1.0 - Spac e Exploration “Human understanding of both Earth and space has changed over time”

1. 1.0 - Space Exploration“Human understanding of both Earth and space has changed over time” • In Topic 1 you will learn about the following key concepts: • technologies for space exploration and observation • reference frames for describing the position and motion of bodies in space. • distribution of matter through space • composition and characteristics of bodies in space For Web links relating to 1.0, visit www.pearsoned.ca/scienceinaction Username: SESscience Password: student

2. 1.1 Early Views About the Cosmos • Objects in the sky have fascinated humans throughout history. • They fuelled the human imagination, marked the passage of time, and foretold the changes in seasons. • Early knowledge of them was passed from generation to generation and from culture to culture, often as legends and folklore. INFO BIT One-Mitt Measure Inuit in the high arctic traditionally used the width of a mitt held at arm’s length to gauge the height of the Sun above the horizon. When the Sun rose to a height of one-mitt width, it meant that seal pups would be born in two lunar cycles. Figure 1.1 The First Nations peoples of the Pacific Northwest thought the night sky was a pattern on a great blanket overhead. The blanket, they believed, was held up by a spinning “world pole,” the bottom of which rested on the chest of a woman underground named Stone Ribs.

3. Tracking Cosmological Events – pg. 372 Our ancestors tracked two very special annual events: • Summer solstice • June 21 • longest day of the year • Marks the beginning of summer • Winter solstice • December 21 • It marks the shortest day of the year • Beginning of winter • “Solstice” is Latin for: • sol meaning sun, and • sticemeaning stop. The earth is actually closer to the sun during the winter solstice however the earth is tilted away from the suns direct rays.

4. The SolsticesWhere the Sun Stops Summer Solstice June 21 Winter Solstice Dec. 21 • Which part of the world is receiving direct rays? • Which part of the world is receiving indirect rays? • Which part of the world is receiving direct rays? • Which part of the world is receiving indirect rays? • What causes the differenct seasons on earth? More animations click here

5. 1.1 Ancient Views About the Cosmos - continued • Prediction of the approach of summer and winter was important to early peoples. Why? • many ancient civilizations built huge monuments to honour their beliefs about the change. • The Ancient Celts set up megaliths, in concentric circles, at Stonehenge to mark the winter and summer solstices. • Ancient African cultures set large rock pillars into patterns to predict the timing of the solstices as well.

6. 1.1 Ancient Views About the Cosmos - continued Another phenomenon honoured by early cultures was the equinox • Spring Equinox - March 21 • Fall Equinox - September 22 • “equinox” is Latin for: • equimeaning equal, and • noxmeaning night. • At the equinox, day and night are of equal length. • The Mayans of Central America built an enormous cylinder-shaped tower at Chichén Itzá in about A.D. 1000 to celebrate the occurrence of the two equinoxes. • Movie Clip “At mid afternoon on the days of the Equinox the shadow that covers the northeast angle of the pyramid is reflected on the stairway and forms triangles of light and shade that imitates the movement of a serpent” http://www.internet-at-work.com/hos_mcgrane/chichen/chichen_kukul.html#equinox

7. 1.1 Ancient Views About the Cosmos - continued • The ancient Egyptians built pyramids to align with the seasonal position of certain stars. • The entrance passage of Khufu, the Great Pyramid at Giza, once lined up with Thuban • Thuban was the closest star showing true north.

8. 1.1 Ancient Views About the Cosmos Planetary Motion • For as long as people have been watching the nightly promenade of stars and planets, they have sought ways of explaining the motions they observed. • Everything in the sky appears to be in motion. The Sun rises and sets. The Moon, in its ever-changing phases, travels across the sky. • Geocentric Model – Movie Clip • Earth-centred “earth is the centre of the universe” • About 2000 years ago • Greek philosopher Aristotle • Had help from Pythagoras and Euclid • Theory lasted for 2000 years.

9. Geocentric Model of Planetary Motion

10. 1.1 Ancient Views About the Cosmos Planetary Motion – Continued • Heliocentric Model – “Sun Centred” • 1530 – polish astronomer Nicholas Copernicus • Was a more simplistic model. • Suggested the Sun was the centre • 100 years later the invention of the telescope supported Copernicus’ theory! • Movie clip • Galileo of Galilei of Italy • 1600’s was the first to view many new objects in space, includes moons on Jupiter, sun spots and the rings of Venus. • Johannes Kepler Danish astronomer came up with the next piece of the puzzle. • The orbits of the planet were not circular but elliptical • More cool clips (must be connected to internet)

11. Heliocentric Model of Planetary Motion Elliptical Orbit

12. Homework Assignment – Check & Reflect Page 376 Q 1-7 & 9 1. Define solstice. What are the significant dates associated with the solstices in the northern hemisphere? 2. What was the ancient monument of Stonehenge believed to be used for? 3. What word is used to describe the times when the length of day equals the length of night? When do these occur? 4. List and describe three monuments built by ancient people to honour celestial bodies. Connect Your Understanding 5. What did the summer and winter solstices indicate to ancient people? 6. Explain the main difference between the heliocentric model of the solar system and the geocentric model. 7. Why was the change from a geocentric model to a heliocentric model considered such a revolutionary idea?