Sooner or later, humanity will have to leave Earth and go in search of a new home - a planet with similar living conditions - in order to build a new civilization there.
For such a large-scale journey, people will need to build a kind of "Noah's Ark" - a spaceship capable of crossing the galaxy and delivering the first settlers to a new place of residence, wherever it is.
How long will this great migration take? And what size should a spaceship be so that it would be possible to take there not only "every creature in pairs", but also everything necessary for the continuation of life and the development of a new world?
A team of scientists from France and the Czech Republic tried to answer these questions by launching the Heritage project and carrying out the necessary calculations.
Thousands of years of journey
At first glance, it may seem that the size of the ship strongly depends on where exactly we are flying, but this is not entirely true.
The fact is that the journey even to the nearest star system will take at least hundreds, if not thousands of years - which means that our ark must be able to support life for many generations.
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Of course, space technologies are constantly improving. However, if you believe not the science fiction writers and screenwriters of Hollywood, but Einstein and his theory of relativity, travel at superluminal speeds, to put it mildly, is unlikely.
Hypothetical options like a wormhole or an Alcubierre bubble are possible, but you can't count on them.
NASA scientists announced last year that a surprisingly Earth-like planet orbiting Proxima Centauri, the closest star to our Sun, may be habitable.
Having considered all the available technologies - both existing and not yet invented, but possible in theory - scientists have calculated that the flight to this planet, in the most optimistic scenario, will take at least a century.
More realistic estimates drive us into depression at all: if we fly to Proxima Centauri today, we will reach our destination in thousands of years (from 6 to 80 thousand, to be exact).
In any case, we need a ship on which the settlers will be able to live for generations in interstellar space, while feeding on something on their own and supplying energy to the engines.
Forget about solar panels - they will not work at such a distance from the Sun: you can charge your smartphone from the light of the stars with about the same success at night.
So how many "Star Colonizers" have to hit the road? And how big should the space ark itself be?
A pair of each creature?
If several generations must change during the journey on the ship, its inhabitants will have to reproduce.
Here you can't get by with new Adam and Eve: there should be enough immigrants to exclude the possibility of incest among close relatives. Otherwise, genetic diseases cannot be avoided on the ship.
French scientists calculated the minimum number of crew members using mathematical modeling.
They tried to take into account all factors - the age of earthlings at the time of departure and life expectancy, the possibility of infertility of some crew members, miscarriages or the birth of twins, and even unforeseen circumstances (in the calculations they appear as an "element of chaos" - for example, the secret birth of a child from another biological father) …
In addition, just in case, the calculations included a "catastrophic event" - for example, a collision of a ship with a meteorite or an epidemic of a disease on board - which at some point will reduce the population of colonizers by 30%.
Taking into account all these factors, according to the most conservative and conservative estimates of researchers, initially there should be 98 colonizers. Moreover, all 49 married couples should be initially selected for DNA analysis to ensure maximum genetic diversity.
If a more modest crew sets out on the road, the success of the mission will already be in question. For example, the chances of survival for 25 married couples are already estimated at about 50%.
And if there are only 32 or even fewer displaced persons, the algorithm leaves them no chance at all (0%) - mainly because of the inevitable incest. Perhaps the descendants of the original crew will fly to Proxima Centauri, but by that time they will no longer be able to establish a viable colony.
Hunger is not aunt
After leaving the Earth, 98 space travelers will give birth to children, and those - grandchildren, even during the life of the first generation. So, judging by the calculations, the maximum population of the ark can reach 500 people.
Given the length of the flight, one cannot count on food supplies. The colonialists will have to provide themselves with food on their own - that is, grow it directly on the ship.
But how much food do they need? After all, the size of the ship depends on this - and therefore the energy consumption for its movement.
These calculations required taking into account not only the size of the crew, but also the average age of the inhabitants of the starship, their height, weight and level of physical activity, in order to understand how many calories they will need each year.
Scientists did not limit the colonizers in the diet and calculated the consumption taking into account the normal diet - that is, so that the ship could not only grow fruits and vegetables (including the production of sugar and vegetable oil), but also engage in animal husbandry - that is, produce meat, fish, dairy products and honey.
Surprisingly, taking into account the use of modern technologies (for example, aeroponics - that is, growing plants in the air, without using soil), half a square kilometer is enough to feed 500 people (0.45 - to be exact).
All aboard
This brings us to the minimum size of our ark.
If we build a ship in the form of a rotating cylinder (so that the centripetal force provides artificial gravity), then the height of the "agricultural compartment" should be 320 meters, and the radius - 224 meters.
Add to this the crew quarters, common areas (such as the dining room, gym, or medical bay), flight control rooms, power generators and engines, and the space (height) of the starship will approximately double. The space ark will be approximately 650 meters high and 450 in diameter.
However, it will still be less than the tallest of the skyscrapers already built: the height of the Burj Khalifa in Dubai is 828 meters. For comparison: the height of the spire of the Ostankino tower is 540 meters, of the Eiffel tower - 324. The ISS is 73 meters long and 20 meters high.
Now the most difficult thing, according to scientists, is to calculate the exact amount of water needed. Just for drinking it will need almost half a million liters. And you also need to water the animals, irrigate the crops - and the ship will, one way or another, gradually lose water along with the air.
This problem, as well as the problem of genetic mutations, the authors of Heritage promise to solve in their next scientific work.
Nikolay Voronin