Latitudes, Longitudes, Perihelion, Aphelion, Solstice & Equinoxes

Latitudes & Longitudes, Perihelion & Aphelion

Latitudes

The angular distance of a place north or south of the earth's equator, or of the equator of a celestial object, usually expressed in degrees and minutes
These are depicted in degrees, minutes and seconds.
Equator is called the 0° latitude.
There are total 180 latitudes in both sides at an interval of 1°.
23½° latitude on the northern hemisphere is called the Tropic of Cancer (23½°N), whereas in the southern hemisphere the same latitude is called the Tropic of Capricorn (23½°S).
The latitude distance of 1° is about 111km.

Longitudes

Angular distance of any place from the prime meridian, on its east or west is called longitude. It is also measured in degrees minutes and seconds. The prime meridian is at 0° and is known as the Greenwich Line as it passes through Greenwich, in London.
There are 360 longitudes in total.
The distance between two adjacent longitudes is about 111.32km, which is less towards the poles and more at the equator.
Earth rotates 360° in 24 hours. So it takes 4mins to rotate by 1° of longitude.
For every 15° of longitudes there is a difference of one hour in time. In this way the time on the 180 E longitude is 12 hours ahead of the Greenwich and that on the 0 -180° W longitudes is 12 hrs behind the time at Greenwich.
180°E longitude is termed as International Date Line.
82°E longitude passing through Naini, near Allahabad (U.P) is standard meridian of India.

Perihelion

When the earth is at the minimum distance from the sun, while in orbit, this position is called perihelion. The earth attains this position on 3rd January.

Aphelion

When the earth is at the maximum distance from the sun, while in orbit, this position is known as aphelion. The earth attains this position on 4th July.

Summer solstice, Winter solstice & Equinoxes

On 21st June sun shines perpendicularly over the Tropic of Cancer. This position is called the summer solstice.
On 22nd December sun shines perpendicularly over the tropic of Capricorn. This position is called winter solstice.
On 21st march and 23rd September duration of day and night becomes equal on earth. 21st march is called spring or vernal equinox whereas 23rd September is called autumn equinox.