1. 1.0 Human understanding of both Earth and space has changed over time.

2. July 20, 1969
The start of outer space exploration

3. "That's one small step for a man, one giant leap for mankind."
Buzz Aldrin
Mike Collins
Neil Armstrong
"That's one small step for a man, one giant leap for mankind."

7. 2800 BC BC
Stonehenge, England

8. Solstice: either of two times in the year when the sun reaches its highest or lowest point in the sky at noon: June 21(longest day) and December 21(shortest day).

9. Pyramid of Kukulkan in Chichen Itza, Mexico
Pyramid of Kukulkan in Chichen Itza, Mexico. Built to celebrate the equinox.

10. Equinox occurs in the spring about March 21 and in the fall about September 22.
The Caracol Observatory at Chichen Itza

11. The Great Pyramid at Giza 2700 BC

12. About 2000 years ago Aristotle proposed an Earth-centered model to explain planetary motion.

14. Heliocentric Model: The Sun as the centre and Earth and the other planets revolve around it.

15. Galileo Galilei

18. Kepler discovered what was missing from the Copernican ideas
Kepler discovered what was missing from the Copernican ideas. The orbits of the planets were ellipses and not circles.

19. The Astronomer’s Tools
Merkhet
Quadrant
Astrolabe
Cross-staff
Early telescope

20. Planet Distance from Sun in AU
Mercury 0.39
Venus 0.72
Earth 1.0
Mars 1.5
Jupiter 5.2
Saturn 9.5
Uranus 19.2
Neptune 30.1
Pluto 39.5
Astronomical unit (AU) is used for measuring “local” distance, those inside our solar system. One AU is equal to the average distance from the centre of Earth to the centre of the sun ( km)
Light Year: Equals the distance that light travels in one year. Light travels at a speed of km/s. In a year, that adds up to about 9.5 trillion km.