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 23.5o

• 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

• 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

• 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