Changes

==== Formation of Seasons ====

==== Formation of Seasons ====

 

The Earth and all other celestial bodies in the Solar System are constantly moving. Rotation, precession and revolution of Earth are directly responsible for seasonal variations in a year. The term ‘Earth Rotation’ refers to the spinning of our planet on its axis, with an equatorial speed of 1040 miles per hour (about 465 meter per second or slightly over 1675 km per hour). One rotation takes twenty-four hours (23.93 hour) and is called a mean solar day. The Earth’s rotation is responsible for the daily cycles of day and night. At any moment in time, one half of the Earth is in sunlight, while the other half is in darkness.

The Earth and all other celestial bodies in the Solar System are constantly moving. Rotation, precession and revolution of Earth are directly responsible for seasonal variations in a year. The term ‘Earth Rotation’ refers to the spinning of our planet on its axis, with an equatorial speed of 1040 miles per hour (about 465 meter per second or slightly over 1675 km per hour). One rotation takes twenty-four hours (23.93 hour) and is called a mean solar day. The Earth’s rotation is responsible for the daily cycles of day and night. At any moment in time, one half of the Earth is in sunlight, while the other half is in darkness.

The Earth's rotation axis is not fixed in the space. The direction of the rotation axis executes a slow ‘Precession’, caused by the gravitational pull of the Sun and the Moon on the Earth. Through each 26 000-year cycle, the direction in the sky to which the axis points goes around a big circle, the radius of which covers an angle of about 23.50. This precession also has an effect on the seasons.

The Earth's rotation axis is not fixed in the space. The direction of the rotation axis executes a slow ‘Precession’, caused by the gravitational pull of the Sun and the Moon on the Earth. Through each 26 000-year cycle, the direction in the sky to which the axis points goes around a big circle, the radius of which covers an angle of about 23.50. This precession also has an effect on the seasons.

The solstices, together with the equinox, are connected with the seasons. They are considered to start or separate the seasons, or fall nearer the middle. A solstice is an astronomical event that happens twice each year when the Sun’s apparent position in the sky, as viewed from Earth, reaches its northernmost or southernmost extremes. This usually happens around June 21st and December 21st. An equinox occurs twice a year, when the tilt of the Earth’s axis is inclined neither away from nor towards the Sun, the center of the Sun being in the same plane as the Earth's equator. Around the equinox, the night and day have approximately equal length and the rays of the Sun shine directly on the equator. This happens on approximately March 20th and September 22nd.

The solstices, together with the equinox, are connected with the seasons. They are considered to start or separate the seasons, or fall nearer the middle. A solstice is an astronomical event that happens twice each year when the Sun’s apparent position in the sky, as viewed from Earth, reaches its northernmost or southernmost extremes. This usually happens around June 21st and December 21st. An equinox occurs twice a year, when the tilt of the Earth’s axis is inclined neither away from nor towards the Sun, the center of the Sun being in the same plane as the Earth's equator. Around the equinox, the night and day have approximately equal length and the rays of the Sun shine directly on the equator. This happens on approximately March 20th and September 22nd.

The Indian Meteorological Department (IMD) designates four different seasons – winter, summer or pre-monsoon, monsoon or rainy season, and post-monsoon season.

The Indian Meteorological Department (IMD) designates four different seasons – winter, summer or pre-monsoon, monsoon or rainy season, and post-monsoon season.

==== Qualities of seasons ====

==== Qualities of seasons ====