Presentation on theme: "The Earth in Space. Solar System In the Milky Way Galaxy What does the sun provide for earth? Light and solar energy 100,000 light years wide 1 ly = 5,878,625,373,183."— Presentation transcript:
The Earth in Space
Solar System In the Milky Way Galaxy What does the sun provide for earth? Light and solar energy 100,000 light years wide 1 ly = 5,878,625,373,183 miles
The Earth It is not a perfect sphere It’s fatter at the equator and the poles are squished: difference of miles We are about 93,000,000 miles from the sun (it takes 8 minutes for sunlight to reach us!) The Earth weighs 6,600 billion billion tons: 6,600,000,000,000,000,000,000 tons or 1,320,000,000,000,000,000,000,000 lbs Closest star = 4.22 ly Voyager 1 = 14 light hours away; took 32 years (1977) to get there ly away - 38,400 mph Sextillion
Earth’s Rotation The Earth rotates on an axis One rotation = 23 hrs., 56 min., 4 sec. = 1 day Rotates eastward We rotate at more than 1000 mph! Why don’t we feel a 1000 mph wind? What would happen if we didn’t rotate?
Earth’s Revolution The Earth revolves around the sun in an oval shaped orbit Closest to sun = in December! 1 revolution = 365¼ days = 1 year We add 1 day in February every 4 years = Leap Year Next one is 2012 We move at 66,700 mph around the sun!
147,000,000 km152,000,000 km Not to scale!
Earth’s Tilt The Earth is tilted 23½ º off parallel from the sun The poles always point to the same spot in space North pole points to the North Star This tilt causes the seasons
Seasons Solstice Longest / shortest day of the year When one pole is ‘pointing’ towards the sun Summer (June) and winter (Dec) Equinox Equal length day and night When both poles are equidistant from sun Spring/Vernal (March) and fall/Autumnal (Sept) N Pole
Darkness Daylight /6 12/12 6/18 12/12 Atlanta
Solar Lines on Earth Arctic Circle Tropic of Cancer Equator Tropic of Capricorn Antarctic Circle
66½º N 23½º N 23½º S 66½º S 0º Not to scale! Direct Solar Energy 24 hrs. darkness Summer Winter 24 hrs. daylight
Darkness /0 12/12 0/24 12/12 At the North Pole Daylight
Svalbard, Norway: Daytime from April 19 to August 23!!! Extremes: 20 hours at the Circles, 186 days at the poles 3 hr time period
66½º N 23½º N 23½º S 66½º S 0º Springor Fall Fall
66½º N 23½º N 23½º S 66½º S 0º Winter Summer Not to scale! Direct Solar Energy 24 hr. darkness 24 hrs. daylight