The Tunguska Event

Perhaps the earliest widely-held theory for the Tunguska explosion was that the world was about to end. As the minutes passed, this theory was dropped in favour of other, less final theories, until today one is hard-pressed to find anyone who truly believes the world ended on the morning of 30 June 1908...

—Kevin Zahnle, Nature, "Leaving No Stone Unturned"

On 30 June 1908, shortly after 7 a.m., residents of the hills northwest of Lake Baikal in Siberia saw a light in the sky, nearly as bright as the sun. This was followed by a flash of light, a sound like artillery fire, and a shockwave that knocked people off their feet and shattered windows. Something had exploded in the forest near the Podkamennaya Tunguska River, with energy equivalent to 10-15 megatons of TNT (However, experiments in 2007 suggested that the blast may have actually been smaller, at "only" 3-5 megatons).

In 1921, Russian mineralogist Leonid Kulik concluded from eyewitness accounts that the explosion was from a meteorite impact. He led an expedition to the Tunguska region, hoping to find and salvage the meteor itself. Instead, they found a 50 kilometer-wide region of scorched and felled trees, with no impact crater to be found.

Today, most scientists agree that The Tunguska Event was caused by a meteoroid exploding in mid-air (similar to but larger than the Chelyabinsk meteor); there's some debate over whether the exploding space rock came from a comet or an asteroid.

Other, less credible but more interesting, theories suggest that the event was caused by: a deuterium-rich meteorite causing an all-natural thermonuclear explosion; a chunk of antimatter; a miniature black hole passing through the Earth; an Alien spacecraft exploding or discharging some alien weaponry; psychic experiments or magic rituals gone wrong; or a test run of Nikola Tesla's Death Ray.

And those are the theories that people believe in Real Life. The fictional references to Tunguska are really out there.

Sub-Trope of Historical In-Joke. Compare Roswell That Ends Well.

The Tunguska Event appears in the following works:

Anime and Manga

Rental Magica claims the Tunguska Event was a case of magical "spell contamination" - an unwanted by-product of magic use.

Comic Books

The Ultimate Marvel Ultimate Galactus miniseries revealed in the first mini (Ultimate Nightmare) that the Tunguska Incident was caused by the Vision crash-landing to Earth. He (she?) was quickly taken into Russian custody and dissected so its Organic Technology could be used to kickstart a Super Soldier project, which means no one learned about Gah Lak Tus until about a year before he was supposed to eat Earth.
- And that Tunguska explosion was said to have happened in 1904 instead of 1908. Sensing some lack of research there.
  - Sensing wrong - Word of God is that the date was moved to make it a century before the release date of the comic in 2004. Warren Ellis, as a rule, does his research.
  - It should be pointed out that 1610 isn't meant to be our universe. For instance, Lands End is at the top point of Scotland in the Ultimate universe.
A Pink Panther comic book claims it was produced by a time-travel hole which happened to open right in the middle of a nuclear rocket launch in the far future.
The Darkness V1 #12. The Tunguska incident is caused by a battle between the Angelus and the Darkness.
The short-lived "Shadowline" imprint also had the explosion as a result of a super-powered battle.
In DC Comics it was the origin of Fireball of the Young Allies, Mr Meteor of the Shadowpact (1908 version) and Red Star of the Teen Titans.
In Hellboy: "Dr Carp's Experiment", it's mentioned in passing that The Heliopic Brotherhood of Ra, an occult society, was believed to be responsible for the explosion.
In Paperinik New Adventures the Tunguska Event is caused by a meteorite made by Unobtainium. The Russian army fights the Evrons over it, but it had already been taken away by locals.
Atomic Robo ascribes to the "Tesla did it" school of thought, naturally - specifically, he used Wardenclyffe Tower to "pinch" reality in order to stop an Eldritch Abomination from manifesting. It only slowed it down.

Film

Ghostbusters:

Dr Ray Stantz: You have been a participant in the biggest interdimensional cross rip since the Tunguska blast of 1909!

In Hellboy, the event was caused by a 20-ton rock, sent to Earth by the Ogdru Jahad. This rock is vital for opening the portal to the Void.
According to the Expanded Universe of the Transformers movies, the event was caused by Shockwave's crash-landing on Earth.

Literature

Alexander Kazantsev published a sci-fi story in 1946 where the explosion was a nuclear-powered Martian spacecraft blowing up. This was likely the source of the Real Life theory that aliens were involved in the explosion; in fact, some readers confused details of the story with the actual events at Tunguska.
In Donald R. Benson's novel And Having Writ the Tunguska event was caused by an alien spaceship crashing. The novel takes place in an alternate timeline where the crew manage to land safely and then spend the next few decades changing history as a side-effect of encouraging the creation of technology that can repair their ship.
Also occurs in the novels Titan, Wizard and Demon, where it was an experiment by the habitat to see if it could hit Earth with a rock should it need to destroy us.
Ebenezar McCoy is implicated for this in one of The Dresden Files books. He probably used an actual asteroid, too; doing so is within his capacity.
Spider Robinson's Callahan's Crosstime Saloon proposed that Tesla's Death Ray caused the event.
In Thomas Pynchon's Against the Day, the event is implied to be connected to Tesla's experiments and/or something invading from Another Dimension and/or a Cosmic Horror unleashed from Under The Earth; it's all a bit confusing.
- Pynchon, confusing? Surely you jest!
  - He'll probably give a perfectly reasonable explanation in his next interview.
In David Brin's Earth, the event was a very small black hole falling into the earth. Which may or may not have been artificially created by aliens to destroy the world before humanity could become a threat. The black hole is more of a MacGuffin, in that it's never resolved where it came from.
- The quantum black hole theory is also the prevailing belief in Larry Niven's Known Space.
The Strugatsky Brothers in their Monday Begins on Saturday had one character put forth a theory that the event was caused by the crash-landing of an alien spacecraft that moved backwards in time (compared to our own). To simplify it, from our perspective, the event was caused by the spacecraft taking off, so there was nothing there afterward. Instead, the humans had to check what was located on that spot before the event (i.e. in the alien's future).
In the Doctor Who Past Doctor Adventures novel Wages of Sin, the Third Doctor takes his companions Liz and Jo back in time to watch the Tunguska event; they become entangled in contemporary Russian politics, but there's nothing weird about the event itself, which is just a meteoroid—as far as they know. In the New Adventures novel Birthright, featuring the Seventh Doctor, the event turns out to have been caused by a TARDIS exploding.
In the Star Trek novel Strangers from the Sky, while the Tunguska explosion was cause by a meteorite impact, it turned out that a Vulcan exploration ship, which had been observing the Earth, had changed the trajectory of the meteorite, which would otherwise have hit a densely populated area of the Earth and wipe out most of human civilization.
In Kage Baker's The Company Novels, a defective Immortal claims responsibility for the event, saying that he found that using time travel in a manner other than the series' standard Stable Time Loop method will punch holes in the fabric of reality. He also claims to have wiped out the dinosaurs. It isn't clear if this is the truth, though; he might've been lying, or just completely insane.
In Stanislaw Lem's The Star Diaries, time-traveling scientists try to straighten the Earth's axial tilt to make the climate more even. However, they screw it up, the machine they use explodes, and a piece of debris causes the Tunguska Event.
William Barton and Michael Capobianco wrote the 1995 Sherlock Holmes short story "The Adventure of the Russian Grave" in which Professor Moriarty's only canonical mathematical paper, The Dynamics Of The Asteroid, is a Batman Gambit designed to engage Holmes' love of mysteries. It is a trap intended to bring him and Watson to Tunguska on that day at that time. When Holmes realizes this, he and Watson run for their lives, barely making it out alive. (This appears to be a Shout-Out to Isaac Asimov's 1985 "Black Widowers" short story "The Ultimate Crime", although Asimov's story does not specifically mention Tunguska by name.)
In Julian May's Intervention, the crash landing alien spaceship version is used. When real aliens visit the site on the centennial of the event, it is widely believed to be a hoax.
In The Mystery of Urulgan by Kir Bulychev, Professor Mueller alludes to the Tunguska Event when he is talking with Veronica about meteors.
In Leviathan, Nikola Tesla caused the explosion by using his Death Ray, Goliath. He wishes to use this weapon to stop the war. Subverted in that it doesn't work. The explosion at Tunguska was actually caused by an asteroid like in real life, and Tesla was only testing Goliath at the same time and ended up believing that he caused the explosion.
In the Superman/Batman novel Enemies and Allies, Lex Luthor's Russian allies have a large kryptonite-bearing meteorite implied to be the Tunguska rock. The radiation has horribly deformed the trees and wildlife around the area, and does the same to humans.
In Alice, Girl from the Future, it is stated that the first attempt in time travel involved a kitten who became the Tunguska Event. A later novel, though, has two researches traveling to see it and finding it a natural phenomenon.
In the Jacek Dukaj's science-fiction/alternative history book entitled Ice (polish: "Lód") Tunguska Event caused dramatic change of the laws of physics.

Live Action TV

Not sure if the event itself was supposed to have something to do with the ultimate alien arc, but there's an episode of The X-Files called "Tunguska", which takes place there.
- It was implied the event had to with the ultimate alien arc, yes. Though it was never adequately explained what exactly had happened.
  - If I recall correctly, it was implied (if not outright stated) to be a meteor strike, the meteor in question containing some of the Black Oil, which was used by the Russian counterpart to the Syndicate.
Doctor Who - Henry van Statten, scavenger of alien tech, claims to have found the cure for the common cold in "the Russian crater".
The Tunguska Event is mentioned by Sulu in an episode of Star Trek: The Original Series as a comparison to a similar event that befalls the crew. Kirk responds, "If I wanted a Russian history lesson, I would have brought Mr. Chekov."

Music

In the music video for Metallica's "All Nightmare Long", the Tunguska Event is the source of alien spores that reanimate the dead, allowing the USSR to conquer America via a mini-Zombie Apocalypse.

Tabletop Games

The Call of Cthulhu (tabletop game) main rules hint that the event may have been caused by someone summoning Azathoth to the area.
- The adventure The Spawn of Azathoth specifies: It was caused by a Seed of Azathoth entering the Earth's atmosphere. The Seed was thrown off by the Spawn of Azathoth (AKA Nemesis) circling the Solar System outside the orbit of Pluto.
A sidebar in one of the books for Promethean: The Created describes a Promethean obsessed with studying the mysteries of the Divine Fire who attempted to summon an arch-qashmal, a being made up of the very energy that powers the universe. Those who last talked to him saw him in the vicinity of Tunguska in 1908...
- In the Hunter: The Vigil sourcebook Witch Finders, the Knights of St. George credit the Tunguska Event to one of their number trying to summon a "faceless angel", one of the entities they secretly worship. Who's right is, as always, up to the Storyteller.
  - "Who's right?" Both of them are. They're obviously the same person.
  - Or it was the mother of all coincidences. "Oh, hey, Frankie-boy. What brings you here?" "Oh, summoning an incredibly powerful creature of the Divine Fire." "Seriously? 'Cause I'm here to call on this weird eldritch abomination thing from the Abyss. What're the odds?" "Would you mind waiting a few hours? I'm not sure how they'll react." "Sorry, Frankie. Ritual started seven hours and five minutes ago. Can't stop it or things will go really" [BOOOOOOM]
  - While the theory that a Promethean had infiltrated or even sincerely joined the Knights of St. George has fascinating potential, the premise upon which the theory is built is wrong. In the strictest sense, the Knights don't really worship the Faceless Angels so much as the exact opposite: they kill "dragons", i.e. supernatural creatures, in an attempt to make sure the Faceless Angels never have their attention drawn to Earth again. Witch Finders actually states that the Tunguska Event was a failure on the part of the Knights, as in something else drew the Angels' attention and they failed to prevent it. Really, the two explanations line up perfectly.
In the GURPS worldbook Black Ops, the event was caused by the spaceship of The Greys crashing.
- Infinite Worlds claims that it was caused by a sliver of a black hole, don't think too hard about that one.
In Necessary Evil for Savage Worlds the event is caused by a Protean speceship.
One of the old Shadowrun gamebooks contains a shadowtalk reference, apparently from one of the immortal elves, which claims they were actually trying to hit a comet with the asteroid that struck Tunguska. Given the conspiracy-theory-obsessed tone of the conversation, this was probably a joke, if not a deliberate Lampshading of early Shadowrun writers' own tendency to trace far too much of real-world past history to the meddlings of immortal elves and/or dragons.
In Ex Tempore, it was caused by an experiment by the Strigae.
In the 5th edition Champions supplement "The Mystic World", we learn that a cabal of evil sorcerors/ritual magicians teamed up to drop the magical equivalent of a tacnuke onto Earth's Archmage. He lived in the Tunguska region, see the top of this page for the outcome.

Video Games

This popped up at the end of Assassin's Creed, when you get into the files of the Ancient Conspiracy, it lists a whole bunch of famed artifacts and strange incidents that actually turns out to be connected to, stolen by, or caused by said Conspiracy. Including the Tunguska Incident which was, apparently, the explosion of a covert laboratory under their control, conducting research on some kind of alien artifact - which, predictably, blew up in their face.
- Expanded in the sequel, which The Truth segments confirm that it was really caused by Tesla's Death Ray that he used to blow up Piece of Eden 34, the Staff, at the Assassin Order's request.
  - Expanded on even further in the comic book spinoff, Assassin's Creed: The Fall, where it turns out it might have been a bit more complicated than that... The protagonist's ancestor was an Assassin sent to retrieve the Staff from Tesla's lab. It's not clear who, if anyone, actually wanted it destroyed
In Impossible Creatures, the Tunguska Event was actually the birth of the Sigma Technology; the machine that combines animals
In Secret Files: Tunguska, the explosion was of alien origin, and its remains are used in research for mind-controlling machine.
In Destroy All Humans! 2, the Tunguska Event turned out to be a crashed Blisk ship.
From what players have pieced together using clues left in the levels, the Nazi Zombies problem from the bonus stages of Call of Duty: World at War seem related to a meteor impact in Tunguska.
The Chimera from the Resistance series crashed on Earth in the event, and dominated the isolated Russian Empire by the 1940s. It Got Worse from there.
One of Civilization 4's modern-era random events is a mysterious explosion that takes out an arctic forest in your territory in a recreation of the Tunguska Event. It's quite useful, since your scientists are better motivated to explore space and prevent similar meteorite impacts, boosting your production speed of the Apollo Program and laboratories.
In Game Mod Red Alert 3 Paradox, the event was a meteorite impact and research on its material left granted the Soviets their magnetic weaponry.
In Crysis during a spied on conversation between a scientist and a Korean General, pieces of alien artifacts are mentioned to have been found in Tunguska, in the sequel it is confirmed, that Jacob Hargreave stole the Nanosuit technology from the Aliens (apparently a scouting troop) during or after the Tunguska event. The last piece in the Nanosuit 2's chemical processes is called the Tunguska Iteration.

Web Comics

Schlock Mercenary's UNS battleplates - the biggest, baddest, mobile space battle fortresses in the terrestrial fleet - were ostensibly designed to protect against asteroid impacts. They are named for places on Earth subjected to such impacts. The one that Big Bad General Xinchub uses as a flagship for a while is named Tunguska, nicknamed "Gus" for purposes of interacting with the AI. It blew up good -- turns out horribly abusing gravitics to show off in the presence of dark matter aliens that dwarf even your impossibly immense ship and are annoyed by the use of gravitics is a bad idea.

Web Original

In Zoofights 4, the Tunguska Event was actually a Cthulhu-esque alien crashing to Earth. In Zoofights tradition, they welded a bunch of armor plates to it and gave it two assault cannons and a rocket launcher. Oh, and it's also obsessed with the Soviet National Anthem and goes berserk if the boombox that plays it 24-7 is ever stopped.

Western Animation

In Teen Titans, it was part of the origin of Red Star.