From Wikipedia, the free encyclopedia

A doomsday event is a specific occurrence which has an exceptionally destructive effect on the human race.^[1] The final outcomes of doomsday events may range from a major disruption of human civilization, to the extinction of human life, to the destruction of the planet Earth, to the annihilation of the entire universe.

A 2006 poll by SciFi.com revealed that virtually all Americans believed that some sort of doomsday scenario could realistically impact the human race, and that many feel that such a scenario is likely to be man-made.^[2]

Contents 1 Scenarios 2 See also 3 Notes 4 External Links

Doomsday events may include:

• Natural occurrences such as

• a global pandemic^[3]

• a geological event such as massive flood basalt volcanism or the eruption of a supervolcano.^[4] One such event, the Toba Eruption, occurred in Indonesia about 71,500 years ago. According to the Toba catastrophe theory, the event may have reduced human populations to only a few tens of thousands of individuals.

• a gamma ray burst or other devastating blast of cosmic radiation.^[5] One especially deadly hypothesized source is a hypernova, produced when a hypergiant star explodes and then collapses, sending vast amounts of radiation sweeping across hundreds or even thousands of lightyears of space. Hypernovae have never been observed; however, a hypernova may have been the cause of the Ordovician-Silurian extinction events. The nearest hypergiant is Eta Carinae, approximately 8000 lightyears distant.

• an abrupt reorientation of Earth's axis of rotation.^[6]

• a drastic increase or decrease in the Sun's energy output

• an impact event caused by the collision of a large meteoroid, asteroid, or comet with Earth. A common theory postulates that the extinction of the dinosaurs occurred approximately 65 million years ago as a result of the Cretaceous-Tertiary extinction event when a large asteroid struck the earth, producing atmospheric dust which blocked solar energy and caused a significant lowering of temperatures worldwide. Evidence for this theory includes a sedimentary layer of iridium in the geological record and a large crater in the area of Chicxulub, Mexico.

• a sudden change in the physical constants governing the universe, such as that created by a Vacuum metastability event^[7]

• the effect of a black hole on the planet Earth.^[8]

• a universal Big Rip or Big Crunch ("Gnab Gib")

• Non-natural events such as:

• the creation of a black hole on or close to Earth^[9]

• a nuclear or biological war

• a cybernetic revolt

• a grey goo inundation

• alien invasion

• Supernatural occurrences such as:

• an act of divine retribution or the Last Judgment. Many religions include beliefs pertaining to the end of time. The Norsemen believed that the world would end in a tremendous battle of the gods known as Ragnarok. In the Christian Bible, the Book of Revelation describes Armageddon, a final battle between the forces of God and the forces of Satan.

In recent human history, the Tunguska event (1908), the Spanish Flu pandemic (1918-19), the atomic bombings of Hiroshima and Nagasaki (1945) and the Chernobyl disaster (1986) stand out as stark reminders that larger-scale events of these kinds are real possibilities.

• Apocalyptic fiction
• Apocalyptic literature
• Doomsday
• Doomsday clock
• Doomsday device
• Doomsday Equation
• Doomsday film
• End of civilization
• End of the world
• Extinction event
• Heinz von Foerster
• Human extinction
• Societal collapse

1. ^ This definition of the expression "doomsday event" is directly derived from compounding the meanings of the adjective "doomsday" and noun "event":
   • Wiktionary defines doomsday (adj) as "concerned with or predicting future universal destruction" or "capable of causing widespread or total destruction" and defines event (noun) as "an occurrence of social or personal importance," with occurrence (noun) defined in turn as "actual instance where a situation arises." (Retrieved Nov. 18, 2006)
   • Random House Webster's Unabridged Electronic Dictionary (1989-1996) defines "doomsday" (adj) as "given to or marked by forebodings or predictions of impending calamity" and "capable of causing widespread or total destruction" and defines "event" (noun) as "something that happens or is regarded as happening; an occurrence, esp. one of some importance" or "something that occurs in a certain place during a particular interval of time."
2. ^ The Doomsday Poll. SciFi.com (2006).
3. ^ "Pandemic". Horizon. BBC. BBC Two. 2006-11-07.
4. ^ USGS Frequently Asked Questions: "What would happen if a 'supervolcano' eruption occurred again at Yellowstone?". U.S. Geological Survey (2005).
5. ^ Wanjek, Christopher (2005-04-06). Explosions in Space May Have Initiated Ancient Extinction on Earth. NASA.
6. ^ Wilford, John Noble (2006-10-12). Study Links Extinction Cycles to Changes in Earth’s Orbit and Tilt.
7. ^ S. Coleman and F. De Luccia (1980). "Gravitational effects on and of vacuum decay". Physical Review D21: 3314. 
8. ^ Black Holes: The Deadliest Force in the Universe. ABC News (2006-08-28).
9. ^ Leake, Jonathan (1999-07-18). "Big Bang machine could destroy Earth". Sunday Times. 

• Countdown to Doomsday with Today Show Host Matt Lauer. SciFi.com (2006).
• Exit Mundi, a collection of doomsday scenarios