Those of us who read and write fantasy and science fiction like our conflicts on a large scale. Forget about family feuds and bickering neighbors–we like wars that engulf whole continents, Dark Lords that threaten to drain the life force of the entire world, and weapons that can take out entire planets.
And since I like to spice my fantasy with a dash of science fiction, I am always interested in world-destroying, humanity-menacing threats from outer space and the many forms they can take.
An Alien Invasion
This is the classic threat, really. From H. G. Wells’ War of the Worlds onward, aliens have invaded our TV screens and our pleasure reading for decades. V: The Final Conflict was one of my favorite sci-fi TV shows as a teen. In movies like Independence Day, Signs, and Titan A.E. and books such as Ender’s Game and The Kraken Wakes, aliens are bent on taking over Earth and destroying or subjecting humanity.

The Thread in Anne McCaffrey’s Pern books is an interesting variation on the alien invasion trope. Thread is biological, but not sentient, a mindless parasite that consumes everything organic.
And then there are stories like Avatar, where the alien invaders are–us.
Meteorite* Strike
We all know how bad a meteorite strike can be–just ask the dinosaurs.
*crickets chirping*
K, so we can’t ask the dinosaurs, but while Earth may survive a big strike by a meteorite or comet, humans may not. This is the scenario in the movies Deep Impact and Armageddon (neither of which I have seen, by the way–these are husband-provided examples).
Or, you can combine the alien invasion and the meteorite strike and get something like Terry Pratchett’s The Fifth Elephant: Giant elephant slams into the Discworld in the dim, dark past, creating vast deposits of fat.

Strange Space Phenomenon
You don’t need to physically harm Earth in order to throw our civilization into chaos.
In John Wyndham’s Day of the Triffids, a shooting star show blinds everyone who sees it. Chaos ensues.
In Blake Crouch’s Run, everyone who witnesses an aurora is suddenly gripped by an uncontrollable homicidal urge to kill everyone who didn’t. Chaos ensues.
In our very real life, scientists warn us that a solar flare could disrupt our technology. Chaos will ensue.
The Vogon Construction Fleet
Yes, this deserves its own category. In Douglas Adams’ Hitchhiker’s Guide to the Galaxy, Earth is destroyed in order to make way for an interstellar bypass.
It’s nothing personal.
Miscellaneous Space Threats
Besides these categories, there are threats by black hole, rogue planets smashing into our own, the inevitable expansion of the sun at the end of its life, and the ripping of the space-time fabric. All of which make the hearts of apocalypse rubber-neckers like me go pitter-patter.
What other threats from outer space–real and imaginary–can you think of?
* Edited to use the correct terminology. See dkoren’s comment below.
One of the best “strange space phenomenon” stories is Asimov’s short, “Nightfall”. Though that doesn’t (and couldn’t) take place on Earth, so I don’t think it quite fits this post… π
For this post I define Earth as any planet where humans live. Otherwise I’d have to disqualify Pern and the Discworld. π
But yes, for the people in “Nightfall” night is a strange phenomenon, though their extreme terror of it is–on further reflection–a bit much. It’s still a powerful story, though.
Fun post!
Technicality (courtesy of growing up with an astronomer for a father), but a meteor can’t do anything to anyone. It’s just a streak of light. It’s the meteorite that’s the solid object that can hit the earth. Meteorites, comets, asteroids… those do the damage. π
Rats! I knew that meteors, meteorites and meteoroids were all different, but I thought I’d picked the right one. Thanks for the correction!
Another strange and dangerous space phenomena is galaxies colliding. How it affects an individual planet depends on which side of the galaxy the planet and it’s star are on when the galaxies collide. (I wish I could say more, but I don’t have enough training in astronomy. My strengths are in anthropology and library science, and my parents’ strengths are in education, biology, and chemistry.) {Smile}
Anne Elizabeth Baldwin
*nod* Yes, potentially a star could get flung out into intergalactic space when that happens. But I imagine the galaxies colliding happens so slowly that the rate of the catastrophe would span many human generations. Not sure if I’ve ever seen it be the major conflict in a book, but then I’m more up on my fantasy than my science fiction!
Wow! My take-home from this post is that I need to read more of this stuff…I’m kind of impressed by your library.
π
I have read a lot of books in my time. π
But what really helps me out is that I keep lists of the books I read (by year). Whenever I do a post like this, I go through my reading lists to see which books I can use as examples. If I didn’t have those lists, I’d flounder (or use Google a lot!).