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Vocabulary Definitions - Earth in Space

Chapter 1-1

pgs. 4-13

Astronomy- The study of the moons, stars and other objects in space

 

Orbit- The path an object takes as it travels. Example: (the Earth orbits the Sun)

 

Ellipse- A slightly elongated circle or oval shape.  The shape of the planets' orbit is an Elliptical Orbit.

 

Period of Rotation- time it takes a planet to make one rotation on its axis  (day)

 

Earth's Period of Rotation- One day = 24 hours 

Period of Revolution- time it takes a planet to make one revolution around the sun  (year)

 

Earth's Period of Revolution - One Year = 365.26 days  or 365 whole days and 1/4 of a day or 365 whole days and 6 hours

 

Axis-Imaginary vertical line through the center of body around which the body rotates, or spins

 

Summer Solstice-time of year when the Northern Hemisphere has its longest day and the Southern Hemisphere has its shortest day: beginning of Summer in the Northern Hemisphere. 

Dates around-June 21st-23rd

 

 Winter Solstice-time of year when the Northern Hemisphere has its shortest day and the Southern Hemisphere has its longest day: beginning of Winter in the Northern Hemisphere. 

Dates around-December 22nd-23rd

 

Vernal Equinox- time of year when day and night are of equal length: beginning of Spring in the Northern Hemisphere.                                              

Dates around-March 21st-23rd

Autumnal Equinox-time of year when day and night are of equal

length: beginning of Autumn in the Northern Hemisphere. 

Dates around-September 21st-23rd

 

 

Reasons for Seasons-

 

 

What is a Leap Year?

 

 

What causes day and night?