by The highlight of the summer is approaching for those of us in the northern hemisphere, but when we prepare for more sunshine and slipping temperatures, our planet turns from the sun at its further point.
On Thursday at 3:55 p.m. ET, our planet reached the so -called aphel – the most distant point in its orbit around the sun, about 3 million miles further away than when it is closest.
This happens every year at the beginning of July, which could sound backwards. If we are most of the sun, shouldn’t it be cooler?
People tend to connect the proximity to heat, so of course it seems to assume that the seasons are caused by the sun by changes in the type of earth. But the removal of the planet has little to do with it.
The real reason for seasonal temperature changes lies in the fact that the earth is inclined.
Our planet rotates at an angle – about 23.5 degrees -, which means that different parts of the world receive more (or less) sunlight depending on the season. In July, the northern hemisphere is inclined towards the sun and brings for a long time and higher sunny angles, which lead to direct sunlight-the summer heat.
An illustration that shows the distance of the earth from the sun and its corner to the sun in the summer summer (June, left) and winter (December, right). – NASA
In contrast, the shape of the earth orbit plays only a subordinate role. Although it is rather oval and rather perfectly circular, the difference between our closest and most distant points in the sun is relatively small.
The earth is currently about 3.1 million miles away from the sun than in early January, when it reached Perihel, its closest point. Compared to its average distance of 93 million miles, this is only about 3.3% difference.
Since the sunlight spreads on the way, even a relatively low change of distance leads to a decline in solar energy that reaches the planet. This is tiny compared to the effect of the earth.
The upper light beam represents a large corner of the sun. The lower light beam represents a smaller one, like what the northern hemisphere experiences in summer. – NASA
How big is the difference? Let’s take a look at some examples.
In cities such as Houston, New Orleans and Phoenix – almost 30 degrees north of the latitude – the amount of solar energy that reaches the earth’s atmosphere in summer is more than twice as high as these cities in winter.
Further north, around 40 degrees, the seasonal swing is even more dramatic. Cities like New York, Denver and Columbus look from around 145 watts per square meter to 430 to 430 in summer – almost a difference of 300%.
While it is true that the earth currently receives less energy from the sun, this detail hardly registers compared to the power of the planet’s inclination. A small angle in the spin of the earth leads much more to shape our seasonal patterns than it could ever have a few million miles.
In the end it is not how close we are to the sun that feels summer and summer – it is how we pointed out.
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