On the day of the summer solstice.. Do the hours of day and night differ on other planets such as Earth?

2024-06-20 2024-06-20T15:33:11Z

Arabia Weather - While we don't feel it, the Earth rotates on its axis once every 24 hours, taking us all with it, and when we are on the side facing the sun, we have daylight and as the Earth continues its rotation, we move to the side away from the sun, and night falls.

If we look at the Earth from above the North Pole, we will see it rotating counterclockwise, causing daylight and darkness to alternate across the globe from east to west. The Earth's rotation around its axis causes the change between day and night, but the changing lengths of day and night depend on your location. On Earth and the time of year, the length of the day is also affected by the tilt of the Earth's axis and its path around the sun.

Why does the length of the day change during the year?

Although the solar day lasts 24 hours, it does not always include 12 hours of daylight and 12 hours of night. We notice that the days are shorter in winter compared to summer, and this is due to the Earth’s axis tilting by 23.5 degrees.

When the Earth moves around the sun during the year, the northern half tilts toward the sun in the summer, making the day longer than the night. In winter, the northern half tilts away from the sun, making the night longer. In the spring and fall, the axis does not tilt toward the sun or away from it. Therefore, the length of the day and night is equal.

The actual number of hours of daylight on any given day of the year varies from place to place. Areas near the equator get about 12 hours of light per day. In contrast, the North Pole sees 24 hours of daylight for a few months in the summer and complete darkness for several months in the winter. , with long periods of sunrise and sunset separating them.

These differences are due to the Earth's axis being tilted by 23.5 degrees. When the Earth revolves around the Sun, its tilted axis remains directed towards the North Star Polaris, making different parts of the Earth receive varying amounts of direct sunlight throughout the year.

What causes the Earth to tilt?

Long ago, it is believed that a large object called Theia collided with the Earth, causing its axis to tilt. This collision sent huge amounts of dust and debris into orbit, creating a large hole in the Earth. Most scientists believe that this debris is what formed our current moon. .

The difference between a solar day and a sidereal day

The Earth rotates approximately once every 24 hours from a solar perspective, the so-called "solar day," and once every 23 hours, 56 minutes and 4 seconds from a stellar perspective, the so-called "sidereal day."

A solar day is the time it takes for the Earth to rotate exactly once so that the Sun appears in the same place in the sky the next day. However, the Earth's movement around the Sun makes measuring a solar day more complicated.

The actual time for one revolution of the Earth around its axis is slightly shorter, about 23 hours and 56 minutes, and astronomers discovered this by observing the time it takes for a star to appear in the same place in the sky the next day, and they called this day the “sidereal day” or “sidereal day.” "Astral".

The Earth's rotation slows down over time; In the past, a day was shorter than it is now; Due to the tidal effects caused by the Moon on the Earth's rotation.

The longest and shortest days of the year

Solstices are points in the Earth's orbit that determine the longest and shortest days of the year. The winter solstice in the northern hemisphere is the shortest day, after which the daylight hours lengthen. The summer solstice in the northern hemisphere is the longest day, after which the daylight hours shorten.

Solstices can also be named by the months they occur. For example, the June solstice is the point in Earth's orbit where the North Pole faces the Sun.

In the Northern Hemisphere, the June solstice is the longest day of the year, while in the Southern Hemisphere it is the shortest day.

Location on the ground

Your location on Earth relative to the equator affects the number of daylight hours per solar day. During the summer in the northern hemisphere, daylight hours increase as you go north. At this time, the North Pole gets a little dark at night.

In winter, the days are shorter the further north you go, but at the equator, the length of day and night is always the same regardless of the season, and for this reason it is called the equator.

Do other planets have day and night?

Yes, all the planets in our solar system rotate on their axes and therefore have cycles of day and night.

Some planets rotate faster than Earth, and some rotate slower. Mars has a day and night cycle similar to Earth, rotating on its axis once every 24.6 hours. As for Venus, it rotates on its axis once every 243 Earth days, which makes Venus’ day slightly longer than its year, as it takes 225 days to revolve around the sun.

The day and night cycle of the planet Mercury is more complex, as it revolves around itself one and a half times during each revolution around the sun. As a result, Mercury's day, from one sunrise to the next, is 176 Earth days long.

Larger planets rotate faster on their axis; Jupiter rotates once every 10 hours, Saturn every 11 hours, and Neptune completes its orbit in 16 hours. In contrast, Pluto rotates on its axis once every 6.4 days.

The length of day and night on other planets

Other planets also experience changes in the length of daylight and nighttime hours because they are tilted on their axes at different angles. Jupiter's axis is tilted by only 3 degrees, so the change in the length of day and night on it is less severe than on Earth. While Neptune's axis is tilted by 30 degrees, which makes the changes in day and night more noticeable.

Uranus presents an interesting situation, as its axis is tilted at an angle of 98 degrees, which means that the north pole of Uranus is directed towards the sun during the arctic summer, and the south pole is in complete darkness. After about 42 Earth years, the opposite happens, as the south polar axis is directed towards the sun and the north polar region is in complete darkness. In the spring and fall, when Uranus's axis is perpendicular to the sun's rays, it undergoes a 17-hour day and night cycle as it rotates around its axis.