Twilight phenomenon is produced when exhaust particles from missile or rocket propellant left in the vapor trail of a

launch vehicle A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage ...

condense, freeze, and then expand in the less dense upper atmosphere. The exhaust plume, which is suspended against a dark sky, is then illuminated by reflective high-altitude sunlight through

dispersion Dispersion may refer to: Economics and finance *Dispersion (finance), a measure for the statistical distribution of portfolio returns * Price dispersion, a variation in prices across sellers of the same item *Wage dispersion, the amount of variat ...

, which produces a spectacular, colorful effect when seen at ground level. The phenomenon typically occurs with launches that take place either 30 to 60 minutes before sunrise or after sunset when a booster rocket or missile rises out of the darkness and into a sunlit area, relative to an observer's perspective on the ground. Because rocket trails extend high into the

stratosphere The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher ...

and

mesosphere The mesosphere (; ) is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere. In the mesosphere, temperature decreases as altitude increases. This characteristic is used to define limits: it be ...

, they catch high-altitude sunlight long after the sun has set on the ground. The small particles in the expanding exhaust plume or "cloud" diffract sunlight and produce the rose, blue, green and orange colors—much like a dispersive

prism PRISM is a code name for a program under which the United States National Security Agency (NSA) collects internet communications from various U.S. internet companies. The program is also known by the SIGAD . PRISM collects stored internet ...

can be used to break light up into its constituent

spectral ''Spectral'' is a 2016 Hungarian-American military science fiction action film co-written and directed by Nic Mathieu. Written with Ian Fried & George Nolfi, the film stars James Badge Dale as DARPA research scientist Mark Clyne, with Max Marti ...

color Color (or colour in English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is the visual perception based on the electromagnetic spectrum. Though co ...

s (the colors of the

rainbow A rainbow is an optical phenomenon caused by refraction, internal reflection and dispersion of light in water droplets resulting in a continuous spectrum of light appearing in the sky. The rainbow takes the form of a multicoloured circular ...

) – thereby making the twilight phenomenon all the more spectacular. The exhaust plume may also take on a corkscrew appearance as it is whipped around by upper-level wind currents. It is typically seen within two to three minutes after a launch has occurred. Depending on weather conditions, it could remain in the sky for up to half an hour before dispersing. At

Vandenberg Space Force Base Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...

in California, more than 2,000 missiles and space boosters have been launched from the central California coastline in northern

Santa Barbara County Santa Barbara County, officially the County of Santa Barbara (), is a county located in Southern California. As of the 2020 United States census, the population was 448,229. The county seat is Santa Barbara, and the largest city is Santa M ...

since December 1958. However, only a small percentage of these launches have created the twilight phenomenon. The same is true with the

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Department of Defense. It is the world's most powerful navy with the largest displacement, at 4.5 million tons in 2021. It has the world's largest aircraft ...

's Strategic Systems Programs, which conducts

Trident II The UGM-133A Trident II, or Trident D5 is a submarine-launched ballistic missile (SLBM), built by Lockheed Martin Space in Sunnyvale, California, and deployed with the United States Navy and Royal Navy. It was first deployed in March 1990, and ...

(D5) missile test flights at sea from Ohio Class

SSBN A ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. These submarines became a major weapon system in the Cold War because of their nuclear deterrence capabil ...

submarines A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or info ...

in the Pacific Test Range off the coast of Southern California, or Kokola Point at

Barking Sands The Pacific Missile Range Facility, Barking Sands is a U.S. naval facility and airport located five nautical miles (9 km) northwest of the central business district of Kekaha, in Kauai County, Hawaii, United States. PMRF is the world's l ...

on the Hawaiian island of

Kauai Kauai (), anglicized as Kauai ( or ), is one of the main Hawaiian Islands. It has an area of 562.3 square miles (1,456.4 km2), making it the fourth-largest of the islands and the 21st-largest island in the United States. Kauai lies 73 m ...

. Some observers have wrongly assumed the missile or rocket creating the aerial spectacle must have malfunctioned or been destroyed while in flight. That belief stems from the appearance of the launch vehicle's contrail as it becomes twisted into knots by upper altitude air currents or

wind shear Wind shear (; also written windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical ...

. To date, no malfunctioning missile or rocket has been known to create the phenomenon. On the rare occasions when a missile or rocket does malfunction, it is destroyed by a

Range Safety Officer In rocketry, range safety or flight safety is ensured by monitoring the flight paths of missiles and launch vehicles, and enforcing strict guidelines for rocket construction and ground-based operations. Various measures are implemented to protect ...

before reaching the altitudes where twilight phenomenon occur. The phenomenon's appearance and intensity varies with viewer location and weather conditions—typically, clear skies with no moonlight, since cloud cover would block one's view. The phenomenon can usually be seen throughout the state of California, and as far away as

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

and

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

. On the East Coast, similar sightings were observed and reported during twilight launches of the

Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...

from

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...

, and observed after other expendable launch vehicles from the U.S. Space Force's launch complexes at

Cape Canaveral Space Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the sta ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

. Numerous nations with a space program — such as the

European Space Agency The European Space Agency (ESA) is a 23-member International organization, international organization devoted to space exploration. With its headquarters in Paris and a staff of around 2,547 people globally as of 2023, ESA was founded in 1975 ...

, the

Russian Space Agency The State Corporation for Space Activities "Roscosmos", commonly known simply as Roscosmos (), is a state corporation of the Russian Federation responsible for space flights, cosmonautics programs, and aerospace research. Originating from ...

, the China National Space Agency, Japan's

JAXA The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into o ...

, India's

ISRO The Indian Space Research Organisation (ISRO ) is India's national space agency, headquartered in Bengaluru, Karnataka. It serves as the principal research and development arm of the Department of Space (DoS), overseen by the Prime Minister o ...

and other countries have experienced the same event.

Examples

*In 2010 a contrail off the coast of Los Angeles, California led observers to believe they had seen a missile launch. *On July 7, 2010, reports of a "

UFO An unidentified flying object (UFO) is an object or phenomenon seen in the sky but not yet identified or explained. The term was coined when United States Air Force (USAF) investigations into flying saucers found too broad a range of shapes ...

" sighting forced

Xiaoshan Xiaoshan suburban district HangzhouZhejiang was formerly a city in its own right, separated by the Qiantang River from Hangzhou proper, but the municipality was annexed by its more populous neighbor in 2001. Xiaoshan has a permanent population wi ...

Airport in

Hangzhou Hangzhou, , Standard Mandarin pronunciation: ; formerly romanized as Hangchow is a sub-provincial city in East China and the capital of Zhejiang province. With a population of 13 million, the municipality comprises ten districts, two counti ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

to temporarily cease operations. A flight crew preparing for descent saw the object—suspected to be a Chinese rocket test—as a bright twinkling light apparently above the runway, and notified the

air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...

department. ATC could not locate it on radar and diverted landing flights. Eighteen flights were affected. Though normal operations resumed four hours later, the incident captured the attention of the Chinese media and sparked a firestorm of speculation on the UFO's identity. *On November 7, 2015 a bright plume of light was seen expanding then "exploding" over south California between 7-8pm. The Orange County Sheriff confirmed that it was a Trident II ballistic missile test firing from the USS Kentucky.

References

{{reflist

Video

RUS Progress MS-10 launch, as seen from the International Space Station over Baikonur, Kazakhstan
Taken by ESA astronaut Alexander Gerst, Nov. 16, 2018
SpaceX Iridium 4 launch, as seen from Alhambra, Calif.
Misrraim Sanchez YouTube video, Dec. 22, 2017
Iridium NEXT IV launch, as seen from Manhattan Beach, Calif.
Scott Gauer YouTube video, Dec. 22, 2017
SpaceX Falcon 9 Launch, Boostback, Entry Burn
Justin Foley's YouTube video, Dec. 22, 2017
SpaceX launch video from Phoenix news helicopter
Entire raw video as seen from PenguinAir Newschopper flying above Phoenix, Arizona Dec. 22, 2017
Explaining The Amazing Rocket Trail Over LA
Scott Manley's YouTube video, Dec. 24, 2017
Falcon 9 rocket launch provides spectacular view in Bakersfield
KBAK-29 Eyewitness News / KBFX-58 Fox News / BakersfieldNow.com (via YouTube), Dec. 22, 2017
Justin Majeczky's 40-second time lapse of U.S. Navy Trident II (D5) missile test, as seen from San Francisco
Vimeo, Nov. 8, 2015
Missile launch over San Francisco
YouTube video, Nov. 8, 2015
Atlas V Rocket Launch view from East Orlando, Florida
YouTube video Sept 2, 2015
Night Time Launch Of Russian Space Rocket Heading To ISS
YouTube video Feb. 15, 2014
Video of "UFO" over Xiaoshan Airport in Hangzhou, China
YouTube video July 7, 2010

External links

A photographer shot an awesome time-lapse of SpaceX’s recent rocket launch from Yuma, Arizona
The Verge, Dec. 26, 2017

Los Angeles Times, Dec. 26, 2017

Los Angeles Times, Dec. 22, 2017

Los Angeles Times, Nov. 8, 2015 (The same missile launch as seen over San Francisco)

Los Angeles Times, Nov. 8, 2015

Los Angeles Times, Nov. 8, 2015
Mystery light streaking across Bay Area skies was a test missile
SF Gate, Nov. 8, 2015
No UFO Here! Mysterious Flying Object Seen in Southern California Was Just a Missile Test
People Magazine Online, Nov. 8, 2015
Everybody lost it when a Navy missile lit up the night sky over the West Coast
Business Insider, Nov. 7, 2015
Rocket Trails at Twilight Illuminate the Sky2020 Hindsight: Whee! Ooh! Aah! Pretty!
Santa Maria Times, Sept. 23, 2005

Treebeard's Stumper Answer, Sept. 27, 2002

Goleta Air & Space Museum, July 14, 2001
Rocket Launches
Fred Bruenjes' Astronomy Stuff, June 7, 2007
Space Archive
Spaceflight

Examples

See also

References

Video

External links