We experience Earth’s revolution around the Sun in the form of seasons. Similarly, have you ever wondered, does the Sun have seasons? So, how to diagram Earth orbit around Sun is important because the circle of illumination will give you more clarity as it bifurcates light and darkness. Also, you will learn how does the angle of the Sun’s rays on Earth determine seasons and Earth’s position right now? Read on to find these out along with the answer to does the Sun have seasons or not.
1. What is a Circle of Illumination?
The circle of illumination is the imaginary line that divides the day from the night. It is the part of the Earth that receives sunlight. The circle of illumination bifurcates the Equator and the latitudes at the autumnal and spring equinoxes. The Solar Equinox is the time when the Sun passes by the Equator. It takes place twice a year, around 20th March and 22nd September.
However, the circle of the illumination line is different from the axis. Our planet rotates along this axis line. The diagram Earth orbit around Sun shows that the Earth’s axis line and the circle of illumination lines are separate as the Earth’s axis line is tilted at 23.5 degrees relative to the Earth’s orbital plane. . (See What is the Vernal Equinox?)
2. What is Circle of Illumination Definition?
The circle of illumination is the imaginary line that bifurcates day from night. It is the illusionary dividing line between the Earth’s sun-exposed surface and the area in darkness. It equally divides Earth’s surface into two halves and passes through the latitudes and Equator. (See When do Days Start to get Longer?)
3. Circle of Illumination divides Earth into?
The circle of illumination line creates an imagined line that splits the Earth’s surface during the spring and autumnal equinoxes, thus separating the surface into night and day.
4. Explain Circle of Illumination Formula
The radius of illuminance or Snell’s window (underwater) for the Circle of Illumination Formula is derived below.
- Using the property of a right-angled triangle,
- tan C = r/h,
- r = h tan C,
Here, C = critical angle, r = radius of the circle of illumination, and h = distance from the interface of the denser medium or height of the cone.
- According to Snells’ law, the relation between refractive indexes of rarer and denser medium is,
µd sin C = µr Sin 900,
- Sin C = µr/µd,
- Using, trigonometry, tan C = [ µr /(µd2-µr2)1/2 )],
- Therefore, the radius of illuminance can be written as r = h [ µr /(µd2–µr2)1/2 )]. (See What is the Absolute Location of the Philippines?)
5. Does the Sun have Seasons?
No, the Sun doesn’t have seasons like Earth. However, there are solar events that happen every 11 years and persist for certain durations. And these events or activities act like seasons. So, does the Sun have seasons? No, it’s not scientifically possible. (See What are the Four Seasons in the Philippines?)
6. Why are there Seasons on Earth?
While discussing does the Sun have seasons, you might wonder why Earth have seasons. When the Earth takes a revolution around the Sun in an imaginary elliptical orbit line, we experience different seasons on our planet. In other words, because the Earth’s spin axis is tilted about its orbit plane, the Earth experiences a variety of seasons. For example, we experience summers in the Northern or Southern Hemisphere when the axis point of Earth faces the Sun.
Likewise, when the axis point of Earth faces away from the Sun, the planet experiences winters. And the Earth’s poles receive very little sunlight because of the planet’s tilt and orbit around the Sun. Due to this, the Earth’s poles have two seasons: summers and winters; thus, the Sun doesn’t set in summers and doesn’t rise during winters at the poles. Also, check out the what are the six seasons in India.
7. What is the Relationship Between Earth and Sun?
The Sun is the source of energy on Earth. It is the sole reason for the existence of every living being on this planet. The planets orbit or revolve around the Sun on an imaginary elliptical orbital line; thus, we experience different seasons throughout the year. Due to the Sun’s strong gravitational pull, all the planets, including our Earth, revolve around the Sun at the same distance and speed. Our Earth is in the habitable zone, meaning that our planet is neither too hot nor too cold to survive. We receive only as much sunlight as is required for survival. Also, check out how many suns are in the Universe?
8. What is the Earth’s Position Relative to the Sun? What is Earth’s Position Right Now?
The Earth is in the third position from the Sun. The Earth’s position right now is at a distance of 150 million Km, almost 93 million miles from the Sun. (See What is the Third Planet closest to the Sun?)
9. How does Angle of Sun Rays on Earth determine Seasons?
The Earth’s axis is always pointed towards the North Star, no matter at what position the Earth is orbiting. Due to this, the Sun rays’ dispersion also deviates. For example, in June, there is a summer season in the Northern Hemisphere because the Sun rays spread at the North Pole and beyond the area encompassing the entire Arctic region.
Likewise, in December, the Northern Hemisphere experiences winter due to the North Pole tilting away from the Sun. Also, the different regions on Earth receive varying amounts of sunlight, meaning those regions that get scattered sunlight receive a limited amount of energy from the Sun, like the North and South poles. Similarly, the Equator receives accumulated and abundant sunlight, so it is always warmer. However, if you are still wondering, does the Sun have seasons, the answer stands no because Sun is a big ball of hydrogen gas and so different from the planets. (See How many Hemispheres on Earth?)
10. Describe Circle of Illumination in Water
An optical man-hole, or Snell’s window, is an occurrence in which a person underwater can view everything above the water surface through a cone of light at 96 degrees. This situation occurs due to the refraction of light that enters the water. In other words, when light enters the water, a person gets a restricted view (in a conical shape) of the water’s surface. (See What is the Difference between Tropical and Polar Regions?)