Well, everything is completely clear about the poles. The polar night cannot instantly change the polar day. After all, the earth moves in orbit around the sun not with races. Therefore, equinoxes must happen at the poles. At these moments, the sun passes from one part of the sky to another. For example, from North to South. The situation at the equator is somewhat different, since the sun is now in the southern part of the sky, then in the north. But, to understand this situation, quite elementary knowledge and logical thinking. At the equalities, the equinox happens on the same days when it happens throughout the Earth and, of course, when at the poles – during the transition of the Sun from one part of the sky to another. The sun makes such a transition twice a year, therefore, equinoxes throughout the Earth occur twice a year. Including the equator. It is at the moment the sun crosses the heavenly equator that the equinoxes occur. Thus, at the end of March and at the end of September throughout the earth, and naturally, at the poles and at the equator, equinoxes occur. The rest of the time, all over the earth, the day is not equal to the night. If we say, which is longer, which is shorter, then it should be remembered that, for example, in the middle latitudes with a decrease in the angle of the sun at the moments of climaxes, the duration of the day is reduced, and when the climax is maximum, the day is the longest. Thus, at the equator, with a decrease in the height of the sun lifting, the day will be reduced. And since a decrease in the angle of the sun rising at the equator will always occur after the sun crossing the heavenly equator, the maximum duration of the day on the equator is at the moments of the equinox. The rest of the time is the day on the equator shorter than the night.
It is very difficult to find at least one land point on the equator, in which the duration of the day is equal to the duration of the night. This is connected with a height above sea level, so the day on the equator is always a few minutes more than night. If we purely hypothetically assume that we make similar measurements of the length of the day at sea level, then the day will really be absolutely equal to the night. How achievable it is practically – a big question!!!
As for the poles, it is more and less clear here – half a year – night, six months – day. To be more accurate, then, for example, at the North Pole – 189 days, night -176.
At the poles, unlike the equator, the day is really not equal to the night. And this is explained, first of all, by the fact that the earth is inclined at an angle of ~ 23.5 degrees. During the northern winter, the North Pole is removed from the sun, so the South Pole, respectively, is approaching. Result-24-hour nights in the north, 24-hour daylight in the south. This is the southern summer.
Six months will pass and the land will move, but it will still maintain the same slope. Now the North Pole will receive a 24-hour daylight, and the South Pole will be in the dark. This endless process was called Northern Summer, Southern Winter.
All previous answers claim that on the equator and at the poles of the Earth the day differs from night. This is certainly true for the condition if the earth were a ball. But the problem is that the Earth is not a ball, but a flattened ellipsoid due to the fact that the equatorial circle is forty kilometers more than meridional. As a result, if you take into account the fact that the equator is a conditional line perpendicular to its rotation, plus we add to this definition that the earth also rotates around the sun, then without taking into account atmospheric interference the sunrise and the entry will differ even at the equator. And if you add atmospheric interference, then this value will increase still. Plus add that the sun is not a point but has a top and bottom in the sky – then add time to sunrise and sunset to this equation. There are cities strictly or near the equator – there the duration of the day differs in a year in a few minutes. Of course, there is no comparison with the cities in our Far North, in Murmansk, due to the above phenomena, the polar night lasts 40 days (the sun does not rise), and the polar day is 60 (the sun does not come in), though the Earth’s speed should be added to this.Around the Sun – in Appogelia slowly, this is when in the northern hemisphere the summer and orbit are longer, and in Pregelia the earth is closer to the sun and the speed of the earth in orbit around the sun is faster.
Yes, indeed, on the equator the day will always be equal to the night. But at the poles of the northern and southern, another situation is already, exactly the opposite. This fact is explained by the inclination of the earth’s axis. It is always tilted exactly twenty -three degrees in relation to the orbit of the Earth.