How many hours in the earthly days. How many in the days of the clock. Day sun and star

How much is a day? You probably think that exactly 24 hours? Depends on the circumstances. A day is a period of time for which the Earth makes one turn around its axis.

So how many day last?

In fact, one turn of the earth around its axis is never exactly twenty-four hours.

In the days of 23 hours 56 minutes and 4 seconds. All my life I lived in lies!

Amazing, but this indicator can fluctuate into one direction or the other side for the whole fifty seconds! This is because the speed of rotation of the Earth changes all the time - due to friction caused by synoptic situations, tides / sings and geological events.

On average, per year for a split second in short, than twenty-four hours.

When these discrepancies were revealed using atomic watches, it was decided to override a second as a fixed share of the "sunny" day, more precisely, a million-scene-forty.

The new second was in use in 1967 and was defined as "time interval equal to 9,192,631,770 radiation periods corresponding to the transition between two ultra-thin levels of the main state of the cesium atom-133 in the absence of perturbation by external fields." More precisely, you can not say - it is only painful to disappear all this at the end of a long day.

The new definition of a second means that sunny day Gradually shifted in relation to atomic. As a result, scientists had to be introduced into the atomic year the so-called "leap second" (or "second coordination") in order to coordinate atomic year with sunny.

From 1972, a leap second was added 23 times. Imagine, otherwise, our days would have increased almost half a minute. And the land continues to slow down its rotation. And, according to scientists, in the XXIII century in our days will be 25 hours.

The last time the "leap second" was added on December 31, 2005 to indicate the International Service for Establishing the Rotation Parameters and the Earth Coordinates Based in the Paris Observatory.

Good news for astronomers and those of us who love when the clock keep up with the movement of the earth around the sun, but headache for computer programs And all the equipment that stands on space satellites.

The idea of \u200b\u200bentering a "leaping second" met a decisive reference from the International Union of Telecommunications, who even made an official proposal to completely cancel it in December 2007.

You can, of course, wait until the difference between universal coordinated time (UTC) and middle time in Greenwich (GMT) reaches exactly an hour (somewhere after 400 years) and then put everything in order. But as long as the debate around what is considered "real" time, continues.

This is all known - 24 hours. But why did it happen? Let's consider in more detail the history of the appearance of the main units of time measurement and find out how many hours in the days of hours, seconds and minutes. And also look, whether it is worth binding these units exclusively to astronomical phenomena.

Where did the day come from? This is the time of one turnover of the Earth around its axis. There is still little that knowing about astronomy, people began to measure the time with such ranges, including each bright and dark.

But there is interesting feature. When do the day begin? From a modern point of view, everything is obvious - a day begin at midnight. People of ancient civilizations considered otherwise. It is enough to look at the very beginning of the Bible, so that in the 1st book of Genesis to read: "... And there was evening, and there was one morning." The day began with this there is a specific logic. The then people focused on the sun village, the day ended. Evening and night is the next day.

But how many hours in the days? Why did the day divided for 24 hours, because there is more conveniently a system system, and much? It would be in days, let's say 10 o'clock, and in every hour 100 minutes, would something change for us? Actually, nothing but numbers, on the contrary, would even be more convenient to make calculations. But a decodent system is far from the only one used in the world.

In used sixties. And the bright half of the day was well divided in half, 6 hours each. Total in the days turned 24 hours. This is quite a convenient division of Babylonians and other peoples.

Ancient Romans counting time occurred even more interesting. The countdown began from 6 am. So they believed from this moment further - the first hour, the third hour. Thus, it is easy to calculate that the "Eleventh-hour employees" are commemorated by Christ are those who begin to work at five o'clock in the evening. Indeed, late!

At six o'clock in the evening, the twelfth hour was assumed. That's how many hours in the days numbered in ancient Rome. But there was still no night hours! The Romans did not forget about them. After the twelfth hour, night guards began. The duty replaced at night every 3 hours. Evening and night time was divided into 4 guards. The first evening guard started at 6 o'clock in the evening and lasted to 9. The second, midnight, lasted from 9 to 12 hours. The third guard, from 12 nights to 3 am, ended when the roosters sang, therefore it was called - "singing of the roosters." The last, fourth guard, was called "Morning" and ended at 6 am. And it all started at first.

The need to share composite parts also the clock has arisen much later, but they have not retreated from the sixties. And then and the minute was divided for seconds. True, it later turned out that it was impossible to rely only on to determine the duration of seconds and the day. By a century, the duration of the day increases by 0.0023 seconds - it seems to be quite small, but enough to get confused on how many seconds in the days. And that's not all the difficulties! One turn around the Sun Our land does not make a permanent amount of day, and this also affects the solution of the question of how many hours in the days of the clock.

Therefore, to simplify the situation, a second was equated to the movement of celestial bodies, but by the time of the processes within the cesium-133 atom in the state of rest. And to match the actual state of affairs with the turnover of the Earth around the Sun, twice a year - December 31 and June 30 - add 2 extra leapsday seconds, and once every 4 years - extra day.

It turns out that in the days of 24 hours, or 1440 minutes, or 86400 seconds.

Here, on Earth, people perceive the time as something of granted. But in fact, because the basis is the most difficult system. For example, the way people calculate the days and years, follows from what is the distance between the planet and the Sun, from the time that the earth is spent on the complete turnover around the gas shone, as well as the time that is spent on the movement of 360 degrees around its axis. The same method is applicable for the rest of the planets in the solar system. Earthlings were accustomed to believe that in the days contained 24 hours, but on other planets the duration of the day is much different. In some cases, they are shorter, in others - longer, sometimes significantly. The solar system is full of surprises, and it's time to learn it.

Mercury is a planet, which is located closest to the sun. Distance This can be from 46 to 70 million kilometers. Given the fact that Mercury takes about 58 terrestrial days to turn on 360 degrees, it is worth understanding that you can see dawn on this planet only every 58 days. But in order to describe the circle near the main shining system, Mercury takes only 88 terrestrial days. This means that the year on this planet lasts about a year and a half.

Venus

Venus, known as "twin land", is the second planet from the sun. The distance from it to the Sun ranges from 107 to 108 million kilometers. Unfortunately, Venus is also the slowest rotating planet, which can be seen when looking at her poles. While absolutely all the planets in the solar system experienced flattening on the poles due to the speed of their rotation, the Venus does not have its signs. As a result, Venus takes about 243 terrestrial days, to circumvent the main shining system once. It may seem strange, but the planet requires 224 days to make a complete rotation around its axis, which means only one thing: day on this planet lasts longer than a year!

Land

When we are talking About the days on earth, people usually represent them as 24 hours, while in fact the period of rotation is only 23 hours and 56 minutes. Thus, one day on earth is equal somewhere 0.9 Earth days. It looks strange, however, people always prefer simplicity and convenience, not accuracy. However, everything is not so simple, and the length of the day can change - sometimes it is even actually 24 hours.

Mars

In many senses, Mars can also be called the twin land. In addition, it has snow poles, selences and even water (albeit in frozen), day on the planet is extremely close to the duration for the day on earth. The turn around its axis occupies 24 hours from Mars, 37 minutes and 22 seconds. So here the day is a little longer than on Earth. As mentioned earlier, seasonal cycles here are also very similar to earthly, therefore, the duration of the day will be similar.

Jupiter

Given the fact that Jupiter is the largest planet Solar systemIt would be possible to expect that the day on it would be incredibly long. But in fact, everything is completely different: the day on Jupiter lasts only 9 hours, 55 minutes and 30 seconds, that is, one day on this planet is about a third of the earth day. This is due to the fact that this gas giant has a very high speed of rotation around its axis. It is because of this that there are also very strong hurricanes on the planet.

Saturn

The situation on Saturn is very similar to the one that is observed on Jupiter. Despite the large size, the planet has a small speed of rotation, therefore, for one period of rotation of 360 degrees, Saturn takes only 10 hours and 33 minutes. This means that one day on Saturn for duration is less than half of the Earth Day. And, again, high speed Rotation leads to incredible hurricanes and even a constant vortex storm in the southern pole.

Uranus

When it comes to uranium, the question of counting the duration of the day becomes difficult. On the one hand, the time of rotation of the planet around its axis is 17 hours, 14 minutes and 24 seconds, which is a little less than a standard Earth day. And this statement would be true if not the strongest axial tilt of uranium. The angle of this inclination is more than 90 degrees. This means that the planet is moving by main star Systems actually on the side. Moreover, with such a scenario, one pole is very for a long time Looks towards the Sun - as many as 42 years. As a result, it can be said that the day in uranium lasts 84 years!

Neptune

The last list is neptune, and the problem of measuring the duration of the day also arises. Complete rotation around its planet axis makes in 16 hours, 6 minutes and 36 seconds. However, there is a snag here - considering the fact that the planet is a gas-ice giant, its poles rotate faster than the equator. Above the time of rotation of the magnetic field of the planet - its equator turns over 18 hours, while the poles are completed circular rotation for 12 hours.

How much is a day? A strange question: since childhood, we know that the day is exactly 24 hours, or 1440 minutes or 86400 seconds. So, not so. The day is the period of time for which the Earth makes one full turn around its axis, and it turns out to never occupy exactly 24 hours.

How many last day?

If you take a distant star for the reference point, and for days to consider the gap for which it will return to the same point, it turns out that one turnover of our planet takes 23 hours 56 minutes and 4 seconds! That is, in the day, the astronomical midnight can wage almost 4 minutes! Moreover, this period is called by stellar days depending on the friction caused by synoptic situations, tides / lowers and geological events change all the time in the range of up to 50 seconds. If you take our sun for reference point, as the ancestors did, then the number is already obtained closer to 24 hours. This is called the sunny day. On average, for the year, taking into account the turnover of the planet around the Sun, the sunny day for a split second in short, than twenty-four hours.

When these discrepancies revealed with the help of the most accurate atomic hours, it was decided to override a second as a fixed share of the "sunny" day, more precisely, a million-scenes-forty-fading.

The new definition of a second means that the sunny day is gradually shifted in relation to atomic. As a result, scientists had to be introduced into the atomic year the so-called "leap second" (or "second coordination") in order to coordinate atomic year with sunny.

The last time the "leap second" was added on December 31, 2005 to indicate the International Service for Establishing the Rotation Parameters and the Earth Coordinates Based in the Paris Observatory.

Good news for astronomers and those of us who love when the clock go pace with the movement of the Earth around the Sun, but a headache for computer programs and all the equipment that stands on space satellites.

Most of the common concepts we master in more early childhood. Despite the age of so much, it is unlikely that someone from the kids require an academic explanation to the simplest concepts - Mom can explain everything literally on the fingers, simple words. For example, "Day is when the sun shines" or "when you walk, and not sleep in the crib." Explanations are imperceptibly accumulated and systematized by forming an understanding of the term.

The meaning of the word "day"

If you look at the planet from the side, you can see quite clear separation on the day and night side. Formally, the simplest explanation is faithful from the point of view of astronomy - the day is considered to be when the light from the star falls on the surface of the planet, around which this planet rotates.

We believe that the day is a bright day of day, and the weather does not play roles. Somewhere there, above the clouds, the sun still shines, therefore, no night, around is not dark. In the same latitudes, this particular principle is observed - such concepts as a "polar day" and "polar night" are based on natural illumination.

In some cases, I mean time at all. For example, when they say "these were sad days" or "in those distant days", we are talking about some distant time in the past, when there were some events.

Division of day

Theoretically, if you rely precisely for the presence of the sun in the sky, the day is divided into two relatively equal parts - day and night. In practice, it turns out that there are morning and evening, which in one degree or another are also highlighted. Morning begins when the scan of the approaching sun appears in the sky, although the night continues formally. When the sun appears above the horizon, the dawn begins, the morning continues and lasts a few more hours while the sun rises to Zenith.

In most cases, the day is the time from about noon to the evening, when the sun begins to decline over the horizon in the West. At the same time they say "ten o'clock in the morning", but "eleven hours of the day", and even in this case options are possible.

How many hours do the day last?

Between the morning and in the evening passes on average six hours, and this is an approximate time. It turns out that day is the whole fourth part of the day. The rest of the time is occupied at night and intermediate states - in the morning and evening.

If the clarifying adjective is added to this, it becomes easier to determine what it is specifically a question. For example, "Light Day" clearly indicates that we are talking about the bright time of the day when not required additional sources artificial lighting. Explaining what day is desirable to immediately arrange accents and clarify that much depends on specific situation and context, otherwise mutual misunderstanding may appear.

Often the length of the day is determined not by the actual number of hours and not durability natural lighting, and extremely subjective sensations. A long or even endless day means that either a person cannot wait for the evening, or managed to perform many different tasks.

Specification of temporary intervals

Often the word "day" is used in the meaning of the "day". For example, "you have three days to eliminate the shortcomings." In the "day" value, this word is used when you need to specify a sufficiently long amount of time.

If you want to put some framework, it can be a "working day" - interpretation in this case provides that weekends and holidays are not considered. In working days, business commitments are taken into account - the execution of orders, the receipt of funds to the bank account and so on. The obsolete concept of "workshop" is similar to the value, this is a unit of collective farmers' work for subsequent payment. When they say "weekends", they mean a day free from all kinds of labor duties, time designed to relax.

Trying to understand what day in the presentation of another person, we usually try to simplify mutual communication as much as possible. Therefore, when we are told "Call tomorrow day," it is better to clarify, at what time interval will be appropriate. For someone and eight o'clock in the morning - the day, and someone else sleeps. If you do not specify, then business etiquette The day is considered an average of 11 am to 16 pm, and good tone It will fit in about the middle of this gap. In other cases, it is better to ask to specify the exact time.