Context:
Recently, on 5th July 2024, Earth experienced aphelion.
What is Aphelion?
- Refers to the point in Earth’s orbit when it is farthest from the Sun.
- Occurs around 3 to 6th July each year (According to NCERT, Aphelion is on 4th July)
- Earth’s perihelion and aphelion dates are not fixed due to variations in its orbit eccentricity.
- Distance between Earth and the Sun extends to approximately 152.5 million kilometres.
At Perihelion, Earth is closest to the Sun, occurring around January 3 annually, with a distance of approximately 147.5 million kilometres.
Significance of Aphelion:
- Variation in Solar Radiation: During early July, Earth’s aphelion slightly reduces the sunlight reaching India, but this has a minor impact on temperatures.
- The difference in solar radiation caused by Earth’s elliptical orbit is only about 3%, showing that seasonal factors are the main influence on India’s temperatures, even at aphelion.
- Stability of the Orbit: The aphelion is a natural consequence of Earth’s elliptical orbit, which is a result of the gravitational interactions between the planets. Maintaining this slightly elliptical orbit is crucial for the long-term stability of the Earth’s climate and habitability.
Perigee and Apogee:
- Perigee –
- The point in the moon’s elliptical orbit that is closest to the Earth.
- At perigee, the moon is at its smallest apparent size and its gravitational pull on the Earth is strongest.
- Apogee –
- The point in the moon’s elliptical orbit that is farthest from the Earth.
- At apogee, the moon is at its largest apparent size and its gravitational pull on the Earth is weakest.
Source: Indian Express
Previous Year Question
On June 21 every year, which of the following latitude(s) experience(s) a sunlight of more than 12 hours ?
1. Equator
2. Tropic of Cancer
3. Tropic of Capricorn
4. Arctic Circle
Select the correct answer using the code given below:
[UPSC Civil Services Exam – 2024 Prelims]
(a) 1 only
(b) 2 only
(c) 3 and 4
(d) 2 and 4
Answer: (d)
Explanation:
On 21st June, the Northern Hemisphere is tilted towards the sun. The rays of the sun fall directly on the Tropic of Cancer. As a result, these areas receive more heat. The areas near the poles receive less heat as the rays of the sun are slanting. The North Pole is inclined towards the sun and the places beyond the Arctic Circle experience continuous daylight for about six months. Since a large portion of the Northern Hemisphere is getting light from the sun, it is summer in the regions north of the equator. The longest day and the shortest night at these places occur on 21st June.
