According to The Other Wiki, a solar flare is a flash of brightness on the sun's surface that causes a sudden release of energy. In Real Life, these are quite common, and (generally) only pose a hazard to astronauts in space. While some potential dangers exist from solar flares on Earth, for the most part, they haven't caused any serious trouble in recent times.note
In fiction, an easy way to cause some sort of disaster is to have a solar flare kickstart the problem. The flare is usually shown as a layer of the sun itself coming off of it and frying anything unfortunate enough to be caught in its path.note In other works, perhaps the flare causes magnetic poles of a planet to flip, which causes all sorts of trouble, either by causing it to become geologically unstable, or ruining every electronic device. In other works, some power coming from the flare causes the dead to rise/machines to come alive/everyone to hang the toilet paper under the roll.
Generally though, in fiction: Flare + Some hapless target = Bad Things Happening.
Of course, Space Is Big and Earth is a very small target. To cause The End of the World as We Know It in real life, a coronal mass ejection would not only have to be traveling in the right direction, but also have the correct vertical orientation relative to Earth's magnetic field in order to be channeled by it rather than blocked. However, the Anthropic Principle naturally dictates that these requirements are met for this form of the trope to take place.
Compare Lightning Can Do Anything, which is another trope of a naturally occurring event causing wonky things to happen. Compare with Star Killing, a larger example where the star is destroyed intentionally to cause disasters.
- Defied in the first chapter of Bait and Switch. The USS Bajor is on a survey mission and is studying a star when they detect a coronal mass ejection. They power up the engines and get out of the way well ahead of time.
- Strange Times Are Upon Us: Brokosh et al. set off a solar flare to destroy a couple Breen warships, but accidentally hit Earth with it, which causes the solar storm of 1859.
- Shows up in Larry Niven short stories:
- "Flare Time" is about one of these. It's about how regular solar flares force the Earth colonists to take shelter and cause Medusa's native life forms to come out of hiding.
- Inconstant Moon: The protagonist initially believes that the sun has gone nova and the world is going to end, but realizes that that can't be the case or it would have finished ending already. Instead, the solar flare just killed everything on the side of the planet facing it.
- In The Maze Runner Trilogy, solar flares and a pandemic that followed led the the demise of civilization, save for a few bases here and there.
- In James A. Michener's Space, a solar flare interrupts the Apollo 18 mission while two astronauts are on the moon. They're both killed; the third astronaut escapes in the command module.
- In Shea and Wilson's Illuminatus!, the disaster that destroyed legendary Atlantis is due to an artificially induced solar flare brought about by an embittered Moral Guardian.
- Suspected to be the case why Mulolowa is barren in Junction Point, as it still has an oxygenated atmosphere despite being lifeless.
- A recurring plot element in the Rihannsu novels is a Romulan-developed technique called "Sunseed", in which a starship can cause a star to produce a directed solar storm of variable yield that can also affect subspace multiple light-years away.
- In My Enemy, My Ally, this is initially used to temporarily blind a Starfleet task force's sensors, covering the Romulan capture of the Vulcan-crewed USS Intrepid. After attacking the Romulan base where the crew is being held, the Enterprise, Intrepid, and the friendly Romulan ship ChR Bloodwing use Sunseed to destroy some of their pursuers.
- Scotty's subplot in The Empty Chair concerns efforts to render Sunseed useless as a military tactic, eventually leading him to use Eisn, the primary of the Romulan home system, to defeat a Romulan attempt to destroy Earth with a Sunseed-derived technology. Early in the book the Romulan Grand Fleet also tries to glass the rebelling colony of Artaleirh by making their sun produce a solar flare, but the Klingons throw a Spanner in the Works.
- The Sword of the Spirits trilogy by John Christopher is apparently set in a medieval society that's arisen after a nuclear war has caused machine technology to be banned. It's later revealed that the disaster was caused by an increase of radiation from solar flares; thanks to Future Imperfect the descendents assumed this as the surviving literature all spoke of fear of nuclear armageddon.
- In Till the Blood Runs Clear solar flares in one system allow Crichton's pod to enter unstable wormholes. However, it needs repairs and the mechanic states that it'll be four years before the flares come again a later episode reveals she was lying.
- In Suns And Lovers solar flares have destroyed two trade stations in a system, and now the third and last of them is threatened. And it turns out that a cult which worshiped the system's star and considered the trade stations blasphemous found a way to "attract" solar flares. The solution is one of the funniest scenes in the series.
- In the Star Trek: Deep Space Nine episode "Shadows and Symbols" the IKS Rotarran uses its tractor beam to cause a solar eruption and destroy a Dominion shipyard.
- The Nova episode "Secrets of the Sun" analyzes the physics and behavior of the Sun in detail, including the potential damage a coronal mass ejection could do to Earth's electric grid.
- Doctor Who. A recurring issue in the series.
- "The Rebel Flesh" has it being a common problem in the 22nd century because of unknown reasons. One kickstarts the plot and causes the clones to become sentient.
- "The Beast Below" has them the reason being why the UK (and other nations) had evacuated to the stars.
- The Fourth Doctor finds humans in an ark in the episode "The Ark in Space" due to flares making the Earth dangerous to live on.
- "In the Forest of the Night" has the Earth about to be incinerated by a truly massive solar flare, thankfully the day is saved thanks to a psychic child and some trees. Apparently this has happened before, as anomalous tree rings reveal.
- A solar storm plays havoc with the defenses of the bank of Karabraxos in "Time Heist" causing the Doctor to realize that the heist was planned out by someone with knowledge from the future. Eventually, the solar storm incinerates the bank and perhaps the entire world of Karabraxos.
- Subversion in "Bad Wolf" - a solar flare causes a brief disturbance for the Game Station, enough for the human controller wired into the system to briefly regain sentience and give the Doctor vital information.
- A variation has occurred in Star Trek: The Next Generation a couple of times, in which starships will create solar flares to destroy enemy ships, including by Klingon commander Kurn in the episode "Redemption", and by the Enterprise, manned by a skeleton crew, in the episode "Descent".
- The episode "Up the Long Ladder" had the plot kicked off when a colony was rendered uninhabitable by solar flares.
- In one episode of Smallville a coronal mass ejection causes Clark's powers to go haywire, alternately activating at random and failing to activate at all, and nearly leading to him being unmasked by a paparazzi passing through town. From this Pete guesses that Clark's abilities are powered by the Sun.
- Stargate SG-1 and Stargate-verse:
- Solar Flares firing up in the route of a Stargate's wormhole can lead to time travel, with three instances of this (the SG-1 episode "1969", the Atlantis episode "The Last Man" and the "Continuum" Direct-to-Video film) affecting the cast directly. It's also used in "2010" to send a message back in time through the gate.
- Also the Atlantis episode "Echoes" has the Atlantis Expedition dealing with a coronal mass ejection (for once, referred to as such rather than a flare) that will completely fry the planet Atlantis is on.
- On The 100, solar flares are a regular problem for people onboard the Ark space station. Ironically, it turns out that, though they've been living in space in order to avoid the radioactive fallout on Earth, they've actually absorbed more radiation, thanks to solar flares, than they would have if they'd returned to the Ground.
- Sid Meierís Alpha Centauri: Played realistically. Flares will just disrupt communications with other civs for a set period of time, opposed to frying the surface. However, atrocities will be kept secret.
- Humanity is barely surviving in the future of A New Beginning thanks to ecological mismanagement turning the world into a wasteland and soon, the last dregs will be wiped out by a solar flare without the ozone layer to protect them.
- In Ciel nosurge, Ra Ciela's sun, Bezel, is dying. It occasionally gives off powerful flares called Wave Bursts, which travel towards Ra Ciela and kill anyone unfortunate enough to be caught in the blast. Justified because Bezel has already reached its red giant phase* and excepting for an area in the north pole protected by an electromagnetic shield and dome, the planet has been fried by the radiation, as the Ra Ciela's own electromagnetic field is already unable to deflect the flares.
- Assassin's Creed. The First Civilization was wiped out when a solar flare hit Earth and caused it to become geologically unstable. The driving goal for the goals up until after III are to stop it from having a second go on the planet.
- Starflight. Solar flares are occurring all over the sector the game is set in, causing entire worlds to be wiped out and is part of the driving motive to search for planets to colonize. Investigating ruins on Earth show that this happened in the distant past as well. The cause of the flares then and now are shown to be the Ancients, who are destroying other sentient life out of self-defense, because the latter thinks they are just starship fuel rather than sentient beings.
- In FTL: Faster Than Light, you may randomly warp near a star which periodically bleches out solar flares. Each time this happens, it starts fires inside your ship. Depending on your ability to keep up with the fires and where they appear, this can range from a minor annoyance to a crippling drawback.
- One of the random events in RimWorld is a solar flare that knocks out all electrical devices for about a day or so.
- Due to a 'geomagnetic event', absolutely nothing electric in nature works in The Long Dark.
- In Cookie Clicker, one possible golden cookie effect is "solar flare", which temporarily boosts your cookie production speed by 10 percentage points per each prism owned.
- Treasure Planet: Battle at Procyon: Solar Flares happen periodically on maps with nearby stars in them, ships caught in the solar flare will receive damage and be set on fire.
- In Robotics;Notes the Earth is currently experiencing very wild, and weird weather caused by frequent solar flares, which are also messing with electronics worldwide and causing them to malfunction and harm people. While this is all happening the main character, Kaito, finds the "Kimijima Kou" files that claim the reason for the solar flares is that the sun is about to explode, and that governments worldwide are trying to cover it up. This turns out to be propaganda by Kimijima however, to distract the public while he attempts to artificially create a solar storm big enough to kill five billion people.
- Vandal Savage's Evil Plan in Justice League: Doom is to launch a rocket at the sun which will create a solar flare and a magnetic trail left by the rocket would guide the flare back to Earth, incinerating the sunward facing side. The flare would wipe out half the world's population and the accompanying Electromagnetic Pulse would stop anything more advanced than a steam engine from working. Then Savage and his Legion of Doom would emerge from their protected base and rule over the survivors.
- The Solar Storm of 1859 (a.k.a. the Carrington Event), which pushed both sets of polar aurorae down to tropical latitudes and caused telegraphs to fail all over the world (while some worked via induced current even after being disconnected from their batteries). If such a storm happened today, it could be devastating to the modern world.
- Almost happened again in 2012. Luckily, we missed it by a week. Had we hit it however.... Fun Fact: there is a 10-12% chance it could happen again in our lifetimes...
- The 1989 Geomagnetic storm that put Quebec into a blackout for nine hours. The effects of the storm were enhanced by the fact that Quebec sits on the Laurentian Shield, a large rock formation that prevented natural grounding. This allowed the energy to take the path of least resistance, such as the electrical transmission lines, causing the entire Hydro-Quebec network to short out.
- The main reason Mars is lifeless (as far as we know) is because its magnetic field was weak enough that the constant bombardment of solar ejecta from the Sun stripped away most of its atmosphere.
- Blasts of solar radiation cause the Earth's atmosphere to expand, increasing the near-negligible Space Friction to considerable level, accelerating the normal process of orbital decay and requiring the Low Earth Orbit satellites to expend their limited fuel supply to correct their orbit, thus reducing their lifetime.
- As any planet within the habitable zone would be tidally locked, therefore not able to produce a magnetic field, these would be a constant danger for anything living around Red Dwarf starsnote