Test: Motions Of The Earth - UPSC MCQ

Earth takes 365 days and 6 hours to complete a revolution around the sun .That's why leap year takes place as after four years 6 hrs each year becomes a total of 24 hrs making the 366 days of the leap year.

Summer Solstice occurs around June 21 when the Northern Hemisphere experiences the longest day and the shortest night. During this time, the Sun is directly overhead at the Tropic of Cancer, and the tilt of the Earth's axis causes the Northern Hemisphere to receive maximum sunlight.

An equinox occurs twice a year

• During an equinox, day and night are approximately equal in length.
• This happens because the Sun is directly above the equator.
• There are two equinoxes each year: March 21st and  September 23rd.
• These events mark the beginning of spring and autumn respectively in many cultures.

 

Earth travels in an elliptical, or oval-shaped, orbit around the sun. As a result, the distance between Earth and the sun varies by about 3% throughout the year.

• On June 21 (Summer Solstice), the Sun's rays fall vertically on the Tropic of Cancer (23.5° North latitude).
• This marks the longest day and shortest night in the Northern Hemisphere, as it receives maximum sunlight.

If the Earth did not rotate, half of the Earth would experience continuous daylight, and the other half would be in continuous darkness. There would be no alternation of day and night on either side, so no part of the Earth would experience a regular cycle of day and night.

• The angle of inclination of the earth's axis with its orbital plane is 66.5 degrees. This tilt is the reason we experience different seasons throughout the year.
• Imagine the Earth leaning just a little bit as it goes around the Sun, causing summer, winter, spring, and autumn to happen at different times of the year.

In a leap year, there are 366 days. This extra day is added to February to keep our calendars accurate. So, a leap year has one extra day compared to a regular year.

The circle of illumination is the imaginary line that separates the day side from the night side on the globe. It represents the boundary where sunlight stops illuminating the earth's surface. An interesting fact is that this line constantly shifts as the earth rotates, causing the transition between day and night.