Question

What is the circle of illumination?

Answer 1

Answer:

The imaginary line which divides the parts of the earth with day and night is called the circle of illumination. The circle of illumination is at right angle to the orbital plane. Thus, the circle of illumination is at an angle of 23.5o to the earth's axis.

Answer 2

• The imaginary line that separates light from the darkness and day from the night is known as the circle of illumination. Earth’s axis refers to an imaginary line going through the centre of the earth from top to bottom. The circle of illumination cuts all latitudes into half on the spring and autumnal equinoxes. The circle of illumination bisects the equator while the circle of illumination separates light from darkness and day from night, the axis is a line along which the earth rotates.