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Earth in Space (a work in progress)

Earth in Space (a work in progress). Dr. Alan F. Weekes. Astronomy. Possibly the oldest science Contrast with astrology: belief system The belief that the positions of the planets and the sun at the time of your birth affects your personality and your future. Calendars

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Earth in Space (a work in progress)

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  1. Earth in Space(a work in progress) Dr. Alan F. Weekes

  2. Astronomy • Possibly the oldest science • Contrast with astrology: belief system The belief that the positions of the planets and the sun at the time of your birth affects your personality and your future.

  3. Calendars • Seasons, festivals, time, flood of the Nile • Year • The time it takes for the sun to rise in the same place • ~365 ¼ days • Month • Roughly the time for the moon to go through its set of phases • Some cultures exactly a month, from new moon to new moon • Asian, Jewish, Moslem • 29.5 days from new moon to new moon

  4. Day • from sunrise to sunrise • 24 hr. • Week • Named for visible moving objects in the sky • Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn • Sunday, Monday, Saturday • Tiwe’s Day (Mars), Woden’s Day (Mercury), Thor’s Day (Jupiter), Frige’s Day (Venus) • lunes, martes, miercoles, jueves, viernes, sabado, domingo

  5. A Little History • Geocentric Theory • Earth is the center of the universe • Everything revolves around the earth • What is apparent, what is observed • agrees with some religious views

  6. Heliocentric Theory Nicholas Copernicus • Sun: the center of the solar system • Copernicus (February 19, 1473 – May 24, 1543) • Polish priest, astronomer • Considered heretical, not published until his death bed in 1543 • People were arrested, tortured and killed for teaching this idea • Galileo under house arrest for years for this idea Giordano Bruno Galileo Galilei

  7. Motions of the Earth • Revolution • Time it takes to revolve around another body, the sun. • Year • 365.24 days for the Earth • Leap years are determined according to the following rule: • Every year that is exactly divisible by 4 is a leap year • except for years that are exactly divisible by 100;these centurial years are leap years only if they are exactly divisible by 400. • Note: The Earth is held in its orbit by the Sun’s gravity.

  8. Rotation • The time it takes for a body to rotate about an axis • Day • 23 hr. 56 min. for the Earth • Relative to distant objects • 24 hr for sunrise to sunrise • The earth has moved a bit in its orbit relative to the sun, so it takes a little longer for the sun to be visible • ~1000 mph at the equator, 800 mph here

  9. Other important characteristics • Size- diameter: 12,756.3 km (7,926 mi) • Orbit: • 149,600,000 km (93,500,000 mi) from Sun • 1.00 astronomical unit (au) from Sun • Elliptical, not circular • More of a squashed circle • Closest to the sun on Jan. 4, 147.5 million km • Farthest from the sun July 4, 152.6 million km • Mass: 5.9972x1024 kg

  10. Science 8 Goby Last Video: Basic Astronomy Per. ___ 9/13/13 5 Things new or interesting to you in the video. 1. 2. 3.

  11. The Seasons • The earth is tilted in its orbit around the sun at 23.5o • The earth is always tilted in the same direction, North Star over the North Pole • 23. 5o North Latitude- Tropic of Cancer • 23. 5o South Latitude- Tropic of Capricorn • 66.5o North Latitude- Arctic Circle • 66.5o South Latitude- Antarctic Circle

  12. Seasons are determined by where the most direct rays of the sun are hitting the Earth.

  13. Animation

  14. Old Farmer’s Almanac Site

  15. The Earth’s Moon • Earth’s companion in space • Large in relation to the Earth • About ¼ diameter of Earth, approx. the size of the U.S. from coast to coast • Diameter: 3,476 km (2,172 mi) • Distance from Earth • Orbit: 384,400 km (240,000 mi) • Mass: 7.35e22 kg • Gravity, about 1/6 of Earth’s

  16. Features of the Moon • Craters • Made by impacts with meteorites • Mare • “seas” made by the outpouring of lava early in the moon’s history • Rays • Bright lines extending out from some newer craters

  17. The Moon’s Motions • Rotation- about 27 1/3 days • Revolution- about 27 1/3 days • The moon keeps the same side toward the Earth as it goes around the Earth • The moon is held in its orbit by the gravitational attraction between the Earth and the moon.

  18. The Moon’s Phases • The geometry of the Earth- Moon- Sun determines the phases of the moon • With the phases of the moon, we are seeing different amounts of the lit portion of the moon. • ½ of the moon is always illuminated by the sun.

  19. The Moon’s Phases

  20. The Moon’s Phases 2

  21. Eclipses • Named after what goes dark. • Solar eclipse • Moon comes between the Earth and the sun. • Occurs during a new moon. • Only a small area sees it (totality). • Next one here,August 21, 2017

  22. Lunar Eclipse • The earth is between the moon and sun. • Full moon • Everyone on the night side of earth sees it. • Next here: October 18, 2013 • Partial

  23. The Tides • The tides in the oceanare a result of the gravitational attraction of the moon and sun on the earth. • There is always a bulge of water facing toward the moon and one away from it. • When you are under a bulge, you have high tide. • When you are between bulges, you have low tide. • The sun also influences tides • The greatest range is at full and new moon, straight line, spring tide. • The least range is at the quarter moons, right angle, neap tide.

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