The rotation of the Earth on its axis causes the variation between day and night. The day/night cycle would be considerably different, if not non-existent, if the Earth did not revolve as it does. The durations of days and nights vary depending on where you are on Earth and the season. In winter, when the Earth is closest to the Sun, it gets light early in the morning and goes down late at night. In summer, when the Earth is farthest from the Sun, it gets dark early and doesn't go back up again until after midnight.
Days and nights are getting longer due to climate change. This means that there is less darkness during each night and more sunlight during each day. Solar radiation levels are expected to increase as well. These factors will lead to an overall increase in the amount of energy that plants absorb from the sun per day. That will need to be compensated for by increasing the amount of time that plants are exposed to the sun per day. This will require moving houses or buildings off of land they currently occupy into lighter soil with more vegetation so that they get enough sunlight.
Climate change will also cause seasons in agriculture to expand north and south at a rate of about 10 degrees per century. This means that farmers will have to move crops around the world to keep them productive - which isn't easy since some regions are already maxed out for certain types of farming.
The rotation of the earth causes the difference between day and night. And the changing of the seasons is driven by the earth's orbit around the sun. In the spring and autumn, the day and night share the same time period (12 hours each season), however in the summer, the day is longer than the night. In the winter, the day is shorter than the night.
There are two reasons why the time changes from day to night: the first is because of daylight savings time, and the second is because of the moon.
Daylight savings time began in the United States during World War I, when an effort was made by local authorities to use manpower and equipment more efficiently by dividing their territories into four daily time zones. The plan was for people to turn off their lights at sunset and on at sunrise, thus saving energy. This would allow factories to operate around the clock, reducing man-hours needed for labor-intensive activities, such as farming and mining.
Today, most countries that use daylight savings time adjust the time by one hour starting in March or April and ending in November or December. However, some countries choose to have a permanent change by moving their clocks ahead of the United States all year round.
The Earth's rotation causes darkness and day to alternate. Because we now know that the Earth's axis is tilted and, as a result, the equator does not always face the Sun directly, various parts of the planet experience uneven lengths of day and night—not exactly 12 hours of day and 12 hours of night all the time. The amount of daylight at any given place on the globe varies by season and latitude.
At the equator, the sun rises due east and sets due west, so the angle of elevation (from the horizon) remains constant throughout the year. At the poles, the sun never rises or sets; instead, it stays continuously over the horizon at both 90 degrees north and 90 degrees south. The amount of daylight at the poles varies with the length of winter and summer; at mid-latitudes, there are two equal peaks of sunlight each year around the spring and fall equinoxes. The duration of these seasons varies from place to place; for example, in Boston they last about four months each but only six weeks in San Francisco.
At high latitudes, there are three periods of light and dark each year: one period when the sun is up and another when it is down. During these times, the amount of daylight changes slowly from season to season because the sun moves across the sky more quickly at higher latitudes.
Day and night are caused by the rotation of a celestial body on its axis, which creates the appearance of the sun rising and setting. Different bodies, however, spin at extremely different speeds. Some may spin far faster than the Earth, while others may spin very slowly, resulting in unusually lengthy days and nights. The Earth's rotational speed is about 1,000 miles per hour, or 647 kilometers per hour.
Bodies like the Earth that rotate quickly tend to have more extreme temperatures between the equator and the poles because they don't have time to spread out the heat from the sun. Bodies like the one we live on that rotate more slowly have more moderate temperatures everywhere on the surface.
Day and night affect all living things on Earth. Plants need sunlight to make food via photosynthesis, so plants must either be exposed to light or be underground where they can hide from light-sensitive pathogens and predators. Animals need darkness to sleep, find food, and communicate with other animals. Humans need daily cycles of light and dark to stay healthy. Our bodies cannot produce vitamin D when we are constantly exposed to light, so we must get this vital nutrient from our diet or supplements. Without darkness, life as we know it would not be possible.
On April 15, 1960, the Earth was given 5 870 hours. That's less than one week of extra time beyond what nature intends!
We have day and night because the Earth spins (or rotates) on an imaginary line known as its axis, and various areas of the world face the Sun or away from it. It takes 24 hours for the Earth to complete one full rotation, which we call a day. During a single day, only part of the planet is in sunlight, but over a period of days or months, all points on the Earth are illuminated by daylight.
The angle at which the Earth intervenes from direct sunlight varies throughout the year, creating different seasons. In winter, the Earth is directly opposite the Sun, with no part of the surface sheltered from its rays; in summer, it is closest to the Sun, covering almost all of Earth with light daytime temperatures. The remaining part of Earth's surface is exposed to the moon during lunar nights. Because the moon slows down as it draws closer to the Earth, each month has about 14 days.
When viewing Earth from space, every hour is visible darkness interrupted by a thin sliver of bright daylight across the globe. From this perspective, the entire Earth cycle between night and day occurs in just a few hours. As you gaze out into space, you are seeing only part of a larger cyclical process that has been going on for many millions of years.
Every 24 hours, the Earth completes a revolution on its axis. We have day and night on Earth because the Earth rotates while the Sun remains stationary. Because the Earth rotates from west to east, this is the case. The rotation of the Earth creates the illusion that the Sun is moving across the sky. At midnight, when the West is rising, the East is about to rise, and vice versa at noon when the East is rising the West is about to rise.
The Earth's atmosphere refracts light from the Sun as it passes through it, causing different parts of the planet to dawn, midday, sunset, and twilight. Reflection from clouds and water also plays a role in how we see the sky.
At night, all visible stars are twinkling due to air turbulence caused by wind or raindrops. The brighter the star, the faster it will appear to be spinning as it orbits the Earth during a given moment of time!
During a clear night with no cloud cover, you can see all the way to the Moon and beyond! The Moon often appears red because it is reflecting light from Earth's atmosphere. As we travel away from Earth, the intensity of this reflection decreases until, at least in theory, it disappears entirely.
Stars that are far away from Earth appear to move slowly across the sky if viewed from our location on Earth.