Astronomy Notes – Unit 1 – Earth
q (1) Earth’s Motion
o rotates about its axis
§ Sidereal Day = _______________
§ Solar Day = _______________
o revolves around the Sun
§ Length of Year = _______________
o Leap Year – Gregorian Calendar
§ adds a 29th day to February in all years evenly divisible by four, except for centennial years (those ending in -00), which receive the extra day only if they are evenly divisible by 400.
o Leap Seconds – Coordinated Universal Time (UTC)
q (2) Tilt of the Earth’s axis - currently = ________________
o varies 22.1 – 24.5 degrees over a 41,000 year cycle
o Seasons
o Summer and Winter Solstice
o Spring (or Vernal) Equinox
o Fall (or Autumnal) Equinox
o Tropic of Cancer, Tropic of Capricorn
o
1) Rotate: __________________________________________________________
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2) Axis: ____________________________________________________________
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3) Revolve: _________________________________________________________
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4)
Summer
Solstice:
__________________________________________________
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5)
Winter
Solstice:
___________________________________________________
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6)
Spring (or
Vernal) Equinox:
________________________________________
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7)
Fall (or
Autumnal) Equinox:
________________________________________
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8) Equator: _________________________________________________________
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9)
Tropic of
Cancer:
_________________________________________________
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10) Tropic of Capricorn:
_______________________________________________
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