History of Space

1. History of Space

2. Caveman times • Consider yourself back in prehistoric times as a cave… person • In the day there is a huge ball in the sky that gives light to see and warmth • When it goes away at night it gets very cold and dark • However at night all these other lights appear. • You might find the sky a scary thing

3. The Sun • The sun has been the focus of a lot of debate. • After all it gives heat and light. It is vital to survival. • Is it any wonder then that almost all religions have some form of sun worship at their core.

4. The sun as a god • Utu – Mesopotamia • Tonatiuh- Aztec • Surya- Hindu • Sol- Norse • Ra- Egypt • Apollo- Greek/Roman • Amaterasu – Japan • Lugh- Celtic • Inti- Inca

5. Stonehedge • Many cultures built structures to follow the sun's motions. • Many scientists believe that the circle of stones at Stonehenge, England was built so that the sun would rise over one of the large rocks when the sun appears at its highest point in the sky, the summer solstice. • Theories behind the construction of Stonehenge are strongly based on astronomical evidence including alignment of stones corresponding to equinox (spring and fall) and solstice (summer and winter), moonrise and moonsets, rising point of Sirius, and the ability to predict eclipses. • In Wyoming, the Big Horn Medicine Wheel was to have a similar function for the Native Americans.

6. Historical Significance of Stars • Lives of ancient civilizations depended on understanding the patterns and seasonal changes • Polaris, the north star, helped early explorers navigate their ships across the oceans

7. Calendar • Primitive calendars were developed based on the observations of the skies which is evident in the 12 constellations of the zodiac in the sky the Sun travels through one year. • Stars also important for farmers – when to plant and harvest their crops. • A calendar is a way of showing days, organized into a schedule of larger units of time, such as weeks, months, season, or years. • Allowed predictions of spring rains, annual flooding, migration of birds, insects and herds of animals • Allows cultures to plan watering for agriculture, predict locations of herds to plan hunting.

8. Egyptian Priests • In ancient Egypt, the arrival of Sirius warned of the flooding of the Nile. • Careful observed patterns of the sky allowed Egyptian priests to hold great power by pretending to cause the floods that they knew would occur at certain times each year.

9. Early Astronomers • Celestial priests and priestesses studied celestial objects, such as the Sun and other stars, the moon and planets. • Learned to predict celestial events such as seasons and eclipses • From historical records, early sky watchers were terrified by the sight of the Moon blocking the Sun’s light and sending Earth into darkness. They did not understand what was happening and were afraid of the unknown.

10. Inca’s • Since ancient times, many cultures have associated the stars and patterns in the sky with their gods or goddesses. • Incas of South America believed that they were descendants of the Sun, and so they worshipped Inti, the sun god with a lavish festival on June 21st. • They valued gold due to its similarity to the Sun in colour and called it “the sweat of the Sun.” Inti’s wife, Mama Kilya was the goddess of the moon. Silver was sacred to her because it glowed like the moon.

11. Milky Way • Incas believed that the Milky Way was a river in the sky. • Incas saw the Milky Way, the band of stars that arc across the sky as a heavenly river.

12. Mayan Civilization • Mayan civilization in Mexico’s Yucatan region built the pyramid around 1000 years ago. • As the Sun sets on the first day of spring and fall, the light and shadow create the appearance of a diamond-backed snake gradually moving down the stairs of the pyramid. The shadows end at a statue of a snake’s head. This phenomenon does not happened on the first day of winter and summer. • Four stairways, plus platform on top, add to a total of 365. • What does 365 represent?

13. Mesopotamian Astronomers • Over 6000 years ago, civilizations developed in the region between Tigris and Euphrates rivers – now the country of Iraq • The Assyrians, Babylonians, Sumerians called Mesopotamians • Were the first astronomers for whom we have evidence of detailed astronomical evidence

14. Heliocentric (sun centred) • Early philosophers thought that the sun orbited a stationary earth. • In 600 BC pythagoras described the sun as a ball of fire that the earth orbited around. • Some reports say he and his followers were executed for heresy against Apollo.

15. Geocentric (Earth centred) • 200 years later Aristotle described a system where the earth was stationary and the sun and stars orbited it. • The stars were fixed on the outer shell of the universe

16. 2000 years pass • This view from Aristotle and later Ptolemy was accepted by the catholic church and remained dogma until the 16th century. • However it was a cumbersome theory requiring many gears within gears to work. • A monk named Nicolas Copernicus proposed that the sun and newfound planets might orbit the sun. • However he published on his deathbed and his work was not read.

17. Galileo (the bad boy of the 17th century) • Galileo was a brilliant physicist • He however did not invent the telescope though he was the first to use it scientifically • Using the telescope he discovered the moons orbiting Jupiter • His rationale was that if those moons could orbit something other than Earth why not everything else.

18. Galileo vs. the Church • Galileo took the work of Copernicus and created his own sun centered model of the solar system. • To make sure it was read he published in Italian not Latin. • He was told to renounce his heresy or face punishment.

19. His reply • Now instead of quietly giving up Galileo produced a play based on his theory • In it two characters debate the two ideas about the solar system • The person arguing the church’s point wins but anyone can see the arguments are weak • Oh the person arguing the church’s view is named Simplicio- the simpleton • Galileo spend the rest of his life under house arrest. • He was pardoned by Pope John Paul in 1980.

20. Legacy of Galileo • We refer to Galileo as the father of the scientific method • This idea is that to discover the truth you must form a hypothesis and collect data dispassionately and see if it supports or refutes the hypothesis • Philosophers like Aristotle believed in coming up with an idea and trying to prove it. • Galileo believed in coming up with an idea and trying to test it.

21. Summary • Early sky watchers paid a lot of attention to the sky. This enabled them to develop accurate calendars, which they used to predict the seasons and other events that were important to them in their daily lives. • Different cultures have different reasons for watching the sky. Ancient Egyptians watched for a Star called Sirius to rise every year because they knew the Nile River would flood soon.

22. Questions • What does the term celestial object mean? Give two examples. 2. Give two examples of why early cultures depended on their observations of the sky. 3. In an e-mail to a friend, explain how calendars were helpful to ancient civilizations. 4. Is the Earth heliocentric or geocentric? Explain. 5. Galileo is referred to as the father of?