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Sunset

A sunset is the daily astronomical phenomenon in which the Sun appears to descend below the horizon, marking the transition from day to night as a result of Earth's rotation on its axis. It is precisely defined as the moment when the upper limb of the Sun's disk disappears below the horizon, with calculations accounting for the Sun's semi-diameter (approximately 16 arcminutes) and atmospheric refraction, which raises the apparent position of the Sun by about 34 arcminutes at the horizon.^[1] This event occurs universally once per day for observers on Earth, though its exact timing varies by geographic location, latitude, and season due to the planet's 23.44-degree axial tilt and orbital path around the Sun.^[2] The visual display of a sunset often features a spectrum of colors, ranging from orange and red to purple and pink, caused by the scattering of sunlight in Earth's atmosphere. As sunlight travels through a longer atmospheric path at sunset compared to midday, shorter blue wavelengths are preferentially scattered away by air molecules (Rayleigh scattering), allowing longer red and orange wavelengths to dominate the view.^[3] Particles such as dust, aerosols, or water droplets can enhance these hues, with clouds acting as a canvas to reflect and diffuse the light, sometimes producing intensified effects known as alpenglow on distant mountains.^[4] The duration of the sunset process—the time for the entire solar disk to pass below the horizon—varies from about 2 minutes near the equator, where the Sun sets nearly vertically, to tens of minutes at higher latitudes (e.g., around 15-30 minutes near 60-70° during solstices) and over an hour near the polar regions due to the Sun's shallower angle.^[5]^[6] Sunsets hold significant cultural and symbolic value across human societies, often representing themes of closure, reflection, and renewal. In Hinduism, for instance, sunset marks a sacred transition period for rituals like the Agnihotra fire offering, symbolizing the cyclical nature of life and the cosmos.^[7] Similarly, in Jewish tradition, the onset of sunset defines key religious observances, such as the start of Shabbat, emphasizing its role in daily spiritual practices.^[8] These interpretations underscore the sunset's enduring place in art, literature, and philosophy as a metaphor for the passage of time and the beauty of impermanence.

Physical Phenomenon

Definition and Observation

A sunset is defined in astronomy as the moment when the upper limb of the Sun's disk appears to touch the horizon and then disappears below it, resulting from Earth's daily rotation on its axis.^[1] This apparent motion occurs as the observer's position on the rotating Earth moves away from the Sun's direct line of sight, marking the transition from daytime to evening.^[2] Sunsets are observable from virtually any location on Earth where the Sun rises and sets, occurring once daily in conjunction with the diurnal cycle driven by Earth's rotation relative to the Sun.^[1] The experience of observing a sunset is influenced by the observer's latitude, which affects the Sun's path and the duration of the event; higher altitudes, such as on mountains, can extend visibility slightly by raising the observer's vantage point; and atmospheric conditions like clarity, humidity, and particulate matter, which determine how sharply the horizon is defined and whether the full disk is visible.^[1] For optimal viewing, an unobstructed horizon line is essential, typically available over open bodies of water like oceans, vast plains, or elevated sites without foreground barriers such as buildings or trees.^[1] In such settings, under average atmospheric conditions, the upper edge of the Sun aligns precisely with the horizon at the defined moment of sunset.^[1]

Timing and Location

Sunset timing varies by location and season, primarily due to Earth's axial tilt of approximately 23.44 degrees, which causes the length of daylight to fluctuate throughout the year. On average, sunset occurs about 12 hours after sunrise, though this interval ranges from less than 6 hours near the poles during winter solstices to nearly 24 hours in summer, depending on latitude.^[9] At the equator, day length remains close to 12 hours year-round, while higher latitudes experience greater seasonal extremes.^[10] The exact time of sunset is calculated using apparent solar time, which accounts for the sun's position relative to the observer's local meridian, adjusted by the equation of time to convert to mean solar time for clock usage. The equation of time, arising from Earth's elliptical orbit and axial tilt, introduces variations of up to about 16 minutes between apparent and mean solar time across the year.^[11] These calculations incorporate the sun's declination—the angular distance north or south of the celestial equator—which shifts seasonally and directly influences the hour angle at which the sun sets.^[12] The position of sunset on the horizon, measured as the azimuth angle from true north, also varies seasonally and by latitude, typically ranging from about 240° (west-southwest) in winter to 300° (west-northwest) in summer for mid-northern latitudes like 40°N. This shift occurs because the sun's declination alters the geometry of its daily path across the sky, with the azimuth determined by spherical trigonometry involving the observer's latitude and the sun's declination at the time of sunset.^[13] Atmospheric refraction bends sunlight, making the sun appear higher in the sky than its geometric position, which delays the observed sunset by approximately 2 minutes compared to the theoretical time without atmospheric effects. This refraction is most pronounced near the horizon, where light rays pass through denser air layers. Observer elevation above sea level further influences timing; higher altitudes depress the apparent horizon, causing sunsets to occur slightly later and thereby lengthening the overall day by a few minutes relative to sea-level calculations.^[14]^[15] In traditional navigation, specific sunset directions were described using compass points from the 32-point rose, such as "west by south" (approximately 258.75°) or "west-southwest" (247.5°), to denote precise bearings for orientation when the sun's position aligned with these points during equinoxes or solstices. These terms, rooted in maritime practice, allowed sailors to calibrate instruments like the solar compass by observing the sun's setting azimuth against known cardinal and intercardinal directions.^[16]^[17]

Optical Effects and Colors

The vibrant colors observed during sunsets arise primarily from Rayleigh scattering, a process in which sunlight interacts with atmospheric molecules, preferentially scattering shorter wavelengths of light. As the sun approaches the horizon, its light travels through a longer path in the Earth's atmosphere compared to midday, increasing the opportunity for scattering. Shorter blue and violet wavelengths are scattered more efficiently out of the direct beam—up to sixteen times more than red light—leaving the transmitted light enriched in longer wavelengths such as yellow, orange, and red.^[18]^[19] This scattering intensity follows the inverse fourth-power dependence on wavelength, expressed as I \propto \frac{1}{\lambda^4}, where I is the scattered intensity and \lambda is the wavelength of light.^[20] The progression of colors in the sunset sky typically begins with pale yellows and oranges near the sun, transitioning to deeper reds higher in the atmosphere as the light path lengthens and more intermediate wavelengths are scattered. This gradient results from the varying optical depths at different altitudes and angles, with the reddest hues appearing just above the horizon where the atmosphere is thickest.^[4] Dust, pollution, or volcanic ash can intensify these hues by introducing larger particles that enhance scattering of red light through Mie scattering, a complementary process to Rayleigh scattering for particles comparable to the wavelength of light. For instance, the 2019 eruption of Russia's Raikoke volcano dispersed ash into the stratosphere, producing unusually vivid purple and blood-red sunsets across North America by amplifying high-altitude glows after the primary colors faded.^[21]^[22] Additional optical effects contribute to the sun's appearance at sunset. Atmospheric refraction bends sunlight, causing the sun's image to elongate horizontally into an oval or flattened shape, particularly noticeable in clear conditions where temperature gradients in the lower atmosphere create differential bending of light rays from the sun's upper and lower limbs. A rarer phenomenon, the green flash, occurs in the final moments as the sun's upper rim disappears below the horizon; prismatic refraction separates the sunlight's spectrum, momentarily isolating the green wavelength at the top edge before it too vanishes, often lasting one to two seconds under ideal viewing conditions like a sharp horizon over calm water.^[23]^[24] The saturation and intensity of sunset colors are further modulated by environmental factors such as humidity, aerosols, and particulate matter. Higher humidity increases water vapor density, promoting additional scattering and more vivid reds and oranges, while aerosols from natural sources like sea salt or human activities scatter light selectively to deepen hues. Particulate matter, including smoke or desert dust, absorbs shorter wavelengths and backscatters reds, leading to more saturated displays in regions with elevated concentrations, as observed in polluted urban areas where sunsets shift toward deeper crimson tones.^[19]^[22]

Astronomical Context

Earth's Rotation and Orbit

The apparent motion of the Sun across the sky, which leads to the daily occurrence of sunset, is primarily due to Earth's rotation on its axis from west to east at an angular speed of approximately 15° per hour relative to the fixed stars, resulting in a mean solar day of 24 hours.^[25] This rotation causes the terminator—the boundary line separating the illuminated dayside from the dark nightside of Earth—to sweep westward across the planet's surface at about 1,670 km/h at the equator, with sunset occurring for an observer when this line passes over their location, transitioning them from daylight to twilight.^[26] Seasonal variations in the timing and direction of sunset arise mainly from Earth's axial tilt of 23.5° relative to its orbital plane around the Sun, which causes the Sun's declination—the angular distance north or south of the celestial equator—to vary throughout the year.^[27] At the summer solstice in the Northern Hemisphere (around June 21), the North Pole tilts maximally toward the Sun, positioning sunset at its northernmost azimuth (about 23.5° north of due west at mid-latitudes), while the winter solstice (around December 21) tilts the North Pole away, shifting sunset to its southernmost point; during the equinoxes (around March 21 and September 23), the tilt aligns the equator toward the Sun, resulting in sunsets due west for all observers. Earth's orbit around the Sun is slightly elliptical, with perihelion (closest approach, about 147 million km in early January) and aphelion (farthest, about 152 million km in early July), leading to a roughly 3.4% variation in distance that modulates incoming solar radiation by up to 6.8% annually—stronger intensity at perihelion but weaker at aphelion—though this has minimal direct impact on sunset timing or day length compared to the axial tilt's dominant effect.^[28]^[29] The mathematical foundation for these variations is the solar declination angle \delta, approximated by the formula

\delta = 23.45^\circ \sin\left(\frac{360^\circ (284 + n)}{365}\right),

where n is the day of the year (January 1 as n=1); this value is essential for calculating the precise azimuth of sunset, which deviates from due west based on the observer's latitude and \delta.^[12]

Sunsets on Other Celestial Bodies

Sunsets on other celestial bodies vary dramatically from Earth's due to differences in atmospheric composition, density, rotation rates, and solar distances, altering the scattering of light and the duration of twilight. On Mars, the thin carbon dioxide atmosphere laden with fine dust particles produces striking blue sunsets, contrasting with the planet's butterscotch-red daytime skies. As sunlight travels through the longer atmospheric path at the horizon, dust scatters shorter-wavelength blue light toward observers more effectively than red, tinting the setting Sun blue.^[30] NASA's Curiosity and Perseverance rovers have documented this effect, capturing sequences where the Sun appears as a blue dot amid dusty red hues during evening twilight.^[31]^[32] Venus presents a markedly different scenario, where a dense carbon dioxide atmosphere overlaid with thick sulfuric acid clouds at about 50 kilometers altitude completely veils the Sun from surface view, rendering direct sunsets invisible and perpetually hazy. The planet's extreme greenhouse effect traps heat, while its retrograde rotation—taking 243 Earth days per spin—combines with an orbital period of 225 Earth days to yield a solar day of roughly 117 Earth days, making sunsets occur only twice per Venusian year and appear as gradual, diffused dimming through the opaque veil.^[33] Simulations based on atmospheric models confirm this obscured, low-contrast transition, with the Sun reduced to a faint glow piercing the cloud layers.^[34] On Saturn's moon Titan, a thick nitrogen-methane atmosphere rich in organic haze generates dim, orange-tinted sunsets, where aerosol particles scatter sunlight to create layered, smog-like skies. NASA's Cassini spacecraft observed these during targeted sunset flybys using its Visual and Infrared Mapping Spectrometer, revealing multiple haze strata that filter light into warm hues and extend the faint glow beyond the geometric horizon. Titan's rotation, tidally locked to Saturn, results in a day-night cycle of about 16 Earth days, prolonging the hazy dusk but dimming the Sun to roughly 1% of Earth's solar intensity due to distance and opacity. Bodies lacking atmospheres, like Mercury and Earth's Moon, feature stark, instantaneous sunsets without scattering or color gradients, as the Sun vanishes abruptly below the horizon, instantly plunging landscapes into shadow with razor-sharp terminators. Mercury's negligible exosphere offers no refraction or diffusion, while the Moon's vacuum ensures no twilight phase, a fact corroborated by Apollo mission reports of sudden light-to-dark shifts over 14.8 Earth-day lunar days. Jupiter's rapid equatorial rotation period of about 9 hours 56 minutes compresses its day-night cycle, resulting in swift sunsets, though its thick atmosphere produces a twilight zone with scattered light transitioning gradually from day to night.^[35]

Human Perspectives

Historical Views

In ancient civilizations, sunsets were often interpreted through mythological lenses as divine journeys or signals from the gods, reflecting a pre-scientific worldview that imbued the phenomenon with spiritual significance. In Egyptian mythology, the sun god Ra was believed to traverse the sky in his solar barque during the day, descending into the underworld at sunset to battle chaos and ensure renewal at dawn, symbolizing the cyclical triumph of order over darkness.^[36] This narrative, central to religious texts like the Book of the Dead, portrayed sunset not as a mere optical event but as a cosmic battle, with Ra's nightly voyage through the Duat underworld culminating in his rebirth. Similarly, other early cultures viewed sunsets as omens or transitions to the realm of the dead, laying the groundwork for later philosophical inquiries into the heavens' mechanics.^[37] By around 2000 BCE, Babylonian astronomers began systematically recording sunsets alongside lunar observations to construct calendars, marking a shift toward empirical tracking despite persisting geocentric assumptions. These records, preserved on cuneiform tablets, noted sunset timings for determining month beginnings via crescent visibility, enabling agricultural and ritual planning with notable precision for the era. This practical focus evolved into formalized geocentric models by the 2nd century CE, as exemplified by Ptolemy's Almagest, which posited Earth as stationary at the universe's center, with the Sun orbiting daily to explain sunset as the Sun's descent below the horizon due to its own motion around our planet.^[38] Ptolemy's system, refined from earlier Hellenistic and Babylonian data, dominated astronomical thought for over a millennium, integrating philosophical notions of a perfect, Earth-centered cosmos where apparent solar motion aligned with sensory experience. The Renaissance heralded a profound reevaluation, with Nicolaus Copernicus's 1543 heliocentric model in De revolutionibus orbium coelestium reinterpreting sunset as the result of Earth's daily rotation rather than the Sun's orbit, challenging geocentric orthodoxy and emphasizing relative motion.^[39] This paradigm shift gained empirical traction through Galileo's telescopic observations published in 1610, including the discovery of Jupiter's moons, which demonstrated that not all celestial bodies orbit Earth and supported the idea of planetary systems centered on the Sun, thereby linking daily phenomena like sunsets to Earth's own axial spin.^[40] By the 19th century, scientific understanding advanced further with John William Strutt (Lord Rayleigh)'s 1871 theory of atmospheric scattering, which mathematically described the colors observed at sunset.^[41] The 20th century solidified relativity's influence on sunset perceptions through the 1919 solar eclipse expeditions led by Arthur Eddington, which measured starlight deflection by the Sun's gravity, confirming Einstein's general theory and revealing how massive bodies warp spacetime to subtly alter apparent positions near the horizon.^[42] Observations from Príncipe and Sobral closely matched predictions, transitioning views of sunset from classical mechanics to a relativistic framework where light paths curve near the Sun. This empirical validation marked the culmination of centuries-long evolution from mythic symbolism to precise astrophysics, underscoring sunsets as windows into cosmic geometry.

Cultural and Symbolic Significance

Sunsets hold profound symbolic meaning across cultures, often representing endings, reflection, and transitions between day and night. In Hinduism, sunset rituals such as the offering of Arghya during Chhath Puja symbolize humility and the close of the day's cycle, honoring the setting sun as a moment of devotion to the life-sustaining Surya.^[43]^[44] In Western traditions, sunsets evoke melancholy, mirroring the transient beauty of life and evoking a sense of poignant closure.^[45] In art and literature, sunsets inspire works that capture their ephemeral glow and emotional depth. Claude Monet's Impressionist paintings from the 1870s and 1880s, such as Sunset on the Seine at Lavacourt, Winter Effect, masterfully depict the shifting colors and light of sunsets, emphasizing the transient nature of perception.^[46] In Romantic literature, William Wordsworth's poetry draws on natural scenes to evoke serene, reflective qualities, celebrating nature's restorative power.^[47] Religiously, sunsets mark sacred transitions in various practices. The Islamic Maghrib prayer, one of the five daily salah, begins immediately after sunset, serving as a communal call to reflection and gratitude at the day's end.^[48] Among some Native American traditions, such as those of the Lakota Sioux, the fading sunset symbolizes the spirit's journey, as expressed in prayers invoking the Great Spirit for a shame-free passage into the afterlife.^[49]^[50] In modern media, sunsets often signify narrative closures, particularly in Western films where characters ride into the horizon, embodying resolution and new beginnings, as seen in John Ford's iconic landscapes.^[51] Tourism capitalizes on this allure, with destinations like Santorini's Oia drawing millions annually for its dramatic caldera sunsets, blending natural beauty with cultural spectacle.^[52]

Twilight Phases

Twilight follows sunset and consists of three distinct phases defined by the angular depression of the Sun's center below the horizon, during which the sky remains partially illuminated by scattered sunlight in the atmosphere.^[1] These phases transition progressively from brighter conditions to near-full darkness, enabling specific activities like outdoor work, navigation, and stargazing.^[53] Civil twilight begins immediately after sunset, when the Sun is between 0° and 6° below the horizon, providing enough illumination from the upper atmosphere for most ordinary outdoor activities without the need for artificial lighting.^[1] During this phase, the sky retains a significant brightness, allowing clear visibility of the landscape and horizon.^[54] It ends when the Sun reaches 6° depression, marking the shift to dimmer conditions.^[55] Nautical twilight follows civil twilight, occurring as the Sun depresses from 6° to 12° below the horizon; at this stage, the illumination level permits the horizon to remain discernible even on moonless nights, facilitating celestial navigation for mariners by allowing identification of stars near the horizon.^[1] The skies grow dimmer, with overhead brightness reducing sufficiently for fainter stars to become visible, though the overall scene is noticeably darker than during civil twilight.^[54] Astronomical twilight is the final phase, spanning the Sun's depression from 12° to 18° below the horizon, where the sky's illumination is faint enough that most stars are observable, making it suitable for astronomical observations with telescopes without interference from solar-scattered light.^[1] Beyond 18° depression, full night begins, with the sky dark enough for all but the brightest celestial objects to be seen clearly.^[56] The duration of these twilight phases varies significantly with latitude and season due to the Earth's axial tilt and orbital position. At higher latitudes, twilight periods are longer because the Sun's path near the horizon is more oblique, taking more time to traverse the required angular depressions; for example, near the equator or in tropical regions, the total time from sunset to full darkness (18° depression) is approximately 70-80 minutes, but practical full darkness for most purposes occurs in about 30 minutes as illumination drops rapidly.^[53] In contrast, during summer at high latitudes within the polar circles, the midnight sun phenomenon prevents the Sun from dipping below 18°, resulting in no astronomical twilight and continuous daylight.^[57] Conversely, during polar night in winter at these latitudes, the Sun remains below 18° for extended periods—up to several months at the poles—skipping twilight phases entirely and yielding continuous full darkness.^[58] Illumination levels during twilight decrease exponentially as the Sun depresses further below the horizon, primarily due to the reduced path length for sunlight scattering in the atmosphere. This rapid dimming follows an approximately exponential decay in sky brightness, with the zenith sky surface brightness increasing by several magnitudes from civil to astronomical twilight (from about 16 mag/arcsec² to over 20 mag/arcsec² in visible bands), leading to a stark contrast between the bright civil twilight and the near-darkness of astronomical twilight.^[59]

Directional and Terminological Variations

In English, the term "sunset" originates from Middle English "son-sett," combining "sun" and "set," referring to the apparent descent of the sun below the horizon, with roots traceable to the late 14th century.^[60] "Sundown," a synonym emerging in the early 17th century, derives from "sun" and "down," possibly as a shortening of "sun-go-down," and is often used interchangeably to denote the same event.^[61] Other poetic synonyms include "eventide," from Old English "æfnung," meaning the approach of evening or time around sunset, and "vesper," borrowed from Latin "vesper," signifying evening or the evening star.^[62]^[63] Across cultures, terminology for sunset reflects linguistic and contextual nuances. In Japanese, "yūgure" (夕暮れ) describes the evening twilight or dusk shortly after sunset, evoking a transitional period of fading light.^[64] In Arabic, "ghurūb" (غُرُوب) literally means the setting or disappearance of the sun, derived from the root "gh-r-b" associated with the west, and holds significance in Islamic tradition as it marks the time for the Maghrib prayer immediately following sunset.^[65] Among the Navajo people, "e'e'aah" refers to evening, sundown, or the western direction where the sun sets, embodying cultural connections to cardinal directions and natural cycles.^[66] The direction of sunset varies from due west due to Earth's axial tilt of 23.5 degrees, with the sun setting up to 23.5 degrees north of west at the summer solstice in the Northern Hemisphere's Tropic of Cancer.^[10] In navigation, the "sunset bearing" denotes the precise compass azimuth of the setting sun, which aids in determining orientation when combined with latitude and date.^[67] Regional differences influence sunset occurrences and timing. In polar regions above the Arctic Circle during summer, the midnight sun phenomenon prevents daily sunsets for periods up to several months, as the sun remains above the horizon continuously.^[68] At the equator, sunset timing remains relatively consistent year-round, occurring near 6:00 PM local time with only minor variations of about 30-40 minutes due to the equation of time and slight orbital effects, contrasting sharply with the more pronounced seasonal shifts at higher latitudes.^[69]

References

[1]
Rise, Set, and Twilight Definitions
For computational purposes, sunrise or sunset is defined to occur when the geometric zenith distance of center of the Sun is 90.8333 degrees. That is, the ...
[2]
Sunset -- from Eric Weisstein's World of Astronomy - ScienceWorld
Sunset is the time at which the trailing limb of the Sun first sets below the horizon. The effect of refraction in the Earth's atmosphere lifts the image of ...
[3]
Why the Sky Changes Colors at Sunset | NOVA - PBS
Oct 11, 2024 · The reason we see different colors at different times has to do with the physics of light. Visible light travels in electromagnetic waves, which we see as the ...
[4]
Curiosities: What determines the colors of the sky at sunrise and ...
Nov 6, 2007 · The colors of the sunset result from a phenomenon called scattering, says Steven Ackerman, professor of meteorology at UW–Madison.
[5]
Sunrise and Sunset Times Near the Solstices
Earliest sunset occurs around November 2 and latest sunrise occurs around February 11. But the total variation in sunrise or sunset times at the equator ...
[6]
https://earthsky.org/tonight/longest-sunsets-around-solstices/
[7]
Sunrise Sunset The science and culture « KaiserScience
Oct 4, 2020 · In Jewish culture the precise time of sundown and sunrise is of practical and religious importance. Observant Jews pray three times daily ...Missing: reliable | Show results with:reliable
[8]
Solar Calculator Glossary - Global Monitoring Laboratory
The solar declination varies from -23.44° at the (northern hemisphere) winter solstice, through 0° at the vernal equinox, to +23.44° at the summer solstice.
[9]
Understanding Astronomy: The Sun and the Seasons - Physics
As you travel southward in the northern hemisphere, the noon sun gets higher and higher. The first qualitative change occurs at 23.5° latitude, where the noon ...<|separator|>
[10]
The Equation of Time - Astronomical Applications Department
We define apparent solar time at a specific location as 12h + the local hour angle (expressed in hours) of the apparent position of the Sun in the sky. Apparent ...
[11]
Declination Angle - PVEducation
The declination angle, denoted by δ, varies seasonally due to the tilt of the Earth on its axis of rotation and the rotation of the Earth around the sun.<|separator|>
[12]
Azimuth Angle of the Sun
The azimuth angle Az of the Sun or a celestial body (St) is depending on it's declination Dec and altitude Alt, and on the latitude Lat of the observer.
[13]
This image shows the path of the Sun across the sky during three ...
Jul 1, 2025 · It also illustrates where the Sun sets on each of these days, with azimuth angles shifting from about 300° (WNW) in summer to 270° (W) at the ...
[14]
Effect of atmospheric refraction on the times of sunrise and sunset
Aug 26, 2022 · The atmospheric refraction causes the sunrise and sunset to appear about 2 minutes early and late respectively when compared to the situation without the ...
[15]
Altitude Correction for Time of Sunrise and Sunset
Aug 10, 2020 · The correction is -2.076*sqrt(elevation in metres)/60, added to the angle, accounting for the sun's apparent size and atmospheric refraction.
[16]
Traditional mariners' compass points
Traditional mariners' compass points ; south, 180° 00′, 180.0° ; south-southwest, 202° 30′, 202.5° ; southwest, 225° 00′, 225.0° ; west-southwest, 247° 30′, 247.5°.
[17]
Solar compass | Navigation, Orientation, Sun-Tracking - Britannica
Sep 11, 2025 · East and west are traditionally synonymous with the directions of sunrise and sunset; north and south are determined by the directions of ...<|control11|><|separator|>
[18]
Red Sunset, Green Flash - HyperPhysics
Since short wavelengths are more efficiently scattered by Rayleigh scattering, more of them are scattered out of the beam of sunlight before it reaches you.
[19]
The Appearance of the Sky - UCAR Center for Science Education
The colors we see in the sky come from sunlight that is scattered by molecules in the atmosphere. This process is called Rayleigh scattering.
[20]
Blue Sky and Rayleigh Scattering - HyperPhysics
The blue sky is caused by Rayleigh scattering, where sunlight scatters off air molecules, more effectively at short wavelengths (blue).Missing: sunsets | Show results with:sunsets
[21]
A volcanic eruption in Russia causes purple sunsets in North America
Oct 9, 2019 · Because ash and acid enhance colors very high in the atmosphere, their glows tend to appear after the more familiar sunset colors have faded, ...Missing: progression | Show results with:progression
[22]
The Color of Clouds - NOAA
Apr 20, 2023 · Therefore, near sunrise and sunset, a cloud's color will be whatever sunlight color it receives after Rayleigh scattering. Mei scattering ...
[23]
Understanding astronomical refraction - Astrophysics Data System
Even though most of the atmosphere ordinarily produces most of the astronomical refraction, sunset distortions are almost entirely due to atmospheric structure ...
[24]
Explaining Green Flashes
Green flashes are by-products of the large variations in astronomical refraction near the horizon. Although there are several kinds of green flash, almost every ...Missing: physics | Show results with:physics
[25]
AstronomyAnswerBook: The Position of the Sun and the Moon
The Sun travels almost exactly 15 degrees in the sky each hour, but that ... terminator on Earth to an accuracy of about 1 degree: First, calculate the ...
[26]
Day/Night Terminator (daily) - Science On a Sphere - NOAA
Because at equinox there is no tilt of the Earth with respect to the sun, the terminator line is parallel to the axis of the Earth and to lines of longitude.
[27]
Milutin Milankovitch - NASA Earth Observatory
Mar 24, 2000 · Today, the Earth's axis is tilted 23.5 degrees from the plane of its orbit around the sun. But this tilt changes.
[28]
Milankovitch (Orbital) Cycles and Their Role in Earth's Climate
Feb 27, 2020 · Earth's axis is currently tilted 23.4 degrees, or about half way between its extremes, and this angle is very slowly decreasing in a cycle that ...Missing: 23.5 | Show results with:23.5
[29]
The Seasons and the Earth's Orbit
The seasons are caused by the 23.4° angular offset (obliquity) between the Earth's axis of rotation and a perpendicular to the Earth's orbital plane with the ...
[30]
What Do Sunrises and Sunsets Look Like on Mars? - NASA Science
May 1, 2019 · Martian sunsets typically stand out for their distinctive blue color. Fine dust in the atmosphere permits blue light to penetrate the atmosphere more ...Perseverance Rover Sunset · Curiosity Rover 'Sun Rays' · Spirit Mars Rover Sunset
[31]
NASA's Curiosity Rover Views Serene Sundown on Mars
May 8, 2015 · The sunset observations help researchers assess the vertical distribution of dust in the atmosphere. "The colors come from the fact that the ...
[32]
Mastcam-Z's First Martian Sunset - Jet Propulsion Laboratory - NASA
Nov 17, 2021 · Martian sunsets typically stand out for their distinctive blue color. Fine dust in the atmosphere permits blue light to penetrate the atmosphere ...
[33]
Venus: Facts - NASA Science
As it sped away from Venus in February 1974, NASA's Mariner 10 spacecraft captured this seemingly peaceful view of Venus. But, contrary to its serene appearance ...
[34]
NASA Scientist Simulates Sunsets on Other Worlds
Jun 22, 2020 · The animations show all-sky views as if you were looking up at the sky through a super wide camera lens from Earth, Venus, Mars, Uranus, and Titan.
[35]
The Journey of the Sun God Re - Egypt Museum
The scene shows the journey of the sun god Re, in his falcon form, seated in his shrine. Detail from the coffin set of Nespawershefyt.
[36]
The Boat of Ra | Research Starters - EBSCO
"The Boat of Ra" refers to the mythological journey of Ra, the ancient Egyptian sun god, who embarks on a daily voyage across the sky.
[37]
Ptolemy and the Geocentric Model - Teach Astronomy
The idea was simple. Earth was stationary at the center and the Sun, Moon, and other planets all moved around Earth. Each object was fixed to a spinning ...Missing: sunset | Show results with:sunset
[38]
The Heliocentric Model
Jan 30, 2008 · Note that a planet still rises in the east and sets in the west on any given night due to the rotation of Earth. This video will focus on a ...Missing: sunset | Show results with:sunset
[39]
When did we realize Earth orbits the Sun? - Astronomy Magazine
In 1610, Galileo turned his new telescope toward Venus. To his amazement, he saw the planet pass through phases just like the Moon. Galileo correctly surmised ...Missing: sunset | Show results with:sunset
[40]
[PDF] The Impact of Aerosols on the Color and Brightness of the Sun and ...
by Rayleigh (1871). Rayleigh scattering produces blue skies so long as the optical thickness of the light path through the atmosphere is small. At twilight ...
[41]
The Solar Eclipse That Made Albert Einstein a Science Celebrity
The eclipse presented a rare chance to verify one of the essential consequences of general relativity, the bending of light by gravity.Missing: sunset | Show results with:sunset
[42]
Sunrise and sunset: Significance and symbolism
Dec 3, 2024 · In Hinduism, sunrise and sunset symbolize key moments for spiritual practices, offering rites to the Sun god, reciting prayers, and celebrating ...
[43]
Embracing the Sunset: The Devotion and Unity of Chhath Puja's...
While the Sun is usually associated with sunrise and new beginnings, the act of offering an Arghya (a ritual offering) to the setting sun symbolizes humility, ...
[44]
Sunsets and Symbolism: What the Setting Sun Represents Across ...
Jun 22, 2025 · The setting sun carries deep meaning across cultures - symbolizing endings, peace, transition, or remembrance, depending on history, belief, ...
[45]
Sunsets in Summer: A Literary and Poetic Exploration of Their ...
Aug 5, 2024 · Whether evoking a sense of melancholy or awe, sunsets serve as powerful metaphors for the astounding complexities of the human experience.
[46]
Sunset on the Seine at Lavacourt, Winter Effect | Petit Palais
Despite the intense cold, Monet painted twenty or so paintings during the first months of 1880, observing the ice on the Seine slowly thawing.
[47]
I Wandered Lonely as a Cloud | The Poetry Foundation
I wandered lonely as a cloud That floats on high o'er vales and hills, When all at once I saw a crowd, A host, of golden daffodils.Missing: sunsets | Show results with:sunsets
[48]
Maghrib Namaz Rakat: A Guide to the Sunset Prayer - MATW Project
Nov 6, 2024 · Maghrib prayer time begins immediately after sunset and lasts until the twilight disappears. Prophet Muhammad (PBUH) emphasized the importance ...
[49]
Native American Prayers - Xavier University
So when life fades, as the fading sunset, my spirit may come to you without shame. - Translated by Lakota Sioux Chief Yellow Lark in 1887. Prayer for Life. Our ...Missing: passage | Show results with:passage
[50]
Native American Symbolic Circles | Inspiration for the Spirit
To the west, the sun sets and the day ends. Thus, the west is considered a place of darkness. It signifies solitude or meditation and crossing into the ...
[51]
[PDF] THE ICONOGRAPHY OF JOHN FORD'S WESTERNS - Linguaculture
This paper follows the way in which the filmography of the movie director John Ford presents cultural icons. We discuss the symbolism of these images and ...
[52]
https://www.santoriniexperts.com/sunset-in-santorini/
[53]
Sunlight and Vitamin D: A global perspective for health - PMC
Sun induced vitamin D synthesis is greatly influenced by season, time of day, latitude, altitude, air pollution, skin pigmentation, sunscreen use, passing ...Missing: sunset | Show results with:sunset
[54]
Does Pollution Really Cause Sunsets? - World Atlas
According to an urban legend, pollution is the cause of a bright vibrant sunset ... The dispersion of these colors causes the different hues viewed during sunset.
[55]
Dear Dot: Is Pollution the Reason for a Beautiful Sunset?
Jan 12, 2024 · ... pollution can enhance sunset beauty, though excessive pollution creates hazy, muted displays. Climate change has also transformed our sunsets.
[56]
The Different Types of Twilight, Dawn and Dusk - Time and Date
Twilight is the time of the day when the Sun illuminates the Earth's atmosphere even though it is below the horizon and not directly visible.Astronomical Twilight · Civil Twilight · Nautical twilight · Golden Hour
[57]
Twilight Types - National Weather Service
There are three categories of twilight that are defined by how far the sun is below the horizon. Civil Twilight, Nautical Twilight, Astronomical Twilight.
[58]
Astronomical definitions | Geoscience Australia
Jun 27, 2014 · Ending of evening civil twilight. Defined as the instant in the evening, when the centre of the Sun is at a depression angle of six degrees (6°) ...
[59]
Do you love twilight? The 3 stages explained - EarthSky
Aug 15, 2025 · The definition of astronomical twilight is the period of time when the center of the sun is 12 degrees below the horizon to 18 degrees below the ...
[60]
Daylight, Darkness and Changing of the Seasons at the North Pole
The darkest time of year at the North Pole is the Winter Solstice, approximately December 21. There has been no sunlight or even twilight since early October.
[61]
Polar Night — The Opposite of Midnight Sun - Time and Date
Jan 13, 2025 · It lasts for about 6 months until the Sun rises again around the vernal (spring) equinox in March when 6 months of Polar Day / Midnight Sun ...
[62]
Measurements of sky brightness at Bosscha Observatory, Indonesia
Walker (1988) found a steady exponential decrease of ~0.4 mag in B and V ... Sky brightness and twilight measurements at Jogyakarta city, Indonesia. J ...<|control11|><|separator|>
[63]
UBVRI twilight sky brightness at ESO-Paranal [*]
Results. The comparison with a low-altitude site shows that Paranal V twilight sky brightness is about 30% lower, implying that some fraction of multiple ...
[64]
Sunset - Etymology, Origin & Meaning
Sunset, from late 14c. Old English roots, means the apparent descent of the sun below the horizon in evening; origin combines sun + set, possibly from ...
[65]
sundown, n. meanings, etymology and more | Oxford English ...
The earliest known use of the noun sundown is in the early 1600s. OED's earliest evidence for sundown is from 1620, in Depos. Bk. Archdeaconries Essex ...
[66]
Eventide - Etymology, Origin & Meaning
evening · from Old English æfnung "the coming of evening, sunset, time around sunset," verbal noun from æfnian "become evening, grow toward evening," from æfen ...
[67]
vesper, n. meanings, etymology and more | Oxford English Dictionary
OED's earliest evidence for vesper is from 1390, in the writing of John Gower, poet. vesper is of multiple origins. Partly a borrowing from Latin. Partly a ...
[68]
夕暮れ, 夕暮, ゆうぐれ, yūgure - Nihongo Master
evening,(evening) twilight - Meaning of 夕暮れ, 夕暮, ゆうぐれ, yūgure. See complete explanation and more examples and pronunciation.
[69]
'Maghrib': Arabic word for sunset marks a significant, and specific, time
Apr 14, 2023 · Ghuroob, which is also derived from those three Arabic letters, can colloquially also mean sunset, but in fact refers specifically to the action ...
[70]
e'e'aah | Navajo Word of the Day
May 4, 2012 · Your Friday, and weekend, word is e'e'aah, which means evening, sundown, sunset, or west. Navajo culture teaches that both nature and the universe are ...
[71]
How to navigate using the Sun
When it comes to sunset, the Poles are still tilted the same way as in the morning and so in midsummer the sun sets close to northwest, and in midwinter it sets ...
[72]
https://oceanwide-expeditions.com/blog/light-in-the-land-of-the-midnight-sun
[73]
Not All Sunrises are Created Equal - Farmers' Almanac
Sunrise and sunset times depend on a number of variables, including longitude, latitude, altitude, and location in relationship to your specific Time Zone.