How long will humanity survive in the universe? 70,000 years ago the human population was almost wiped out by the supervolcano Toba. I don't need to say anything.
And it's likely that another similar eruption will happen in the next 10,000 years. And a supervolcano is just one of the events that could threaten the survival of human civilization. The future is full of danger.
In this video we're going to see what the great threats to human civilization are going to be in order to be able to defend them and extend the lifespan of our civilization. Even one of these threats is a threat that could destroy even a civilization that has already spread across a galaxy. So let's get started.
Time is short. Part 1 - Surviving on Earth The first threat to humanity is basically around the corner, which are the consequences of climate change caused by human activities. Ah, the comments session on this video is going to be fantastic.
The increase in the planet's average temperature means more energy for the atmosphere to use in events ranging from extreme storms to floods and droughts becoming increasingly common. Which destroys the infrastructure and human capacity to produce food, which, believe me, is very important for our survival. In addition to the short-term effects, the warming of the planet could cause the basin to melt which could raise sea levels by 3 to 4 meters within the next 10,000 years.
And the great danger here is not that climate change will kill all human beings at once, but that a much warmer planet is incompatible with the existence of a technologically advanced civilization. If the worst-case scenario of climate change happens, it could destroy our industrial and scientific capacity. And without the capacity to create new technologies, we will be in the perfect position to fall victim to extreme disasters that will happen sooner or later.
Without advanced technology, our extinction is only a matter of time. Overcoming this challenge means preparing to deal with and mitigate the damage of extreme weather events and changes on the planet, but also learning to use cleaner forms of energy, especially nuclear fusion. Mastering nuclear fusion would completely change the logic of energy production in the world.
And besides being a clean and perfect source of energy, nuclear fusion can greatly assist in large-scale space exploration, which today seems like science fiction, but will become essential for the long-term survival of our species, as we will see shortly. If we learn to deal with extreme climate events on the planet, we will ensure our survival for the next millions of years. Or at least until we encounter the first event more extreme than that.
A catastrophic event, such as the fall of a large asteroid or the eruption of a super volcano, like Yellowstone. Super volcanoes are a serious problem, and they can cause massive destruction very quickly. But the main danger is that they have the ability to dramatically alter the planet's climate very rapidly, causing artificial winters that can last for years and thus affect human food production.
If civilization wants to endure for a long time, we need to have mitigation and reconstruction plans to prevent such an event from causing the collapse of everything we have built and will build. One thing I would like to make clear is that this type of threat is not necessarily something that affects us or will affect us in the time we have left to live. But if we think as a humanity and in long periods of time, statistics are not in our favor.
For example, in about 100 million years, it is almost certain that another impact with similar intensity to the one that wiped out the dinosaurs will happen. Any trace of us will have turned into dust by then, but possible living humans will need to deal with the problem. Fortunately, we are already learning to deal with asteroids through NASA's DART project.
We literally made a probe collide with an asteroid and successfully changed its trajectory. And we also have a catalog of the most dangerous known asteroids and are constantly keeping an eye on them. The most dangerous moments for a fatal impact are the next centuries, while we are still not fully capable of deflecting asteroids.
And this ability will be very important in a million years. The solar system is going to receive an unrequested visit. A star is going to pass inside the solar system.
The invader is the star Gliese 710, which is already coming in our direction. Its passage so close to the Sun will cause extreme gravitational disturbances of the comets that currently inhabit the Oort cloud, which is a cloud of comets located at the edge of the solar system. Several of these comets will be redirected to the inner solar system, and an unprecedented comet shower will occur as a consequence.
There is a very high chance that at least one of them will collide with Earth. Furthermore, there is a chance that this event will eject planet Earth as a whole from the solar system, turning our planet into an orphan planet. If this happens and we still don't have space colonies, it's game over for human civilization, which by this point in the video would have lasted a maximum of one million years.
And this stellar visit will not by any means be the only catastrophe that will threaten the life of Earth in the next millions of years. More extreme events will undoubtedly occur; it's just a matter of time. For example, as time goes on, the Sun will become increasingly hotter.
This is the natural life process of our star. And with that, Earth will become increasingly less habitable, until around one billion years in the future, the average temperature of our planet will be around 47 degrees Celsius. People from Rio de Janeiro will flock to the beaches of Copacabana, or rather, the desert of Copacabana.
Because at that point, a significant portion of the ocean water will have evaporated. So, if humanity wants to last more than a billion years, we need to have an escape plan from Earth. But what if humanity were to end today?
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Part 2 - Colonizing the Solar System If we want to survive as long as possible in the universe, we need to leave Earth and create functional colonies on Mars, the moons of Jupiter, and maybe even in space itself using generational ships. And that would drastically increase the lifespan of humanity. By doing it right, it is almost certain that humanity could last at least until the end of the Solar System, which is projected to happen in about 4 or 5 billion years.
Or at least that would be the case if gamma-ray bursts didn't exist. Gamma-ray bursts are events so dramatic and energetic that they can wipe out life in an entire solar system in the blink of an eye. When a large star, more than 8 times the size of the Sun, exhausts all its fuel, it explodes into a supernova, releasing massive amounts of energy.
Part of this energy is emitted as gamma rays, which are extremely dangerous, high-energy radiation. Fortunately, this extreme radiation is only emitted in two specific directions during a supernova, and even if one occurs near the Sun, it is unlikely that the worst of the gamma rays would hit our Solar System. But rare events eventually happen, and it is more likely than not that our Solar System will be hit by at least one gamma-ray burst emission from a supernova within 500 million years.
And there is no solution for that! If a gamma-ray burst hits your favorite stellar system, it will be sterilized nearly instantaneously. Any carbon-based molecule will be disassembled by the extreme radiation, and guess what is made of carbon molecules?
In other words, colonizing our Solar System would buy us a few hundred million years of survival, or even up to a billion years if we are very lucky with when the gamma-ray bursts will come. But even if life in the Solar System can't survive that, humanity can. If we want to survive more than 500 million years, we'll need to leave the Solar System.
Part 3 - Colonizing the Galaxy And that's why we need to visit the stars closest to us within the lifetime of a human being. That said, these journeys won't be short, and will probably take decades. But if the idea is to keep humanity in existence, we need to take enough people to live long and prosperous lives outside the Solar System.
And preferably they need to reproduce too. What a terrible journey! Colonizing the galaxy effectively and creating colonies independent of the Solar System is not going to be easy.
In fact, it's going to be an immense technological challenge for which science doesn't even have a solution yet. So let's take a look at science fiction ideas. The least used version of colonizing the galaxy is to use a generational ship, which is basically a society inside a ship.
Instead of taking a few people at a time, we're going to take all of humanity right away. And along with a large number of people, we would also need to take everything they need to stay alive. Food, water and ways of producing energy.
It's not at all obvious how feasible and realistic it would be to build such a ship. On the other hand, the alternatives involve solving problems in science that we don't even know have a solution yet. For example, one of these problems is finding out how to make human beings biologically immortal.
In other words, putting an end to aging and death by disease. Which would allow us to travel between the stars much more calmly. Alternatively, we could also learn to suspend and restart a person's life using cryogenics.
Which at least in theory could help us send large dormant populations to other stars much more efficiently. That said, these two scenarios require new technologies that may not even be possible. And the ideal version for colonizing space, at least in a practical way, would be to solve the difficult problem of consciousness and learn how to upload human minds into machines.
Machines cope much better with the dangers of space. So instead of sending humans into space in spaceships, humans can be the spaceships. That said, this solution involves one of the most difficult problems in science and one of the most fervent discussions in philosophy.
If we reach the galaxy and become a civilization that colonizes other stars, that makes humanity basically indestructible. And there is only one phenomenon that can affect an entire galaxy and threaten humanity from that point on. Galaxy collisions.
In 5 billion years the Andromeda galaxy will collide and merge with the Milky Way. And the danger here is the radical aversion of a star visiting the solar system. A collision of galaxies will cause an absurd level of gravitational instability around the entire Milky Way.
And that could throw entire star systems into the void of space. If at that point humanity has colonies only in a few stars around the galaxy, there is a non-negligible chance that all of them will be affected by the collision. The ideal is to have colonized good portions of the galaxy within the next 5 billion years.
Come on guys, there's time! And with patience, you might even make it to some small dwarf galaxy orbiting our Milky Way. If we conquer the galaxy, we'll receive the biggest prize in terms of how long we'll live as a civilization.
We'll be able to inhabit the universe for the entire Star Age. And that means 100 trillion years of prosperity. And then we'll reach our last stage of survival.
100 trillion years is a long time, but that time will also pass. There's a phrase I really like that says the days are long, but the years are short. And in 100 trillion years there will only be a few hundred stars shining in the galaxy.
At that point, our galaxy will no longer be our galaxy. It will be a real giant monster that is the result of the merger of all the galaxies in our local group. Once the last stars are extinguished, there will be no new stars.
And there will be no useful energy to use in the universe. If humanity arrives at this point unprepared, it will mean going out with the stars. To go beyond, to inhabit the post-star universe, we need to change the attitude of human civilization after conquering the galaxy.
And the ideal would be to start when the last galaxy in the local group merges with the Milky Way. From then on, no new galactic events will take place. And from that point onwards, humanity's focus would need to be on storing hydrogen for use after the natural end of the stars' lives.
If the first step to survival is to expand, the next step is to prevent stars from burning out their energy sources too quickly. This attitude would literally change the history of the universe, and buy time so that we could live on even after the universe fades away. Perhaps the last 100 stars shining in the galaxy will be humanity's last shelters.
But shelters that aren't going to burn out anytime soon, because humans have saved all the rest of the galaxy's hydrogen for those 100 stars. Or even better, humans saved all the hydrogen to use as an energy source known in the cosmos, black holes. Nothing known generates energy on such a scale as throwing matter into black holes.
Except that to use the energy from one, we have to learn how to basically make a cosmic dam. We'll need to use the movement of falling gas in the black hole as a source of energy. In addition, we would also need to capture the light emitted by the accretion disk around the black hole to somehow generate energy from it.
These disks can shine much brighter than stars, they produce energy extremely efficiently. Living around a black hole and using it as an energy source would probably maximize our lifespan in the universe. That said, black holes will exist for trillions of trillions of trillions of trillions of years.
And if we manage to inhabit the universe for a fraction of that, I would already consider it a tremendous success. Man, if I make it to 100 years I'll be happy. In short, the lifespan of our civilization will depend on how far we go in the universe.
If we never leave Earth, it is unlikely that we will last much longer than a few million years. If we reach the solar system, our lifespan jumps to almost a billion years. And conquering the galaxy would buy us hundreds of trillions of years, or even more depending on how disciplined we are in conserving resources.
But what about you? If you were to guess how long humanity will still last, how many years would you guess? Thank you very much and until next time.
