On 5th July 2012 at 8.45 a.m. celestial event of “Earth in Aphelion” will occur involving Sun & Earth. Planet Earth will be at farthest point it can get to sun this year in its elliptical orbit around Sun at 1.017 AU (152 Million km approx) from Sun. Astronomically this is phenomena is known as “Aphelion”. Whereas on 5rd January 2012 Planet Earth it was at closest point (Perihelion) to Sun at 0.983 AU (147 million km).
Belief & Ignorance: Generally people think that its distance of Earth from Sun which determines if it is Hot or Cold temperatures. Whereas the truth is Tilt of Earth as it rotates on its axis at 23.4 Degrees is responsible for Seasons.
For example: In January Month when Earth was close to Sun in India the temperatures were cold. Whereas when Earth is far from Sun say in months of May to July compared to January it was Summer and now followed by winter. Hence facing of earth towards and away from Sun due to its tilt at 23.4 Degrees is responsible.
What is Aphelion & Perihelion?
Earth revolves around sun in a elliptical orbit. So at one point of time during its journey around sun it will be at closest point it can get (perihelion) and one point of time during the year it would be at farthest point (aphelion).
How Earth Axial Tilt 23.4 Degress contributes to be Reason for Changing Seasons ?
The Earth’s axis is tilted 23.5 degrees away from the plane of the ecliptic.
In other words at it rotates on it axis at one point in the Earth’s orbit, the north pole of the Earth is pointed towards the Sun. This is summer for the northern hemisphere. And then 6 months later, when the Earth is at the opposite side of its orbit, the North Pole is pointed away from the Sun; that’s winter in the north, and summer in the south hemisphere.