Here on Earth, people take time for granted. But in fact, at the heart of everything lies an extremely complex system. For example, the way people calculate days and years follows from the distance between the planet and the Sun, the time it takes the Earth to complete a revolution around the gas star, and the time it takes to move 360 degrees around its planet. axes. The same method is applicable for the rest of the planets in the Solar System. Earthlings are accustomed to thinking that a day contains 24 hours, but on other planets the length of the day is much different. In some cases they are shorter, in others they are longer, sometimes significantly. The solar system is full of surprises, and it's time to explore it.
Mercury
Mercury is the planet that is closest to the Sun. This distance can be from 46 to 70 million kilometers. Considering the fact that Mercury takes about 58 Earth days to turn 360 degrees, it is worth understanding that on this planet you will only be able to see the sunrise once every 58 days. But in order to describe a circle around the main luminary of the system, Mercury requires only 88 Earth days. This means that a year on this planet lasts approximately one and a half days.
Venus
Venus, also known as Earth's twin, is the second planet from the Sun. The distance from it to the Sun is from 107 to 108 million kilometers. Unfortunately, Venus is also the slowest rotating planet, which can be seen when looking at its poles. While absolutely all the planets in the solar system have experienced flattening at the poles due to the speed of their rotation, Venus shows no signs of it. As a result, Venus takes about 243 Earth days to go around the system’s main luminary once. This may seem strange, but the planet takes 224 days to complete a full rotation on its axis, which means only one thing: a day on this planet lasts longer than a year!
Earth
When talking about a day on Earth, people usually think of it as 24 hours, when in fact the rotation period is only 23 hours and 56 minutes. Thus, one day on Earth is equal to about 0.9 Earth days. It looks strange, but people always prefer simplicity and convenience over accuracy. However, it's not that simple, and the length of the day can vary - sometimes it's even actually 24 hours.
Mars
In many ways, Mars can also be called Earth's twin. In addition to having snowy poles, changing seasons, and even water (albeit in a frozen state), the day on the planet is extremely close in length to a day on Earth. Mars takes 24 hours, 37 minutes and 22 seconds to rotate around its axis. Thus, the days here are slightly longer than on Earth. As mentioned earlier, the seasonal cycles here are also very similar to those on Earth, so the day length options will be similar.
Jupiter
Considering the fact that Jupiter is the largest planet in the solar system, one would expect it to have incredibly long days. But in reality, everything is completely different: a day on Jupiter lasts only 9 hours, 55 minutes and 30 seconds, that is, one day on this planet is about a third of an Earth day. This is due to the fact that this gas giant has a very high rotation speed around its axis. It is because of this that the planet also experiences very strong hurricanes.
Saturn
The situation on Saturn is very similar to that observed on Jupiter. Despite its large size, the planet has a low rotation speed, so one rotation period of 360 degrees takes Saturn only 10 hours and 33 minutes. This means that one day on Saturn is less than half the length of an Earth day. And, again, the high rotation speed leads to incredible hurricanes and even a constant vortex storm at the south pole.
Uranus
When it comes to Uranus, the question of calculating the length of the day becomes difficult. On the one hand, the planet's rotation time around its axis is 17 hours, 14 minutes and 24 seconds, which is slightly less than a standard Earth day. And this statement would be true if not for the strong axial tilt of Uranus. The angle of this inclination is more than 90 degrees. This means that the planet is moving past the main star of the system, actually on its side. Moreover, in this situation, one pole faces the Sun for a very long time - as much as 42 years. As a result, we can say that a day on Uranus lasts 84 years!
Neptune
Last on the list is Neptune, and here the problem of measuring the length of the day also arises. The planet completes a full rotation around its axis in 16 hours, 6 minutes and 36 seconds. However, there is a catch here - given the fact that the planet is a gas-ice giant, its poles rotate faster than the equator. The rotation time of the planet's magnetic field was indicated above - its equator rotates in 18 hours, while the poles complete their circular rotation in 12 hours.
>> Day on Mercury
- the first planet of the solar system. Description of the influence of the orbit, rotation and distance from the Sun, the day of Mercury with a photo of the planet.
Mercury- an example of a planet in the solar system that loves to go to extremes. This is the closest planet to our star, which is forced to experience strong temperature fluctuations. Moreover, while the illuminated side suffers from heat, the dark side freezes to critical levels. Therefore, it is not surprising that the day of Mercury does not fit into the standards.
How long is a day on Mercury?
The situation with Mercury's daily cycle does seem strange. A year spans 88 days, but the slow rotation doubles the day! If you were on the surface, you would watch the sun rise/set for as long as 176 days!
Distance and orbital period
It is not only the first planet from the Sun, but also the owner of the most eccentric orbit. If the average distance extends over 57,909,050 km, then at perihelion it approaches 46 million km, and at aphelion it moves away by 70 million km.
Due to its proximity, the planet has the fastest orbital period, varying depending on its position in orbit. It moves most quickly at a short distance, and slows down at a distance. The average orbital speed is 47322 km/s.
Researchers thought that Mercury repeats the situation of the Earth's Moon and is always turned to the Sun with one side. But radar measurements in 1965 suggested that axial rotation was much slower.
Sidereal and sunny days
We now know that the resonance of axial and orbital rotation is 3:2. That is, there are 3 revolutions per 2 orbits. At a speed of 10,892 km/h, one revolution around the axis takes 58,646 days.
But let's be more precise. The rapid orbital speed and slow sidereal rotation make it so that a day on Mercury lasts 176 days. Then the ratio is 1:2. Only the polar regions do not fit into this rule. For example, the crater on the northern polar cap is always in the shadow. The temperature there is low, so it allows you to conserve ice reserves.
In November 2012, the assumptions were confirmed when MESSENGER used a spectrometer and looked at ice and organic molecules.
Yes, add to all the oddities the fact that a day on Mercury spans 2 whole years.
Here on Earth, we tend to take time for granted, never considering that the increments in which we measure it are quite relative.
For example, the way we measure our days and years is actually a result of our planet's distance from the Sun, the time it takes to revolve around it, and to rotate on its own axis. The same is true for other planets in our solar system. While we Earthlings calculate the day in 24 hours from dawn to dusk, the length of one day on another planet differs significantly. In some cases, it is very short, while in others, it can last more than a year.
Day on Mercury:
Mercury is the closest planet to our Sun, ranging from 46,001,200 km at perihelion (closest distance to the Sun) to 69,816,900 km at aphelion (farthest). Mercury takes 58.646 Earth days to rotate around its axis, meaning that a day on Mercury takes approximately 58 Earth days from dawn to dusk.
However, it takes only 87,969 Earth days for Mercury to circle the Sun once (aka its orbital period). This means that a year on Mercury is equivalent to approximately 88 Earth days, which in turn means that one year on Mercury lasts 1.5 Mercury days. Moreover, Mercury's northern polar regions are constantly in shadow.
This is due to its axial tilt of 0.034° (compared to Earth's 23.4°), which means Mercury does not experience extreme seasonal changes where days and nights can last for months, depending on the season. It is always dark at the poles of Mercury.
A day on Venus:
Also known as Earth's twin, Venus is the second closest planet to our Sun - ranging from 107,477,000 km at perihelion to 108,939,000 km at aphelion. Unfortunately, Venus is also the slowest planet, a fact that is obvious when you look at its poles. Whereas the planets in the solar system experienced flattening at the poles due to their rotational speed, Venus did not survive it.
Venus rotates at a speed of only 6.5 km/h (compared to Earth's rational speed of 1670 km/h), which results in a sidereal rotation period of 243.025 days. Technically, this is minus 243.025 days, since Venus's rotation is retrograde (i.e., spinning in the opposite direction of its orbital path around the Sun).
Nevertheless, Venus still rotates around its axis in 243 Earth days, that is, many days pass between its sunrise and sunset. This may seem strange until you know that one Venusian year lasts 224,071 Earth days. Yes, Venus takes 224 days to complete its orbital period, but more than 243 days to go from dawn to dusk.
Thus, one Venus day is slightly more than a Venusian year! It's good that Venus has other similarities with Earth, but it's clearly not a daily cycle!
Day on Earth:
When we think of a day on Earth, we tend to think of it as simply 24 hours. In truth, the sidereal rotation period of the Earth is 23 hours 56 minutes and 4.1 seconds. So one day on Earth is equivalent to 0.997 Earth days. It's strange, but then again, people prefer simplicity when it comes to time management, so we round up.
At the same time, there are differences in the length of one day on the planet depending on the season. Due to the tilt of the Earth's axis, the amount of sunlight received in some hemispheres will vary. The most striking cases occur at the poles, where day and night can last for several days and even months, depending on the season.
At the North and South Poles during winter, one night can last up to six months, known as the "polar night". In summer, the so-called “polar day” will begin at the poles, where the sun does not set for 24 hours. It's actually not as simple as I would like to imagine.
A day on Mars:
In many ways, Mars can also be called “Earth’s twin.” Add seasonal variations and water (albeit frozen) to the polar ice cap, and a day on Mars is pretty close to a day on Earth. Mars makes one revolution around its axis in 24 hours. 
37 minutes and 22 seconds. This means that one day on Mars is equivalent to 1.025957 Earth days.
Seasonal cycles on Mars are similar to ours on Earth, more than on any other planet, due to its 25.19° axial tilt. As a result, Martian days experience similar changes with the Sun, which rises early and sets late in the summer and vice versa in the winter.
However, seasonal changes last twice as long on Mars because the Red Planet is at a greater distance from the Sun. This results in a Martian year lasting twice as long as an Earth year—686.971 Earth days or 668.5991 Martian days, or sols.
Day on Jupiter:
Given the fact that it is the largest planet in the solar system, one would expect the day on Jupiter to be long. But, as it turns out, a day on Jupiter officially lasts only 9 hours, 55 minutes and 30 seconds, which is less than a third of the length of an Earth day. This is due to the fact that the gas giant has a very high rotation speed of approximately 45,300 km/h. This high rotation rate is also one of the reasons why the planet has such strong storms.
Note the use of the word formally. Since Jupiter is not a solid body, its upper atmosphere moves at a different speed than at its equator. Basically, the rotation of Jupiter's polar atmosphere is 5 minutes faster than that of the equatorial atmosphere. Because of this, astronomers use three reference frames.
System I is used in latitudes from 10°N to 10°S, where its rotation period is 9 hours 50 minutes and 30 seconds. System II is applied at all latitudes north and south of them, where the rotation period is 9 hours 55 minutes and 40.6 seconds. System III corresponds to the rotation of the planet's magnetosphere, and this period is used by the IAU and IAG to determine the official rotation of Jupiter (i.e. 9 hours 44 minutes and 30 seconds)
So, if you could theoretically stand on the clouds of a gas giant, you would see the sun rise less than once every 10 hours at any latitude of Jupiter. And in one year on Jupiter, the Sun rises approximately 10,476 times.
Day on Saturn:
The situation of Saturn is very similar to Jupiter. Despite its large size, the planet has an estimated rotation speed of 35,500 km/h. One sidereal rotation of Saturn takes approximately 10 hours 33 minutes, making one day on Saturn less than half an Earth day.
Saturn's orbital period is equivalent to 10,759.22 Earth days (or 29.45 Earth years), with a year lasting approximately 24,491 Saturn days. However, like Jupiter, Saturn's atmosphere rotates at different speeds depending on latitude, requiring astronomers to use three different reference frames.
System I covers the equatorial zones of the South Equatorial Pole and the North Equatorial Belt, and has a period of 10 hours 14 minutes. System II covers all other latitudes of Saturn except the north and south poles, with a rotation period of 10 hours 38 minutes and 25.4 seconds. System III uses radio emissions to measure Saturn's internal rotation rate, which resulted in a rotation period of 10 hours 39 minutes 22.4 seconds.
Using these different systems, scientists have obtained various data from Saturn over the years. For example, data obtained during the 1980s by the Voyager 1 and 2 missions indicated that a day on Saturn is 10 hours, 45 minutes and 45 seconds (±36 seconds).
In 2007, this was revised by researchers in UCLA's Department of Earth, Planetary and Space Sciences, resulting in the current estimate of 10 hours and 33 minutes. Much like Jupiter, the problem with accurate measurements stems from the fact that different parts rotate at different speeds.
Day on Uranus:
As we approached Uranus, the question of how long a day lasts became more complex. On the one hand, the planet has a sidereal rotation period of 17 hours 14 minutes and 24 seconds, which is equivalent to 0.71833 Earth days. Thus, we can say that a day on Uranus lasts almost as long as a day on Earth. This would be true if it were not for the extreme tilt of the axis of this gas-ice giant.
With an axial tilt of 97.77°, Uranus essentially revolves around the Sun on its side. This means that its north or south points directly toward the Sun at different times in its orbital period. When it is summer at one pole, the sun will shine continuously there for 42 years. When the same pole is turned away from the Sun (that is, it is winter on Uranus), there will be darkness there for 42 years.
Therefore, we can say that one day on Uranus, from sunrise to sunset, lasts as long as 84 years! In other words, one day on Uranus lasts as long as one year.
Also, as with other gas/ice giants, Uranus rotates faster at certain latitudes. Therefore, while the planet's rotation at the equator, approximately 60° south latitude, is 17 hours and 14.5 minutes, the visible features of the atmosphere move much faster, completing a complete rotation in just 14 hours.
Day on Neptune:
Finally, we have Neptune. Here, too, measuring one day is somewhat more complicated. For example, Neptune's sidereal rotation period is approximately 16 hours, 6 minutes and 36 seconds (equivalent to 0.6713 Earth days). But due to its gas/ice origin, the planet's poles replace each other faster than the equator.
Considering that the planet's magnetic field rotates at a rate of 16.1 hours, the equatorial zone rotates approximately 18 hours. Meanwhile, the polar regions rotate within 12 hours. This differential rotation is brighter than any other planet in the Solar System, resulting in strong latitudinal wind shear.
In addition, the planet's axial tilt of 28.32° leads to seasonal variations similar to those on Earth and Mars. Neptune's long orbital period means that a season lasts for 40 Earth years. But since its axial tilt is comparable to Earth's, the change in the length of its day during its long year is not so extreme.
As you can see from this summary of the various planets in our solar system, the length of the day depends entirely on our frame of reference. In addition, the seasonal cycle varies depending on the planet in question and where on the planet the measurements are taken.
Time on Earth is taken for granted. People don't realize that the interval by which time is measured is relative. For example, days and years are measured based on physical factors: the distance from the planet to the Sun is taken into account. One year is equal to the time it takes for the planet to circle the Sun, and one day is the time it takes to completely rotate around its axis. The same principle is used to calculate time on other celestial bodies of the solar system. Many people are interested in how long a day is on Mars, Venus and other planets?
On our planet, a day lasts 24 hours. It takes exactly this many hours for the Earth to rotate around its axis. The length of the day on Mars and other planets is different: in some places it is short, and in others it is very long.
Definition of time
To find out how long a day is on Mars, you can use solar or sidereal days. The last measurement option represents the period during which the planet makes one rotation around its axis. The day measures the time it takes for the stars in the sky to become in the same position from which the countdown began. Star Trek Earth is 23 hours and almost 57 minutes.
A solar day is a unit of time during which the planet rotates around its axis relative to sunlight. The principle of measuring this system is the same as when measuring the sidereal day, only the Sun is used as a reference point. Sidereal and solar days can be different.
How long is a day on Mars according to the stellar and solar system? A sidereal day on the red planet is 24 and a half hours. A solar day lasts a little longer - 24 hours and 40 minutes. A day on Mars is 2.7% longer than on Earth.
When sending vehicles to explore Mars, the time on it is taken into account. The devices have a special built-in clock, which diverges from the earth’s clock by 2.7%. Knowing how long a day is on Mars allows scientists to create special rovers that are synchronized with the Martian day. The use of special clocks is important for science, since Mars rovers are powered by solar panels. As an experiment, a clock was developed for Mars that took into account the solar day, but it was not possible to use it.
The prime meridian on Mars is considered to be the one that passes through a crater called Airy. However, the red planet does not have time zones like Earth.
Martian time
Knowing how many hours there are in a day on Mars, you can calculate the length of a year. The seasonal cycle is similar to the Earth's: Mars has the same inclination as the Earth (25.19°) in relation to its own orbital plane. The distance from the Sun to the red planet varies at various periods from 206 to 249 million kilometers.
Temperature readings differ from ours:
- average temperature -46 °C;
- during the period of removal from the Sun, the temperature is about -143 ° C;
- in summer - -35 °C.
Water on Mars
Scientists made an interesting discovery in 2008. The Mars rover discovered water ice at the planet's poles. Before this discovery, it was believed that only carbon dioxide ice existed on the surface. Even later, it turned out that precipitation falls in the form of snow on the red planet, and carbon dioxide snow falls near the south pole.
Throughout the year, storms are observed on Mars that extend over hundreds of thousands of kilometers. They make it difficult to track what is happening on the surface.
A year on Mars
The red planet circles the Sun in 686 Earth days, moving at a speed of 24 thousand kilometers per second. A whole system for designating Martian years has been developed.
While studying the question of how long a day on Mars is in hours, humanity has made many sensational discoveries. They show that the red planet is close to Earth.
Length of a year on Mercury
Mercury is the planet closest to the Sun. It rotates around its axis in 58 Earth days, that is, one day on Mercury is 58 Earth days. And to fly around the Sun, the planet needs only 88 Earth days. This amazing discovery shows that on this planet, a year lasts almost three Earth months, and while our planet circles the Sun, Mercury makes more than four revolutions. How long is a day on Mars and other planets when compared with Mercury time? This is surprising, but in just one and a half Martian days a whole year passes on Mercury.
Time on Venus
The time on Venus is unusual. One day on a given planet lasts 243 Earth days, and a year on this planet lasts 224 Earth days. It seems strange, but such is the mysterious Venus.
Time on Jupiter
Jupiter is the largest planet in our solar system. Based on its size, many people think that the day lasts long on it, but this is not so. Its duration is 9 hours 55 minutes - this is less than half the length of our earthly day. The gas giant rotates rapidly around its axis. By the way, because of it, constant hurricanes and strong storms rage on the planet.
Time on Saturn
A day on Saturn lasts about the same as on Jupiter, 10 hours 33 minutes. But a year lasts approximately 29,345 Earth years.
Time on Uranus
Uranus is an unusual planet, and determining how long daylight hours will last on it is not so easy. A sidereal day on the planet lasts 17 hours and 14 minutes. However, the giant has a strong axis tilt, causing it to orbit the Sun almost on its side. Because of this, at one pole summer will last 42 Earth years, while at the other pole it will be night at that time. When the planet rotates, the other pole will be illuminated for 42 years. Scientists have come to the conclusion that a day on the planet lasts 84 Earth years: one Uranian year lasts almost one Uranian day.
Time on other planets
While studying the question of how long a day and a year last on Mars and other planets, scientists have found unique exoplanets where a year lasts only 8.5 Earth hours. This planet is called Kepler 78b. Another planet, KOI 1843.03, was also discovered with a shorter rotation period around its sun - just 4.25 Earth hours. Every day a person would become three years older if he lived not on Earth, but on one of these planets. If people could adjust to the planetary year, then it would be best to go to Pluto. On this dwarf, a year is 248.59 Earth years.
