Unit E – Space Exploration Lesson 4-1: (sec 1.1 and 1.2) Early Views About the Cosmos and Discovery through technology

A. Tracking the Cosmos looked to the skies to ancient people predict the coming of summer and winter marks the longest day of the year… summer solstice June 21 in the Northern Hemisphere marks the winter solstice shortest day of the year… Dec 21 in the Northern Hemisphere slide 1 of 7

predict the timing of the solstices many were built to ancient structures predict the timing of the solstices eg) Stonehenge are two times in the year when daylight and nighttime are equal in length (March 21 and September 21) equinoxes slide 2 of 7

B. Planetary Motion objects in the sky are constantly moving ancient peoples wished to make sense of it all of planetary movement and star movement emerged models slide 3 of 7

patterns assigned to groups of stars in the night sky constellations are patterns assigned to groups of stars in the night sky constellations http://amazing-space.stsci.edu/tonights_sky/ slide 4 of 7

C. Geocentric Model 2000 years ago proposed an Aristotle Earth-centered (geocentric) model of the universe http://images.google.ca/imgres?imgurl=http://www.phys.unt.edu/Astronomy/online_course_files/sample_pages/header.jpg&imgrefurl=http://www.phys.unt.edu/Astronomy/online_course_files/sample_pages/03_6_3.html&h=159&w=588&sz=38&tbnid=DX0wgZ_uKZ2IjM:&tb sun, moon, Mercury, Venus, Mars, Saturn and Jupiter orbit Earth early astronomers used this model to but couldn’t explain other calculate moon phases celestial events slide 5 of 7

D. Heliocentric Model in suggested a sun-centered (heliocentric) model of the universe 1530, Copernicus Earth and the other planets orbit the sun in the was the first scientist to 1600’s, Galileo use a telescope slide 6 of 7

studied and recorded the Brahe movement of the planets later, added orbits to the model elliptical (oval-shaped) Kepler slide 7 of 7

Discovery Through Technology 1.2 Discovery Through Technology

A. Astronomical Tools were used by Egyptians to merkhets and quadrants chart the stars Arabians used astrolabes and cross-staffs scientists like Galileo used telescopes, which contained combinations of different lenses telescopes are still used to observe objects in space slide 1 of 3

B. Astronomical Units units like are for measuring distance in space metres and centimetres too small is the distance from astronomical unit (AU) the center of the Earth to the center of the Sun 1 AU = 149,599,000 km AU’s are used to describe positions of objects in our solar system slide 2 of 3

C. Light Years in one second, light travels 300,000 km sunlight takes to reach Earth 8.5 minutes a is the distance traveled by light in one year: light-year 9,500,000,000,000 km = 9.5 trillion km light-years are used to measure great distances between stars and galaxies slide 3 of 3

Assignments: Worksheet 1 and 2 