Motion Of The Earth
Motion Of The Earth
Earth's motion has been divided into two parts
(a) Rotation
(b) Revolution
Rotation:- Rotation is the movement of earth Rotation on its axis.
Rotation is responsible for the cycle of day and might, so this motion is also called Daily motion. (23hours, 56 minutes, 4 second)
Revolution:- The earth also revolves around the sun in an elliptical path and completes. its one Revolution in 365day and 6 hours. Elliptical Path is Geoid.
→ Earth Revolves around the sum at a speed of 108000 km/h or, average speed above 27 km/second.
# Perihelion :- When the earth is at the minimum distance from the sun. then this position is called perihelion. The earth attains this position on 3 January.
Distance=147 million.
# Aphelion:- When the earth is at the maximum distance from the sun, them this position is known as Aphelion.
→ The earth attains this position on 4-6 July, Distance = 152 million km.
→It is winter in the Northern Hemisphere, When the earth is at the perihelion. Earth experiences summers in the Northern Hemisphere When the earth is at Aphelion.
# Average distance between Earth and Sun 150 million km.
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| Perihelion and Aphelion. |
Season change through earth
→ Change in seasonal cycle is due to the fact that earth is inclined 23½° from its Vertical axis.
→ on 21 march or 23 September, The sun's rays are perpendicular to equator, due to which day and night are equal.
→ on 21 June, The day in the Northern Hemisphere is Longest, night is very short. The sum shines Vertically on the tropical cancer.
→ on December 22, The sun shines brightly on the tropic of Capricorn, During this period days are longer and nights are shorter in the Southern Hemisphere.
→ 21 march is called Spring or, vernal Equinox, whereas 23 September is termed as Autumn Equinox.
→At the North Pole, 6 months of day begin with the Vernal equinox and 6 months of night begin with the Autumnal Equinox, Such condition is also found in the Southern Hemisphere
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| Earth Seasons |
Eclipses
Types of Eclipses
• Lunar Eclipse
(a) Penumbral Lunar Eclipse.
(b) Pertial Lunar Eclipse.
(c) Total Eclipse.
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| Lunar Eclipse |
(a)Total Solar eclipse.
(b) Annular.
(c) Partial.
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| Solar Eclipse |
• When Sun, Earth and Moon are in a straight lime, then this situation is called Conjunction opposition or, Syzygy in which Conjunction is formed in the case of solar eclipse and opposition is formed in the case of Lunar eclipse.
• Lunar Eclipse always occurs on a full moon.
• Solar eclipse always occurs during Amavasya. The moon is tilted 5° on its axis.
• A maximum of seven Lunar eclipses and Seven solar eclipses can occur in a year. Sometimes total solar eclipses are seen, but total Lunar eclipses are not often seen. Because there is a different in the size of the sun, moon and earth.
• During a Solar Eclipse, ultraviolet rays are emitted by the Sun in a large amount. Due to this, it is forbidden to look at a solar eclipse with the naked eyes.
• There occurs a condition of diamond ring around the Sun during the full solar eclipse.
• A total Solar eclipse cannot last more than 8 minutes.
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