Most We master commonly used concepts back in early childhood. Despite the age of the whys, it is unlikely that any of the children require an academic explanation for the most simple concepts- Mom can explain everything literally on her fingers, in simple words. For example, “day is when the sun is shining” or “when you are walking and not sleeping in a crib.” Explanations quietly accumulate and systematize, forming an understanding of the term.
Meaning of the word "day"
If you look at the planet from the outside, you can see a very clear division into day and night sides. Formally, the simplest explanation turns out to be correct from the point of view of astronomy - daylight is considered to be the time when light from the star around which this planet rotates falls on the surface of the planet.
We believe that day is the daylight hours, and the weather does not play a role. Somewhere there, above the clouds, the sun is still shining, therefore, it is not night now, it is not dark around. In the circumpolar latitudes, this very principle is observed - concepts such as “polar day” and “polar night” are based precisely on natural illumination.
In some cases, this means time in general. For example, when they say “those were the days of sorrow” or “in those distant days,” we are talking about some distant time in the past when some events took place.
Dividing the day into parts
Theoretically, if we rely specifically on 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 is morning and evening, which are also illuminated to one degree or another. Morning begins when the reflection of the approaching sun appears in the sky, although technically it is still night. When the sun appears above the horizon, dawn begins, morning continues and lasts for several more hours until the sun rises to its zenith.
In most cases, day is the time from approximately noon to evening when the sun begins to decline above the horizon in the west. At the same time, they say “ten o’clock in the morning,” but “eleven o’clock in the afternoon,” and even in this case, variations are possible.
How many hours does a day last?
On average, six hours pass between morning and evening, and this approximate time. It turns out that a day is only a quarter of a day. The rest of the time is occupied at night and in intermediate states - morning and evening.
If a qualifying adjective is added, it becomes easier to determine what exactly is being said. For example, “daylight” clearly indicates that we are talking specifically about daylight hours, when switching on is not required additional sources artificial lighting. When explaining what a day is, it is advisable to immediately place emphasis and clarify that much depends on the specific situation and context, otherwise mutual misunderstanding may arise.
Often the length of the day is determined not by the actual number of hours or the duration of natural light, but solely by subjective sensations. A long or even endless day means that either a person cannot wait until evening, or he has managed to complete many different tasks.
Specification of time intervals
The word “day” is often used to mean “day”. For example, “you have three days to eliminate the shortcomings.” In the meaning of “day”, this word is used when you need to indicate a sufficiently long amount of time.
If you need to set some limits, then it can be a “working day” - the interpretation in this case provides that weekends and holidays are not considered. Working days take into account business obligations - fulfillment of orders, receipt of funds in a bank account, and so on. Similar meaning has an outdated concept of “workdays”, this is a unit for recording the labor of collective farmers for subsequent payment. When they say “day off,” they mean a day free from all kinds of labor responsibilities, time reserved for rest.
When trying to understand what a day is in the minds of another person, we usually try to simplify mutual communication as much as possible. Therefore, when they tell us “call tomorrow afternoon,” it is better to clarify in what time period the call will be appropriate. For some, eight o’clock in the morning is already day, while others are still sleeping. If you don’t specify, then according to business etiquette, a day is considered on average from 11 a.m. to 4 p.m., and it would be good practice to fit in approximately in the middle of this interval. In other cases, it is better to ask for the exact time.
How long is a day? You probably think that exactly 24 hours? Depends on the circumstances. A day is the period of time during which the Earth makes one rotation around its axis.
So how long is a day?
In fact, one rotation of the Earth around its axis never takes exactly twenty-four hours.
There are 23 hours, 56 minutes and 4 seconds in a day. All my life I've lived a lie!
It's amazing, but this indicator can fluctuate one way or the other for as much as fifty seconds! This is because the speed of the Earth's rotation changes all the time - due to friction caused by synoptic situations, tides and geological events.
On average, over the course of a year, a day is a fraction of a second shorter than twenty-four hours.
When these discrepancies were identified using atomic clock, it was decided to redefine the second as a fixed fraction of a “solar” day - more precisely, one million six hundred to forty thousandths.
The new second came into use in 1967 and is defined as “an interval of time equal to 9,192,631,770 periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom in the absence of disturbance external fields" You can’t say it more precisely - it’s just too painful to say all this at the end of a long day.
The new definition of the second means that the solar day gradually shifts relative to the atomic one. As a result, scientists had to introduce atomic year the so-called “leap second” (or “coordination second”) in order to coordinate the atomic year with the solar year.
Since 1972, the leap second has been added 23 times. Imagine, otherwise our day would have increased by almost half a minute. And the Earth continues to slow down its rotation. And, according to scientists, in the 23rd century there will be 25 hours in our day.
The last time the “leap second” was added was on December 31, 2005, at the direction of the International Service for the Estimation of Earth's Rotation and Coordinates, based at the Paris Observatory.
Good news for astronomers and those of us who like clocks to keep pace with the Earth's movement around the Sun, but headache For computer programs and all the equipment that is on space satellites.
The idea of introducing a “leap second” met with decisive resistance from International Union telecommunications, which even made an official proposal to cancel it completely back in December 2007.
You can, of course, wait until the difference between Coordinated Universal Time (UTC) and Greenwich Mean Time (GMT) reaches exactly an hour (in about 400 years) and then put everything in order. In the meantime, the debate around what is considered “real” time continues.
To the question: How many actual hours, minutes and seconds are there in a day? given by the author Albatross the best answer is the period of rotation of the earth relative to a point spring equinox called sidereal days. It is equal to 23h 56m 04.0905308s. Please note that the sidereal day is a period relative to the spring point, not the stars.
Answer from Crooked[active]
1440 minutes, (23 hours 59 minutes 59 seconds).
Answer from Zhaksylyk Usenov[active]
23 hours 56 minutes 4 seconds
Answer from Andrew Skquirtle[newbie]
Guys, leap year runs up not because of the day, but because of the rotation around the Sun, +6 hours every year, but even there it’s not exactly, in 2015 a leap second was added in the fall
Answer from I-beam[newbie]
I think it is less than exactly 24 hours because there is a leap year, in which February has one more day than everywhere else!
Answer from Denis Shabalov[newbie]
There are 24 hours 1 minute 6 seconds in a day
Answer from Maxim Antonov[newbie]
The need to divide the clock into its component parts arose much later, but they did not deviate from the sexagesimal system even then. And then the minute was divided into seconds. True, it later became clear that relying only on astronomical observations There is no way to determine the duration of seconds and days. Over the course of a century, the length of the day increases by 0.0023 seconds - it seems like very little, but enough to get confused about the question of how many seconds there are in a day. And that's not all the difficulties! Our Earth does not complete one revolution around the Sun in exactly the same number of days, and this also affects the solution to the question of how many hours there are in a day. Therefore, to simplify the situation, a second was not equated to movement. celestial bodies, and to the time of processes occurring inside the cesium-133 atom in a state of rest. And to match the actual state of affairs with the Earth’s revolution around the Sun, 2 extra leap seconds are added twice a year - on December 31 and June 30, and an additional day is added once every 4 years. In total, it turns out that there are 24 hours in a day, or 1440 minutes, or 86400 seconds. - Read more on FB.ru:
Answer from Olga K.[guru]
There are solar days (24 hours) and sidereal days (23 hours 56 minutes 4 seconds).
This is where he comes running, “Red day of the calendar! Hurray-!” February 29th!
Answer from Alexey Polshchikov[newbie]
Due to my scrupulousness, I had to do the math and now I’m a little perplexed... I also immediately assumed that this is why February 29 exists (but according to calculations, it turns out that February 29 should happen every year) ... and I’ll say that something doesn’t add up here.. 3 minutes 56 seconds of each day we count:
3 minutes 56 seconds = 236 seconds
236 * (365*4) = 236*1460 = 344560 SECONDS RUNNED IN 4 YEARS
In theory, it should just be 1 day (the above date is February 29) (leap year), but we count this as 344,560 seconds:
344560:60= 5742.66666667 minutes
5742.66666667:60= 95.7111111112 hours
95.7111111112:24 = 3.98796296297 days
In short, it turns out that there should be a leap year every year... There's a catch somewhere...
Answer from Andrey Yeleskin[guru]
And there are also librations of the earth caused by the braking of rotation by tides, mass movements, which will increase by a thousandth of a second per day.
Answer from SLESHEL[expert]
Well, what about the clock, it accurately calculates 60 seconds per minute, 60 minutes per hour, and 24 hours per day
Spanish Football Championship 2015 2016 on Wikipedia
Spanish Football Championship 2015 2016
Spanish Football Championship 2015 2016 lineups on Wikipedia
Look at the Wikipedia article about Spanish Football Championship 2015 2016 lineups
Day on Wikipedia
Look at the Wikipedia article about Sutki
Everyone knows this - 24 hours. But why did this happen? Let's take a closer look at the history of the appearance of the basic units of time and find out how many hours, seconds and minutes there are in a day. We’ll also see whether it’s worth linking these units exclusively to astronomical phenomena.
Where did the day come from? This is the time of one revolution of the earth around its axis. Still knowing little about astronomy, people began to measure time in such ranges, including light and dark times at each time.
But there is interesting feature. When does the day start? WITH modern point everything is obvious from the viewpoint - the day begins at midnight. People of ancient civilizations thought differently. It is enough to look at the very beginning of the Bible to read in the 1st book of Genesis: “... and there was evening, and there was one morning.” The day began with There is a certain logic to this. People of that time were guided by the sun setting, the day was over. Evening and night are already the next day.
But how many hours are there in a day? Why was the day divided into 24 hours, since the decimal system is more convenient, and much more convenient? If there were, say, 10 hours in a day, and 100 minutes in each hour, would anything change for us? Actually, nothing but numbers; on the contrary, it would even be more convenient to carry out calculations. But the decimal system is far from the only one used in the world.
They used the sexagesimal counting system. And the light half of the day was well divided in half, 6 hours each. In total, there were 24 hours in a day. This rather convenient division was taken from the Babylonians by other peoples.
The ancient Romans counted time in an even more interesting way. The countdown started at 6 am. So they counted from that moment forward - hour one, hour three. Thus, one can easily consider that the “eleventh hour workers” remembered by Christ are those who begin work at five o’clock in the evening. It's really too late!
At six o'clock in the evening it was twelve o'clock. This is how many hours in a day were counted in ancient Rome. But there were still night hours left! The Romans did not forget about them. After the twelfth hour the night watches began. The guards changed at night every 3 hours. Evening and night time was divided into 4 watches. The first evening watch began at 6 pm and lasted until 9. The second, midnight, lasted from 9 to 12. The third watch, from 12 at night to 3 in the morning, ended when the roosters crowed, which is why it was called “rooster crowing.” The last, fourth watch was called “morning” and ended at 6 am. And it all started all over again.
The need to divide the clock into its component parts arose much later, but they did not deviate from the sexagesimal system even then. And then the minute was divided into seconds. True, it later became clear that it is impossible to rely only on the duration of seconds and days to determine the duration of seconds and days. Over the course of a century, the length of the day increases by 0.0023 seconds - it seems like very little, but enough to get confused about the question of how many seconds there are in a day. And that's not all the difficulties! Our Earth does not complete one revolution around the Sun in exactly the same number of days, and this also affects the solution to the question of how many hours there are in a day.
Therefore, to simplify the situation, the second was equated not to the movement of celestial bodies, but to the time of processes occurring inside the cesium-133 atom at rest. And to correspond to the actual state of affairs with the Earth’s revolution around the Sun, 2 extra leap seconds are added twice a year - on December 31 and June 30, and an additional day is added once every 4 years.
In total, it turns out that there are 24 hours in a day, or 1440 minutes, or 86400 seconds.