia. Cepheus and Cassiopeia. Taken by Poseidon. Mother Taken by Poseidon. Mother of Perseusof Perseus

Greek and Roman AstronomyGreek and Roman Astronomy

Cassiopeia- Queen of Cassiopeia- Queen of Ethiopia who claimed she Ethiopia who claimed she was as beautiful as the was as beautiful as the NereidsNereids

Draco- first lawgiver in Draco- first lawgiver in ancient Greeceancient Greece

Greek and Roman AstronomyGreek and Roman Astronomy

Orion- Greek Orion- Greek HunterHunter

Pegasus- winged Pegasus- winged horse of Poseidonhorse of Poseidon

BibliographyBibliography

www.learnwhatsup.comwww.learnwhatsup.com www.egyptology.com/astronomy.htmwww.egyptology.com/astronomy.htm www.spacetoday.orgwww.spacetoday.org www.astronomy.comwww.astronomy.com www.greek-astronomy.comwww.greek-astronomy.com Clagett, Marshall. Clagett, Marshall. Ancient Egyptian Science Volume II.Ancient Egyptian Science Volume II.

American Philosophical Society, Philadelphia. 1995.American Philosophical Society, Philadelphia. 1995. Hoskin, Michael. Hoskin, Michael. The Cambridge Illustrated History of The Cambridge Illustrated History of

Astronomy.Astronomy. Cambridge University Press, Cambridge. 1997. Cambridge University Press, Cambridge. 1997. Lockyer, J. Norman. Lockyer, J. Norman. The Dawn of Astronomy.The Dawn of Astronomy. The MIT Press, The MIT Press,

Cambridge. 1964.Cambridge. 1964. O’Neil, W.M. O’Neil, W.M. Early Astronomy From Babylonia to Early Astronomy From Babylonia to

Copernicus.Copernicus. Sydney University Press, Sydney. 1986. Sydney University Press, Sydney. 1986.