Latitudes and longitudes
- Globe is a true model of the earth.
- A needle is fixed through the globe in a tilted manner - axis.
- Globe divides it into equal parts - equator.
- Equator represents the zero-degree latitude.
- Parallels lines of latitude – from equator to poles.
The four important parallels of latitude are
- Tropic of cancer (23½°N) - Northern Hemisphere.
- Tropic of Capricorn (23½°S) – Southern Hemisphere.
- Arctic of circle (66½°N) – North of Equator.
- Antarctic circle (66½°S) – South of Equator.
Heat zones of the earth
- Torrid zone (Maximum heat) - between the tropic of cancer & the tropic of Capricorn.
- Temperate zones (Moderate Temperature) - Arctic circle and the tropic of cancer in the northern hemisphere, the Antarctic circle and the tropic of Capricorn in the southern.
- Frigid zones (Very cold), receive the sunlight of very low intensity - north to the Arctic circle and that south to the Antarctic circle.
- Tropic of Capricorn - contain sub polar points at the december(or southern) Solstice, sun can easily directly head
- 90 ° below the the horizon at solar mod latitude on june solstice
- Currently, 23°26'11.4, Moving - 15 meters per year
- 10 countries, 3 continent & 3 Water bodies
Day Light Saving Time
- Setting clock forwarded one hour from standard time during summar
- In Southern Hemisphere (Australia, New Zealand, most of South America) - Starts in September-November & end in March-April
- In North Hemisphere (North America, Europe, Asia) - Start in March-April & End in September-November
Latitude
- Line from east to west or west to east.
- Measure north to south.
- Point latitude (North & South Pole).
- Largest latitude (Equator) decrease towards pole.
- Away from the equator, the size of the parallels of latitude decrease.
Longitudes
- The line of reference running from the north pole to the south pole - meridians of longitude.
- Measures west to east.
- All meridians are of straight line except 180° is zig zag line.
- The meridian which passes through Greenwich, where the British royal observatory is located – Prime meridian.
Inclination of the Earth’s Axis and its effects.
- Earth rotate on tilted axis. Angle of 23.5°
- During the earth revolution around the sun, polar region spend long period pointed towards the sun in summers, long period point away from the sun during winter.
- Variation in the length of daytime & night time from season to season are due to the revolution of the earth on a tilted axis.
- Local and Standard Time and the
- International Date Line, Calendar.
- Largely based on 180° Meridian (not fully), Passes through pacific ocean
- Difference between time in places is almost one day.
Time
- As the earth rotates from west to east, those places east of Greenwich will be ahead of Greenwich time and those to the west will be behind it.
- The earth rotates 360° in about 24 hours.
- At any place, a watch can be adjusted to read at 12 o’clock when the sun is at the highest point in the sky.
International Date line
- Separate two consecutive calender days
- Has bends to include all oh Kiribati, Soman, Tonga & Tokelau in the Eastern Hemisphere
- GMT is now abbreviated as UTC (Coordinated Universal Time)
- Move east to west loss time, move west to east gain Time.
Standard time
- The local time various places are different, so it is necessary to adopt the local time of some central meridian of a country as the standard time.
- 82½°E is treated as the standard meridian of India. The local time at this meridian is known as the Indian standard time (IST).
- India located east of Greenwich at 82° 30’E, is 5 hours and 30 minutes ahead of GMT. [Allahabad (82° 30’)]
- Some countries have a great longitudinal extent and so they have adopted more than one standard time
- Russia – eleven standard times.
- Earth has 24-time zone (1 hrs each – 15° of longitude, 4 min - 1° of longitude)
Motion of the Earth
Rotation (Day & Night)
- Bringing gaseous rotation not uniform & differential rate of rotation.
Revolution (Seasonal)
- 18.5 miles per second or 66,000 m.p.h.
- Sun along with the solar system it is revolving around the milky way galaxy approximately centering the milky way galaxy.
- Various lengths of Day & Night.
- Solstice – Direct sun rays in tropic of cancer.
- Summer Solstice – Longest day and shortest night.
- Winter Solstice – Shortest day and longest night.
- Equinox – Equal days and Night (Sun rays directly fall on Equator)
Solar Eclipses
- Moon passes between Sun & Earth, shadow of moon cast on earth.
- Types of Eclipses (Distance between sun,moon & Earth define types)
- Partial Solar eclips - sun,moon & Earth not exactly lined up.
- Total solar Eclips - sun,moon & Earth must be in direct line
- Annular Solar Eclips - partially type of solar eclipse. Sun, Moon & Earth not only in straight line but also in same plane.
- Shadow never be more than 166 miles wide.
- Moon shadow is narrow when it reaches earth
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