The Death Star is a colossal weapon the size of a good moon. Shooting point-blank at the defenseless planet Alderaan, the homeland of Princess Leia, the Death Star completely destroys it. The planet disappears in the flames of a titanic explosion, scattering debris throughout the solar system. A billion souls simultaneously scream in agony, causing an outrage in the Force that is felt anywhere in the galaxy.
But is a weapon like the Death Star from the Star Wars movie really possible? Is it possible to organize and direct a battery of laser cannons so that an entire planet evaporates as a result? What about the famous lightsabers that Luke Skywalker and Darth Vader wielded, which are a beam of light but can easily cut through armored steel? Will rayguns, like the phasers in Star Trek, become the right weapon for future generations of law enforcement and soldiers?
The new, original and mind-boggling Star Wars special effects made a compelling impression on millions of viewers, but critics had a different opinion. Some of them argued that yes, of course, the filmmakers sincerely tried to entertain the viewer, but in fact, such things are completely impossible. Critics never tired of repeating like an incantation: beam cannons the size of the moon, capable of blowing an entire planet to small pieces, is something unheard of; swords from a suddenly solidifying light beam are also impossible. All this is too much even for a distant, distant galaxy. This time, George Lucas, the acclaimed master of special effects, skidded a bit.
It may be hard to believe, but an unlimited amount of energy can be “stuffed” into a light beam; there are no physical limitations. The creation of a Death Star or lightsaber does not contradict any laws of physics. Moreover, beams of gamma radiation capable of blowing up the planet actually exist in nature. The titanic burst of radiation generated by a distant mysterious source of gamma-ray bursts is capable of creating an explosion in deep space, second only in power to the Big Bang itself. Any planet that manages to be in the sight of such a "gun" will actually be fried or torn to pieces.
Beam weapons in history
The dream of harnessing radiation energy is not really new at all; its roots go back to ancient religion and mythology. The Greek god Zeus is famous for shooting mortals with lightning. The northern god Thor wielded a magic hammer, Mjellnir, capable of throwing lightning, while the Hindu god Indra fired an energy beam from a magic spear.
The idea of the ray as a real practical weapon first appeared in the works of the great Greek mathematician Archimedes, perhaps the greatest scientist of antiquity, who managed to develop his own version of primitive differential calculus two thousand years before Newton and Leibniz. It is believed that in the legendary battle of 214 BC. against the troops of the Roman general Marcellus during the Second Punic War, Archimedes, helping to defend the Syracuse kingdom, built a large battery of solar reflectors, focused the sun's rays on the sails of enemy ships and thus set them on fire. (Scientists are still debating whether such a beam weapon could actually work; several groups of scientists have tried, with varying results, to replicate this achievement.)
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Beam guns hit the pages of science fiction in 1889 with HG Wells' classic War of the Worlds. In this novel, aliens from Mars destroyed entire cities by directing beams of thermal energy from cannons mounted on their tripods to them. During World War II, the Nazis, always ready to research and adopt the latest technological advances in order to use them to conquer the world, also experimented with various types of ray guns, including acoustic devices that focused powerful sound beams using parabolic mirrors.
The weapon, which is a focused beam of light, captured the public's imagination after the release of the James Bond movie Goldfinger; it was the first Hollywood movie to feature a laser. (In it, the legendary British spy was tied to a metal table, and a powerful laser beam slowly approached him, gradually melting the table between his legs and threatening to cut the hero in half.)
Initially, physicists only laughed at the idea of beam guns, expressed in Wells' novel, because such guns violated the known laws of optics. According to Maxwell's equations, the light that we see around us is incoherent (i.e., it is a jumble of waves with different frequencies and phases) and quickly scatters. It was once believed that a coherent, focused, uniform beam of light - such as a laser beam - was impossible to achieve.
Quantum revolution
Everything changed after the advent of quantum theory. Already at the beginning of the XX century. it became clear that, although Newton's laws and Maxwell's equations very successfully describe the motion of planets and the behavior of light, there is a whole class of phenomena that they cannot explain. Sadly, they did not say anything about why materials conduct electricity, why metals melt at certain temperatures, why gases emit light when heated, why some substances become superconductive at low temperatures. To answer any of these questions, you need to understand the internal dynamics of atoms. The revolution is ripe. Newtonian physics, after 250 years of domination, awaited its overthrow; at the same time, the collapse of the old idol was supposed to herald the beginning of the labor pains of the new physics.
In 1900, Max Planck in Germany suggested that energy is not continuous, as Newton believed, but exists in the form of small discrete "portions" called "quanta". Then, in 1905, Einstein postulated that light is also composed of these tiny discrete packets (or quanta), later called photons. With this simple yet powerful idea, Einstein was able to explain the photoelectric effect, namely why metals, when irradiated with light, emit electrons. Today, the photoelectric effect and the photon are the basis for television, lasers, solar panels, and much of modern electronics. (Einstein's theory of the photon was so revolutionary that even Max Planck, who usually ardently supported Einstein, at first could not believe in it. Planck wrote about Einstein: “The factthat sometimes he misses … as, for example, he did with the hypothesis of light quanta, one cannot, in all conscience, blame him. ")
Then in 1913 the Danish physicist Niels Bohr gave us a completely new picture of the atom; Bohr's atom resembled a miniature solar system. But, unlike the real solar system, electrons in an atom can move around the nucleus only within discrete orbits or shells. When an electron "jumps" from one shell to another, which is closer to the nucleus and has less energy, it emits a photon of energy. Conversely, when an electron absorbs a photon with a certain energy, it "jumps" higher, to a shell that is farther from the nucleus and has more energy.
In 1925, with the advent of quantum mechanics and the revolutionary work of Erwin Schrödinger, Werner Heisenberg and many others, an almost complete theory of the atom was born. According to quantum theory, an electron was a particle, but it also had an associated wave, which gave it both the properties of a particle and a wave. This wave obeyed the so-called Schrödinger wave equation, which made it possible to calculate the properties of the atom, including all the "jumps" of electrons postulated by Bohr.
Until 1925, atoms were considered mysterious objects; many, like the philosopher Ernst Mach, did not believe in their existence at all. After 1925 man had the opportunity not only to look deeply into the dynamics of the atom, but also to predict its properties quite reliably. Surprisingly, this meant that with a sufficiently powerful computer at hand, one could deduce the properties of chemical elements directly from the laws of quantum theory. Just as Newtonian physics, with a sufficiently large computing machine, would allow scientists to calculate the motion of all celestial bodies in the universe, quantum physics, according to scientists, made it possible in principle to calculate all the properties of the chemical elements of the universe. In addition, having a sufficiently powerful computer,one could compose the full wave function of a human being.
Masers and lasers
In 1953, Professor Charles Townes of the University of California at Berkeley, together with his colleagues, managed to obtain the first beam of coherent radiation, namely microwaves. The device was called a maser (maser - after the first letters of the words of the phrase "microwave amplification through stimulated emission of radiation", that is, "amplification of microwaves through the stimulation of radiation.") Later, in 1964, Townes, together with Russian physicists Nikolai Basov and Alexander Prokhorov received the Nobel Prize. Soon, the scientists' results were extended to visible light. The laser was born. (The phaser, on the other hand, is a fantastic device made famous by Star Trek.)
The basis of the laser is a special medium that will actually transmit the laser beam; it can be a special gas, crystal or diode. Then you need to pump energy into this environment from the outside - using electricity, radio waves, light or a chemical reaction. The unexpected influx of energy excites the atoms in the medium, causing the electrons to absorb energy and jump onto the higher-energy outer electron shells.
In such an excited, pumped state, the medium becomes unstable. If, after that, a beam of light is sent through it, then the photons of the beam, colliding with the atoms, will cause a sudden dump of electrons to lower orbits and the release of additional photons. These photons, in turn, will cause even more electrons to emit photons - and soon a chain reaction of atoms "collapse" to an unexcited state will begin with the almost simultaneous release of a huge amount of photons - trillions and trillions of them - all into the same beam. The fundamental feature of this process is that in some substances, with an avalanche-like release, all photons vibrate in unison, that is, they are coherent.
(Imagine dominoes lined up in a row. In the lowest energy state, each knuckle lies flat on the table. In the high-energy, inflated state, the knuckles stand upright, like the inflated atoms of a medium. By pushing one knuckle, you can cause a sudden simultaneous release of all this energy, just like the same as it happens when the laser beam is born.)
Only a few materials are capable of working in a laser; this means that only in special substances when a photon collides with an excited atom, a photon is emitted that is coherent to the first. This property of matter leads to the fact that all the photons in the emerging stream vibrate in unison, creating a thin laser beam. (Contrary to popular legend, the laser beam does not always remain as thin as at the very beginning. For example, a laser beam fired into the Moon will gradually expand along the way and give a spot several kilometers in size on the surface of the Moon.)
A simple gas laser is a tube filled with a mixture of helium and neon. When electricity is passed through the tube, the atoms absorb energy and become excited. Then, if there is a sudden release of all the energy stored in the gas, a beam of coherent light is born. This beam is amplified by two mirrors installed at both ends of the tube, so that the beam is reflected from them in turn and rushes along the tube from side to side. One of the mirrors is completely opaque, but the other transmits a small fraction of the incident light, thus releasing the beam outward.
Today, lasers can be found everywhere - in the grocery store cash register, in the fiber optic cable that gives you access to the Internet, in a laser printer or CD player, and in a modern computer. Lasers are used in eye surgery, tattoo removal, and even in beauty salons. In 2004, lasers were sold worldwide for more than $ 5.4 billion.
Types of lasers and their features
New lasers are being discovered almost every day now; as a rule, we are talking about the discovery of a new substance that can work in a laser, or the invention of a new method of pumping energy into the working fluid.
The question is, are these technologies suitable for making ray guns or lightsabers? Can you build a laser big enough to power the Death Star? Today, there is a staggering variety of lasers that can be classified according to the material of the working fluid and the way in which energy is pumped (it could be electricity, a powerful light beam, even a chemical explosion). We list several types of lasers.
• Gas lasers. This category also includes the extremely common helium-neon lasers, which produce a very familiar red beam. They are pumped up with radio waves or electricity. Helium-neon lasers are low-power. But carbon dioxide gas lasers can be used for blasting operations, for cutting and smelting metals in heavy industry; they are capable of giving an extremely powerful and completely invisible beam;
• Chemical lasers. These powerful lasers are charged by chemical reactions such as the combustion of ethylene and nitrogen trifluoride NF3. These lasers are powerful enough to be used in the military field. In the United States, the chemical principle of pumping is used in air and ground combat lasers capable of delivering a beam of power in the millions of watts and designed to shoot down short-range missiles in flight.
• Excimer lasers. These lasers also get their energy from a chemical reaction, which usually involves an inert gas (i.e., argon, krypton, or xenon) and some kind of fluoride or chloride. They emit ultraviolet light and can be used in the electronics industry to etch tiny transistors on semiconductor chips, and in eye surgery for delicate Lasik operations.
• Semiconductor lasers. The diodes we use so widely in all kinds of electronic devices can produce powerful laser beams that are used in cutting and welding industries. These same semiconductor lasers also work in cash registers, reading barcodes from your chosen products.
• Dye lasers. These lasers use organic dyes as a working medium. They are extremely useful in generating ultra-short pulses of light, which are often on the order of one trillionth of a second.
Lasers and beam guns?
Given the vast variety of commercial lasers and the power of military lasers, it’s hard not to wonder why we don’t have ray guns and cannons that are usable on the battlefield? In science fiction films, ray guns and pistols of one sort or another are usually the most common and familiar weapons. Why aren't we working on such a weapon?
The simple answer to this question is that we do not have sufficient portable power sources. This is not a trifle. Beam weapons would require miniature batteries the size of a palm, but matching the power of a huge power plant. Currently, the only way to get the power of a large power plant for use is to build one. And the smallest military device that can serve as a container for such energies is a miniature hydrogen bomb, which, unfortunately, can destroy not only the target, but yourself.
There is also a second problem - the stability of the emitting substance, or working fluid. In theory, there is no limit to the amount of energy that can be pumped into a laser. But the problem is that the working body of a hand-held laser pistol would be unstable. Crystal lasers, for example, overheat and crack if you pump too much energy into them. Consequently, creating an extremely powerful laser - one that could vaporize an object or neutralize an enemy - might require explosive energy. In this case, naturally, one can no longer think about the stability of the working fluid, because our laser will be disposable.
Problems with the creation of portable power sources and stable emitting materials make the existence of ray guns impossible with the current state of the art. In general, you can create a ray gun only if you bring a cable to it from a power source. Perhaps with the use of nanotechnology, we may someday be able to create miniature batteries that can store or generate energy that would be enough to create powerful bursts - a necessary attribute of hand-held laser weapons. Currently, as we have seen, nanotechnology is in its infancy. Yes, scientists have succeeded in creating at the atomic level some devices - very ingenious, but completely impractical, such as atomic abacus or atomic guitar. But it may well happen that what else in this or, say,in the next century, nanotechnology will indeed give us miniature batteries to store fabulous amounts of energy.
Lightsabers have the same problem. With the release of Star Wars in 1970, toy lightsabers became an instant hit with boys. Many critics considered it their duty to point out that in reality such devices are impossible. First, light cannot be solidified. Light moves at the speed of light, so it is impossible to solidify it. Secondly, a beam of light cannot be abruptly cut off in space, as lightsabers do in Star Wars. The ray of light cannot be stopped, it is always in motion; a real lightsaber would go far into the sky.
In fact, there is a way to make a kind of lightsaber out of plasma, or superheated ionized gas. If the plasma is heated sufficiently, it will glow in the dark and cut steel, by the way, too. A plasma lightsaber could be a thin telescopic tube that extends from a handle.
Hot plasma is released into the tube from the handle, which then exits through small holes along the entire length of the "blade". The plasma rises from the hilt along the blade and out into a long, glowing cylinder of superheated gas, hot enough to melt steel. Such a device is sometimes called a plasma torch.
Thus, we can create a high-energy device that resembles a lightsaber. But here, as in the situation with ray guns, you will first have to acquire a powerful portable battery. So either you use nanotechnology to create a miniature battery that can supply your lightsaber with an enormous amount of energy, or you have to connect it to a power source using a long cable.
So, while ray guns and lightsabers can be made in some form today, the hand-held weapons we see in sci-fi movies are not possible with the current state of the art. But later in this century, or maybe in the next, the development of the science of materials and nanotechnology may well lead to the creation of one or another type of beam weapon, which allows us to define it as a Class I impossibility.
Energy for the Death Star
To build the Death Star, a laser cannon capable of destroying an entire planet and bringing terror to the galaxy, as shown in Star Wars, you need to create the most powerful laser imaginable. Currently, the most powerful lasers on Earth are probably used to obtain temperatures that in nature can only be found in the cores of stars. Perhaps these lasers and the fusion reactors based on them will someday help us on Earth to harness stellar energy.
In fusion reactors, scientists are trying to reproduce the processes that take place in space during the formation of a star. At first, the star appears as a huge ball of unformed hydrogen. Then gravitational forces compress the gas and thereby heat it up; gradually the temperature inside reaches astronomical values. For example, deep in the heart of a star, the temperature can rise to 50-100 million degrees. It's hot enough in there for the hydrogen nuclei to stick together; in this case, helium nuclei appear and energy is released. In the process of fusing helium from hydrogen, a small part of the mass is converted into energy according to Einstein's famous formula E = mc2. This is the source from which the star draws its energy.
Scientists are currently trying to harness the energy of nuclear fusion in two ways. Both paths turned out to be much more difficult to implement than previously thought.
Inertial confinement for laser fusion
The first method is based on the so-called inertial confinement. With the help of the most powerful lasers on Earth, a piece of the sun is artificially created in the laboratory. The solid state neodymium glass laser is ideal for reproducing the highest temperatures found only in stellar cores. The experiment uses laser systems the size of a good factory; a battery of lasers in such a system fires a series of parallel beams into a long tunnel. These powerful laser beams are then reflected from a system of small mirrors mounted around the spherical volume. Mirrors precisely focus all laser beams, directing them onto a tiny ball of hydrogen-rich material (such as lithium deuteride, the active ingredient in a hydrogen bomb). Scientists typically use a ball the size of a pinhead and weigh only about 10 mg.
The laser flash instantly heats up the surface of the ball, causing the top layer of the substance to evaporate and the ball to be sharply compressed. It "collapses", and the resulting shock wave reaches its very center and makes the temperature inside the ball jump up to millions of degrees - the level necessary for the fusion of hydrogen nuclei to form helium nuclei. Temperature and pressure reach such astronomical values that the Lawson criterion is fulfilled, the same one that is also fulfilled in the cores of stars and in the explosions of hydrogen bombs. (Lawson's criterion states that certain levels of temperature, density, and retention time must be reached in order to trigger a thermonuclear fusion reaction in a hydrogen bomb, star, or reactor.)
In the process of inertial confinement thermonuclear fusion, a huge amount of energy is released, including in the form of neutrons. (The temperature of lithium deuteride can reach 100 million degrees Celsius, and the density is twenty times that of lead.) A burst of neutron radiation from the ball occurs. Neutrons fall into a spherical “blanket” of matter that surrounds the reactor chamber and heat it up. Then the resulting heat is used to boil water, and the steam can already be used to rotate the turbine and generate electricity.
The problem, however, is to focus the high-energy beams and spread their radiation evenly over the surface of the tiny ball. The first major attempt at laser fusion was Shiva, a twenty-beam laser system built at Lawrence Livermore National Laboratory (LLNL) and launched in 1978 (Shiva is the multi-armed goddess of the Hindu pantheon, reminiscent of a multi-beam laser system.) "Shiva" proved to be discouraging; nevertheless, with its help, it was possible to prove that laser thermonuclear fusion is technically possible. Later the "Shiva" was replaced by the "Nova" laser, which tenfold surpassed the "Shiva" in power. But the "Nova" was not able to provide proper ignition to the hydrogen ball. Howbeit,both of these systems paved the way for targeted research at the new National Ignition Facility (NIF), construction of which began at LLNL in 1997.
The NIF is expected to begin work in 2009. This monstrous machine is a battery of 192 lasers that produce an enormous power of 700 trillion watts in a short pulse (the total output of approximately 70,000 large nuclear power units). It is a state-of-the-art laser system designed specifically for the complete fusion of hydrogen-saturated balls. (Critics also point to its obvious military significance - after all, such a system is capable of simulating the process of detonating a hydrogen bomb; perhaps it will create a new type of nuclear weapon - a bomb based solely on the fusion process, which no longer requires a uranium or plutonium atomic charge to detonate.)
But even the NIF system, designed to support the process of thermonuclear fusion and containing the most powerful lasers on Earth, cannot even remotely compare in power with the destructive power of the Death Star, known to us from Star Wars. To create such a device, we will have to look for other sources of energy.
Magnetic confinement for fusion
The second method that scientists could in principle use to energize Death Rides is known as magnetic confinement - the process by which a hot hydrogen plasma is held in place by a magnetic field.
This method, quite possibly, will serve as a prototype for the first commercial thermonuclear reactors. Currently, the most advanced project of this type is the International Thermonuclear Experimental Reactor (ITER). In 2006, several countries (including the European Union, the United States, China, Japan, Korea, Russia and India) decided to build such a reactor at Cadarache in southern France. In it, hydrogen must be heated up to 100 million degrees Celsius. It is possible that ITER will become the first thermonuclear reactor in history, which will be able to produce more energy than it consumes. It is designed to produce 500 MW of power in 500 seconds (the current record is 16 MW in one second). It is planned that the first plasma will be produced at ITER by 2016,and the installation will be fully operational in 2022. The project is worth $ 12 billion and is the third most expensive science project in history (after the Manhattan Project and the International Space Station).
In appearance, the ITER installation looks like a large donut, braided from the outside with huge rings of electrical winding; hydrogen circulates inside the donut. The winding is cooled to a state of superconductivity, and then a huge amount of electricity is pumped into it, creating a magnetic field that keeps the plasma inside the donut. When an electric current is passed directly through the donut, the gas inside it heats up to stellar temperatures.
The reason why scientists are so interested in the ITER project is simple: in the long term, it promises to create cheap energy sources. Fusion reactors are fueled by ordinary seawater, rich in hydrogen. It turns out, at least on paper, that thermonuclear fusion can provide us with a cheap and inexhaustible source of energy.
So why don't we still have fusion reactors? Why is it already several decades - since the moment in the 1950s. a process diagram was developed - can't we get real results? The problem is, hydrogen fuel is incredibly difficult to compress evenly. In the cores of stars, gravity forces the hydrogen to take on an ideal spherical shape, as a result of which the gas heats up cleanly and evenly.
Laser thermonuclear fusion in the NIF requires that the laser beams that ignite the surface of the hydrogen ball are exactly the same, and this is extremely difficult to achieve. In installations with magnetic confinement, the fact that the magnetic field has a north and south poles plays an important role; as a result, it is extremely difficult to compress the gas uniformly into the correct sphere.
The best we can create is a donut-shaped magnetic field. But the process of compressing a gas is like squeezing a balloon in your hands. Every time you squeeze the ball from one end, the air pushes it out in another place. Compressing the ball simultaneously and evenly in all directions is not an easy task. Hot gas usually leaks out of the magnetic bottle; sooner or later, it reaches the walls of the reactor, and the process of thermonuclear fusion stops. This is why it is so difficult to compress hydrogen sufficiently and keep it compressed even for a second.
Unlike modern nuclear power plants, where the fission of atoms occurs, a fusion reactor will not produce a large amount of nuclear waste. (Each of the traditional nuclear power units produces 30 tons of extremely hazardous nuclear waste per year. In contrast, the nuclear waste from a fusion reactor will be mostly radioactive steel, which will remain after its disassembly.)
One should not hope that thermonuclear fusion will completely solve the energy problems of the Earth in the near future. Frenchman Pierre-Gilles de Gennes, Nobel laureate in physics, says: “We say we will put the sun in a box. Nice idea. The problem is, we don't know how to make this box. But the researchers hope that, if all goes well, in forty years ITER will help scientists pave the way for the commercial production of thermonuclear energy - energy that could one day be the source of electricity for our homes. Someday, perhaps, fusion reactors will allow us on Earth to safely use stellar energy and thereby mitigate our energy problems. But even magnetically confined thermonuclear reactors will not be able to power weapons like the Death Star. This will require completely new developments.
Nuclear-pumped X-ray lasers
There is another possibility of building a Death Star laser cannon based on today's technology - using a hydrogen bomb. A battery of X-ray lasers, harnessing and focusing the power of nuclear weapons, could, in theory, provide enough power to operate a device capable of blowing up an entire planet.
Nuclear reactions release about 100 million times more energy per unit mass than chemical ones. A piece of enriched uranium no larger than a tennis ball would be enough to burn an entire city in a whirlwind of fire, despite the fact that only 1% of the uranium mass is converted into energy. As we said, there are many ways to pump energy into the working fluid of a laser, and hence into the laser beam. The most powerful of these methods - far more powerful than all others - is to harness the energy of a nuclear bomb.
X-ray lasers are of enormous importance, both military and scientific. The very short wavelength of X-ray radiation makes it possible to use such lasers for probing at atomic distances and deciphering the atomic structure of complex molecules, which is extremely difficult to do with conventional methods. The ability to "see" atoms in motion and to distinguish between their location within a molecule makes us look at chemical reactions in a completely new way.
A hydrogen bomb emits a tremendous amount of energy in the form of X-rays, so X-ray lasers can be pumped with the energy of a nuclear explosion. In science, X-ray lasers are most closely associated with Edward Teller, the "father" of the hydrogen bomb.
Incidentally, it was Teller in the 1950s. testified before Congress that Robert Oppenheimer, who previously headed the Manhattan Project, could not be entrusted with further work on the hydrogen bomb due to his political views. Teller's testimony resulted in Oppenheimer being defamed and denied access to classified materials; many prominent physicists have never been able to forgive Teller for this.
(My own contacts with Teller began in high school. I then conducted a series of experiments on the nature of antimatter, won the grand prize at the San Francisco Science Fair and a trip to the National Science Fair in Albuquerque, New Mexico. Together with Teller, who always paid attention to talented young physicists, I took part in a local television program. Later I received from Teller an engineering scholarship named after Hertz, which helped me pay for my studies at Harvard. Several times a year I went to Teller's home in Berkeley, and there got to know his family closely.)
In principle, the Teller X-ray laser is a small nuclear bomb surrounded by copper rods. The explosion of a nuclear weapon generates a spherical blast wave of intense X-ray radiation. These high-energy beams pass through copper rods, which act as the working fluid of the laser and focus the X-ray energy into powerful beams. The resulting X-rays can then be directed at enemy warheads. Of course, such a device can only be used once, since a nuclear explosion would self-destruct the X-ray laser.
The first X-ray laser test, dubbed the Cabra test (Calba), was carried out in 1983. A hydrogen bomb was detonated in an underground mine, and then a random stream of X-rays from it was focused and converted into a coherent X-ray laser beam. The tests were initially found to be successful; in fact, it was this success in 1983 that inspired President Reagan to make a historic statement of intent to build a defensive shield from Star Wars. This launched a multi-billion dollar program to build a network of devices like nuclear-pumped X-ray lasers to shoot down enemy ICBMs. The work on this program continues today. (Later it turned out that a sensor designed to register and measure radiation during a historical test,was destroyed; thus, his testimony could not be trusted.)
Is it really possible to shoot down ballistic missile warheads with such a non-trivial device? It is not excluded. But it should not be forgotten that the enemy can come up with many simple and inexpensive ways to neutralize such weapons (for example, one could trick the radar by firing millions of cheap decoys; or spin the warhead to scatter X-rays in this way; or come up with a chemical coating that would protect the warhead from the X-ray). In the end, the enemy could simply mass-produce warheads that would pierce the Star Wars shield simply by their sheer numbers.
Therefore, nuclear-pumped X-ray lasers are currently unable to protect against missile attack. But is it possible to create on their basis a Death Star capable of destroying an entire planet or become an effective means of protection against an approaching asteroid?
Death Star Physics
Is it possible to create a weapon capable of destroying an entire planet, like in Star Wars? In theory, the answer is simple: yes. And in several ways.
There are no physical limitations for the energy released by the detonation of a hydrogen bomb. This is how it goes. (A detailed description of the hydrogen bomb even today is classified by the US government as the highest category of secrecy, but in general terms its device is well known.) A hydrogen bomb is made in several stages. By combining the required number of stages in the correct sequence, you can get a nuclear bomb of almost any predetermined power.
The first stage is a standard fission bomb, or atomic bomb; it uses the energy of uranium-235 to generate an X-ray burst, as happened in Hiroshima. A split second before the explosion of an atomic bomb blows everything to shreds, an expanding sphere of powerful X-ray pulse appears. This radiation overtakes the actual explosion (since it moves with the speed of light); they manage to focus it again and send it to a container with lithium deuteride, the active substance of a hydrogen bomb. (Exactly how this is done is still a state secret.) X-rays fall on the lithium deuteride, causing it to instantly collapse and heating it to millions of degrees, causing a second explosion, much more powerful than the first. The X-ray burst resulting from this second explosionyou can then refocus on a second batch of lithium deuteride and cause a third explosion. Here is the principle by which you can place many containers of lithium deuteride side by side and get a hydrogen bomb of unimaginable power. Thus, the most powerful bomb in the history of mankind was the two-stage hydrogen bomb, which was detonated in 1961 by the Soviet Union. Then there was an explosion with a capacity of 50 million tons of TNT equivalent, although theoretically this bomb was capable of giving a power of more than 100 megatons of TNT (which is about 5000 times more than the power of the bomb dropped on Hiroshima).the most powerful bomb in human history was the two-stage hydrogen bomb, which was detonated in 1961 by the Soviet Union. Then there was an explosion with a capacity of 50 million tons of TNT, although theoretically this bomb was capable of giving a power of more than 100 megatons of TNT (which is about 5000 times more than the power of the bomb dropped on Hiroshima).the most powerful bomb in human history was the two-stage hydrogen bomb, which was detonated in 1961 by the Soviet Union. Then there was an explosion with a capacity of 50 million tons of TNT equivalent, although theoretically this bomb was capable of giving a power of more than 100 megatons of TNT (which is about 5000 times more than the power of the bomb dropped on Hiroshima).
However, completely different powers are needed to ignite an entire planet. To do this, the Death Star would have to launch thousands of such X-ray lasers into space, which would then have to be fired simultaneously. (For comparison, at the height of the Cold War, the United States and the Soviet Union each stockpiled about 30,000 nuclear bombs.) The combined energy of such a huge number of X-ray lasers would have been enough to ignite the planet's surface. Therefore, the Galactic Empire of the future, hundreds of thousands of years distant from us, could, of course, create such a weapon.
For a highly developed civilization, there is another way: to create a Death Star that would use the energy of a cosmic source of gamma-ray bursts. From such a Death Star, a burst of radiation would emanate, second only to the Big Bang in power. Sources of gamma-ray bursts are a natural phenomenon, they exist in space; nevertheless, it is conceivable that someday an advanced civilization could harness their enormous energy. It is possible that if we take control of the rotation of a star long before its collapse and the birth of a hypernova, then it will be possible to direct the "shot" of the source of gamma-ray bursts to any point in space.
Sources of gamma-ray bursts
Cosmic sources of GRBs were first noticed in the 1970s. on the Vela satellites launched by US military satellites, designed to detect "extra flashes" - evidence of an illegal nuclear bomb explosion. But instead of flares on the surface of the Earth, satellites recorded giant bursts of radiation from space. The initial surprise discovery sparked panic at the Pentagon: Are the Soviets testing new nuclear weapons in deep space? Later it was found that the bursts come uniformly from all directions of the celestial sphere; this meant that they were actually coming to the Milky Way galaxy from outside. But, if we assume a truly extragalactic origin of the bursts, then their power will turn out to be truly astronomical - after all, they are able to "illuminate" the entire visible universe.
After the collapse of the Soviet Union in 1990, the Pentagon unexpectedly declassified a huge amount of astronomical data. Astronomers were amazed. They suddenly realized that they were facing a new mysterious phenomenon from those that are forced from time to time to rewrite textbooks and reference books.
The duration of gamma-ray bursts is short, ranging from a few seconds to several minutes, so a carefully organized sensor system is needed to detect and analyze them. First, satellites register a burst of gamma radiation and send the exact coordinates of the source to Earth. The obtained coordinates are transmitted to optical or radio telescopes, which, in turn, are aimed at a specified point in the celestial sphere.
Although not everything is known about gamma-ray bursts at the moment, one of the theories of their origin says that the sources of gamma-ray bursts are “hypernovae” of extraordinary strength, leaving behind massive black holes. In this case, it turns out that the sources of gamma-ray bursts are monstrous black holes in the stage of formation.
But black holes emit two jets, two streams of radiation, from the south pole and from the north, like a spinning top. The radiation of the gamma-ray burst that we register belongs, apparently, to one of these streams - the one that turned out to be directed towards the Earth. If the flux of gamma radiation from such a source were directed exactly to the Earth, and the source itself were in our galactic vicinity (at a distance of several hundred light years from Earth), its power would be sufficient to completely destroy life on our planet.
First, an electromagnetic pulse created by X-rays from a gamma-ray burst source would have disabled all electronic equipment on Earth. A powerful beam of X-rays and gamma radiation would cause irreparable harm to the earth's atmosphere, destroying the protective ozone layer. Then a stream of gamma rays would warm up the Earth's surface, causing monstrous firestorms that would eventually engulf the entire planet. Perhaps the source of gamma-ray bursts would not have blown up the planet, as shown in the movie "Star Wars", but it would certainly have destroyed all life on it, leaving behind a charred desert.
It can be assumed that a civilization that has outstripped us in development by hundreds of millions of years will learn to direct such black holes to the desired target. This can be achieved by learning to control the motion of planets and neutron stars and direct them to a dying star at a precisely calculated angle just before collapse. Relatively little effort will be enough to deflect the star's axis of rotation and aim it in the desired direction. Then the dying star will turn into the largest beam cannon imaginable.
Summarize. The use of powerful lasers to create portable or hand-held beam weapons and lightsabers should be classified as class I impossibility - most likely, this will become possible in the near future, or, say, in the next hundred years. But the extremely difficult task of aiming a rotating star before exploding and turning it into a black hole, i.e. converting it into a Death Star, should be considered as a Class II impossibility - something that does not clearly contradict the laws of physics (after all, the sources of gamma-ray bursts exist in reality), but can only be realized far in the future, after thousands or even millions of years.
From the book: "Physics of the Impossible".
