The solar system has long been of no particular interest to science fiction writers. But, surprisingly, for some scientists, our "home" planets do not cause much inspiration, although they have not yet been practically explored.
Having barely cut a window into space, mankind is torn into unknown distances, and not only in dreams, as before.
Sergei Korolev also promised to soon fly into space "on a trade union ticket", but this phrase is already half a century old, and the space odyssey is still the lot of the elite - too expensive a pleasure. However, two years ago, HACA launched the ambitious 100 Year Starship project, which involves a phased and multi-year creation of the scientific and technical foundation for space flights.
This unparalleled program should attract scientists, engineers and enthusiasts from around the world. If everything is crowned with success, in 100 years mankind will be able to build an interstellar ship, and we will move around the solar system like on trams.
So what problems need to be solved for starflying to become a reality?
TIME AND SPEED ARE RELATIVE
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Astronautics of automatic vehicles seem to some scientists to be an almost solved problem, oddly enough. And this despite the fact that there is absolutely no point in launching machines to the stars with the current snail speeds (about 17 km / s) and other primitive (for such unknown roads) equipment.
Now the American spacecraft Pioneer-10 and Voyager-1 have left the solar system, and there is no longer any connection with them. Pioneer 10 is heading towards the star Aldebaran. If nothing happens to him, he will reach the vicinity of this star … in 2 million years. In the same way, other devices crawl across the expanses of the Universe.
So, regardless of whether a ship is inhabited or not, to fly to the stars, it needs a high speed, close to the speed of light. However, this will help solve the problem of flying only to the closest stars.
“Even if we managed to build a star ship that could fly at a speed close to the speed of light,” wrote K. Feoktistov, “the travel time in our Galaxy alone will be counted in millennia and tens of millennia, since its diameter is about 100,000 light years old. But much more will pass on Earth during this time."
According to the theory of relativity, the course of time in two systems moving one relative to the other is different. Since at great distances the ship will have time to develop a speed very close to the speed of light, the difference in time on Earth and on the ship will be especially great.
It is assumed that the first target of interstellar flights will be Alpha Centauri (a system of three stars) - the closest to us. You can fly there at the speed of light in 4.5 years, on Earth during this time it will take ten years. But the greater the distance, the greater the difference in time.
Remember the famous "Andromeda Nebula" by Ivan Efremov? There, the flight is measured in years, and earthly. A beautiful fairy tale, you will not say anything. However, this coveted nebula (more precisely, the Andromeda galaxy) is located at a distance of 2.5 million light years from us.
According to some calculations, the journey will take more than 60 years for astronauts (according to starship hours), but a whole era will pass on Earth. How will their distant descendants meet the space "Neaderthals"? And will the Earth be alive at all? That is, returning is basically meaningless. However, like the flight itself: we must remember that we see the Andromeda nebula galaxy as it was 2.5 million years ago - as long as its light travels to us. What is the point of flying to an unknown target, which, perhaps, has not existed for a long time, at least in its former form and in the old place?
This means that even flights with the speed of light are justified only to relatively close stars. However, vehicles flying at the speed of light are still living only in theory, which resembles science fiction, however, scientific.
PLANET SIZE SHIP
Naturally, first of all, scientists came up with the idea to use the most effective thermonuclear reaction in the ship's engine - as already partially mastered (for military purposes). However, to travel in both directions at a speed close to light, even with an ideal system design, a ratio of the initial mass to the final mass is required not less than 10 to the thirtieth power. That is, the spaceship will be like a huge composition with fuel the size of a small planet. It is impossible to launch such a colossus into space from Earth. And to assemble in orbit - too, not without reason scientists do not discuss this option.
The idea of a photon engine using the principle of matter annihilation is very popular.
Annihilation is the transformation of a particle and antiparticle, when they collide, into any other particles different from the original ones. The best studied is the annihilation of an electron and a positron, which generates photons, the energy of which will move the spaceship. Calculations by American physicists Ronan Keane and Wei-ming Zhang show that modern technologies can be used to create an annihilation engine capable of accelerating a spacecraft to 70% of the speed of light.
However, further problems begin. Unfortunately, using antimatter as propellant is not easy. During annihilation, bursts of powerful gamma radiation occur, which are fatal to astronauts. In addition, contact of the positron fuel with the ship is fraught with a fatal explosion. Finally, there are still no technologies for obtaining a sufficient amount of antimatter and its long-term storage: for example, an antihydrogen atom “lives” now for less than 20 minutes, and the production of a milligram of positrons costs 25 million dollars.
But, suppose, over time, these problems can be resolved. However, a lot of fuel will still be needed, and the starting mass of the photon starship will be comparable to the mass of the Moon (according to Konstantin Feoktistov).
BREAK THE SAIL
The most popular and realistic starship today is considered a solar sailing ship, the idea of which belongs to the Soviet scientist Friedrich Zander.
A solar (light, photon) sail is a device that uses the pressure of sunlight or a laser on a mirror surface to propel a spacecraft.
In 1985, the American physicist Robert Forward proposed a design for an interstellar probe accelerated by the energy of microwave radiation. The project envisioned that the probe would reach the nearest stars in 21 years.
At the XXXVI International Astronomical Congress, a project of a laser starship was proposed, the motion of which is provided by the energy of lasers in the optical range, located in orbit around Mercury. According to calculations, the path of a starship of this design to the star epsilon Eridani (10.8 light years) and back would take 51 years.
“It is unlikely that the data obtained from travels in our solar system, we will be able to make significant progress in understanding the world in which we live. Naturally, thought turns to the stars. After all, earlier it was understood that flights near the Earth, flights to other planets of our solar system are not the ultimate goal. Paving the way to the stars seemed like the main task."
These words do not belong to a science fiction writer, but to the designer of spaceships and cosmonaut Konstantin Feoktistov. According to the scientist, nothing particularly new in the solar system will be found. And this despite the fact that the person has so far only reached the moon …
However, outside the solar system, the pressure of sunlight will approach zero. Therefore, there is a project to disperse a solar sailing ship with laser installations from some asteroid.
All this is still a theory, but the first steps are already being taken.
In 1993, a 20-meter-wide solar sail was first deployed on the Russian Progress M-15 ship as part of the Znamya-2 project. When the Progress docked with the Mir station, its crew installed a reflector deployment unit on board Progress. As a result, the reflector created a bright spot 5 km wide, which passed through Europe to Russia at a speed of 8 km / s. The spot of light had a luminosity roughly equivalent to the full moon.
So, the advantage of a solar sailboat is the lack of fuel on board, the disadvantages are the vulnerability of the sail structure: in fact, it is a thin foil stretched over the frame. Where is the guarantee that on the way the sail will not receive holes from cosmic particles?
The sailing option may be suitable for launching robotic probes, stations and cargo ships, but not suitable for manned return flights. There are other spaceship projects, but they, in one way or another, resemble the ones listed above (with the same large-scale problems).
SURPRISES IN THE INTERSTELLAR SPACE
It seems that many surprises await travelers in the Universe. For example, barely leaning out of the solar system, the American spacecraft Pioneer-10 began to experience a force of unknown origin, causing weak deceleration. Many assumptions have been made, up to the yet unknown effects of inertia or even time. There is still no unambiguous explanation for this phenomenon; a variety of hypotheses are being considered: from simple technical ones (for example, the reactive force from a gas leak in the apparatus) to the introduction of new physical laws.
Another device, Voyadger-1, recorded an area with a strong magnetic field on the border of the solar system. In it, the pressure of charged particles from interstellar space forces the field created by the Sun to become denser. The device also registered:
an increase in the number of high-energy electrons (about 100 times) that penetrate into the solar system from interstellar space;
a sharp rise in the level of galactic cosmic rays - high-energy charged particles of interstellar origin.
And this is just a drop in the ocean! However, what is known today about the interstellar ocean is enough to cast doubt on the very possibility of surfing the vastness of the Universe.
The space between the stars is not empty. There are residues of gas, dust, particles everywhere. When trying to move at a speed close to the speed of light, each atom colliding with the ship will be like a particle of cosmic rays of high energy. The level of hard radiation during such a bombardment will inadmissibly increase even when flying to the nearest stars.
And the mechanical effect of particles at such speeds is like explosive bullets. According to some calculations, every centimeter of the starship's shield will be continuously fired at 12 rounds per minute. It is clear that no screen can withstand such an impact for several years of flight. Or it will have to have an unacceptable thickness (tens and hundreds of meters) and mass (hundreds of thousands of tons).
Actually, then the spaceship will consist mainly of this screen and fuel, which will require several million tons. Due to these circumstances, flights at such speeds are impossible, especially since on the way you can run into not only dust, but also something larger, or get trapped in an unknown gravitational field. And then death is again inevitable. Thus, if it is possible to accelerate the spaceship to subluminal speed, then it will not reach the final goal - it will encounter too many obstacles on its way. Therefore, interstellar flights can be carried out only at significantly lower speeds. But then the time factor makes these flights meaningless.
It turns out that it is impossible to solve the problem of transporting material bodies over galactic distances with speeds close to the speed of light. It makes no sense to burst through space and time with a mechanical structure.
MOLE HOLE
Scientists, trying to overcome the inexorable time, have invented how to “gnaw holes” in space (and time) and “fold” it. They invented a variety of hyperspace jumps from one point in space to another, bypassing intermediate areas. Now scientists have joined the science fiction writers.
Physicists began to look for extreme states of matter and exotic loopholes in the Universe, where you can move at superluminal speed, contrary to Einstein's theory of relativity.
This is how the idea of a wormhole came about. This hole brings together the two parts of the Universe like a cut through a tunnel connecting two cities separated by a high mountain. Unfortunately, wormholes are only possible in an absolute vacuum. In our Universe, these burrows are extremely unstable: they can simply collapse before a spacecraft gets there.
However, the effect discovered by the Dutchman Hendrik Casimir can be used to create stable wormholes. It consists in the mutual attraction of conducting uncharged bodies under the influence of quantum oscillations in a vacuum. It turns out that the vacuum is not completely empty, it is subject to fluctuations in the gravitational field, in which particles and microscopic wormholes spontaneously appear and disappear.
It remains only to find one of the holes and stretch it, placing it between two superconducting balls. One mouth of the wormhole will remain on Earth, while the other spacecraft will move at near-light speed to the star - the final object. That is, the spaceship will, as it were, pierce a tunnel. Once the starship reaches its destination, the wormhole will open for real lightning-fast interstellar travel, the duration of which will be calculated in minutes.
BUBBLE OF CURVATION
Akin to the theory of wormholes is bubble curvature. In 1994, the Mexican physicist Miguel Alcubierre performed calculations according to Einstein's equations and found the theoretical possibility of wave deformation of the spatial continuum. In this case, space will shrink in front of the spacecraft and simultaneously expand behind it. The spaceship is, as it were, placed in a curvature bubble, capable of moving with unlimited speed. The genius of the idea is that the spaceship rests in a bubble of curvature, and the laws of relativity are not violated. In this case, the curvature bubble itself moves, locally distorting space-time.
Despite the inability to travel faster than light, nothing prevents space from moving or the propagation of deformation of space-time faster than light, which is believed to have happened immediately after the Big Bang during the formation of the universe.
All these ideas do not yet fit into the framework of modern science, but in 2012, NASA representatives announced the preparation of an experimental test of Dr. Alcubierre's theory. Who knows, maybe Einstein's theory of relativity will someday become part of a new global theory. After all, the process of cognition is endless. This means that one day we will be able to break through the thorns to the stars.
Irina GROMOVA