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That day, the Earth crosses what is called aphelion, a word of Greek origin meaning "far from the sun"
"The aphelion is the point of Earth's orbit around the Sun in which is the Earth, further away from our star and perihelion (near the Sun) is just the opposite point, it's the point of the orbit of the Earth in which the Earth is closer to the Sun, "explained to BBC Mundo Nayra Rodrguez Eugenio, astrophysics and developer of the Institute of Astrofsica de Canarias
" In perihelion, the Sun is about 147 million km from Earth, and when it is in the aphelion, it is about 152 million km from the Sun. "
The distance varies because the orbit of the Earth around the Sun is not a perfect but elliptical circumference.
In the aphelion, "the Earth is a little further, 5 million kilometers from the Sun", than in perihelion.
Speed
The aphelion was held every year between July 2nd and 7th. Perihelion took place this year on January 3rd.
The greatest distance between the Earth and the Sun will be recorded on July 6 at 17:46 GMT, while the planet and its star are at 152,095,566 km.
Largest distance results in a lower speed.
As Keple's second law says, when the planets are close to the Sun in their orbit, they move faster than when they are farther apart.
The greater distance in aphelion means that the translocation orbital velocity is less than 103,536 km per hour, or more than 7,000 km per hour less than perihelion velocity.
Seasons
The greater or lesser distance to the sun during aphelion or perihelion does not correspond at all to temperature variations during the seasons.
"The seasons are produced by the tilt of the axis of rotation of the Earth in relation to the plane that it describes around the Sun, what we call the ecliptic", said Rodrigue Eugenio.
"This axis is inclined at about 23.5 degrees and so when we are in the northern hemisphere summer, the north axis, that is to say the pole north of the Earth, point further toward the direction of the Sun. "
"On the other hand, in winter, our north pole points in the opposite direction, this is not exactly the opposite because they are close to 23.5 degrees, but point in the opposite direction to Sun."
More water in the southern hemisphere
The summer of the northern hemisphere coincides with the aphelion, "receives more solar radiation in the northern hemisphere, because the sun is higher in the horizon and also has more hours of sunshine, "says astrophysics.
In the southern hemisphere, on the other hand, summer coincides with perihelion.
"This could make us think that in the southern hemisphere the temperature rises more than in the north in summer, because apart from inclination, the Earth is also closer to the Sun," explains Rodrigue Eugenio.
But this is not the case
What happens is that "in the southern hemisphere, there is more water and that means that the temperature does not increase much".
"This seems to be due to the fact that the earth warms up much more easily than water and, because the southern hemisphere has a greater proportion of its surface covered with water, the Excess energy is absorbed by it. "
Therefore, in summer, both in the southern hemisphere and in the northern hemisphere, the temperature is about the same, explained astrophysics.
(Source: http://www.bbc.com)
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