Heliophysicists - astronomers who study the Sun have more than once made humanity shudder, talking about their theories of an unexpected stopping of thermonuclear reactions inside our star. And, although in practice the alarm is invariably false, it makes you think about a lot. Will humanity be able to revive after the death of all living things in the solar system?
Ice and fire
A boiling kettle removed from the stove will not cool down instantly, even in the refrigerator. In the same way, if our star is ever extinguished, the Earth will still store heat in the depths for several million years. However, the earthlings themselves will feel the icy breath of space much earlier. Within a week, the average temperature on our planet will reach 17 degrees below zero, and in a year it will drop to 40. Ice will shackle the seas and oceans, not to mention lakes and rivers, the ice shell will cover deep warm waters for hundreds of millennia. After millions of years, a constant temperature of 160 degrees below zero will be established on the surface, at which the heat of the earth's core will fight the cosmic cold …
Tropical flora and fauna will be the first to die in a few weeks. The agony of the polar vegetation and inhabitants of the Arctic seas can last for several decades. Only the inhabitants of the ocean depths near thermal springs and microorganisms existing in the earth's crust will remain.
People could survive for several centuries in underground and underwater cities using volcanic heat, nuclear and geothermal energy, but food sources will inevitably be depleted and completely disappear …
Is there a reasonable way out of such a disastrous situation?
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Generation ship
The most radical way to save the earth's civilization during the explosion or extinction of the Sun was once proposed by the famous French science fiction writer Francis Karsak in his novel "Flight of the Earth". There, the Earth, driven by fantastic engines, simply leaves the dying solar system and begins a long search for a new "star home". It is curious that recently astronomers have actually discovered unusual "rogue planets" that somehow lost their native stars and travel alone across the vastness of the Galaxy.
In a very different style, Clifford Simak's A Generation Reached the Goal is written. The beginning of the story gives off mysticism - all these vague discourses about the End, about its foreshadowing Roar, about the chaos from which the Ship arose … But in the end it turns out that the mysterious End is just the end of the journey; terrifying Rumble - the roar of the included engines; and the Ship itself is an ordinary starship, one of many sent from Earth to the stars.
Thirty generations, replacing on the Ship during the flight, allow you to transfer a weak spark of life to other worlds. So once primitive people transferred an eternally burning fire from one site to another.
In the middle of the 20th century, the famous American physicist Freeman Dyson drew a very real scheme of the "ship of generations", reminiscent of Simak's "ark". In 1959 he proposed a project for an explosive ship.
In fact, Dyson's starship was a giant hemisphere with a diameter of 150 kilometers and a mass of 240 million tons. It was supposed to install a shield behind it, which would simultaneously push the ship forward and protect it from atomic bomb explosions. Because it was the explosions that were going to set this bulk in motion. Dyson calculated that the ship would accelerate to 10,000 km / s. At this speed, the journey to the constellation Proxima and Alpha Centauri would have taken no more than 150 years.
True, just for acceleration it would take at least three decades and 25 million atomic charges. A great way to dispose of atomic weapons! True, according to Dyson's own estimates, the construction of the starship will take at least 200 years. But on the other hand, with its help, it will be possible to preserve the gene pool of mankind and, if possible, the most valuable representatives of the animal and plant world. This could help revive our civilization, say, when a large asteroid falls, "problems" with our star or alien aggression.
Dreams of a great dreamer
The idea that people will someday settle throughout the Galaxy was expressed many years ago by the Russian thinker Konstantin Eduardovich Tsiolkovsky.
In 1926, the scientist, summarizing his theoretical considerations, drew up a "Plan for the conquest of interplanetary spaces." According to him, initially, in near-earth orbit, it is necessary to mount "vast settlements" that exist due to solar energy. Then humanity will move from the nearest orbits into the asteroid belt, which can be used to build spaceships and cities. After the exploration of nearby stars is completed, the flying asteroid cities will embark on an interstellar voyage that could last tens or even hundreds of years. For Tsiolkovsky it did not matter how many generations would change on such a starship during the voyage. The main thing is that the goal will be achieved and people will settle along the Milky Way.
Since then, this idea has been diligently exploited by science fiction, making it part of the generally accepted image of our future. The flight to the stars is now considered only a stage in the colonization of the Milky Way and other galaxies. However, a century after the first speculative projects, we learned a lot about ourselves and the Universe, which calls into question the ease of galactic travel and the development of promising star systems.
The main problem is related to the size of the visible space of the Metagalaxy, not to mention the entire Universe. Even the closest Tau Ceti system to us is 12 light years from Earth, which is 100 billion times farther than the Moon.
Of course, it is unrealistic to cover such a distance in conventional spacecraft with chemical rocket fuel, operated by the same crew. You will need to build some kind of "space ark", large enough to transport not only people, but also animals with plants, and a fair amount of parts in case of a breakdown of the starship.
But a large ship will not be able to develop maximum speed, and it will be difficult for him to maneuver, not to mention braking at the end point.
There is one more stumbling block. Many such "arks" have long been launched on Earth: remember all these islands lost in the ocean. When meeting with civilization, the tribes that inhabited them - alas - could only boast of the ability to live in harmony with nature. There was a chasm between them and the rest of the world! But the "space ark" will be in much greater isolation than any earthly island …
Guinea pigs?
A flight to the stars will require either a long deep cryo-sleep or a high-quality artificial replacement of the Earth's environment. At the same time, it is impossible to predict in advance how effective such a replacement will be, designed to preserve the memories of the home planet: the situation is too complicated for modeling. Accordingly, any "stellar ark" will be an experiment, and its inhabitants - guinea pigs. Moreover, even if the first generation voluntarily agrees to "the torment of universal loneliness," then their descendants can behave completely unpredictable. It is even difficult to imagine what an interstellar mission could degenerate into if entire generations were born, live and die in a confined space a trillion times smaller than the Earth, without any possibility of leaving it.
In order for the experiment to continue under environmental constraints, the crew will have to adhere to strict rules. Some of the activities required for the ship to function will become mandatory. Accordingly, the choice of work will also not be free. The harsh conditions will eventually lead to a totalitarian system of the “ark” society, which is likely to trigger a wave of protests, riots, or even revolutions.
However, the real problems will begin when the crew of the "ark" successfully reaches the nearest planetary system.
Elementary logic dictates: it is almost unrealistic to find a planet sterile from harmful organisms with an earthly atmosphere and an acceptable climate. Most likely, such a new world would already have its inhabitants. Therefore, contact is inevitable, the consequences of which are impossible to predict.
The following option is more constructive and safe: the colonists will meet an extinct world like our Mars and “terraform” it using local resources. This, of course, will require a titanic work over the centuries. And all this time, the "ark" will remain the temporary home of the colonists.
The first step of space expansion
We realized that the main drawback of the projects of "ships of generations" is the threat of moral and social degradation of "star colonists". But besides this, there are many other difficulties, including the optimal choice of the goal of colonization, colonization itself, possible encounters with aliens and, finally, the probable senselessness of the project itself. Indeed, over the centuries of travel of the "ark", earthlings may well master some technologies "under spatial transitions" and in the blink of an eye find themselves in front of a ship worn out by "cosmic currents".
Of course, space robots will be the first to rush to the distant stars, although this does not correspond to the main principle of the "Ark" project - the colonization of space by mankind. The Starshot "laser" mini-probe is already being prepared. With the help of it, within the framework of the Breakthrough Starshot mission, the Russian millionaire Yuri Milner and the famous British physicist Stephen Hawking plan to reach Alpha Centauri. The technical part of the project is led by Californian physicist Philip Lubin.
According to calculations, a miniature cybernetic apparatus can reach Alpha Centauri in just a couple of decades. With this light, Starshot will reach Mars in a few days, and with ten-ton luggage - in about a month. Of course, he will also have problems with complex maneuvers and especially with braking. It will be difficult for him to move through interstellar clouds of gas and dust, because at such speeds even a microscopic speck of dust turns into a large-caliber projectile! And yet, most scientists enthusiastically perceive the Milner-Hawking project, seeing in it the first real step in the space expansion of mankind. And it may very well be that it really is so.
Oleg Arsenov