A twilight phenomenon is produced when exhaust particles from missile or rocket propellant left in the

vapor trail Contrails (; short for "condensation trails") or vapor trails are line-shaped clouds produced by aircraft engine exhaust or changes in air pressure, typically at aircraft cruising altitudes several miles above the Earth's surface. Contrails ar ...

of a

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and ...

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 and mesosphere, 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 usually refers to: * Prism (optics), a transparent optical component with flat surfaces that refract light * Prism (geometry), a kind of polyhedron Prism may also refer to: Science and mathematics * Prism (geology), a type of sedimentary ...

can be used to break light up into its constituent

spectral ''Spectral'' is a 2016 3D military science fiction, supernatural horror fantasy and action-adventure thriller war film directed by Nic Mathieu. Written by himself, Ian Fried, and George Nolfi from a story by Fried and Mathieu. The film stars ...

color Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are assoc ...

s (the colors of the

rainbow A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows c ...

) – 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 AFB 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 th ...

in California, more than 1,800 missiles and space boosters have been launched from the central California coastline in northern

Santa Barbara County Santa Barbara County, California, officially the County of Santa Barbara, is located in Southern California. As of the 2020 census, the population was 448,229. The county seat is Santa Barbara, and the largest city is Santa Maria. Santa Barba ...

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 Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...

's Strategic Systems Programs, which conducts

Trident II A trident is a three- pronged spear. It is used for spear fishing and historically as a polearm. The trident is the weapon of Poseidon, or Neptune, the God of the Sea in classical mythology. The trident may occasionally be held by other marine ...

(D5) missile test flights at sea from Ohio Class SSBN submarines 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 larg ...

on the

Hawaiian island The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Ku ...

of Kauai. 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 (or 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 or horizont ...

. 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 the field of rocketry, range safety may be assured by a system which is intended to protect people and assets on both the rocket range and downrange in cases when a launch vehicle might endanger them. For a rocket deemed to be ''off course' ...

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 ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

Nevada Nevada ( ; ) is a state in the Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the 7th-most extensive, ...

and

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

. 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 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. Its official program ...

from

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

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 National Aeronautics and Space Administration's (NASA) ten field centers. Since December 1968 ...

, and observed after other expendable launch vehicles from the

U.S. Space Force The United States Space Force (USSF) is the space service branch of the U.S. Armed Forces, one of the eight U.S. uniformed services, and the world's only independent space force. Along with its sister branch, the U.S. Air Force, the Space ...

'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 statio ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

. Numerous nations with a space program — such as the European Space Agency, the

Russian Space Agency The State Space Corporation "Roscosmos" (russian: Государственная корпорация по космической деятельности «Роскосмос»), commonly known simply as Roscosmos (russian: Роскосмос) ...

, the China National Space Agency, Japan's JAXA, India's ISRO and other countries have experienced the same event.

Examples

*In 2010 a

contrail Contrails (; short for "condensation trails") or vapor trails are line-shaped clouds produced by aircraft engine exhaust or changes in air pressure, typically at aircraft cruising altitudes several miles above the Earth's surface. Contrails ar ...

from an airplane in California had people believing they had seen a missile launch. *On July 7, 2010, reports of a "

UFO An unidentified flying object (UFO), more recently renamed by US officials as a UAP (unidentified aerial phenomenon), is any perceived aerial phenomenon that cannot be immediately identified or explained. On investigation, most UFOs are id ...

" sighting forced

Xiaoshan Xiaoshan is one of ten urban districts of the prefecture-level city of Hangzhou, the capital of Zhejiang Province, East China. Xiaoshan was formerly a city in its own right, separated by the Qiantang River from Hangzhou proper, but the municipal ...

Airport in

Hangzhou Hangzhou ( or , ; , , Standard Mandarin pronunciation: ), also romanized as Hangchow, is the capital and most populous city of Zhejiang, China. It is located in the northwestern part of the province, sitting at the head of Hangzhou Bay, whic ...

, China 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 airs ...

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