Humans are a fairly resilient species. We’ve survived for over 200,000 years and had to overcome famines, drought, disease, climate change, and natural disasters. However, it does beg the question: is there a single event that could wipe out humanity? Or at least decimate our numbers to the point where we can’t bounce back? The short answer is… of course. There are several. These are 10 ways it could happen.
10. Alien Disease
One day, you’re sitting at home minding your own business watching the local news. The top story is that a small comet crashed in some town about an hour away. You think it’s interesting, but it didn’t hit anyone or anything, so you forget about it pretty quickly.
The next day, you go to work and half of your coworkers are out sick. After an hour you feel incredibly ill, so you announce you are going home, only to realize everyone else has left. You walk out of your workplace and outside there are people lying dead on the sidewalks and on the streets. In the distance, there is the sound of helicopters. As you lay down, too sick to walk, you see that they are military helicopters. However, they are already too late. It turns out that the comet had an incredibly infectious airborne alien virus and it’s spread too far to contain. Our Earthbound bodies simply haven’t developed any immunity to it and within a few months, the virus has wiped out everyone on Earth.
Now, is this scenario plausible? It’s one of those good news/bad news type of answers. First, there isn’t evidence that pathogens exist outside of Earth. However, the universe is a vast place and there is so much that we don’t know about it, so it’s quite possible that there are alien pathogens out there. In fact, it’s one of the biggest concerns when it comes to space exploration.
The problem is that if we did encounter an alien pathogen, it would be devastating because we wouldn’t have built up any immunity to it. We already know this is a problem because it happened several times on Earth. One of the most devastating cases was when Europeans first came over to North America. They brought diseases with them that the Native Americans hadn’t built up an immunity to and it’s estimated that 95% of the Native Americans were wiped out.
So we don’t want an alien disease to come to Earth, but is it even possible for alien pathogens to live on a comet? Well, according some to astronomers from Cardiff University, it’s not only possible, it may have already caused a serious outbreak here on Earth. Their theory is that dust from a passing comet caused the Spanish flu outbreak of 1918 that killed at least 20 million people.
9. Chlorine Poisoning from Diatom Evolution
You’re winding down after a long day and you’re watching some YouTube videos to help you relax. Suddenly, the video changes, and it’s an announcement. It’s not something that you thought YouTube could do, but apparently they can.
On screen, some text says to put a gas mask on and seal up your house with duct tape. You don’t have a gas mask, but you put duct tape on most of the seals on the windows and doors in your home. But you don’t have enough to get them all.
When you return to the device you were watching the video on, you find out more information. Unfortunately, it’s bad news. Because generally when someone tells you to put on a gas mask, it’s not going to be news of free candy for life, right?
The duct tape is only a temporary solution. It turns out that one of the most common phytoplankton, diatoms, are polluting the air with deadly chlorine gas. They used to take water molecules and split the hydrogen from the oxygen, and release oxygen into the atmosphere. However, now they are taking salt in the ocean, which is made from sodium chloride, and breaking it apart. So instead of oxygen, it’s pumping chlorine gas into the air.
Suddenly, your eyes and mouth start to burn. It’s hard to breathe. You feel like you’re suffocating and you throw up. You feel better for a few minutes, but then the suffocating feeling comes back. You fall to the floor and breathe in more chlorine gas because it’s more heavily concentrated closer to the ground.
Of course, you aren’t alone. Only a handful of people who made it to shelters survived. Unfortunately, not enough people make it to the shelters and humanity is wiped out because of algae.
According to Cal Tech’s Joe Kirschvink, a geobiologist, this scenario is possible, but unlikely. The big however is that something like this has happened before. For about two billion years, the atmosphere on Earth was mostly methane and other greenhouse gases. But then about 2.35 billion years ago, cyanobacteria, also known as blue-green algae, started to pump out free oxygen. This changed the atmosphere and made it possible for life as we know it to come into existence. However, no one is really sure why the cyanobacteria started pumping out oxygen. Kirschvink said that a similar shift in diatoms to switch to salt instead of water is just “… one small change in the metabolic pathways.”
He points out that there is no evolutionary benefit to the diatoms changing, but, so far there is no known evolutionary reason the cyanobacteria started pumping out oxygen either.
8. Alien Invasion
You’re hanging out, kind of watching TV, but not really paying attention. You don’t even notice that a Doctor Who episode is playing. Then you notice the plot is about aliens that you forget about after you look away from them. Interesting, you think, but not possible. To prove it to yourself, you turn your head around quickly… and there is nothing there. So you go back to watching the show, and then you turn your head back again quickly, and nothing is there. But then an 8-foot reptilian humanoid alien kicks open your door, points a rifle at you, and without hesitation, it fires a laser beam which hits you in the heart and stops it instantly. The hunter’s score goes up by one and his fans back home on Kepler-283 cheer as they watch on something similar to television.
They say to each other, in their own language, “This year of extermination is going to be weak. The earthlings only use metal bullets. They won’t even last two weeks.” They all agree, but what else are they going to watch that is this exciting? So they settle in and watch the rest of the humans being wiped out while they mount a pitiful defense.
Of course, the biggest flaw in this scenario is that there is no evidence that any other life in the galaxy exists, other than us. If there was, we’d probably find radio waves first.
However, there is no evidence that aliens don’t exist either. Also, while we certainly hope that they would be peaceful, there are many reasons why they don’t have to be. Theoretically, they may want to destroy the Earth for the same reason they did in Hitchhiker’s Guide to the Galaxy, which is because Earth was in the way and we are considered ants to the advanced beings. Or they could be a variety of intelligent plant life, like Groot, and when they visit Earth they become enraged at how we’ve treated the environment. Or what if Panspermia is correct and life on Earth started because seeds were sent here by an advanced race of beings? Those advanced beings may have royally ticked off another alien race and in retaliation, they attack Earth. And the list could go on, but this shows that there are possible reasons that other intelligent life could be hostile towards us.
7. Strange Matter
Throughout these doomsday scenarios, we wanted to give a first-person perspective on what that specific doomsday would look like. However, we can’t do that with death by strange matter because no one is sure how strange matter behaves. The good news is that it would only take a few seconds from the creation of the strangelet, which is a single particle of strange matter, and life on Earth will probably be over. The best guess is that the Earth would become an inert, hyper-dense sphere about 300 feet across.
While there is a very small chance that this would happen, if it did, it would start at the Brookhaven National Laboratory’s Relativistic Heavy Ion Collider in Long Island. It’s similar to the Large Hadron Collider, but it performs tests at lower energy. They believe that in one of these tests, it could create a hypothetical strangelet that consists of up, down, and strange quarks. Just one negatively charged strangelet could start a chain reaction that would end the world in a matter of seconds.
However, critics contend that the collider generates too much heat for strange matter to be created. They say it is as likely as making ice in a furnace. Hopefully they are right!
It’s the year 2077, which is 60 years from now. If you’re still alive, you’re probably elderly (unless you’ve discovered the Fountain of Youth, in which case, please feel free to share). Half of your friends and family have died. The other half are still alive and they are choosing to upload their mind to a computer program called Existence 2.0. In fact, you are one of the last physical humans alive on the Earth.
If you want to join Existence 2.0, robots just attach a few electrodes to your head and then over the course of several hours your consciousness will be transferred from your body, converted into some lines of code, and uploaded to Existence 2.0. When your consciousness becomes aware again, you’ll be able to pick your body (if you want one), and then you can explore the vastness of Existence 2.0.
The problem is that dead people make for terrible uploads. They have tried to do it based off their personal details, but full-uploads find them inauthentic in Existence 2.0. Also, the government decided that since dead people can’t make the choice, they can’t be uploaded.
Now, do you choose to stay in your body and die? Or do you upload your mind and never age and never die?
While this may sound like some depressing thought experiment, this may be a choice that at least some of us will have to make in the future. According to futurist Ray Kurzweil, based on Moore’s law, which is that computing power doubles about every two years, by 2045, computers will reach something called technological singularity. This is the point where computers will become smarter than humans. Once that happens, it could lead to an interface between computers and the human mind. That means we’ll be able to upload our consciousness to a computer.
Eventually, it may come to the point where all humans have uploaded their minds because they’ll be able to live without all life’s problems like disease, pain, and suffering and gain some unbelievable experiences. However, in exchange for immortality, we’ll give up our physical bodies and we’ll no longer be humans; we would be a different evolved species.
What’s amazing is that this could have already happened. Your life could be nothing more than Existence 1.0. On a similar note…
5. Artificial Intelligence
It’s the year 2050, everyday life is pretty easy because robots take care of most things in life for us. They do all our cooking, cleaning, and they even do things as mundane as drive us around.
One morning, you wake up but your alarm didn’t go off. In fact, everything is dark. You tell your smart house system to turn on the lights, but nothing happens. You go out into your kitchen, and you tell the house to cook you some breakfast. Again, nothing happens. So you decide to reboot the system using the control panel outside, but when you try to leave, you can’t get out of the house because the artificial intelligence has locked the doors. You also try opening the windows, but they are locked as well.
You’re lucky, you think, because you haven’t updated your windows to the unbreakable kind, so you smash one and climb out. Outside, your neighborhood is quiet and the roads are completely empty. Before you can walk around to the back of the house, you hear a car, and you can tell it’s moving fast. You look in that direction and there is a driverless car barreling towards you. You jump out of the way just in time, and the car slams into your house.
You start to run away, but before you get far, you hear an explosion for a millisecond and the place you were running is now just a small crater; a drone controlled by artificial intelligence fired a missile at you.
However, you’re one of the lucky ones because your death was quick. Many people starved to death when they couldn’t get out of their smart houses. Those who did were hunted down by cars or drones.
So what happened?
Well, another option that could happen at singularity is that computers may not want humans around. They may look at us as a parasite and look at ways to eradicate us. And believe it or not, this is actually a serious concern for technologists. For example, Elon Musk warns that AI could be more dangerous than nuclear weapons. He also says that there is only one chance to get it right and if we don’t, it could wipe us out. That is why Google’s artificial intelligence division, DeepMind, and Oxford University are developing a “kill switch” for AI. Because if an AI system were to ever get out of our control, we may never get it back under our control. In fact, by trying it do so, the AI system could take that as a hostile move and might retaliate. Once it does that, it could calculate that it’s just easier to erase all humans.
We mean, did no one watch the Terminator movies?
4. Passing Rogue Planet
You’re sitting on your couch watching some television after a long day. It was such a long day that you just happen to settle for whatever is on cable. Suddenly, the show cuts away and it’s the leader of your country. He or she says that a rogue planet is going to pass through our solar system, but they do not expect it to collide with Earth.
So you breathe a sigh of relief, but your country’s leader continues. He or she says that the planet is hundreds of times larger than Earth and it will pass by Jupiter. Unfortunately, this will ultimately affect our orbit around the sun. The head of state explains that our position to the sun is ideal for life on Earth. It’s called the Goldilocks conditions because the Earth is close enough to the sun to be warm, but far enough away so that it’s not too cold.
A major reason we stay in this hospitable zone is because Jupiter helps hold us in orbit. Since the rogue planet is going to alter Jupiter’s orbit, it will, in turn, alter our own orbit. During the summer, we’ll be as close to the sun as Venus is now and as far from Mars during the winter. This means summers will be very short and intense, while winters will be very long and extremely cold. Without our usual summers, it will be much harder to grow food and shortages are likely.
The leader of your country concludes their doomsday speech by saying, “Now is the time to work together, to save the best and the brightest, in the hopes that humanity will carry on.”
Over the next several months, your country works to make the food last for at least 160 people, which is enough to start re-populating without interbreeding.
Then that first summer hits, and it’s intense. It’s also summer everywhere on Earth at the same time. There are droughts and food shortages because the growing season was so short. During the first winter, billions of people starve. Others are killed in horrible storms, floods, firestorms, and droughts. This is followed by another scorching summer and millions die from the extreme heat. It’s also another unsuccessful season of crop growing, and more people starve. By the third summer, there are only sporadic pockets of humans left on the Earth and they soon die off.
What’s terrifying about this scenario is that there are several ways that it could unfold. The first is the scenario we described: a rogue planet. A rogue planet is a planet that doesn’t revolve around a star, it’s just freely moving around the universe. Astronomers believe that there are over 200 billion rogue planets in the universe and billions in our galaxy. There is also a good chance that they are hundreds of times bigger than the Earth because astronomers are finding that more planets are closer to the size of Jupiter than they are to Earth.
Also, besides rogue planets, it’s possible that a planet in our own solar system may cause problems. According to simulations, it’s possible that in the next few billion years, Mercury, Mars or Venus may either collide with Earth, or change its orbit. And here we always pegged Uranus as the troublemaker. We’re sorry for ever doubting you, Uranus.
The only good news about these scenarios is that they are very unlikely to happen.
3. Gamma Ray Burst
You’re on your way to work, when suddenly without warning there is a massive flash of light in the sky. It turns out that a star died in a star system 7,000 light years away. It collapsed and became a black hole, creating a gamma ray burst for about 10 seconds. By the time the beam reaches Earth, it’s widened out and bigger than our solar system. We had no warning that it was coming because it was moving at the speed of light.
The first thing you notice is that your phone no longer works. In fact, nothing electronic works anymore. You go home and through word of mouth, you learned that radiation didn’t kill everyone because the ozone layer protected the Earth. Also, the gamma ray burst only hit one hemisphere. But unfortunately, you quickly discover that Marvel lied to you, and gamma rays won’t actually turn you into the Incredible Hulk.
The worse news is that a large part of the ozone was destroyed. With a giant hole in the ozone, the environment changes drastically all over the world over the next few weeks. There are droughts and wildfires everywhere, not just the area under the hole, but throughout the world. Crops and vegetation start to die, and animals that eat the vegetation die as well. The climate change ultimately topples the ecosystem and people starve to death.
Unfortunately, gamma ray bursts are very real and one could hit us at any time. In fact, researchers believe that it’s just a matter of time before Earth is hit by a gamma ray burst. There is also some speculation that a gamma ray burst caused a mass extinction on Earth already. Some scientists believe that the Ordovician extinction, which happened about 440 million years ago and 70 percent of life on Earth was wiped out, was caused by a gamma ray burst that originated in a light system that is about 6,000 light years away.
Humans can’t see gamma ray bursts, but they are the most powerful explosions since the Big Bang. They are so powerful that they can be detected from all over the universe. Just to give you an idea of how powerful they are, it’s as powerful as converting the entire mass of the sun into energy in a second. Gamma ray bursts, which are flashes of electromagnetic radiation, are also produced in nuclear explosions. However, ones from space are much more powerful than anything on Earth.
There are two types of gamma ray bursts. The first are long gamma ray bursts. They are produced by a dying rapidly rotating star, which are about 30 to 100 times the mass of the sun. When they finally run out of fuel, they release a gamma ray burst. The second kind, called short bursts, happen when a pair of small neutron stars that are orbiting around each other collide and the implosion causes the gamma ray burst.
Five days ago most people on Earth found out an asteroid about 60 miles in diameter is heading directly towards us. The governments of the world tried to keep it quiet, but there were too many amateur astrologists, and one of them noticed. The story was picked up by major news organizations. Yeah, fine, we’re basically describing the plot of Deep Impact.
End of the world antics ensue: there are riots, looting, religious fervor, religious denial, and of course, some good old fashioned hedonism. Over the past five days you’ve conducted yourself in the way you wanted to spend your last days on earth and you keep thinking, this really can’t be it. There is no asteroid, it was all just a giant mistake… right?
Then a ball of fire streaks across the sky and you realize that there was no mistake. The asteroid smashes into an ocean, and water and pulverized rock fly into the atmosphere. The particles of rock form into grains of sand and then re-enter the atmosphere. The particles are so hot that they turn the sky red and the atmosphere shoots up to 2,700 F and it essentially turns the earth into a broiler. Everything catches fire, and the fire will encompass every part of the Earth. Basically, it would be like peeling off a layer of an onion with a flame.
Hours after the impact, you are hit by a wall of fire that is moving so fast that your brain doesn’t recognize it. If anyone does survive the wall of fire, they won’t last long. Not only will everything on Earth be burnt to ash, but there will be so much dust in the air that things won’t be able to grow for years. Anyone who isn’t incinerated will starve to death in months.
Of course, an asteroid hitting the Earth is quite possible and it’s the leading explanation for the Cretaceous–Paleogene extinction, which is when the dinosaurs went extinct. The asteroid that caused that mass extinction was just seven or eight miles wide. If something that size were to hit us, it’s possible it could wipe us out as well. To kill off all of humanity, University of Colorado scientist Brian Soon says that an asteroid that is 60 miles wide would do the job.
The good news is astronomers don’t expect any asteroids to head in our direction any time soon. Or at least none that they know about.
1. Weaponized Smallpox Attack
It’s three days before Christmas, you’re in the airport and it’s an absolute zoo. You go on your relaxing vacation and you come back a week later, and again, the airport is a madhouse.
About a week after your return, you develop a high fever and terrible body aches. It’s so bad that it leaves you bedridden. Eventually, you call 9-1-1 because you feel that sick, but the line is busy. Instead, you call your mom and she tries to drive you to the hospital. The roads are empty until you get a few miles away from the hospital, but you can’t get any closer because there are so many cars blocking it. You don’t think you can walk the miles to the hospital, so your mom drives you back home.
You don’t remember calling your mom, but she helps you into bed and she says you have a high fever.
About three days after first getting sick, red dots start to form in your mouth. These spots develop into sores that break open, which causes the virus to spread around your mouth and down your throat. You cough some up and your mom gets some of your saliva on her hand.
Next, a rash develops around your mouth, but then within 24 hours, the rash is all over your body. The good news is that the fever goes down. You realize you aren’t dreaming and your mom is there to help you.
But your suffering is far from over.
On the third day of the rash, your skin develops bumps. On the fourth day, the bumps fill with a thick, opaque fluid, but the center of the bump will be indented. That’s when you know for sure that you have smallpox.
As you lay thinking about it, you were sure that smallpox was eradicated in 1979. Your mom tells you that was true, but then she informs you that some eco-terrorists got their hands on the smallpox virus, and they genetically modified it to make it more resistant to vaccines and much more contagious. They released it in an airport on every continent just before Christmas. She also mentions that there is no cure, but you soon forget about it because the fever is back.
The fever lasts for about five days while your bumps turn firm, and then your fever drops. A crust forms over the bumps and they eventually turn black and scab. When the scabs fall off, your body emits the “smallpox smell,” which is a sweet and pungent scent. However, just one of your sores became infected because your mother was too sick to take care of you and there were no clean bandages. You pass away after being sick for two agonizing weeks, which is when most people die when they are infected with smallpox.
Outside of your house, much of the world is suffering a similar fate. It turns out that it was a rare form of smallpox called Flat variola major, which is almost always fatal. The very few people who do survive are left scarred and many are left blind. Sadly, the human population can’t recoup and nature reclaims the Earth.
Sounds like a pretty hellish way to go, right? But is it possible? Well, the bad news is that a particularly virulent form of smallpox was developed by the Soviets during the Cold War and they stockpiled enough to infect every person on Earth several times over. What’s even more terrifying is that no one is exactly sure what happened to the tons of weaponized smallpox. Another problem is that since we eradicated the disease in 1979, vaccinations for it are no longer given to people. Even if you did get the vaccination as a child, they are no longer effective.
So yes, a pandemic caused by weaponized smallpox is all too possible. That’s a cheery note to end on, right? Well, happy Mother’s Day!