Earth, the Moon, and the Sun

• How can it be daytime here and night time somewhere else in the world?
• In Canada, the time is exactly 12 hours behind.
• If it is 11am Monday in Taiwan, It is 11pm Sunday in Canada

• People used to think the earth did not move and the sun moved around us
• Today we know that it is the Earth that moves around the Sun thanks to Galileo
• When the Earth moves, it also rotates or turns around

• Because the Earth rotates, night and day happen in different places

• AXIS is a line that runs from the top of the earth to the bottom
• The Earth’s axis it tilted (not straight up and down)

• Earth is tilted at about 23.5^o
• Some scientist think that the Earth was hit by a large rock that pushed it to the side
• It has stayed like that since it happened

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• The earth rotates, but it also revolves around the Sun
• ROTATE means to spin, revolve means to go in a circle around the Sun

• The whole trip around the Sun takes 3651/4 days.
• The 1/4 day is why in February we have 29 days every four years
• The whole trip around is

called an ORBIT

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• The world is divided into many parts
• The equator divides the Earth into two parts: the northern and southern hemispheres

• Why is it summer in one hemisphere when it is winter in the other?
• One part of the year the sun is closer to the northern while the other it is closer to the southern hemisphere

The Moon

• The moon looks big from Earth but it is much smaller than the stars and the Sun
• It looks close because it is about 384,000 km away from the earth

• The moon is about ¼ the size of Earth
• If the Earth were a basketball, the moon would be a tennis

ball