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Twilight phenomenon

{{Short description|Weather phenomenon associated with rocketry}}

Image:TwilightPhenom.jpg site in northern Santa Barbara county) lights up the night sky over Vandenberg Air Force Base following the launch of a Minuteman III missile September 19, 2002 (Official USAF Photo by Dennis Fisher, 30th Communications Squadron)]]

File:Twilight_phenomenon_in_the_wake_of_a_Minotaur_I_launch_from_Vandenberg_AFB,_CaIif.jpg

Twilight phenomenon is produced when exhaust particles from missile or rocket propellant left in the vapor trail of a launch vehicle 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, 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 can be used to break light up into its constituent spectral colors (the colors of the rainbow) – thereby making the twilight phenomenon all the more spectacular.{{Cite web|url=https://www.afspc.af.mil/News/Article-Display/Article/251865/twilight-phenomenon-lights-up-sky/|archive-url=https://web.archive.org/web/20181010174356/https://www.afspc.af.mil/News/Article-Display/Article/251865/twilight-phenomenon-lights-up-sky/|url-status=dead|archive-date=October 10, 2018|title = Twilight phenomenon lights up sky}}

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 in California, more than 2,000 missiles and space boosters have been launched from the central California coastline in northern Santa Barbara County 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's Strategic Systems Programs, which conducts Trident II (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 on the Hawaiian island 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. 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 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, Nevada and Utah. On the East Coast, similar sightings were observed and reported during twilight launches of the Space Shuttle from NASA's Kennedy Space Center, and observed after other expendable launch vehicles from the U.S. Space Force's launch complexes at Cape Canaveral Space Force Station in Florida.

{{external media

|video1 = [https://www.youtube.com/watch?v=uByWR5edPKk Time-lapse of rocket exhaust above the Sea of Japan in the evening of December 9, 2022.]

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Numerous nations with a space program — such as the European Space Agency, the Russian Space Agency, the China National Space Agency, Japan's JAXA, India's ISRO and other countries have experienced the same event.

Examples

File:Twilight Phenomena Infographic.png

  • In 2010 a contrail off the coast of Los Angeles, California led observers to believe they had seen a missile launch.{{cite news | first=Maggie | last=McKee | title=Mystery 'missile' likely a jet contrail, says expert | date=2010-11-09 | publisher=New Scientist | url=https://www.newscientist.com/article/dn19704-mystery-missile-likely-a-jet-contrail-says-expert.html | accessdate=2010-11-10 | archiveurl=https://web.archive.org/web/20101110210639/http://www.newscientist.com/article/dn19704-mystery-missile-likely-a-jet-contrail-says-expert.html | archivedate=2010-11-10 | url-status=live }}
  • On July 7, 2010, reports of a "UFO" sighting forced Xiaoshan Airport in Hangzhou, China to temporarily cease operations.{{Cite web

|url = http://www.nationalledger.com/ledgerdc/article_272633158.shtml

|title = China Airport UFO - Mystery or Military?

|work = National Ledger

|date = July 10, 2010

|accessdate = July 11, 2010

|url-status = dead

|archiveurl = https://web.archive.org/web/20100713134301/http://www.nationalledger.com/ledgerdc/article_272633158.shtml

|archivedate = July 13, 2010

}} 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 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.{{Cn|date=April 2024}}

  • 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.{{Cite web|title = Mystery Light in Southern California Sky Sparks Anxiety - CNN.com|url = http://www.cnn.com/2015/11/08/us/southern-california-navy-test-mystery-light/index.html|website = CNN|date = 8 November 2015|accessdate = 2015-11-08}}

See also

References

{{reflist}}

Video

  • [https://www.youtube.com/watch?v=DXyffXoq9_8 RUS Progress MS-10 launch, as seen from the International Space Station over Baikonur, Kazakhstan] Taken by ESA astronaut Alexander Gerst, Nov. 16, 2018
  • [https://www.youtube.com/watch?v=c4Xpu-jN6gw SpaceX Iridium 4 launch, as seen from Alhambra, Calif.] Misrraim Sanchez YouTube video, Dec. 22, 2017
  • [https://www.youtube.com/watch?v=EFrFe4MKfco Iridium NEXT IV launch, as seen from Manhattan Beach, Calif.] Scott Gauer YouTube video, Dec. 22, 2017
  • [https://www.youtube.com/watch?v=UU5KpfOT-_Y SpaceX Falcon 9 Launch, Boostback, Entry Burn] Justin Foley's YouTube video, Dec. 22, 2017
  • [https://www.youtube.com/watch?v=QHYx-ueq0Kg SpaceX launch video from Phoenix news helicopter] Entire raw video as seen from PenguinAir Newschopper flying above Phoenix, Arizona Dec. 22, 2017
  • [https://www.youtube.com/watch?v=CJ6nn8fZOmc Explaining The Amazing Rocket Trail Over LA] Scott Manley's YouTube video, Dec. 24, 2017
  • [https://www.youtube.com/watch?v=JRzZl_nq6fk Falcon 9 rocket launch provides spectacular view in Bakersfield] KBAK-29 Eyewitness News / KBFX-58 Fox News / BakersfieldNow.com (via YouTube), Dec. 22, 2017
  • [https://vimeo.com/145029572 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
  • [https://www.youtube.com/watch?v=3bYcLEdank4 Missile launch over San Francisco] YouTube video, Nov. 8, 2015
  • [https://www.youtube.com/watch?v=Td0CPo-J2jo Atlas V Rocket Launch view from East Orlando, Florida] YouTube video Sept 2, 2015
  • [https://www.youtube.com/watch?v=XeWMonmz9mU Night Time Launch Of Russian Space Rocket Heading To ISS] YouTube video Feb. 15, 2014
  • [https://www.youtube.com/watch?v=j3Cm85DWisM Video of "UFO" over Xiaoshan Airport in Hangzhou, China] YouTube video July 7, 2010

External links

  • [https://www.theverge.com/2017/12/26/16820028/jesse-watson-photographer-time-lapse-spacexs-falcon-9 A photographer shot an awesome time-lapse of SpaceX’s recent rocket launch from Yuma, Arizona] The Verge, Dec. 26, 2017
  • [http://www.latimes.com/local/lanow/la-me-ln-spacex-launch-dashcam-crash-20171226-story.html Dashcam video shows three-car crash as freeway drivers brake for SpaceX rocket launch] Los Angeles Times, Dec. 26, 2017
  • [http://www.latimes.com/local/lanow/la-me-space-x-sky-20171222-story.html What was that light in the sky? SpaceX Falcon 9 launch offers dramatic show over L.A.] Los Angeles Times, Dec. 22, 2017
  • [http://www.latimes.com/local/california/la-me-ln-navy-test-fire-20151107-html-htmlstory.html Light from Navy test fire courses across the Southern California and Arizona sky] Los Angeles Times, Nov. 8, 2015 (The same missile launch as seen over San Francisco)
  • [http://www.latimes.com/local/lanow/la-me-ln-mystery-lights-above-l-a-bring-fear-anger-and-questions-20151108-story.html Mystery light above L.A. brings fear, anger and questions] Los Angeles Times, Nov. 8, 2015
  • [http://www.latimes.com/local/lanow/la-me-ln-missile-test-20151108-story.html UFO scares are the price we pay for secret missile tests, expert says] Los Angeles Times, Nov. 8, 2015
  • [http://www.sfgate.com/bayarea/article/Mystery-light-streaking-across-Bay-Area-skies-was-6617835.php Mystery light streaking across Bay Area skies was a test missile] SF Gate, Nov. 8, 2015
  • [http://www.people.com/article/ufo-los-angeles-san-diego-california-navy-missile-test No UFO Here! Mysterious Flying Object Seen in Southern California Was Just a Missile Test] People Magazine Online, Nov. 8, 2015
  • [http://www.businessinsider.com/bright-light-in-the-sky-west-coast-2015-11 Everybody lost it when a Navy missile lit up the night sky over the West Coast] Business Insider, Nov. 7, 2015
  • [http://scribol.com/science/rocket-trails-at-twilight-illuminate-the-sky Rocket Trails at Twilight Illuminate the Sky]
  • [http://www.tomsfotos.com/travel/rocket-twilight-phenomenon.html Rocket Twilight Phenomenon]
  • [http://www.2020hindsight.org/2005/09/22/whee-ooh-aaah-pretty/ 2020 Hindsight: Whee! Ooh! Aah! Pretty!]
  • [http://santamariatimes.com/news/local/rocket-puts-on-streak-show/article_20e2ec36-3fa2-5329-befd-1166bea98d72.html Rocket puts on "Streak" show] Santa Maria Times, Sept. 23, 2005
  • [http://www.rain.org/~mkummel/stumpers/27sep02a.html National Defense Light Show] Treebeard's Stumper Answer, Sept. 27, 2002
  • [http://www.air-and-space.com/20010714%20VAFB%20Minuteman-II.htm Minuteman-II launch from Vandenberg AFB] Goleta Air & Space Museum, July 14, 2001
  • [http://www.moonglow.net/ccd/pictures/rocket/ Rocket Launches] Fred Bruenjes' Astronomy Stuff, June 7, 2007
  • [http://www.spacearchive.info/ Space Archive]
  • [http://www.socal-skylights.org/sky_vandenberg.html SoCal SkyLights]

Category:Spaceflight