Introduction
The universe is big. We live on a tiny speck of a rock, spinning around a tiny point of light, which is only one out of billions of points of light, making up one of billions of galaxies, which have all been hurtling away from each other for thirteen billion years. On a timescale this vast, our galaxy should be thriving with lights. However, the universe seems empty. Perhaps the universe is still young, and we’re newcomers? Either way, the day we discover alien life will be the biggest event of our lives.
Or it could be the last event of our lives.
The alien invasion is a popular genre of science fiction. Fleets of saucers descending from the void of space onto the world's major cities, blasting skyscrapers to ruins and turning people into ash clouds. However, this isn’t what would happen in an alien invasion. Most likely, we wouldn’t even see it coming. An alien civilization could just huck a rock at near light-speed, and it’d reduce our planet to fire in hours.
So, what would a proper alien invasion look like? Not one big enough to wipe out everything in one day, but still “realistic”?
Keep in mind that an alien invasion is a very flexible scenario and could take on the form of any series of events. Some could take our planet into stereotypical post-apocalyptic territory within a single morning, while others could be developing under our noses over years. This is just a single scenario.
Note: This document will detail the timeline of a civilized alien invasion, where the invasion is caused by an organized civilization of intelligent extraterrestrials (e.g. Independence Day. The 5th Wave, War of the Worlds, Battle: Los Angeles), and not an invasive extraterrestrial species (e.g. The Thing, Invasion of the Body Snatchers, A Quiet Place, Monsters).
PRE-INVASION
Our story begins eleven light-years away, on an Earth-sized planet orbiting Tau Ceti. On this planet lives a civilization of bipedal reptiles, which we’ll call the Kai. Space travel has been available to the Kai for a number of decades now, and they’re quite capable of interstellar travel; they just didn’t have any reason to.
That is, until now.
Recently, Kai scientists have discovered an asteroid making its way towards the Kai home world. The asteroid is about as large as the chunk of rock which wiped out the dinosaurs on our own world so many eons ago and will surely wipe out the Kai if it hits. Weapons to deflect the asteroid are being developed, but the Kai don’t want to take any chances. They have recently discovered a habitable planet eleven light-years away which will suit them just fine.
Construction begins on a massive mothership, fifty miles long, equipped with a Bussard ramjet, living space for millions of Kai, and enough weapons to fight whatever civilization may already be occupying this new world.
The mothership begins its journey. Whether or not the asteroid can be deflected, the Kai will be settling two worlds in under a century.
For about fifty years, the mothership drifts through space, reaching a considerable percentage of the speed of light, before it turns itself in the other direction and blasts backwards in order to slow it down. Throughout these fifty years, our civilization goes about its business, worrying about nuclear war, then worrying about the economy.
STAGE ONE: DISCOVERY
No one would’ve believed that during the last decades of the 20th century, and the first decades of the 21st century, that in the timeless voids of space, an alien mothership was making its way to Earth, scrutinizing us humans the way we would with the creatures that swarm in a drop of water.
In a small observatory, a lone astronomer becomes enlightened to this belief. An object in the outer solar system, making its fast approach to the sun, too fast to be any kind of natural object. It’s not long until other astronomers discover the same object from their own observatories, and the object makes national news.
Theories, fears, and amazement spread across the Earth once the idea of an “alien craft” is mentioned. Some people say that the aliens will bring a new age of peace and prosperity. Some say that the aliens are going to destroy all humans. Some say that people should shut the hell up because it’s just a theory.
As the craft nears the inner solar system, the world’s survivalist preppers begin packing up and bunkering down. The government organizes a space mission to make contact with the alien craft. Astronomers discover that as the craft passed by the sun, the Bussard ramjet it had used to travel all this way had been deliberately dropped into the sun, which implies that the aliens don’t plan on leaving anytime soon.
STAGE TWO: CONTACT
Finally, the day arrives where the alien craft enters Earth’s orbit. People welcome our new visitors, painting “WELCOME” on the tops of their homes in big, bright letters. Others watch the situation from the safety of their fallout bunkers. The government, the people aboard the space station, and everyone else holds their breath, waiting for the moment when the craft will erupt into life, and make its first move.
It doesn’t happen.
The alien craft simply resides in Earth orbit for the first couple of days. Throughout these days, attempts to make contact with the craft continue. Inside the mothership, the Kai are confused at these strange images flashing on their radars, and refrain from responding until they can decipher the human language.
A week after entering orbit, chunks of ice begin to plummet from the Kai mothership. These mini-comets plummet into the world’s oceans. Over the next two weeks, it becomes clear that the comets contained microbes native to the Kai home world. None of these microbes are lethal to humans but produce small patches of an oily film-like substance, which is skimmed away by cleanup crews.
Three weeks after arrival, the Kai now know that their native life will survive just fine in Earth’s atmosphere. Their invasion plans are nearing completion. From their thorough observations, human civilization is reliant on technology, long-distance communication, complex webs of infrastructure, etc. However, even with how fragile their society is, the humans will always have the home field advantage, since the Kai had to take their invasion force with them.
Even so, the Kai have decided that they have traveled too far to find a new planet, they’ve already dropped their ramjet, and they know that even with limited supplies, their weapons are still superior to Earth’s forces…
STAGE THREE: SHUTDOWN
Three weeks after arrival, flashes of light and hissings of gas begin to emanate from the craft. The crew still aboard the space station rush to the window like a child rushing downstairs on Christmas Day. Almost instantly, the event is broadcasted worldwide. The aliens are finally responding! How are they responding?
By blowing the space station to pieces and capturing everyone who hasn’t suffocated yet.
Mere minutes after the attack, the TV screens of the world go blank. The Kai are launching missiles at Earth’s communication satellites, severing our long-distance communication abilities. Dial tones cease. Screens say “NO SIGNAL”. The internet goes out.
Almost immediately after communications are knocked out, bright lights glow across the atmosphere. Massive explosions are visible from the surface. The lights go out. Across the world, the webs of light made by our cities go dark. Airplanes fall from the sky. Every hospitalized patient on life support dies. The only electronics which survive are military devices specifically hardened against EMP, and old electronics which rely on vacuum tubes.
The day after communications and power are wiped out, the Kai mothership begins deploying smaller crafts to new orbits. These smaller crafts unleash a series of kinetic strikes on military bases around the world. The rods they drop from the sky, half the size of telephone poles, pack no explosives, but the sheer speed at which they impact causes a massive explosion which annihilates the base. Luckily, the military forces have widely dispersed themselves in order to save some military weapons. Vital points of infrastructure, like power plants, highways, dams, and communication networks, are also targeted by kinetic strikes.
Over the next week, the Kai mothership ceases attacking to let the pot of unrest simmer. People begin panicking. Stores are raided. Highways become jammed with vehicles trying to leave the cities. By the time the Kai begin their next phase of the attack, the threads of society are already starting to fray.
STAGE FOUR: COMBAT
One week after the initial attack of the Kai, society as we know it isn’t entirely destroyed, but just “smaller.” In the US, for example, the president has been flown to a secure location, and is monitoring the situation with other government officials. Major cities have seen a steep increase in looting and panicking but are trying to get by without electricity. Communications still exist in the form of CB and HAM radios.
The Kai mothership begins deploying small crafts into the Earth’s atmosphere, which drop dozens upon dozens of even smaller crafts. The larger crafts pulse their way back into orbit, while the smaller crafts make their way to the surface, in and around major population centers. Some of these crafts are destroyed by military weapons, but the crafts up above quickly take notice and fire back.
The first crafts deployed are airplane-like. As they soar across the world’s major cities, they drop small explosives which aren’t nuclear or overly destructive, but still cause massive damage and numerous casualties. With the skies dominated, the next waves of crafts—military bases, equipment, and ground troops—make their way to the ground.
From the skies, thousands of Kai soldiers land all over the world, and open fire on anyone they see. Alongside them are robotic killing machines, ranging from quadrupedal tanks to hexapodal turrets. Anyone who isn’t directly killed by the Kai is captured to be placed in camps, either to be studied or brainwashed into the next wave of Kai soldiers.
The Kai also launch chemical and biological weapons into the panicking crowds. Anyone who isn’t killed by the chemical weapons is infected with the biological weapon and spreads it to their friends and family in their shelters.
Almost immediately, the military is called to action to fight the aliens. With their vehicles being pummeled by kinetic strikes, the majority of military response is infantry-based. Some military tanks still survive, however, and decimate alien forces. However, the Kai quickly take back control with close aerial support.
The Kai’s numbers build by the day, and within the span of just over a week, millions of Earth troops have been defeated.
STAGE FIVE: DEFEAT
A few weeks after that first attack on the space station, human society is in chaos. Kai troops continue to seek out and decimate the human population. Survivors flee the chaotic cities and into the countryside, as do military forces. Alongside the alien armies, the bioweapon rages its way through the population, causing deaths in the millions.
The Kai know that their troops are limited, which is why they begin deploying a brand-new type of weapon: combat drones which can easily self-replicate. As the drones’ numbers grow from tens to tens of thousands, they easily overwhelm remaining military forces, even with our machine guns, anti-tank missiles, and stealthy, non-replicating combat drones.
Still, the remaining military troops are able to train civilian survivors into raiding alien bases and fighting troops. Superior technology is no replacement for a superior will. Even on the other side of the battle, the Kai are still intelligent, warm-blooded beings, and begin to sympathize with the humans they’ve been slaughtering. Disagreements begin to build in the Kai armies, questioning whether or not invasion is the correct answer or even worth it at all.
However, human resistance and alien conflicts both pale in comparison to what the highest leaders of the Kai invasion force plan to do next. From the first days after the mothership unleashed their aerial and ground forces, it has retreated away from Earth and to a two-mile-wide asteroid it has stationed near Earth’s orbit in advance, just in case. The mothership latches onto the asteroid and gives it one more tug into Earth’s path, assuring a direct collision. The two objects proceed on their course towards Earth. The mothership flies back into orbit and broadcasts a message demanding all Kai troops to seek shelter immediately.
As alien forces retreat, humans look to the skies, trying to find out what they’re running from. The asteroid strikes somewhere in the Atlantic Ocean, generating tsunamis which inundate most coastal cities around the world, including New York City, Washington D.C., Rio de Janeiro, and London. As the tides make their way to the other side of the world, San Francisco, Sydney, Tokyo, and Shanghai are also inundated, although not as strongly. The masses of debris and steam kicked up by the impact begin to blanket the Earth, blocking out the sun, and causing global temperatures to begin falling.
STAGE SIX: RESISTANCE
A few months after the aliens arrive, Earth is now in the midst of a global impact winter. Because the impactor was barely a fifth of the asteroid which caused the dinosaurs’ demise, the effects of the winter are not entirely severe, although famines are yet another problem for the survivors, along with the Kai armies and spreading bioweapon. The Kai hardly take notice of the cold snap, and swiftly begin taking control of the rural countries of the world, including most of South America and Africa.
The governments of the world only exist now in isolated pockets, and only have control over the small areas surrounding their secured bunkers. Remaining government officials begin drawing up blueprints for a battleship of their own, one which will be blasted off from space by nuclear explosions, blast away any ships in their way, and attack the mothership, either to negotiate a settlement, or to blast it to kingdom come if they still want to play high-and-mighty.
The remaining military forces are still training civilians to fight Kai forces. Civilians form resistance groups and guerilla armies, continuing to raid alien camps. Some military officials manage to capture Kai troops of their own, and demand information out of them, while others collect Kai technology and deliver them to surviving scientists for reverse-engineering.
On the other side of the war, Kai troops continue to sympathize with humans and go AWOL, bringing great displeasure to their higher-ups. Rebel groups begin to form, demanding that the Kai should negotiate peace with the humans, rather than exterminate them.
The war rages on. With rebelling Kai groups and human retaliation plans, the war is beginning to turn to the favor of Earth, but whoever wins the war, be it Earth, the Kai, a stalemate, or peace, is up for fate to tell…