During twilight, the Sun is below the horizon. This means that there is no daylight, which illuminates Earth’s surface and lower atmosphere. Animals that feed on light migrate to the twilight zone to seek food. Depending on the latitude, the duration of twilight can vary.
Twilight’s duration depends on latitude
Several factors determine the length of twilight, including time of year, time zone, and latitude. The length of twilight is usually shorter in the tropics and longer in the high latitudes. This length is also affected by weather conditions, cloud cover, and the elevation of the sun in the sky.
Twilight is a natural lighting condition that occurs after sunset. It is characterized by the geometric center of the sun being at least 18 degrees below the horizon. This condition is also referred to as blue hour. In addition to being a natural lighting condition, twilight is also popular with photographers because it is the shortest time that the sky is illuminated. During twilight, the sun’s rays are spread over a wider area, resulting in a slanting appearance. It is usually characterized by deep blue shades.
Twilight lasts for a short period of time at low latitudes. It is short at the equator and can last up to a few hours at high latitudes. Twilight is also known as blue hour, but it is not the same as civil twilight. Civil twilight occurs from sunset to sunrise in the Northern Hemisphere. It is usually about 30 minutes long, but the interval between civil twilight and sunrise is shorter in the spring and summer.
At low latitudes, the sun’s apparent movement is perpendicular to the horizon, whereas at high latitudes, the sun’s apparent motion is inclined. As latitude increases, the orbital speed of the Earth slows down. Twilight can last for as long as two weeks at the North Pole and up to a month at the South Pole. At the South Pole, twilight is not possible in the summer.
In the northern hemisphere, civil twilight occurs during the months of June, July, and August. Twilight is also available during the winter solstice, but is shorter than during the summer. It usually lasts about 31 minutes, and it is about 40 minutes long during the summer solstice. The interval between civil twilight and the beginning of sunrise is also shorter during the winter.
During the summer, the sun moves through six degree bands of sun angle. The distance between the six degree line and the horizon is slightly longer than the distance between the 18 degree line and the horizon. At close latitudes, the sun can only sink to 18 degrees below the horizon. This condition of twilight is referred to as “blue hour.” The sun moves to a depression of 108 degrees at the Equator and reaches a depression of 18 degrees at the North Pole. During twilight, it is possible to observe the Southern Lights, which are caused by solar refraction.
The length of twilight is affected by many factors, including latitude, time of year, and the angle of the horizon. It is also affected by the presence of clouds and air pollution. It is usually less than an hour in the tropics and tropical regions and is usually shorter at the equator. The length of twilight in low latitudes is about 20 minutes, while it is longer at high latitudes.
Twilight is light produced by sunlight scattering in the upper atmosphere
During twilight, light produced by sunlight scattering in the upper atmosphere becomes partially visible. The intensity of the twilight sky changes from one twilight period to another. This phenomenon is caused by multiple scattering and ground-based aerosol. The intensity of twilight afterglows varies depending on the haze and stratospheric clouds. This process is known as crepuscular. The term “crepuscular” is sometimes used metaphorically. This type of light is also called “crepuscular rays”. The rays appear to converge towards the Sun.
Twilight is usually seen in the Northern Hemisphere. It can last until sunrise and sunset, depending on latitude and time of year. Twilight occurs in the evening from about 6:00PM to 8:00PM, and in the morning from about 7:00AM to 8:00AM. It also happens during the summer solstice. This period occurs when the geometric center of the sun is about twelve degrees below the horizon. Twilight can last from sunset to sunrise at latitudes that are at least 48 degrees south and at latitudes that are at least 48 degrees north. The duration of twilight depends on the angle of the horizon, latitude, and time of year.
The twilight background is strongly polarized near the zenith, due to linear polarization of Rayleigh scattering by angle 90deg. Multiple scattering and ground-based aerosol contribute to the background radiation ratio. The amount of scattering is approximately constant.
Multiple scattering accounting is a technique that allows estimation of the total amount of scattering. It was first introduced by Rozenberg (1966). It is based on the fact that multiple scattering occurs during the dark stage of twilight. This accounting leads to a satisfactory agreement with the observational data.
Multiple scattering accounting is also available for the twilight sky. This method can be used to estimate the background radiation ratio, assuming that sufficient multiple scattering occurs. This method is particularly useful in discriminating against scattered solar radiation. It can be used to measure the twilight airglow emissions and to enhance zenith measurements. This method can also be used to estimate the depolarization of the twilight background.
Depolarization occurs when light is scattered by aerosols in the troposphere. During the dark stage of twilight, ground-based aerosols and other aerosols in the troposphere cause the sky to be depolarized. This causes a shift in the brightness of the background. In the case of twilight near the zenith, depolarization becomes noticeable only during the evening, when the geometric center of the sun is at least 12 degrees below the horizon.
It is important to remember that the optical properties of the mesosphere, stratosphere, and troposphere are dependent on the density and scattering properties of the ground-based aerosols. These particles are the main source of multiple scattering during the dark stage of twilight. The concentration of aerosols is greater near the ground.
Animals migrate to find food in the twilight-zone
Hundreds of species of fish and crustaceans, as well as a number of other creatures, migrate to the twilight zone in search of food. This area, which lies hundreds of meters below the ocean’s surface, is one of the planet’s last great wildernesses. Scientists are beginning to understand the dynamic nature of this largely unexplored space. They are also tagging top predators with high-tech sensors to better understand how they move through the ocean.
The twilight zone is a vast region of global oceans, ranging from about 650 feet to about 3,300 feet deep. It is home to some of the planet’s most bizarre life forms. These creatures have incredible adaptations to life in the dimly lit waters. They have specialized organs that allow them to detect vibrations and to use bioluminescence to find food. In addition, these creatures have the ability to glow and blink in different colors to scare off predators.
Scientists believe that up to one million species could potentially be living in the twilight zone. These animals are likely targets of nascent commercial fishing efforts. They are also believed to help with ocean carbon sequestration. These creatures can also be used as food for farmed fish. Several species of lanternfish feed at the surface, while others migrate nearly 2,000 feet deep to feed.
Many of the twilight zone animals are tiny. For example, the viperfish has large teeth that help it to capture prey. These creatures have specialized organs that help them detect vibrations and avoid predators. Many animals also use bioluminescence to attract prey and camouflage themselves. These animals also blink in different colors to attract mates.
The twilight zone is one of the world’s most important marine habitats, playing a critical role in ocean carbon sequestration. It is a place where scientists are finding evidence of diel vertical migration, which refers to the movement of marine life along the water column. As the tide moves, plankton and other organisms move from the twilight zone to the surface. These organisms then feed on phytoplankton, which absorb carbon dioxide. This movement is one of the most important steps in the marine food web.
There are several species that live in the twilight zone, including the humboldt squid and bristlemouth fish. The bristlemouth is the most widely distributed vertebrate on the planet, with about quadrillion individuals worldwide.
The twilight zone is considered one of the world’s last great wildernesses, but scientists are beginning to understand the dynamic nature of this largely unexplored space. It is also being studied to help stave off climate change. Scientists are collecting water samples from the twilight zone and using new tools to help them map its food web. These tools include stable isotopes, genetic material from aquatic animals, and environmental DNA. This information gives scientists clues about where species live and where they eat. It also helps researchers determine relative abundances.