Galaxy colonization
I could never be attributed to the fierce optimists in the question of flying to other stars. Yes, I would very much like to believe that someday (I would like it earlier) we will find a practical way to move faster than light. But, alas, so far nothing portends his appearance.
However, recently I have been forced to bow to the fact that the colonization of other stellar systems is rather just a matter of time ...
The first problem that arises before us when trying to colonize other stellar systems is unimaginable distances.
There are many ideas how to overcome them using only well-known physical principles. Alas, most of these ideas are qualitative, and when you try to quantify them, everything collapses.
')
For example, there are ideas of acceleration using an electromagnetic gun of a particular design. Extending the "barrel" of the gun, you can achieve arbitrarily high speed (within the speed of light, of course). But let's estimate the required length of the trunk: if we want to get at least 10% of the speed of light, then with uniform acceleration of 1g it will take a month for which the ship will fly 300 astronomical units (radii of the earth orbit) ... Even if we assume the emergence of a technology that ensures human survival when accelerating 100g for many hours, the trunk will still be larger than the diameter of the Earth's orbit.
Well, let's accelerate differently - shine a hyper-powered laser in the solar sail. The laser beam has an infinite length, so it can accelerate at a distance of 300 astronomical units. But even here there are “small” problems: even if we omit the need for kilometer-sized laser optics, how to create a laser with an output power of hundreds of terawatts, i.e. a couple orders of magnitude more than the power of all the power plants of the world combined, it is absolutely not clear.
In addition, such projects do not solve the problem of braking at the end point of the path ...
But there is one realistic option - a thermonuclear engine.
Yes, so far the controlled thermonuclear fusion has not reached the stage of practical application, but it is already clear that here the question is purely technical. And even if, in the end, installation of gigantic dimensions is required, it is still a maximum of kilometers, and not of astronomical units. Estimates of the specific impulse for an engine based on an inertial confinement fusion reactor give a value of 1,000,000-2,000,000 seconds, or 10,000-20,000 km / s. Take the middle of this range - 15 000 km / s. This is 5% of the speed of light. Given that chemical rockets with a specific impulse of about 3.5 km / s can accelerate spacecraft to 14 km / s, we can expect that a rocket with a specific impulse at 5% of the speed of light will accelerate the spacecraft to 20%. However, you still need to slow down ... So the flight speed will be at 10% of the speed of light. is that enough?
The distance to the nearest stars is 4-5 light years. Those. hypothetically, they can be flown less than during the lifetime of one person - in 40-50 years. But here's the bad luck: near these stars no suitable planets for colonization were found.
The nearest star, near which planets were discovered, is potentially suitable for colonization — Tau Ceti. Before it, on a thermonuclear rocket has been flying for 120 years ...
On the one hand, there is a simple solution: the ship of generations. Those. a closed ecosystem is created in which astronauts “multiply and multiply” the entire flight. Only great-grandchildren of those who went to the flight reach the destination. But morally this option is absolutely unacceptable: after all, if the first crew consciously made the decision to fly a life-long, then for what their grandchildren are doomed to live their whole life in a “tin can” surrounded by endless darkness of emptiness is not at all clear. Moreover, if the first crew can be carefully selected and prepared, being sure that they will withstand it psychologically, then it is too optimistic to expect that their grandchildren will not go crazy with such a fate.
However, the last ten years periodically hear the news of successful experiments on anabiosis. Until now, anabiosis was immersed, at best, pigs, but this year in Pittsburgh, Pennsylvania, they are going (and perhaps have already managed) to try for a few hours to immerse the seriously injured people in anabiosis, which it is impossible to save without it. This is another matter altogether ... Of course, the idea even to temporarily replace all of its blood with a special liquid and to be frozen after that does not look very attractive, but for colonization of the galaxy you can’t do anything. A ship with 1200 settlers in a “freeze” and a dozen “on watch” looks quite realistic. Each year, the watch is replaced, so that all 1200 will have time to stay on it for one year, and in one it will go through the “conservation” procedure twice. Upon arrival, all the colonists are "brought to life" and are engaged in the development of a new planet.
But one unresolved hitch: of those who send the colonists on their way, no one will ever even know about success will die earlier. There is no question whatsoever of this colonization for those who remain on Earth. So why is this necessary?
As a matter of fact, it was the last paragraph of the last paragraph that was the basis of my skepticism for many years: even if technical problems can be overcome, volunteers can also be found for an expedition to hell, but why would someone invest insane money and other resources in a project that promises nothing practically useful?
Everything decisively changed with the advent of the Mars One project: even if he himself failed, the idea of ​​making a grand show of a basically meaningless expedition to colonize another planet obviously would not die. Sooner or later, mankind will master the entire solar system, bring the technology of anabiosis to perfection, develop the technology of a thermonuclear engine to the required level and study the planets of nearby stars with automatic probes. And there will definitely be someone who considers the income from the interstellar scale show sufficient for astronomical investments in the first manned spacecraft. Thousands, perhaps only hundreds of years, will pass, and history will repeat again, not in the Solar System anymore, but in a new colony that will send the ship to where no man’s foot has yet gone.
Since I am writing about the inevitability of humanity’s colonization of the Galaxy, one cannot help but touch upon the question of why we have not yet arrived to us from other planets.
The authors often assume that the exponential growth in the number of colonies should lead to the colonization of the entire Galaxy in a relatively short time - tens of millions of years maximum. And since tens of millions of years in terms of the lifetime of stars is nothing, our planet should have been colonized by a highly developed civilization even before our appearance. It is concluded from this that there are simply no other civilizations.
But, forgive me, where does the exponent come from? .. So far, in the immediate environment of the Earth, besides Tau Ceti, one can count on the suitability for colonization of only the planets of the star Gliese 581, which is already more than 200 years of flight. And then there is every chance that the atmospheres of her planets were frozen out on their dark side, then there is no such option either. It is quite logical to assume that no more than a couple of new expeditions will be able to send colonies, and some will not even find directions for flight, except back to the parent colony. In such a situation, the increase in the number of colonies may even be just linear, and then the time of the "capture" of the Galaxy exceeds the age of the Universe by orders of magnitude. Even with a more optimistic scenario, it will still be about billions of years. And this is very serious, even on an astronomical scale.
However, recently I have been forced to bow to the fact that the colonization of other stellar systems is rather just a matter of time ...
Spaceship
The first problem that arises before us when trying to colonize other stellar systems is unimaginable distances.
There are many ideas how to overcome them using only well-known physical principles. Alas, most of these ideas are qualitative, and when you try to quantify them, everything collapses.
')
For example, there are ideas of acceleration using an electromagnetic gun of a particular design. Extending the "barrel" of the gun, you can achieve arbitrarily high speed (within the speed of light, of course). But let's estimate the required length of the trunk: if we want to get at least 10% of the speed of light, then with uniform acceleration of 1g it will take a month for which the ship will fly 300 astronomical units (radii of the earth orbit) ... Even if we assume the emergence of a technology that ensures human survival when accelerating 100g for many hours, the trunk will still be larger than the diameter of the Earth's orbit.
Well, let's accelerate differently - shine a hyper-powered laser in the solar sail. The laser beam has an infinite length, so it can accelerate at a distance of 300 astronomical units. But even here there are “small” problems: even if we omit the need for kilometer-sized laser optics, how to create a laser with an output power of hundreds of terawatts, i.e. a couple orders of magnitude more than the power of all the power plants of the world combined, it is absolutely not clear.
In addition, such projects do not solve the problem of braking at the end point of the path ...
But there is one realistic option - a thermonuclear engine.
Yes, so far the controlled thermonuclear fusion has not reached the stage of practical application, but it is already clear that here the question is purely technical. And even if, in the end, installation of gigantic dimensions is required, it is still a maximum of kilometers, and not of astronomical units. Estimates of the specific impulse for an engine based on an inertial confinement fusion reactor give a value of 1,000,000-2,000,000 seconds, or 10,000-20,000 km / s. Take the middle of this range - 15 000 km / s. This is 5% of the speed of light. Given that chemical rockets with a specific impulse of about 3.5 km / s can accelerate spacecraft to 14 km / s, we can expect that a rocket with a specific impulse at 5% of the speed of light will accelerate the spacecraft to 20%. However, you still need to slow down ... So the flight speed will be at 10% of the speed of light. is that enough?
Live to land
The distance to the nearest stars is 4-5 light years. Those. hypothetically, they can be flown less than during the lifetime of one person - in 40-50 years. But here's the bad luck: near these stars no suitable planets for colonization were found.
The nearest star, near which planets were discovered, is potentially suitable for colonization — Tau Ceti. Before it, on a thermonuclear rocket has been flying for 120 years ...
On the one hand, there is a simple solution: the ship of generations. Those. a closed ecosystem is created in which astronauts “multiply and multiply” the entire flight. Only great-grandchildren of those who went to the flight reach the destination. But morally this option is absolutely unacceptable: after all, if the first crew consciously made the decision to fly a life-long, then for what their grandchildren are doomed to live their whole life in a “tin can” surrounded by endless darkness of emptiness is not at all clear. Moreover, if the first crew can be carefully selected and prepared, being sure that they will withstand it psychologically, then it is too optimistic to expect that their grandchildren will not go crazy with such a fate.
However, the last ten years periodically hear the news of successful experiments on anabiosis. Until now, anabiosis was immersed, at best, pigs, but this year in Pittsburgh, Pennsylvania, they are going (and perhaps have already managed) to try for a few hours to immerse the seriously injured people in anabiosis, which it is impossible to save without it. This is another matter altogether ... Of course, the idea even to temporarily replace all of its blood with a special liquid and to be frozen after that does not look very attractive, but for colonization of the galaxy you can’t do anything. A ship with 1200 settlers in a “freeze” and a dozen “on watch” looks quite realistic. Each year, the watch is replaced, so that all 1200 will have time to stay on it for one year, and in one it will go through the “conservation” procedure twice. Upon arrival, all the colonists are "brought to life" and are engaged in the development of a new planet.
But one unresolved hitch: of those who send the colonists on their way, no one will ever even know about success will die earlier. There is no question whatsoever of this colonization for those who remain on Earth. So why is this necessary?
Financing
As a matter of fact, it was the last paragraph of the last paragraph that was the basis of my skepticism for many years: even if technical problems can be overcome, volunteers can also be found for an expedition to hell, but why would someone invest insane money and other resources in a project that promises nothing practically useful?
Everything decisively changed with the advent of the Mars One project: even if he himself failed, the idea of ​​making a grand show of a basically meaningless expedition to colonize another planet obviously would not die. Sooner or later, mankind will master the entire solar system, bring the technology of anabiosis to perfection, develop the technology of a thermonuclear engine to the required level and study the planets of nearby stars with automatic probes. And there will definitely be someone who considers the income from the interstellar scale show sufficient for astronomical investments in the first manned spacecraft. Thousands, perhaps only hundreds of years, will pass, and history will repeat again, not in the Solar System anymore, but in a new colony that will send the ship to where no man’s foot has yet gone.
So why haven't you arrived yet?
Since I am writing about the inevitability of humanity’s colonization of the Galaxy, one cannot help but touch upon the question of why we have not yet arrived to us from other planets.
The authors often assume that the exponential growth in the number of colonies should lead to the colonization of the entire Galaxy in a relatively short time - tens of millions of years maximum. And since tens of millions of years in terms of the lifetime of stars is nothing, our planet should have been colonized by a highly developed civilization even before our appearance. It is concluded from this that there are simply no other civilizations.
But, forgive me, where does the exponent come from? .. So far, in the immediate environment of the Earth, besides Tau Ceti, one can count on the suitability for colonization of only the planets of the star Gliese 581, which is already more than 200 years of flight. And then there is every chance that the atmospheres of her planets were frozen out on their dark side, then there is no such option either. It is quite logical to assume that no more than a couple of new expeditions will be able to send colonies, and some will not even find directions for flight, except back to the parent colony. In such a situation, the increase in the number of colonies may even be just linear, and then the time of the "capture" of the Galaxy exceeds the age of the Universe by orders of magnitude. Even with a more optimistic scenario, it will still be about billions of years. And this is very serious, even on an astronomical scale.
Source: https://habr.com/ru/post/362281/
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