By: Harleen Sohi & Navpreet Sidhu

Early Times  people thought earth was the center of the universe  believing that everything else including the Sun, the Moon, and other planets revolved around earth  that was called the Geocentric Model

Early Times Early Astronomers  Claudius Ptolemy – Greek, from 2 nd century C.E  Nicolaus Copernicus - Polish/ Renaissance,1 st person to formulate a comprehensive heliocentric cosmology  Galileo Galilei – Italian, helped play a major role in science revolution  Johannes Kepler - German, a key figure in the 17 th century scientific revolution

The Moon  only natural satellite of Earth  fifth largest satellite in the solar system

Formation of the Moon  most accepted theory : Giant impact theory  planetary body(same size as mars) crashed into the young earth  large pieces of earth scattered in space  pieces than ended up orbiting earth and building into a sphere over a million years

Surface of the Moon  lunar highlands : light, heavily cratered areas of the surface  no atmosphere  covered in craters FUN FACT : All the mountains on the moon have names !

Moon’s Phases  moon doesn’t have its own light  reflects light from the sun  29.5 days to revolve completely around earth  increasing sunlit- waxing  decreasing sunlit- waning

Earth and Moon Interactions  Earth is affected by the moon’s gravitational pull (moon and earth are so close to each other)  ocean waters are attracted from lunar gravity  low & high tides form

Earth  the planet we live on  third planet from the sun in the solar system  densest and 5 th largest of the 8 planets in the solar system

Rotation & Tilt  Earth spins west to east on its axis  full rotation takes 23 hours 56 minutes and 4 seconds (one whole day)  sun rises in the east and sets in the west (day & night)

Axis Tilt  axis is tilted at 23.5°  sunlight strikes earth at different angles  positioning of the sun: north = winter, south = summer, equator = sun all year

Solstices  summer solstice: longest day of year = June 21  winter solstice: shortest day of year = Dec. 21  south have opposite solstice dates Fact: During the summer in far northern regions of the world, the sun may even be visible at midnight.

Lets Check Your Understanding Answer the following questions on your handout. 1) What is the same size as mars? 2) What is it called when people thought all the planets, moon, and sun revolved around earth? 3) Which astronomer presented new observations? 4) What is the summer solstice date for the north? 5) Explain the earth’s rotation. Which way does it spin? How long does it take?

Answers 1) C. Planetary Body 2) Geocentric Model 3) Nicolaus Copernicus 4) C. June 21 5) Earth spins from west to east on its axis and takes 23 hours 56 minutes and 4 seconds to complete on full rotation.

Sources:  evolvernetwork.org  hdwpapers.org  123rf.com  scienceblogs.com  en.wikipedia.org  glogster.com  blogs.agu.org