Transcript Intro To Astronomy

Intro To Astronomy
Words you should know:
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Rotation: Earth spinning like a top
Axis: invisible line that passes through
the Earth and the North and South
Poles
Words You Should Know:
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Revolution: Movement of one object
around another…
The Earth revolves around the sun
Orbit: the path of the object as it
revolves
Words You Should Know
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Longitude: Tells how many degrees
East or West you are from the Prime
Meridian (Greenwich, England)
(vertical lines on globe)
Latitude: Tells how many degrees
North or South you are from the
Equator (horizontal lines on globe)
Day and Night
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Day and night is caused by Earth’s
rotation.
The side of the Earth that faces the
sun has day and the side that is facing
away from the sun is night
The amount of day and night depends
on the season and your latitude
Why does the sun rise in the
East and Set in the West?
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The Earth rotates west to east, so the
sun appears to rise in the East and set
in the West
The exact location of the rise/set
depends on the time of the year
Does the moon rise and
set?
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Yes the moon rises and sets
As the Earth rotates part of the Earth
is facing the moon and part is not
Due to the Moons revolution around
the Earth and the shape of its orbit,
the moon rises about 50 minutes later
each day
Keeping Time Throughout
Time
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Believed that Chinese had first calendar
Egyptians created a calendar 6000
years ago – they knew a year was 365
days based on observations of a star (Sirius)
– They had 12 months of 30 days and an extra 5
days not in a month
More Calendar History
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Many civilizations had lunar calendars
(Chinese, Babylonians, Greeks, Jews and
Arabs)
Julius Caesar and the Romans created a
calendar very similar to our current calendar
– called the Julian Calendar
Current Calendar (the Gregorian
calendar) was created in the 15th century
Leap Years
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A solar year is actually 365 days 5
hours 48 minutes and 46 seconds…
So we have an extra day every 4 years
Century years have a leap year only if
they can be divisible by 400.