Why Does The Time Of Sunrise And Sunset Change Everyday?

Sunrise and sunset are phenomena that occur every day, although their time changes depending on where you are on the planet. While many of us take these events for granted, it is fascinating to investigate the reasons behind the temporal disparities. Several factors, including the Earth's rotation on its axis, tilt, and orbit around the Sun, can explain differences in dawn and dusk times.

This Story also Contains

1. Earth's Rotation
2. Latitude And Longitude
3. Earth's Tilt
4. Earth's Orbit

In this article, we will go through each of these aspects in depth and provide a better understanding of why sunrise and sunset times change from place to location on Earth.

Earth's Rotation

The Earth revolves around an imaginary axis that connects the North and South Poles. This rotation takes approximately 24 hours to complete one full revolution, resulting in the day-night cycle.

The cycle of day and night is created by the rotation of the Earth, as different regions of the world are exposed to sunlight at different times. When a specific section of the Earth is facing the Sun, it is day; when it is facing away from the Sun, it is night. This rotational cycle produces a natural 24-hour day, with approximately 12 hours of daylight and 12 hours of darkness.

Because of the Earth's rotation, different portions of the planet are exposed to sunlight at different times. For example, when it is a day in North America, it is night in Asia because North America faces the Sun and Asia faces away from it. The precise timing of sunrise and sunset varies depending on a location's latitude and longitude on Earth. Locations near the equator have more regular sunrise and sunset times throughout the year, whereas locations near the poles have more dramatic variations in daylight hours.

Latitude And Longitude

Latitude and longitude are the two coordinates used to specify the location of any point on the surface of the Earth. Latitude is the angular distance of a location north or south of the equator, which is an imaginary line that circles the Earth at 0 degrees latitude. Longitude is the angular distance of a location east or west of the prime meridian, which is an imaginary line that runs from the North Pole to the South Pole through Greenwich, England.

Sunrise and sunset times are affected by latitude because the angle at which the Sun's rays strike the Earth's surface varies with latitude. The closer a region is to the equator, the more direct the Sun's rays are, thus the period of darkness between sunrise and sunset is shorter. This means that areas near the equator have shorter and more constant dawn and sunset times throughout the year, with only a few minutes separating the longest and shortest days.

Longitude also affects sunrise and sunset times because the Earth rotates from west to east. This means that places located further to the east experience sunrise and sunset earlier than places located further to the west. For example, if it is noon in New York City, it is 9 am in Los Angeles and 5 pm in London. Therefore, the exact time of sunrise and sunset can vary significantly depending on a location's longitude.

Also check - Mathematical Models In Epidemiology: The Covid-19 Pandemic

Earth's Tilt

The Earth is tilted on its axis by approximately 23.5 degrees relative to its orbital plane around the Sun. This tilt is what creates the different seasons on Earth.

The tilt affects sunrise and sunset times because it causes the Sun's rays to hit the Earth's surface at different angles throughout the year. When the Earth is tilted towards the Sun, the Sun's rays are more direct, causing longer daylight hours and shorter periods of twilight between sunrise and sunset. Conversely, when the Earth is tilted away from the Sun, the Sun's rays are more oblique, causing shorter daylight hours and longer periods of twilight.

Seasonal fluctuations in daylight hours are also caused by the tilt. The hemisphere inclined towards the Sun sees its longest day and shortest night of the year at the summer solstice, which occurs around June 21 in the Northern Hemisphere and December 21 in the Southern Hemisphere. Conversely, the hemisphere tilted away from the Sun experiences its shortest day and longest night of the year around the winter solstice, which happens around December 21 in the Northern Hemisphere and June 21 in the Southern Hemisphere. The equinoxes, which occur around March 21t and September 21, indicate the points at which the Earth's tilt is perpendicular to the Sun's rays, resulting in nearly equal levels of daylight and darkness throughout the world.

Earth's Orbit

The Earth's orbit around the Sun is elliptical and takes around 365.25 days to complete. The length of a year on Earth is determined by this orbit.

The orbit affects the timing of sunrise and sunset because the Earth's position in its orbit changes throughout the year. When the Earth is at its closest point to the Sun, known as perihelion, the Sun's rays are more direct, causing slightly shorter periods of twilight between sunrise and sunset. Conversely, when the Earth is at its furthest point from the Sun, known as aphelion, the Sun's rays are more oblique, causing slightly longer periods of twilight.

The orbit also causes variations in daylight hours throughout the year. When the Earth is at its closest point to the Sun, the hemisphere tilted towards the Sun experiences more intense sunlight, resulting in longer daylight hours and shorter periods of twilight between sunrise and sunset. When the Earth is at its furthest point from the Sun, the hemisphere tilted towards the Sun experiences less intense sunlight, resulting in shorter daylight hours and longer periods of twilight. This causes seasonal variations in daylight hours, with longer days and shorter nights during the summer in the hemisphere tilted towards the Sun, and shorter days and longer nights during the winter in the hemisphere tilted away from the Sun.

Also check - Forward And Reverse Genetics: Differences And Similarities