Most recently, I went to buy a winter wardrobe for myself, because very soon The sun will stop heating that part of the Earth where I live. But why is this happening, every year more than half of humanity experiences serious climate change, then the heat comes, then the cold, then moderate weather reigns in their region. For many, the favorite time of the year is spring, because it is not too hot yet, but there are no sub-zero temperatures either. This state of affairs is due to the fact that planet Earth has not stood still for 365 days, but rotates around its axis and the star in a certain orbit.

Why does the sun shine differently throughout the year?

Sunlight hitting Earth will never be the same, since the planet in outer space is not exactly, and tilted to 23 degrees. This is the first reason for this circumstance, because depending on the position of the Earth at a particular moment, Photons cannot reach the South and North Poles in the same way, but warm weather always remains at the equator, but here the second very important factor comes into play.

It lies in the fact that the orbit of the planet is not round, but oval, therefore, at different periods of passage along it, the Earth turns out to be closer to the luminary, then moves away from it. In addition to all this, our planet rotates around its axis within 24 hours, and therefore, each hemisphere turning away from the rays of the sun and there comes the night.

Why does the earth rotate

Despite the fact that the Universe is huge, everything in it is arranged very finely and harmoniously. All space objects interact with each other through gravitational attraction, which causes the constant rotation of the earth around the sun, since the mass of the luminary is greater, respectively, the force gravity is much stronger.

Nature thought everything through thoroughly, because if photons always warmed only, for example, one side of the planet, or its tilt angle was higher, there would be no balance. Some celestial bodies suffer from such an imbalance, on one side of them there may be an extraordinary heat, and the other at that moment freezes and becomes covered with ice sheets. So, in summary, it should be noted three reasons uneven lighting throughout the year, namely:

1. The tilt of the earth's axis.
2. oval orbit.
3. daily rotation.

As it turned out, everything is quite simple and clear.

The sun influences the Earth quite strongly. The sun emits light and, as the earth rotates on its own axis, day and night are obtained. Sunlight brings heat which, with the rotation of the Earth around the Sun and the tilt of the Earth's axis (by 23.5°), causes the seasons to change. Most of the light and heat comes from direct sunlight.

sunlight

The rays of the sun at any time can only illuminate one half of the earth's surface. Sunlight equally reaches the North and South Poles only twice a year - September 23 and March 21 - the days of the equinox (Figure 1). On these two days, the direct rays of the Sun fall vertically on the Equator.
From September 23 to December 21, the rays of the Sun gradually expand their zone of impact on the Earth from the South Pole and recede from the North Pole. On December 21, the rays reach 23.5 ° for South Pole(Antarctic zone) and are unable to reach the North Pole by the same 23.5° (Arctic zone). On this day, the area south of the Antarctic Circle (Antarctica) receives constant sunlight, while the area north of the Arctic Circle (Arctic) remains without sunlight. Try to analyze it with a globe. Find on the globe the Antarctic and Arctic Circles (parallels in the Northern and Southern hemispheres with latitudes of 66.5 °).
On December 22, the rays of the Sun cover the entire zone up to the Antarctic Circle and leave the zone of the Arctic Circle by 23.5° (Figure 2). And on June 21, the opposite is true - the rays completely leave the area of ​​the Antarctic Circle and illuminate the area of ​​the Arctic Circle. Now the South Pole is in darkness, and North Pole receives constant sunlight (Figure 3). This explains the semi-annual day and night at the North and South Poles.
When the light falls directly on the Tropic of the North (23.5° north of the Equator), the day in the Northern Hemisphere is at its maximum longer than the night (June 21).
When the light falls directly on the Tropic of the South (23.5° south of the equator), the day in the Northern Hemisphere is as short as possible at night (December 22).

Is the Sun exactly in the south at 12 noon?

At noon, the Sun reaches its highest position in the south. When it reaches this point, it is said that the true the local time- 12 hours. At this moment, the shadow from the vertically standing pillar is the shortest. Unfortunately, due to uneven movement The Earth's orbit The sun also does not move uniformly across the sky. Therefore, it does not appear exactly due south every 24 hours.

In order to keep track of time independent of the “whims” of the true Sun, astronomers have come up with an “average Sun” that moves uniformly. It exists, of course, only on paper. When the "mean sun" reaches its highest position in the south, it is considered to be 12 o'clock local mean time. The difference between true and mean local time is called the equation of time. It varies throughout the year ranging from -14.3 to +16.3 minutes.

But there is another problem. For example, when in Hamburg the Sun is at its highest point, in Berlin it has already passed it, and in Bremen it has not yet reached this position. Thus, the average local time in the three cities would be different. However, this is very inconvenient for transport and other services. AT Central Europe all people live according to Central European time, which does not correspond to the true position of the Sun in the sky.

But the governments of several countries have agreed that the average European time will be considered solar time at 15 degrees east longitude. In summer, one more hour is added to this time to lengthen the morning hours and shorten the evening hours. This is the so-called summer time. Therefore, in the summer in areas of Europe that live according to this schedule, the Sun reaches highest point in the sky around 13:00. The same is happening in Russia.

Question 1. In what movements does the Earth participate?

The earth is involved in several types of movements:

1) Movement with solar system around the center of the galaxy. One revolution is a galactic year (230 or 280 million years).

2) Movement around the Sun in an elliptical orbit close to a circle with a radius of about 149.6 million km. The circulation period is a year. The plane of the orbit is called the plane of the ecliptic.

3) The rotation of the Earth around its axis - one revolution per day.

Question 2. What are the consequences of the movements of the Earth?

The rotation of the Earth around its axis has several consequences: the change of day and night, the oblateness of the Earth at the poles, more uniform heating of the planet's surface.

Question 3. What is a globe?

Globe - a three-dimensional model of the Earth or another planet, as well as a model of the celestial sphere (celestial globe). Unlike maps, there are no distortions and breaks on the globe, so the globe is convenient for obtaining general idea about the location of continents and oceans.

Question 4. What are the seasons?

There are 4 seasons: Winter, Spring, Summer, Autumn.

Question 5. What is the reason for the presence of seasons on Earth?

The consequence of the motion of the Earth around the Sun, the inclination of the axis of rotation of the Earth to the plane of the orbit and the constancy of this inclination is a regular change of seasons on Earth.

Question 6. What is equal to the angle formed by the earth's axis with the plane of the earth's orbital motion?

The angle formed by the Earth's axis with the plane of the Earth's orbital motion is 66.5 degrees.

Question 7. What are the dates of the days of the spring and autumn equinoxes, summer and winter solstices.

The spring equinox is March 21st and the autumnal equinox is September 23rd. The summer solstice is June 22nd and the winter solstice is December 22nd.

Question 8. Why does the Sun illuminate the Earth differently during the year?

The Earth's axis of rotation is slightly inclined to the plane of the Earth's orbit. To be precise, the angle formed by the earth's axis and the plane of the orbit is 66.5. The Earth's axis of rotation has a definite and unchanging tilt. During the annual movement of our planet around the Sun, the Earth turns to the Sun with either the Northern or the Southern Hemisphere.

Question 9. Why does the seasons change?

During the annual movement of our planet around the Sun, the Earth turns to the Sun with either the Northern or the Southern Hemisphere. In the summer months (June-August), the Northern Hemisphere is turned towards the Sun more than the Southern. During these months it is summer in the Northern Hemisphere and winter in the Southern Hemisphere. Because during these months, the Southern Hemisphere, as it were, turned away from the Sun and receives much less light and heat.

Question 10. In what month do they meet New Year in Australia?

Question 11. When is day equal to night in the Northern Hemisphere? In the South?

The days when the Sun illuminates both hemispheres in exactly the same way, when the length of day and night is the same in both hemispheres, are called the days of the equinox: September 23 is the day of the autumn equinox, and March 21 is the day of the spring equinox.

Question 12. When is spring in Russia, what season will it be in southern Africa?

It will be autumn in southern Africa.

Question 13. When we have summer, what season will it be in Canada?

In Canada, just like we will have summer.

Question 14. What determines the angle of incidence of sunlight on earth's surface?

The angle of incidence of sunlight on the earth's surface depends on geographical latitude, on the area and on the time of year.

Question 15. Why are the sun's rays falling on the earth's surface under different angles, bring different amount light and heat?

The lower the Sun is above the horizon, the smaller the angle of incidence of the sun's rays on the Earth's surface. The smaller the angle of incidence of the rays, the less solar energy - light and heat - per unit area of ​​the Earth's surface.

Question 16. Patriotic War 1812 began on June 24, and the Great Patriotic War on June 22. Why do you think these two wars started almost on the same day?

Because these days were the beginning of summer, and the longest daylight in the Northern Hemisphere falls on June 22nd. These circumstances favor the conduct of hostilities.

Sometimes many of us think about questions about how everything works in our world. And quite often there are questions about the principles of "work" of our universe.

For example, why does the Sun illuminate the Earth in different ways? And today we will deal with this situation.

Different illumination of the Earth by the Sun

When it comes to the fact that the Sun illuminates our planet in different ways, it means that in different parts of the Earth there are different air temperatures, and there is also a change of seasons.

In fact, the explanation for such phenomena is considered quite simple, and in order to understand the principles of "work", we suggest that you familiarize yourself with the information below.

Why does the Sun illuminate the Earth differently?

If we talk about why there are cold and warm zones on our planet, why the Sun's rays fall on the surface of our planet in different ways, then the main reason is two factors:

1. The earth has a spherical shape. If our planet were flat, all its parts would be equidistant from the rays of our natural star. Accordingly, in all parts of the planet, approximately the same temperature would be observed, and, most likely, the weather. However, the Earth is spherical, which means that some of its sections are located at somewhat more distant distances from our luminary. So, for example, a section of the equatorial zone of the planet Earth is always closest to the Sun. And, starting from it, both up and down, the surface of the planet begins to gradually move away from the star, which leads to the fact that the temperature there is lower.
2. The Earth, in relation to the Sun, is not in a completely vertical state. Our planet rotates at an angle with respect to the Sun, so its different parts are at different distances from our natural star. This also, of course, affects the different lighting and heating of the planet's surface.

Why is there winter and summer on planet Earth

As for why there is a change in the seasons on our planet, this phenomenon also has a fairly simple explanation. And it concerns precisely the fact that the Earth rotates around its axis at an angle with respect to the Sun. As you know, we also carry out rotational movements around the Sun. And in the aggregate, such movements, as well as our inclined position, lead to the fact that at different times of the year, different parts of our planet are closer to the Sun or further away from it. Thus, the seasons change, as well as the warming and cooling associated with seasonal changes.