The vast majority of meteor impacts are completely harmless, but there have been a fair number of meteor and asteroid impacts on Earth in pre-human history that have caused large-scale devastation. In theory, a large enough asteroid hitting Earth could wipe out all higher life forms.
Specific meteor impacts/events:
- The Tunguska Event may have been a meteor or asteroid impact.
- The Nemesis (Star) Theory is that extinctions have happened in cycles caused by a dark star that hurls meteors or comets through our solar system.
- The Peekskill Meteorite of 1992 was so bright and noteworthy it was videotaped by at least 16 independent people across the state of New York.
- The Younger Dryas Impact Event is a proposed explanation for the death of the Clovis culture and the mass extinction of North American megafauna circa 10,900 BCE. The theory proposes that a meteor impact resulted in wildfires covering most of the continent.
- The Cretaceous–Tertiary extinction event may have been caused by an asteroid impact.
Technically, a meteor is smaller than an asteroid. A meteor is larger than an atom, but probably not larger than 10 meters in size. An asteroid, on the other hand, could be miles long. This distinction probably only matters if gaming with astronomers, or if trying to roleplay an astronomer. If you're players are a stickler for accuracy, though, it may be important to get that right. A meteor could ruin a city, or burn down a large forest, but it would probably take a comet or asteroid to wipe out humanity.
Many large meteors move through our solar system at about 30 kilometers per second. That's pretty fast. When they hit our planet's atmosphere, they heat up to 100,000 Co or more. Particularly large and bright meteors are known as bolides, but are also sometimes just referred to as fireballs.
When a meteor hits the ground it often splashes molten metal. These blobs of metal, once cooled off and solidified, are called tektites.
Game and Story Use
- If you really want to threaten your campaign world with global extinction, accept no substitutes for a full-on asteroid impact. The larger asteroids would hit with more destructive force than an atomic bomb.
- Asteroids could be used as a Weapon of Mass Destruction by a sufficiently advanced space-faring society (or space terrorists). Using something as simple as space tug boats or a tractor beam you could divert a near earth object (or the equivalent) so that it would cross the path of a planet you were at war with. The scary thing is that in a civilization where space travel is common-place, anyone with even a modest bit of wealth could easily buy the unregulated tech to perform this doomsday terrorism. Even a small ship, given enough time and fuel, could alter the course of a large asteroid.
- Smaller meteors might not be a huge disaster initially, but could be a way for an alien virus or organism to come to Earth. Day of the Triffids, Invasion of the Body Snatchers, The Andromeda Strain, and even some Zombie Apocalypse films all riff off of this concept.
- Phlebotinum could fall to earth in the form of meteors. Should the PCs see something light up the night sky, they know there will be valuables worth the expedition to retrieve them. (And probably some competing parties attempting to gather the magic rocks first.
- In a setting where every magic item has to be made from space rocks, there would be implied limits to just how common magic could be. This would be one way to let a rare powerful item exist in an otherwise low fantasy setting. All the really potent magic items need to be forged from tektite metals, of which there's a finite supply.
- In Ancient Rome, there were numerous temples that housed strange rocks, including many that fell as meteors. The Romans considered these to be avatars of, or sacred to, the Gods.