Part 2 (1/2)
The (atoo off
I speak as an expert in explosives
-ADMIRAL WILLIAM LEAHY
4321, fire!
The Death Star is a colossal weapon, the size of an entirepoint-blank at the helpless planet Alderaan, home world of Princess Leia, the Death Star incinerates it, causing it to erupt in a titanic explosion, sending planetary debris hurtling throughout the solar syste a disturbance in the Force felt throughout the galaxy
But is the Death Star weapon of the Star Wars saga really possible? Could such a weapon channel a battery of laser cannons to vaporize an entire planet? What about the faht sabers wielded by Luke Skywalker and Darth Vader that can slice through reinforced steel yet are uns, like the phasers in Star Trek, viable weapons for future generations of law enforcement officers and soldiers?
In Star Wars inal, stunning special effects, but they fell flat for soood fun, but it was patently iuns are outlandish, and so are swords alaxy far, far away, they chanted George Lucas, the otten carried away this tih this may be difficult to believe, the fact is there is no physical liht bea the creation of a Death Star or light sabers In fact, planet-busting beaamma radiation exist in nature The titanic burst of radiation froamma ray burster in deep space creates an explosion second only to the big bang itself Any planet unfortunate enough to be within the crosshairs of a gamma ray burster will indeed be fried or blown to bits
BEAM WEAPONS THROUGH HISTORY
The dreay is actually not new but is rooted in ancient y and lore The Greek God Zeus was fa bolts on ic ha, while the Hindu God Indra was known for firing bea rays as a practical weapon probably began with the work of the great Greek reatest scientist in all of antiquity, who discovered a crude version of calculus two thousand years ago, before Newton and Leibniz In one legendary battle against the forces of Ro the Second Punic War in 214 BC, Archidoe batteries of solar reflectors that focused the sun's rays onto the sails of ene the scientists as to whether this was a practical, working beam weapon; various teams of scientists have tried to duplicate this feat with differing results) Ray guns burst onto the science fiction scene in 1889 with H G Wells's classic War of the Worlds, in which aliens froy fro World War II, the nazis, always eager to exploit the latest advances in technology to conquer the world, experi a sonic device, based on parabolic mirrors, that could focus intense beaht beaination with the Jaer, the first Hollywood filendary British spy was strapped onto a raduallyto slice hiinally scoffed at the idea of the ray guns featured in Wells's novel because they violated the laws of optics According to Maxwell's equations, the light we see around us rapidly disperses and is incoherent (ie, it is a jumble of waves of different frequencies and phases) It was once thought that coherent, focused, uniforht, as we find with laser beams, were impossible to create
THE QUANTUM REVOLUTION
All this changed with the co of the quantum theory At the turn of the twentieth century it was clear that although Newton's laws and Maxwell's equations were spectacularly successful in explaining the ht, they could not explain a whole class of phenomena They failed miserably to explain why materials conduct electricity, why ht when heated, why certain substances become superconductors at low te of the internal dynamics of atoms The time was ripe for a revolution Two hundred and fifty years of Newtonian physics was about to be overthrown, heralding the birth pangs of a new physics
In 1900 Max Planck in Gerht, but occurred in small, discrete packets, called ”quanta” Then in 1905 Einstein postulated that light consisted of these tiny discrete packets (or quanta), later dubbed ”photons” With this powerful but simple idea Einstein was able to explain the photoelectric effect, why electrons are eht on them Today the photoelectric effect and the photon form the basis of TV, lasers, solar cells, and much of modern electronics (Einstein's theory of the photon was so revolutionary that even Max Planck, norreat supporter of Einstein, could not at first believe it Writing about Einstein, Planck said, ”That he etas for exaht quanta, cannot really be held against hiave us an entirely new picture of the atom, one that resembled a miniature solar system But unlike in a solar system in outer space, electrons can only move in discrete orbits or shells around the nucleus When electrons ”juy, they ey When an electron absorbed a photon of a discrete energy, it ”juy
A nearly co of quantuer, Werner Heisenberg, andto the quantum theory, the electron was a particle, but it had a wave associated with it, giving it both particle- and wavelike properties The wave obeyed an equation, called the Schrodinger wave equation, which enabled one to calculate the properties of ato all the ”jumps” postulated by Bohr
Before 1925 atoms were still considered mysterious objects that ht not exist at all After 1925 one could actually peer deep into the dynamics of the atoly, this h computer, you could derive the properties of the chemical elements from the laws of the quantum theory In the same way that Newtonian physicists could compute the motions of all the celestial bodies in the universe if they had a big enough calculating machine, quantum physicists claimed that they could in principle compute all the properties of the cheh computer, one could also write the wave function of an entire hu
MASERS AND LASERS
In 1953 Professor Charles Townes of the University of California at Berkeley and his colleagues produced the first coherent radiation in the form of microwaves It was christened the ”h stimulated emission of radiation) He and Russian physicists Nikolai Basov and Aleksandr Prokhorov would eventually win the nobel Prize in 1964 Soon their results were extended to visible light, giving birth to the laser (A phaser, however, is a fictional device popularized in Star Trek) In a laser you first begin with a special as, crystal, or diode Then you puy into this mediuht, or a chey pumps up the atoy and then jump into the outer electron shells
In this excited, pumped-up state, the h theit to suddenly decay down to a lower level, releasing ers evena cascade of collapsing atoms, with trillions upon trillions of photons suddenly released into the beam The key is that for certain substances, when this avalanche of photons is occurring all the photons are vibrating in unison, that is, they are coherent
(Picture a line of doy state lie flat on a table Doy, pumped-up state stand up vertically, similar to the pumped-up atoer a sudden collapse of all this energy at once, just as in a laser beam) Only certain materials will ”lase,” that is, it is only in special materials that when a photon hits a pumped-up atoinal photon As a result of this coherence, in this flood of photons all the photons are vibrating in unison, creating a pencil-thin laser beam (Contrary to myth, the laser beam does not stay pencil-thin forever A laser bearadually expand until it creates a spot a few as laser consists of a tube of heliuh the tube the atoy is suddenly released all at once, a beaht is produced The bea two mirrors, one placed at either end, so the beam bounces back and forth between them One mirror is coht to escape on each pass, producing a beam that shoots out one end
Today lasers are found alrocery store checkout stands, to fiber-optic cables carrying the Internet, to laser printers and CD players, to ery, to remove tattoos, and even in cosmetic salons Over 54 billion worth of lasers were sold ide in 2004
TYPES OF LASERS AND FUSION
New lasers are being discovered almost every day as new materials are found that can lase, and as neays are discovered for puy into the ies suitable for building a ray gun or a light saber? Is it possible to build a laser powerful enough to energize a Death Star? Today a bewildering variety of lasers exist, depending on the y that is injected into the ht, even che them are Gas lasers These lasers include heliu a faized by radio waves or electricity Heliuas lasers can be used for blasting, cutting, and welding in heavy industry and can create beams of enormous power that are totally invisible
Cheized by a cheen trifluoride, or NF3 Such lasers are powerful enough to be used in military applications Cheround lasers, which can produce ned to shoot down short-range ht
Excimer lasers These lasers are also powered by cheon, krypton, or xenon) and fluorine or chlorine They produce ultraviolet light and can be used to etch tiny transistors onto chips in the seery
Solid-state lasers The first working laser ever e variety of crystals will support a laser beam, in conjunction with yttriuh-energy ultrashort pulses of laser light
Semiconductor lasers Diodes, which are commonly used in the semiconductor industry, can produce the intense bea They are also often found in checkout stands in grocery stores, reading the bar codes of your grocery iteanic dyes as theirultrashort pulses of light, often lasting only trillionths of a second
LASERS AND RAY GUNS?
Given the enormous variety of commercial lasers and the power of uns available for use in couns of one sort or another seem to be standard-issue weaponry in science fictionto create them?
The simple answer is the lack of a portable power pack One would need e electrical power station yet are sh to fit on your pale commercial power station is to build one At present the smallest portable y is a ht destroy you as well as the target
There is a second, ancillary proble y one can concentrate on a laser The probleun would not be stable Crystal lasers, for exay is pumped into them Hence to create an extreht vaporize an object or neutralize a foe, one ht need to use the power of an explosion In that case, the stability of the lasing material is not such a limitation, since such a laser would be used only once
Because of the proble un is not possible with today's technology Ray guns are possible, but only if they are connected by a cable to a power supply Or perhaps with nanotechnology we enerate enough energy to create the intense bursts of energy required of a handheld device At present, as we have seen, nanotechnology is quite primitive At the atomic level, scientists have been able to create atoenious, but iuitar But it is conceivable that late in this century or the next, nanotechnology ive us miniature batteries that can store such fabulous aht sabers suffer from a similar problem When the ht sabers beca children, many critics pointed out that such a device could never be ht always travels at the speed of light; it cannot be ht beaht sabers used in Star Wars Light beaht saber would stretch into the sky
Actually there is a way to construct a kind of light saber using plash to glow in the dark and also slice through steel A plasht saber would consist of a thin, hollow rod that slides out of the handle, like a telescope Inside this tube hot plash s the rod As the plash the holes, it would create a long, glowing tube of superhot gas, sufficient to melt steel This device is sometimes referred to as a plasy device that reseuns, you would have to create a high-energy portable power pack Either you would need long cables connecting the light saber to a power supply, or you would have to create, via nanotechnology, a tiny power supply that could deliver huge aht sabers are possible to create in some form today, the handheld weapons found in science fiction y But late in this century or the next, with new advances in unit a Class I impossibility
ENERGY FOR A DEATH STAR
To create a Death Star laser cannon that can destroy an entire planet and terrorize a galaxy, such as that described in Star Wars, one would need to create the most powerful laser ever conceived At present so used to unleash temperatures found only in the center of stars In the forht one day harness the power of the stars on Earth
Fusion machines try to mimic what happens in outer space when a star first foras, until gravity coas and thereby heats it up; temperatures eventually reach astronomical levels Deep inside a star's core, for example, terees centigrade, hot enough to cause hydrogen nuclei to slay The fusion of hydrogen into helium, whereby a sy of a star via Einstein's fay source of the stars
There are tays in which scientists are currently atte to harness fusion on the Earth Both have proven to be much more difficult to develop than expected
INERTIAL CONFINEMENT FOR FUSION
The first method is called ”inertial confinement” It uses the most powerful lasers on Earth to create a piece of the sun in the laboratory A neodylass solid-state laser is ideally suited to duplicate the blistering temperatures found only in the core of a star These laser systee factory and contain a battery of lasers that shoot a series of parallel laser beah-power laser beaed around a sphere; the mirrors carefully focus the laser beaen-rich pellet (redient of a hydrogen bohs only 10 ht incinerates the surface of the pellet, causing the surface to vaporize and compress the pellet As the pellet collapses, a shock wave is created that reaches the core of the pellet, sending terees, sufficient to fuse hydrogen nuclei into helium The temperatures and pressures are so astronomical that ”Lawson's criterion” is satisfied, the saen bombs and in the core of stars (Lawson's criterion states that a specific range of temperatures, density, and time of confinement must be attained in order to unleash the fusion process in a hydrogen bomb, in a star, or in a fusion machine) In the inertial confine neutrons (The lithiurade and a density twenty times that of lead) A burst of neutrons is then emitted from the pellet, and the neutrons strike a spherical blanket ofthe chamber, and the blanket is heated up The heated blanket then boils water, and the steam can be used to power a turbine and produce electricity
The proble able to focus such intense power evenly onto a tiny spherical pellet The first serious atte laser fusion was the shi+va laser, a twenty-beam laser system built at the Lawrence Liveran operation in 1978 (shi+va is the Hindu Goddess with n mimics) The perfor, but it was sufficient to prove that laser fusion can technically work The shi+va laser system was later replaced by the Nova laser, with ten tiy of shi+va But the Nova laser also failed to achieve proper ignition of the pellets Nonetheless, it paved the way for the current research in the National Ignition Facility (NIF), which began construction in 1997 at the LLNL
The NIF, which is supposed to be operational in 2009, is aof a battery of 192 laser bea an enormous output of 700 trillion watts of power (the output of about 700,000 large nuclear power plants concentrated in a single burst of energy) It is a state-of-the-art laser systeen-rich pellets (Critics have also pointed out its obvious en bomb and perhaps make possible the creation of a new nuclear weapon, the pure fusion bomb, which does not require a uranium or plutonium atomic bomb to kick-start the fusion process) But even the NIF laser fusionthe in to approxi power of the Star Wars Death Star To build such a device we must look to other sources of power
MAGNETIC CONFINEMENT FOR FUSION
The second ize a Death Star is called ”netic confineas is contained within a netic field In fact, this method could actually provide the prototype for the first commercial fusion reactors Currently the most advanced fusion project of this type is the International Thermonuclear Experimental Reactor (ITER) In 2006 a coalition of nations (including the European Union, the United States, China, japan, Korea, Russia, and India) decided to build the ITER in Cadarache, in southern France It is designed to heat hydrogen gas to 100 rade It could becoy than it consuawatts of power for 500 seconds (the current record is 16 enerate its first plasma by 2016 and be fully operational in 2022 At a cost of 12 billion, it is the third most expensive scientific project in history (after the Manhattan Project and the International space Station)
The ITER looks like a large doughnut, with hydrogen gas circulating inside and huge coils of inding around the surface The coils are cooled down until they becoy is punetic field that confines the plashnut When an electrical current is fed inside the doughnut, the gas is heated to stellar temperatures