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The Story of Nuclear Energy 


Nuclear Fi 

Beyond Fusion 
by Isaac Asimov 


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The Project Gutenberg EBook of Worlds Within Worlds: The Story of Nuclear 
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Title: Worlds Within Worlds: The Story of Nuclear Energy, Volume 3 (of 3) 
Nuclear Fission; Nuclear Fusion; Beyond Fusion 

Author: Isaac Asimov 

Release Date: August 30, 2015 [EBook #49821] 

Language: English 


Produced by Stephen Hutcheson, Dave Morgan and the Online 
Distributed Proofreading Team at 

Worlds Within Worlds: 

The Story of Nuclear Energy 
Volume 3 

Nuclear Fission • Nuclear Fusion • Beyond Fusion 

by Isaac Asimov 

United States Atomic Energy Commission 
Office of Information Services 

Library of Congress Catalog Card Number 75-189477 

Nothing in the history of mankind has opened our eyes to the possibilities of 
science as has the development of atomic power. In the last 200 years, people 
have seen the coming of the steam engine, the steamboat, the railroad 
locomotive, the automobile, the airplane, radio, motion pictures, television, the 
machine age in general. Yet none of it seemed quite so fantastic, quite so 
unbelievable, as what man has done since 1939 with the atom ... there seem to be 
almost no limits to what may lie ahead: inexhaustible energy, new worlds, ever- 
widening knowledge of the physical universe. 

Isaac Asimov 

Photograph of night sky 

Nuclear energy is playing a vital role in the life of every man, woman, and 
child in the United States today. In the years ahead it will affect 

increasingly all the peoples of the earth. It is essential that all Americans 
gain an understanding of this vital force if they are to discharge 
thoughtfully their responsibilities as citizens and if they are to realize fully 
the myriad benefits that nuclear energy offers them. 

The United States Atomic Energy Commission provides this booklet to 
help you achieve such understanding. 


Dr. James R. Schlesinger, Chairman 

James T. Ramey 

Dr. Clarence E. Larson 

William O. Doub 

Dr. Dixy Lee Ray 

Isaac Asimov 

ISAAC ASIMOV received his academic degrees from Columbia 
University and is Associate Professor of Biochemistry at the Boston 
University School of Medicine. He is a prolific author who has written 
over 100 books in the past 18 years, including about 20 science fiction 
works, and books for children. His many excellent science books for the 
public cover subjects in mathematics, physics, astronomy, chemistry, and 
biology, such as The Genetic Code, Inside the Atom, Building Blocks of the 
Universe, Understanding Physics, The New Intelligent Man’s Guide to 
Science, and Asimov’s Biographical Encyclopedia of Science and 
Technology. In 1965 Dr. Asimov received the James T. Grady Award of the 
American Chemical Society for his major contribution in reporting science 
progress to the public. 

Photograph of night sky 


Introduction 5 
Atomic Weights 6 
Electricity 11 

Units of Electricity 11 
Cathode Rays 13 
Radioactivity 17 
The Structure of the Atom 25 
Atomic Numbers 30 
Isotopes 35 
Energy 47 

The Law of Conservation of Energy 47 

Chemical Energy 50 
Electrons and Energy 54 
The Energy of the Sun 55 
The Energy of Radioactivity 57 


Mass and Energy 69 
The Structure of the Nucleus 75 

The Proton 75 
The Proton-Electron Theory 76 
Protons in Nuclei 80 
Nuclear Bombardment 82 
Particle Accelerators 86 
The Neutron 92 
Nuclear Spin 92 
Discovery of the Neutron 95 
The Proton-Neutron Theory 98 
The Nuclear Interaction 101 
Neutron Bombardment 107 


Nuclear Fission 117 

New Elements 117 

The Discovery of Fission 122 
The Nuclear Chain Reaction 127 

The Nuclear Bomb 131 
Nuclear Reactors 141 
Nuclear Fusion 146 
The Energy of the Sun 146 
Thermonuclear Bombs 148 
Controlled Fusion 150 
Beyond Fusion 158 
Antimatter 158 
The Unknown 163 
Reading List 165 

Enrico Fermi (left) and Niels Bohr discuss physics as they stroll along the Appian Way outside Rome in 


New Elements 

In 1934 Enrico Fermi began his first experiments involving the bombardment of 
uranium with neutrons—experiments that were to change the face of the world. 

Fermi had found that slow neutrons, which had very little energy, were easily 
absorbed by atomic nuclei—more easily than fast neutrons were absorbed, and 
certainly more easily than charged particles were. 

Often what happened was that the neutron was simply absorbed by the nucleus. 
Since the neutron has a mass number of 1 and an atomic number of 0 (because it 
is uncharged), a nucleus that absorbs a neutron remains an isotope of the same 
element, but increases its mass number. 

For instance, suppose that neutrons are used to bombard hydrogen-1, which then 
captures one of the neutrons. From a single proton, it will become a proton plus 
a neutron; from hydrogen-1, it will become hydrogen-2. A new nucleus formed 
in this way will be at a higher energy and that energy is emitted in the form of a 
gamma ray. 

Sometimes the more massive isotope that is formed through neutron absorption 
is stable, as hydrogen-2 is. Sometimes it is not, but is radioactive instead. 
Because it has added a neutron, it has too many neutrons for stability. The best 
way of adjusting the matter is to emit a beta particle (electron). This converts 
one of the neutrons into a proton. The mass number stays the same but the 
atomic number increases by one. 

The element rhodium, for example, which has an atomic number of 45, has only 
1 stable isotope, with a mass number of 103. If rhodium-103 (45 protons, 58 
neutrons) absorbs a neutron, it becomes rhodium-104 (45 protons, 59 neutrons), 
which is not stable. Rhodium-104 emits a beta particle, changing a neutron to a 
proton so that the nuclear combination becomes 46 protons and 58 neutrons. 

This is palladium-104, which is stable. 

Fermi’s laboratory in Rome in 1930. 

As another example, indium-115 (49 protons, 66 neutrons) absorbs a neutron and 
becomes indium-116 (49 protons, 67 neutrons), which gives off a beta particle 
and becomes tin-116 (50 protons, 66 neutrons), which is stable. 

There are over 100 isotopes that will absorb neutrons and end by becoming an 
isotope of an element one higher in the atomic number scale. Fermi observed a 
number of these cases. 

Having done so, he was bound to ask what would happen if uranium were 
bombarded with neutrons. Would its isotopes also be raised in atomic number— 
in this case from 92 to 93? If that were so it would be very exciting, for uranium 
had the highest atomic number in the entire scale. Nobody had ever discovered 
any sample of element number 93, but perhaps it could be formed in the 

In 1934, therefore, Fermi bombarded uranium with neutrons in the hope of 
obtaining atoms of element 93. Neutrons were absorbed and whatever was 
formed did give off beta particles, so element 93 should be there. However, four 
different kinds of beta particles (different in their energy content) were given off 
and the matter grew very confusing. Fermi could not definitely identify the 
presence of atoms of element 93 and neither could anyone else for several years. 
Other things turned up, however, which were even more significant. 

Before going on to these other things, however, it should be mentioned that 
undoubtedly element 93 was formed even though Fermi couldn’t clearly 
demonstrate the fact. In 1939 the American physicists Edwin Mattison McMillan 
(1907- ) and Philip Hauge Abelson (1913- ), after bombarding 

uranium atoms with slow neutrons, were able to identify element 93. Since 
uranium had originally been named for the planet, Uranus, the new element 
beyond uranium was eventually named for the planet Neptune, which lay beyond 
Uranus. Element 93 is therefore called “neptunium”. 

Lise Meitner 

Emilio Segre 

Edwin M. McMillan 

Otto R. Frisch 

Glenn T. Seaborg 

Philip H. Abelson 

What happened was exactly what was expected. Uranium-238 (92 protons, 146 
neutrons) added a neutron to become uranium-239 (92 protons, 147 neutrons), 
which emitted a beta particle to become neptunium-239 (93 protons, 146 

In fact, neptunium-239 also emitted a beta particle so it ought to become an 
isotope of an element even higher in the atomic number scale. This one, element 
94, was named “plutonium” after Pluto, the planet beyond Neptune. The isotope, 
plutonium-239, formed from neptunium-239, was only feebly radioactive, 
however, and it was not clearly identified until 1941. 

The actual discovery of the element plutonium came the year before, however, 
when neptunium-238 was formed. It emitted a beta particle and became 
plutonium-238, an isotope that was radioactive enough to be easily detected and 
identified by Glenn Theodore Seaborg (1912- ), and his co-workers, who 

completed McMillan’s experiments when he was called away to other defense 

Neptunium and plutonium were the first “transuranium elements” to be produced 
in the laboratory, but they weren’t the last. Over the next 30 years, isotopes were 
formed that contained more and more protons in the nucleus and therefore had 
higher and higher atomic numbers. At the moment of writing, isotopes of every 
element up to and including element 105 have been formed. 

A number of these new elements have been named for some of the scientists 
important in the history of nuclear research. Element 96 is “curium”, named for 
Pierre and Marie Curie; element 99 is “einsteinium” for Albert Einstein; and 

element 100 is “fermium” for Enrico Fermi. 

Element 101 is “mendelevium” for the Russian chemist Dmitri Mendeleev, who 
early in 1869 was the first to arrange the elements in a reasonable and useful 
order. Element 103 is “lawrencium” for Ernest O. Lawrence. “Rutherfordium” 
for Ernest Rutherford has been proposed for element 104. 

And “hahnium” for Otto Hahn (1879-1968), a German physical chemist whose 
contribution we will come to shortly, has been proposed for element 105. 

Neptunium, however, was not the first new element to be created in the 
laboratory. In the early 1930s, there were still 2 elements with fairly low atomic 
numbers that had never been discovered. These were the elements with atomic 
numbers 43 and 61. 

In 1937, though, molybdenum (atomic number 42) had been bombarded with 
neutrons in Lawrence’s laboratory in the United States. It might contain small 
quantities of element 43 as a result. The Italian physicist Emilio Segre (1905- 
), who had worked with Fermi, obtained a sample of the bombarded 
molybdenum and indeed obtained indications of the presence of element 43. It 
was the first new element to be manufactured by artificial means and was called 
“technetium” from the Greek word for “artificial”. 

The technetium isotope that was formed was radioactive. Indeed, all the 
technetium isotopes are radioactive. Element 61, discovered in 1945 and named 
“promethium”, also has no stable isotopes. Technetium and promethium are the 
only elements with atomic numbers less than 84 that do not have even a single 
stable isotope. 

The Discovery of Fission 

But let us get back to the bombardment of uranium with neutrons research that 
Fermi had begun. After he had reported his work, other physicists repeated it and 
also got a variety of beta particles and were also unable to decide what was 
going on. 

Lise Meitner and Otto Hahn in their laboratory in the 1930s. 

One way to tackle the problem was to add to the system some stable element that 
was chemically similar to the tiny traces of radioactive isotopes that might be 
produced through the bombardment of uranium. Afterwards the stable element 
could probably be separated out of the mixture and the trace of radioactivity 
would, it was hoped, be carried along with it. The stable element would be a 

Among those working on the problem were Otto Hahn and his Austrian co¬ 
worker, the physicist Lise Meitner (1878-1968). Among the potential carriers 
they added to the system was the element, barium, which has an atomic number 
of 56. They found that a considerable quantity of the radioactivity did indeed 
accompany the barium when they separated that element out of the system. 

A natural conclusion was that the isotopes producing the radioactivity belonged 
to an element that was chemically very similar to barium. Suspicion fell at once 
on radium (atomic number 88), which was very like barium indeed as far as 
chemical properties were concerned. 

Lise Meitner, who was Jewish, found it difficult to work in Germany, however, 
for it was then under the rule of the strongly anti-Semitic Nazi regime. In March 
1938 Germany occupied Austria, which became part of the German realm. 
Meitner was no longer protected by her Austrian citizenship and had to flee the 
country and go to Stockholm, Sweden. Hahn remained in Germany and 
continued working on the problem with the German physical chemist Fritz 
Strassman (1902- ). 

Although the supposed radium, which possessed the radioactivity, was very like 
barium in chemical properties, the two were not entirely identical. There were 
ways of separating them, and Hahn and Strassman busied themselves in trying to 
accomplish this in order to isolate the radioactive isotopes, concentrate them, 
and study them in detail. Over and over again, however, they failed to separate 
the barium and the supposed radium. 

Slowly, it began to seem to Hahn that the failure to separate the barium and the 
radioactivity meant that the isotopes to which the radioactivity belonged had to 
be so much like barium as to be nothing else but barium. He hesitated to say so, 
however, because it seemed unbelievable. 

If the radioactive isotopes included radium, that was conceivable. Radium had 

an atomic number of 88, only four less than uranium’s 92. You could imagine 
that a neutron being absorbed by a uranium nucleus might make the latter so 
unstable as to cause it to emit 2 alpha particles and become radium. Barium, 
however, had an atomic number of 56, only a little over half that of uranium. 
How could a uranium nucleus be made to turn into a barium nucleus unless it 
more or less broke in half? Nothing like that had ever been observed before and 
Hahn hesitated to suggest it. 

While he was nerving himself to do so, however, Lise Meitner, in Stockholm, 
receiving reports of what was being done in Hahn’s laboratory and thinking 
about it, decided that unheard-of or not, there was only one explanation. The 
uranium nucleus was breaking in half. 

Actually, when one stopped to think of it (after getting over the initial shock) it 
wasn’t so unbelievable at that. The nuclear force is so short-range, it barely 
reaches from end to end of a large nucleus like that of uranium. Left to itself, it 
holds together most of the time, but with the added energy of an entering 
neutron, we might imagine shock waves going through it and turning the nucleus 
into something like a quivering drop of liquid. Sometimes the uranium nucleus 
recovers, keeps the neutron, and then goes on to beta-particle emission. And 
sometimes the nucleus stretches to the point where the nuclear force doesn’t 
quite hold it together. It becomes a dumbbell shape and then the electromagnetic 
repulsion of the two halves (both positively charged) breaks it apart altogether. 

It doesn’t break into equal halves. Nor does it always break at exactly the same 
place, so that there were a number of different fragments possible (which was 
why there was so much confusion). Still, one of the more common ways in 
which it might break would be into barium and krypton. (Their respective atomic 
numbers, 56 and 36, would add up to 92.) 

Meitner and her nephew, Otto Robert Frisch (1904- ), who was in 

Copenhagen, Denmark, prepared a paper suggesting that this was what was 
happening. It was published in January 1939. Frisch passed it on to the Danish 
physicist Niels Bohr (1885-1962) with whom he was working. The American 
biologist William Archibald Arnold (1904- ), who was also working in 

Copenhagen at the time, suggested that the splitting of the uranium nucleus into 
halves be called “fission”, the term used for the division-in-two of living cells. 
The name stuck. 

In January 1939, just about the time Meitner and Frisch’s paper was published, 
Bohr had arrived in the United States to attend a conference of physicists. He 
carried the news of fission with him. The other physicists attending the 
conference heard the news and in a high state of excitement at once set about 
studying the problem. Within a matter of weeks, the fact of uranium fission was 
confirmed over and over. 

One striking fact about uranium fission was the large amount of energy it 
released. In general, when a very massive nucleus is converted to a less massive 
one, energy is released because of the change in the mass defect, as Aston had 
shown in the 1920s. When the uranium nucleus breaks down through the 
ordinary radioactive processes to become a less massive lead nucleus, energy is 
given off accordingly. When, however, it breaks in two to become the much less 
massive nuclei of barium and krypton (or others in that neighborhood) much 
more energy is given off. 

It quickly turned out that uranium fission gave off something like ten times as 
much nuclear energy per nucleus than did any other nuclear reaction known at 
the time. 

Even so, the quantity of energy released by uranium fission was only a tiny 
fraction of the energy that went into the preparation of the neutrons used to bring 
about the fission, if each neutron that struck a uranium atom brought about a 
single fission of that 1 atom. 

Under those conditions, Rutherford’s suspicion that mankind would never be 
able to tap nuclear energy probably still remained true. (He had been dead for 2 
years at the time of the discovery of fission.) 

However, those were not the conditions. 

The Nuclear Chain Reaction 

Earlier in this history, we discussed chain reactions involving chemical energy. A 
small bit of energy can ignite a chemical reaction that would produce more than 
enough energy to ignite a neighboring section of the system, which would in turn 
produce still more—and so on, and so on. In this way the flame of a single match 
could start a fire in a leaf that would burn down an entire forest, and the energy 

given off by the burning forest would be enormously higher than the initial 
energy of the match flame. 

Might there not be such a thing as a “nuclear chain reaction”? Could one initiate 
a nuclear reaction that would produce something that would initiate more of the 
same that would produce something that would initiate still more of the same 
and so on? 

In that case, a nuclear reaction, once started, would continue of its own accord, 
and in return for the trifling investment that would serve to start it—a single 
neutron, perhaps—a vast amount of breakdowns would result with the delivery 
of a vast amount of energy. Even if it were necessary to expend quite a bit of 
energy to produce the 1 neutron that would start the chain reaction, one would 
end with an enormous profit. 

What’s more, since the nuclear reaction would spread from nucleus to nucleus 
with millionths-of-a-second intervals, there would be, in a very brief time, so 
many nuclei breaking down that there would be a vast explosion. The explosion 
was sure to be millions of times as powerful as ordinary chemical explosions 
involving the same quantity of exploding material, since the latter used only the 
electromagnetic interaction, while the former used the much stronger nuclear 

The first to think seriously of such a nuclear chain reaction was the Hungarian 
physicist Leo Szilard (1898-1964). He was working in Germany in 1933 when 
Adolf Hitler came to power and, since he was Jewish, he felt it would be wise to 
leave Germany. He went to Great Britain and there, in 1934, he considered 
certain new types of nuclear reactions that had been discovered. 

In these, it sometimes happened that a fast neutron might strike a nucleus with 
sufficient energy to cause it to emit 2 neutrons. In that way the nucleus, 
absorbing 1 neutron and emitting 2, would become a lighter isotope of the same 

But what would happen if each of the 2 neutrons that emerged from the original 
target nucleus struck new nuclei and forced the emission of a pair of neutrons 
from each. There would now be a total of 4 neutrons flying about and if each 
struck new nuclei there would next be 8 neutrons and so on. From the initial 
investment of a single neutron there might soon be countless billions initiating 

nuclear reactions. 

Szilard, fearing the inevitability of war and fearing further that the brutal leaders 
of Germany might seek and use such a nuclear chain reaction as a weapon in 
warfare, secretly applied for a patent on a device intending to make use of such a 
nuclear chain reaction. He hoped to turn it over to the British Government, 
which might then use its possession as a way of restraining the Nazis and 
keeping the peace. 

However, it wouldn’t have worked. It took the impact of a very energetic neutron 
to bring about the emission of 2 neutrons. The neutrons that then emerged from 
the nucleus simply didn’t have enough energy to keep things going. (It was like 
trying to make wet wood catch fire.) 

But what about uranium fission? Uranium fission was initiated by slow neutrons. 
What if uranium fission also produced neutrons as well as being initiated by a 
neutron? Would not the neutrons produced serve to initiate new fissions that 
would produce new neutrons and so on endlessly? 

It seemed very likely that fission produced neutrons and indeed, Fermi, at the 
conference where fission was first discussed, suggested it at once. Massive 
nuclei possessed more neutrons per proton than less massive ones did. If a 
massive nucleus was broken up into 2 considerably less massive ones, there 
would be a surplus of neutrons. Suppose, for instance, uranium-238 broke down 
into barium-138 and krypton-86. Barium-138 contains 82 neutrons and krypton- 
86 50 neutrons for a total of 132. The uranium-238 nucleus, however, contains 
146 neutrons. 

The uranium fission process was studied at once to see if neutrons were actually 
given off and a number of different physicists, including Szilard, found that they 

Now Szilard was faced with a nuclear chain reaction he was certain would work. 
Only slow neutrons were involved and the individual nuclear breakdowns were 
far more energetic than anything else that had yet been discovered. If a chain 
reaction could be started in a sizable piece of uranium, unimaginable quantities 
of energy would be produced. Just 1 gram of uranium, undergoing complete 
fission, would deliver the energy derived from the total burning of 3 tons of coal 
and would deliver that energy in a tiny fraction of a second. 

Szilard, who had come to the United States in 1937, clearly visualized the 
tremendous explosive force of something that would have to be called a “nuclear 
bomb”. Szilard dreaded the possibility that Hitler might obtain the use of such a 
bomb through the agency of Germany’s nuclear scientists. 

Partly through Szilard’s efforts, physicists in the United States and in other 
Western nations opposed to Hitler began a program of voluntary secrecy in 1940, 
to avoid passing along any hints to Germany. What’s more, Szilard enlisted the 
services of two other Hungarian refugees, the physicists Eugene Paul Wigner 
(1902- ) and Edward Teller (1908- ) and all approached Einstein, who 

had also fled Germany and come to America. 

Leo Szilard 

Eugene P. Wigner 

Einstein was the most prestigious scientist then living and it was thought a letter 
from him to the President of the United States would be most persuasive. 
Einstein signed such a letter, which explained the possibility of a nuclear bomb 
and urged that the United States not allow a potential enemy to come into 
possession of it first. 

Largely as a result of this letter, a huge research team was put together in the 
United States, to which other Western nations also contributed, with but one aim 
—to develop the nuclear bomb. 

The Nuclear Bomb 

Although the theory of the nuclear bomb seemed clear and simple, a great many 
practical difficulties stood in the way. In the first place, if only uranium atoms 
underwent fission a supply of uranium had at least to be obtained in pure form, 
for if the neutrons struck nuclei of elements other than uranium, they would 
simply be absorbed and removed from the system, ending the possibility of a 
chain reaction. This alone was a heavy task, since there had been so little use for 
uranium in quantity that there was almost no supply in existence and no 
experience in how to purify it. 

Secondly, the supply of uranium might have to be a large one, for neutrons didn’t 
necessarily enter the first uranium atom they approached. They moved about 
here and there, making glancing collisions, and travelling quite a distance, 
perhaps, before striking head-on and entering a nucleus. If in that time they had 
passed outside the lump of uranium, they were useless. 

Franklin D. Roosevelt 

Albert Einstein 
Old Grove Rd. 

Nassau Point 
Peconic, Long Island 

August 2nd, 1939 

F.D. Roosevelt, 

President of the United States, 

White House 
Washington, D.C. 


Some recent work by E. Fermi and L. Szilard, which has been 
communicated to me in manuscript, leads me to expect that the 

element uranium may be turned into a new and important source of 

energy in the immediate future. Certain aspects of the situation 
which has arisen seem to call for watchfulness and, if necessary, 
quick action on the part of the Administration. I believe 
therefore that it is my duty to bring to your attention the 

following facts and recommendations: 

In the course of the last four months it has been made probable- 
through the work of Joliot in France as well as Fermi and Szilard 
in America-that it may become possible to set up a nuclear chain 
reaction in a large mass of uranium, by which vast amounts of 
power and large quantities of new radium-like elements would be 
generated. Now it appears almost certain that this could be 

achieved in the immediate future. 

This new phenomenon would also lead to the construction of bombs, 
and it is conceivable-though much less certain-that extremely 
powerful bombs of a new type may thus be constructed. A single 
bomb of this type, carried by boat and exploded in a port, might 
very well destroy the whole port together with some of the 
surrounding territory. However, such bombs might very well prove 
to be too heavy for transportation by air. 

Albert Einstein 

The United States has only very poor ores of uranium in moderate 
quantities. There is some good ore in Canada and the former 
Czechoslovakia, while the most important source of uranium is 
Belgian Congo. 

In view of this situation you may think it desirable to have some 
permanent contact maintained between the Administration and the 
group of physicists working on chain reactions in America. One 
possible way of achieving this might be for you to entrust with 
this task a person who has your confidence and who could perhaps 
serve in an inofficial capacity. His task might comprise the 

a) to approach Government Departments, keep them informed of the 
further development, and put forward recommendations for 
Government action, giving particular attention to the problem of 
securing a supply of uranium ore for the United States; 

b) to speed up the experimental work, which is at present being 
carried on within the limits of the budgets of University 
laboratories, by providing funds, if such funds be required, 
through his contacts with private persons who are willing to make 
contributions for this cause, and perhaps also by obtaining the 
co-operation of industrial laboratories which have the necessary 

I understand that Germany has actually stopped the sale of uranium 
from the Czechoslovakian mines which she has taken over. That she 
should have taken such early action might perhaps be understood on 
the ground that the son of the German Under-Secretary of State, 
von Weizsacker, is attached to the Kaiser-Wilhelm-Institut in 
Berlin where some of the American work on uranium is now being 

Yours very truly. 


(Albert Einstein) 

As the quantity of uranium within which the fission chain reaction was initiated 
grew larger, more and more of the neutrons produced found a mark and the 
fission reaction would die out more and more slowly. Finally, at some particular 
size—the “critical size”—the fission reaction did not die at all, but maintained 
itself, with enough of the neutrons produced finding their mark to keep the 
nuclear reaction proceeding at a steady rate. At any greater size the nuclear 

reaction would accelerate and there would be an explosion. 

It wasn’t even necessary to send neutrons into the uranium to start the process. In 
1941 the Russian physicist Georgii Nikolaevich Flerov (1913- ) found that 

every once in a while a uranium atom would undergo fission without the 
introduction of a neutron. Occasionally the random quivering of a nucleus would 
bring about a shape that the nuclear interaction could not bring back to normal 
and the nucleus would then break apart. In a gram of ordinary uranium, there is a 
nucleus undergoing such “spontaneous fission” every 2 minutes on the average. 
Therefore, enough uranium need only be brought together to surpass critical size 
and it will explode within seconds, for the first nucleus that undergoes 
spontaneous fission will start the chain reaction. 

First estimates made it seem that the quantity of uranium needed to reach critical 
size was extraordinarily great. Fully 99.3% of the metal is uranium-238, 
however, and, as soon as fission was discovered, Bohr pointed out that there 
were theoretical reasons for supposing that it was the uranium-235 isotope 
(making up only 0.7% of the whole) that was the one undergoing fission. 
Investigation proved him right. Indeed, the uranium-238 nucleus tended to 
absorb slow neutrons without fission, and to go on to beta-particle production 
that formed isotopes of neptunium and plutonium. In this way uranium-238 
actually interfered with the chain reaction. 

In any quantity of uranium, the more uranium-235 present and the less uranium- 
238, the more easily the chain reaction would proceed and the lower the critical 
size needed. Vast efforts were therefore made to separate the 2 isotopes and 
prepare uranium with a higher than normal concentration of uranium-235 
(“enriched uranium”). 

Of course, there was no great desire for a fearful explosion to get out of hand 
while the chain reaction was being studied. Before any bomb could be 
constructed, the mechanism of the chain reaction would have to be studied. 
Could a chain reaction capable of producing energy (for useful purposes as well 
as for bombs) be established? To test this, a quantity of uranium was gathered in 
the hope that a controlled chain reaction of uranium fission could be established. 
For that purpose, control rods of a substance that would easily absorb neutrons 
and slow the chain reaction were used. The metal, cadmium, served admirably 
for this purpose. 

Then, too, the neutrons released by fission were pretty energetic. They tended to 
travel too far too soon and get outside the lump of uranium too easily. To 
produce a chain reaction that could be studied with some safety, the presence of 
a moderator was needed. This was a supply of small nuclei that did not absorb 
neutrons readily, but absorbed some of the energy of collision and slowed down 
any neutron that struck it. Nuclei such as hydrogen-2, beryllium-9, or carbon-12 
were useful moderators. When the neutrons produced by fission were slowed, 
they travelled a smaller distance before being absorbed in their turn and the 
critical size would again be reduced. 

Toward the end of 1942 the initial stage of the project reached a climax. Blocks 
of graphite containing uranium metal and uranium oxide were piled up in huge 
quantities (enriched uranium was not yet available) in order to approach critical 
size. This took place under the stands of a football stadium at the University of 
Chicago, with Enrico Fermi (who had come to the United States in 1938) in 


The large structure was called an “atomic pile” at first because of the blocks of 
graphite being piled up. The proper name for such a device, and the one that was 
eventually adopted, was, however, “nuclear reactor”. 

On December 2, 1942, calculations showed that the nuclear reactor was large 
enough to have reached critical size. The only thing preventing the chain 
reaction from sustaining itself was the cadmium rods that were inserted here and 
there in the pile and that were soaking up neutrons. 

Cutaway model of the West Stands of Stagg Field showing the first pile in the squash court beneath it. 

The exterior of the building. 

Graphite layers form the base of the pile, left. On the right is the seventh layer of graphite and edges of the 
sixth layer containing 3V4-inch pseudospheres of black uranium oxide. Beginning with layer 6, alternate 
courses of graphite containing uranium metal and/or uranium oxide fuel were separated by layers of solid 
graphite blocks. 

Tenth layer of graphite blocks containing pseudospheres of black and brown uranium oxide. The brown 
briquets, slightly richer in uranium, were concentrated in the central area. On the right is the nineteenth 
layer of graphite covering layer 18 containing slugs of uranium oxide. 

One by one the cadmium rods were pulled out. The number of uranium atoms 
undergoing fission each second rose and, finally, at 3:45 p.m., the uranium 
fission became self-sustaining. It kept going on its own (with the cadmium rods 
ready to be pushed in if it looked as though it were getting out of hand— 
something calculations showed was not likely). 

News of this success was announced to Washington by a cautious telephone call 
from Arthur Holly Compton (1892-1962) to James Bryant Conant (1893- ). 

“The Italian navigator has landed in the new world”, said Compton. Conant 
asked, “How were the natives?”, and the answer was, “Very friendly”. 

This was the day and moment when the world entered the “nuclear age”. For the 
first time, mankind had constructed a device in which the nuclear energy being 
given off was greater than the energy poured in. Mankind had tapped the 
reservoirs of nuclear energy and could put it to use. Had Rutherford lived but 6 
more years, he would have seen how wrong he was to think it could never be 

The people of earth remained unaware of what had taken place in Chicago and 
physicists continued to work toward the development of the nuclear bomb. 

Enriched uranium was successfully prepared. Critical sizes were brought low 
enough to make a nuclear bomb small enough to be carried by plane to some 
target. Suppose one had 2 slabs of enriched uranium, each below critical size, 
but which were above critical size if combined. And suppose an explosive 
device were added that, at some desired moment, could be set off in such a way 
that it would drive 1 slab of enriched uranium against the other. There would be 
an instant explosion of devastating power. Or suppose the enriched uranium 
were arranged in loosely packed pieces to begin with so that the flying neutrons 
were in open air too often to maintain the chain reaction. A properly arranged 
explosion might compress the uranium into a dense ball. Neutron absorption 
would become more efficient and again, an explosion would follow. 

Nuclear Fission of Uranium: A neutron hits the nucleus of an atom of uranium. The neutron splits the 
nucleus into two parts and creates huge amounts of energy in the form of heat. At the same time other 
neutrons are released from the splitting nucleus and these continue the fission process in a chain reaction. 

On July 16, 1945, a device that would result in a nuclear explosion was set up 
near Alamogordo, New Mexico, with nervous physicists watching from a safe 
distance. It worked perfectly; the explosion was tremendous. 

By that time Nazi Germany had been defeated, but Japan was still fighting. Two 
more devices were prepared. After a warning, one was exploded over the 
Japanese city of Hiroshima on August 6, 1945, and the other over Nagasaki 2 
days later. The Japanese government surrendered and World War II came to an 

It was with the blast over Hiroshima that the world came to know it was in the 
nuclear age and that the ferocious weapon of the nuclear bomb existed. (The 
popular name for it at the time was “atomic bomb” or “A-bomb”.) 

During the war, German scientists may have been trying to develop a nuclear 
bomb, but, if so, they had not yet succeeded at the time Germany met its final 
defeat. Soviet physicists, under Igor Vasilievich Kurchatov (1903-1960), were 
also working on the problem. The dislocation of the war, which inflicted much 
more damage on the Soviet Union than on the United States, kept the Soviet 
effort from succeeding while it was on. However, since the Soviets were among 
the victors, they were able to continue after the war. 

In 1949 the Soviets exploded their first nuclear bomb. In 1952 the British did the 
same; in 1960, the French; and in 1964, the Chinese. 

Although many nuclear bombs have been exploded for test purposes, the two 
over Hiroshima and Nagasaki have been the only ones used in time of war. 

Nor need nuclear bombs be considered as having destructive potential only. 
There is the possibility that, with proper precautions, they might be used to make 
excavations, blast out harbors or canals, break up underground rock formations 
to recover oil or other resources, and in other ways do the work of chemical 
explosives with far greater speed and economy. It has even been suggested that a 
series of nuclear bomb explosions might be used to hurl space vehicles forward 

in voyages away from earth. 

Nuclear Reactors 

The development of the nuclear chain reaction was not in the direction of bombs 
only. Nuclear reactors designed for the controlled production of useful energy 
multiplied in number and in efficiency since Fermi’s first “pile”. Many nations 

12 ] 

now possess them, and they are used for a variety of purposes. 

The USS Nautilus, the world’s first nuclear powered submarine, in New York harbor. 

In 1954 the first nuclear submarine the USS Nautilus was launched by the 
United States. Its power was obtained entirely from a nuclear reactor, and it was 
not necessary for it to rise to the surface at short intervals in order to recharge its 
batteries. Nuclear submarines have crossed the Arctic Ocean under the ice cover, 
and have circumnavigated the globe without surfacing. 

In 1959 both the Soviet Union and the United States launched nuclear-powered 
surface vessels. The Soviet ship was the icebreaker, Lenin, and the American 
ship was a merchant vessel, the NS Savannah. 

In the 1950s nuclear reactors were also used as the source of power for the 
production of electricity for civilian use. The Soviet Union built a small station 
of this sort in 1954, which had a capacity of 5,000 kilowatts. The British built 
one of 92,000 kilowatt capacity, which they called Calder Hall. The first 
American nuclear reactor for civilian use began operation at Shippingport, 
Pennsylvania, in 1958. It was the first really full-scale civilian nuclear power 
plant in the world. 

The world appeared to have far greater sources of energy than had been 
expected. The “fossil fuels”—coal, oil and natural gas—were being used at such 
a rate that many speculated that the gas and oil would be gone in decades and the 
coal in centuries. Was it possible that uranium might now serve as a new source 
that would last indefinitely? 

It was rather disappointing that it was uranium-235 which underwent fission, 

because that isotope made up only 0.7% of the uranium that existed. If uranium- 
235 were all we had and all we ever could have, the energy supply of the world 
would still be rather too limited. 

There were other possible “nuclear fuels”, however. There was plutonium-239, 
which would also fission under neutron bombardment. It had an ordinary half- 
life (for a radioactive change in which it gave off alpha particles) of 24,300 
years, which is long enough to make it easy to handle. 

But how can plutonium-239 be formed in sufficient quantities to be useful? After 
all, it doesn’t occur in nature. Surprisingly, that turned out to be easy. Uranium- 
238 atoms will absorb many of the neutrons that are constantly leaking out of the 
reactor and will become first neptunium-239 and then plutonium-239. The 
plutonium, being a different element from the uranium, can be separated from 
uranium and obtained in useful quantities. 

Such a device is called a “breeder reactor” because it breeds fuel. Indeed, it can 
be so designed to produce more plutonium-239 than the uranium-235 it uses up, 
so that you actually end up with more nuclear fuel than you started with. In this 
way, all the uranium on earth (and not just uranium-235) can be considered 
potential nuclear fuel. 

The Shippingport Atomic Power Station, the first full-scale, nuclear-electric station built exclusively for 
civilian needs, provides electricity for the homes and factories of the greater Pittsburgh area. The 
pressurized-water reactor, which now has a 90,000-net-electrical-kilowatt capacity, began commercial 
operation in 1957. The reactor is in the large building in the center. 

The lights of downtown Pittsburgh. 

The first breeder reactor was completed at Arco, Idaho, in August 1951, and on 
December 20 produced the very first electricity on earth to come from nuclear 
power. Nevertheless, breeder reactors for commercial use are still a matter for 

the future. 

Another isotope capable of fissioning under neutron bombardment is uranium- 
233. It does not occur in nature, but was formed in the laboratory by Seaborg and 
others in 1942. It has a half-life of 162,000 years. It can be formed from 
naturally occurring thorium-232. Thorium-232 will absorb a neutron to become 

thorium-233. Then 2 beta particles are given off so that the thorium-233 
becomes first protactinium-233 and then uranium-233. 

If a thorium shell surrounds a nuclear reactor, fissionable uranium-233 is formed 
within it and is easily separated from the thorium. In this way, thorium is also 


added to the list of earth’s potential nuclear fuels. 

If all the uranium and thorium in the earth’s crust (including the thin scattering 
of those elements through granite, for instance) were available for use, we might 
get up to 100 times as much energy from it as from all the coal and oil on the 
planet. Unfortunately, it is very unlikely that we will ever be able to make use of 
all the uranium and thorium. It is widely and thinly spread through the crustal 
rocks and much of it could not be extracted without using up more energy than 
would be supplied by it once isolated. 

Another problem rests with the nature of the fission reaction. When the uranium- 
235 nucleus (or plutonium-239 or uranium-233) undergoes fission, it breaks up 
into any of a large number of middle-sized nuclei that are radioactive—much 
more intensely radioactive than the original fuel. (It was from among these 
“fission products” that isotopes of element 61 were first obtained in 1945. 
Coming from the nuclear fire, it reminded its discoverers of Prometheus, who 
stole fire from the sun in the Greek myths, and so it was called “promethium”.) 

The fission products still contain energy and some of them can be used in 
lightweight “nuclear batteries”. Such nuclear batteries were first built in 1954. 
Some batteries, using plutonium-238 rather than fission products, have been put 
to use in powering artificial satellites over long periods. 

Unfortunately, only a small proportion of the fission products can be put to 
profitable use. Most must be disposed of. They are dangerous because the 
radiations they give off are deadly and cannot be detected by the ordinary senses. 
They are very difficult to dispose of safely, and they must not be allowed to get 
into the environment, especially since some of them remain dangerous for 
decades or even centuries. 

The Experimental Breeder Reactor No. 2 building complex in Idaho. The reactor is in the dome-shaped 


The Energy of the Sun 

As it happens, though, nuclear fission is not the only route to useful nuclear 

Aston’s studies in the 1920s had shown that it was the middle-sized nuclei that 
were most tightly packed. Energy would be given off if middle-sized nuclei were 
produced from either extreme. Not only would energy be formed by the breakup 
of particularly massive nuclei through fission, but also through the combination 
of small nuclei to form larger ones (“nuclear fusion”). 

In fact, from Aston’s studies it could be seen that, mass for mass, nuclear fusion 
would produce far more energy than nuclear fission. This was particularly true in 
the conversion of hydrogen to helium; that is, the conversion of the individual 
protons of 4 separate hydrogen nuclei into the 2-proton—2-neutron structure of 
the helium nucleus. A gram of hydrogen, undergoing fusion to helium, would 
deliver some fifteen times as much energy as a gram of uranium undergoing 

As early as 1920, the English astronomer Arthur Stanley Eddington (1882-1944) 
had speculated that the sun’s energy might be derived from the interaction of 
subatomic particles. Some sort of nuclear reaction seemed, by then, to be the 
most reasonable way of accounting for the vast energies constantly being 
produced by the sun. 

The speculation became more plausible with each year. Eddington himself 
studied the structure of stars, and by 1926 had produced convincing theoretical 
reasons for supposing that the center of the sun was at enormous densities and 
temperatures. A temperature of some 15,000,000 to 20,000,000°C seemed to 
characterize the sun’s center. 

At such temperatures, atoms could not exist in earthly fashion. Held together by 

the sun’s strong gravitational field, they collided with such energy that all or 
almost all their electrons were stripped off, and little more than bare nuclei were 
left. These bare nuclei could approach each other much more closely than whole 
atoms could (which was why the center of the sun was so much more dense than 
earthly matter could be). The bare nuclei, smashing together at central-sun 
temperatures, could cling together and form more complex nuclei. Nuclear 
reactions brought about by such intense heat (millions of degrees) are called 
“thermonuclear reactions”. 

As the 1920s progressed further studies of the chemical structure of the sun 
showed it to be even richer in hydrogen than had been thought. In 1929 the 
American astronomer Henry Norris Russell (1877-1957) reported evidence that 
the sun was 60% hydrogen in volume. (Even this was too conservative; 80% is 
considered more nearly correct now.) If the sun’s energy were based on nuclear 
reactions at all, then it had to be the result of hydrogen fusion. Nothing else was 
present in sufficient quantity to be useful as a fuel. 

More and more was learned about the exact manner in which nuclei interacted 
and about the quantity of energy given off in particular nuclear reactions. It 
became possible to calculate what might be going on inside the sun by 
considering the densities and temperatures present, the kind and number of 
different nuclei available, and the quantity of energy that must be produced. In 
1938 the German-American physicist Hans Albrecht Bethe (1906- ) and the 

German astronomer Carl Friedrich von Weizsacker (1912- ) independently 

worked out the possible reactions, and hydrogen fusion was shown to be a 
thoroughly practical way of keeping the sun going. 

Thanks to the high rate of energy production by thermonuclear reactions and to 
the vast quantity of hydrogen in the sun, not only has it been possible for the sun 
to have been radiating energy for the last 5,000,000,000 years or so, but it will 
continue to radiate energy in the present fashion for at least 5,000,000,000 years 
into the future. 

Hans Bethe 

Even so, the sheer quantity of what is going on in the sun is staggering in earthly 
terms. In the sun 650,000,000 tons of hydrogen are converted into helium every 
second, and in the process each second sees the disappearance of 4,600,000 tons 

of mass. 

Thermonuclear Bombs 

Could thermonuclear reactions be made to take place on earth? The conditions 
that exist in the center of the sun would be extremely difficult to duplicate on the 
earth, so there was a natural search for any kind of nuclear fusion that would 
produce similar energies to those going on in the sun but which would be easier 
to bring about. 

There are 3 hydrogen isotopes known to exist. Ordinary hydrogen is almost 
entirely hydrogen-1, with a nucleus made up of a single proton. Small quantities 
of hydrogen-2 (deuterium) with a nucleus made up of a proton plus a neutron 
also exist and such atoms are perfectly stable. 

In 1934 Rutherford, along with the Australian physicist Marcus Laurence Elwin 
Oliphant (1901- ) and the Austrian chemist Paul Harteck (1902- ) sent 

hydrogen-2 nuclei flying into hydrogen-2 targets and formed hydrogen-3 (also 
called “tritium” from the Greek word for “third”) with a nucleus made up of a 
proton plus 2 neutrons. Hydrogen-3 is mildly radioactive. 

Hydrogen-2 fuses to helium more easily than hydrogen-1 does and, all things 
being equal, hydrogen-2 will do so at lower temperatures than hydrogen-1. 
Hydrogen-3 requires lower temperatures still. But even for hydrogen-3 it still 
takes millions of degrees. 

Hydrogen-3, although the easiest to be forced to undergo fusion, exists only in 
tiny quantities. 

Hydrogen-2, therefore, is the one to pin hopes on especially in conjunction with 
hydrogen-3. Only 1 atom out of every 6000 hydrogen atoms is hydrogen-2, but 
that is enough. There exists a vast ocean on earth that is made up almost entirely 
of water molecules and in each water molecule 2 hydrogen atoms are present. 
Even if only 1 in 6000 of these hydrogen atoms is deuterium that still means 
there are about 35,000 billion tons of deuterium in the ocean. 

What’s more, it isn’t necessary to dig for that deuterium or to drill for it. If ocean 
water is allowed to run through separation plants, the deuterium can be extracted 

without very much trouble. In fact, for the energy you could get out of it, 
deuterium from the oceans, extracted by present methods and without allowing 
for future improvement, would be only one-hundredth as expensive as coal. 

The deuterium in the world’s ocean, if allowed to undergo fusion little by little, 
would supply mankind with enough energy to keep us going at the present rate 
for 500,000,000,000 years. To be sure, to make deuterium fusion practical, it 
may be necessary to make use of rarer substances such as the light metal lithium. 
This will place a sharper limit on the energy supply but even if we are careful, 
fusion would probably supply mankind with energy for as long as mankind will 

Then, too, there would seem to be no danger of hydrogen fusion plants running 
out of control. Only small quantities of deuterium would be in the process of 
fusion at any one time. If anything at all went wrong, the deuterium supply could 
be automatically cut off and the fusion process, with so little involved, would 
then stop instantly. Moreover, there would be less reason to worry about atomic 
wastes, for the most dangerous products—hydrogen-3 and neutrons—could be 
easily taken care of. 

It seems ideal, but there is a catch. However clear the theory, before a fusion 
power station can be established some practical method must be found to start 
the fusion process, which means finding some way for attaining temperatures in 
the millions of degrees. 

One method for obtaining the necessary temperature was known by 1945. An 
exploding fission bomb would do it. If, somehow, the necessary hydrogen-2 was 
combined with a fission bomb, the explosion would set off a fusion reaction that 
would greatly multiply the energy released. You would have in effect a 
“thermonuclear bomb”. (To the general public, this was commonly known as a 
“hydrogen bomb” or an “H-bomb”.) 

In 1952 the first fusion device was exploded by the United States in the Marshall 
Islands. Within months, the Soviet Union had exploded one of its own and in 
time thermonuclear bombs thousands of times as powerful as the first fission 
bomb over Hiroshima were built and exploded. 

All thermonuclear bombs have been exploded only for test purposes. Even 
testing seems to be dangerous, however, at least if it is carried on in the open 

atmosphere. The radioactivity liberated spreads over the world and may do slow 
but cumulative damage. 

Controlled Fusion 

However effective a fusion bomb may be in liberating vast quantities of energy, 
it is not what one has in mind when speaking of a fusion power station. The 
energy of a fusion bomb is released all at once and its only function is that of 
utter destruction. What is wanted is the production of fusion energy at a low and 
steady rate—a rate that is under the control of human operators. 

The sun, for instance, is a vast fusion furnace 866,000 miles across, but it is a 
controlled one—even though that control is exerted by the impersonal laws of 
nature. It releases energy at a very steady and very slow rate. (The rate is not 
slow in human terms, of course, but stars sometimes do release their energy in a 
much more cataclysmic fashion. The result is a “supernova” in which for a short 
time a single star will increase its radiation to as much as a trillion times its 
normal level.) 

The sun (or any star) going at its normal rate is controlled and steady in its 
output because of the advantage of huge mass. An enormous mass, composed 
mainly of hydrogen, compresses itself, through its equally enormous 
gravitational field, into huge densities and temperatures at its center, thus 
igniting the fusion reaction—while the same gravitational field keeps the sun 
together against its tendency to expand. 

There is, as far as scientists know, no conceivable way of concentrating a high 
gravitational field in the absence of the required mass, and the creation of 
controlled fusion on earth must therefore be done without the aid of gravity. 
Without a huge gravitational force we cannot simultaneously bring about sun- 
center densities and sun-center temperatures; one or the other must go. 

On the whole, it would take much less energy to aim at the temperatures than at 
the densities and would be much more feasible. For this reason, physicists have 
been attempting, all through the nuclear age, to heat thin wisps of hydrogen to 
enormous temperature. Since the gas is thin, the nuclei are farther apart and 
collide with each other far fewer times per second. To achieve fusion ignition, 
therefore, temperatures must be considerably higher than those at the center of 

the sun. In 1944 Fermi calculated that it might take a temperature of 50,000,000° 
to ignite a hydrogen-3 fusion with hydrogen-2 under earthly conditions, and 
400,000,000° to ignite hydrogen-2 fusion alone. To ignite hydrogen-1 fusion, 
which is what goes on in the sun (at a mere 15,000,000°), physicists would have 
to raise their sights to beyond the billion-degree mark. 

A supernova photographed on March 10, 1935. 

The same star on May 6. 

This would make it seem almost essential to use hydrogen-3 in one fashion or 
another. Even if it can’t be prepared in quantity to begin with, it might be formed 
by neutron bombardment of lithium, with the neutrons being formed by the 
fusion reaction. In this way, you would start with lithium and hydrogen-2 plus a 
little hydrogen-3. The hydrogen-3 is formed as fast as it is used up. Although in 
the end hydrogen is converted to helium in a controlled fusion reaction as in the 
sun, the individual steps in the reaction under human control are quite different 
from those in the sun. 

Still, even the temperatures required for hydrogen-3 represent an enormous 
problem, particularly since the temperature must not only be reached, but must 
be held for a period of time. (You can pass a piece of paper rapidly through a 
candle flame without lighting it. It must be held in the flame for a short period to 
give it a chance to heat and ignite.) 

The English physicist John David Lawson (1923- ) worked out the 

requirements in 1957. The time depended on the density of the gas. The denser 
the gas, the shorter the period over which the temperature had to be maintained. 
If the gas is about one hundred-thousand times as dense as air, the proper 
temperature must be held, under the most favorable conditions, for about one 
thousandth of a second. 

There are a number of different ways in which a quantity of hydrogen can be 
heated to very high temperatures—through electric currents, through magnetic 
fields, through laser beams and so on. As the temperature goes up into the tens 
of thousands of degrees, the hydrogen atoms (or any atoms) are broken up into 
free electrons and bare nuclei. Such a mixture of charged particles is called a 
“plasma”. Ever since physicists have begun to try to work with very hot gases, 

with fusion energy in mind, they have had to study the properties of such 
“plasma”, and a whole new science of “plasma physics” has come into existence. 

But if you do heat a gas to very high temperatures, it will tend to expand and thin 
out to uselessness. How can such a super-hot gas be confined in a fixed volume 
without an enormous gravitational field to hold it together? 

An obvious answer would be to place it in a container, but no ordinary container 
of matter will serve to hold the hot gas. You may think this is because the 
temperature of the gas will simply melt or vaporize whatever matter encloses it. 
This is not so. Although the gas is at a very high temperature, it is so thin that it 
has very little total heat. It does not have enough heat to melt the solid walls of a 
container. What happens instead is that the hot plasma cools down the moment it 
touches the solid walls and the entire attempt to heat it is ruined. 

What’s more, if you try to invest the enormous energies required to keep the 
plasma hot despite the cooling effect of the container walls, then the walls will 
gradually heat and melt. Nor must one wait for the walls to melt and the plasma 
to escape before finding the attempt at fusion ruined. Even as the walls heat up 
they liberate some of their own atoms into the plasma and introduce impurities 
that will prevent the fusion reaction. 

Any material container is therefore out of the question. 

Fortunately, there is a nonmaterial way of confining plasma. Since plasma 
consists of a mixture of electrically charged particles, it can experience 
electromagnetic interactions. Instead of keeping the plasma in a material 
container, you can surround it by a magnetic field that is designed to keep it in 
place. Such a magnetic field is not affected by any heat, however great, and 
cannot be a source of material impurity. 

In 1934, the American physicist Willard Harrison Bennett (1903- ) had 

worked out a theory dealing with the behavior of magnetic fields enclosing 
plasma. It came to be called the “pinch effect” because the magnetic field 
pinched the gas together and held it in place. 

The first attempt to make use of the pinch effect for confining plasma, with 
eventual ignition of fusion in mind, was in 1951 by the English physicist Alan 
Alfred Ware (1924- ). Other physicists followed, not only in Great Britain, 

but in the United States and the Soviet Union as well. 

The first use of the pinch effect was to confine the plasma in a cylinder. This, 
however, could not be made to work. The situation was too unstable. The plasma 
was held momentarily, then writhed and broke up. 

Plasma in a magnetic field. 

Enormous machines and complex equipment, such as the Scyllac machine shown above, are required for 
nuclear fusion research. 

Attempts were made to remove the instability. The field was so designed as to be 
stronger at the ends of the cylinder than elsewhere. The particles in the plasma 
would stream toward one end or another and would then bounce back producing 
a so-called “magnetic mirror”. 

In 1951 the American physicist Lyman Spitzer, Jr. (1914- ) had worked out 

the theoretical benefits to be derived from a container twisted into a figure-eight 
shape. Eventually, such devices were built and called “stellarators” from the 
Latin word for “star”, because it was hoped that it would produce the conditions 
that would allow the sort of fusion reactions that went on in stars. 

All through the 1950s and 1960s, physicists have been slowly inching toward 
their goal, reaching higher and higher temperatures and holding them for longer 
and longer periods in denser and denser gases. 

In 1969 the Soviet Union used a device called “Tokamak-3” (a Russian 
abbreviation for their phrase for “electric-magnetic”) to keep a supply of 
hydrogen-2, a millionth as dense as air, in place while heating it to tens of 
millions of degrees for a hundredth of a second. 

A little denser, a little hotter, a little longer—and controlled fusion might become 

15 ] 




Is there anything that lies beyond fusion? 

When hydrogen undergoes fusion and becomes helium, only 0.7% of the original 
mass of the hydrogen is converted to energy. Is it possible to take a quantity of 
mass and convert all of it, every bit, to energy? Surely that would be the ultimate 
energy source. Mass for mass, that would deliver 140 times as much energy as 
hydrogen fusion would; it would be as far beyond hydrogen fusion as hydrogen 
fusion is beyond uranium fission. 

And, as a matter of fact, total annihilation of matter is conceivable under some 

In 1928 the English physicist Paul Adrien Maurice Dirac (1902- ) presented 

a treatment of the electron’s properties that made it appear as though there ought 
also to exist a particle exactly like the electron in every respect except that it 
would be opposite in charge. It would carry a positive electric charge exactly as 
large as the electron’s negative one. 

If the electron is a particle, this suggested positively charged twin would be an 
“antiparticle”. (The prefix comes from a Greek word meaning “opposite”.) 

P. A. M. Dirac 

The first picture of the positron (left) was taken in a Wilson cloud chamber. On the right is C. D. Anderson, 
the discoverer of the positron. 

The proton is not the electron’s antiparticle. Though a proton carries the 
necessary positive charge that is exactly as large as the negative charge of the 
electron, the proton has a much larger mass than the electron has. Dirac’s theory 

required that the antiparticle have the same mass as the particle to which it 

In 1932 C. D. Anderson was studying the impact of cosmic particles on lead. In 
the process, he discovered signs of a particle that left tracks exactly like those of 
an electron, but tracks that curved the wrong way in a magnetic field. This was a 
sure sign that it had an electric charge opposite to that of the electron. He had, in 
short, discovered the electron’s antiparticle and this came to be called the 

Positrons were soon detected elsewhere too. Some radioactive isotopes, formed 
in the laboratory by the Joliot-Curies and by others, were found to emit positive 
beta particles—positrons rather than electrons. When an ordinary beta particle, 
or electron, was emitted from a nucleus, a neutron within the nucleus was 
converted to a proton. When a positive beta particle, a positron, was emitted, the 
reverse happened—a proton was converted to a neutron. 

A positron, however, does not endure long after formation. All about it were 
atoms containing electrons. It could not move for more than a millionth of a 
second or so before it encountered one of those electrons. When it did, there was 
an attraction between the two, since they were of opposite electric charge. 
Briefly they might circle each other (to form a combination called 
“positronium”) but only very briefly. Then they collided and, since they were 
opposites, each cancelled the other. 

The process whereby an electron and a positron met and cancelled is called 
“mutual annihilation”. Not everything was gone, though. The mass, in 
disappearing, was converted into the equivalent amount of energy, which made 
its appearance in the form of one or more gamma rays. 

(It works the other way, too. A gamma ray of sufficient energy can be 
transformed into an electron and a positron. This phenomenon, called “pair 
production”, was observed as early as 1930 but was only properly understood 
after the discovery of the positron.) 

Of course, the mass of electrons and positrons is very small and the amount of 
energy released per electron is not enormously high. Still, Dirac’s original theory 
of antiparticles was not confined to electrons. By his theory, any particle ought to 
have some corresponding antiparticle. Corresponding to the proton, for instance, 

there ought to be an “antiproton”. This would be just as massive as the proton 
and would carry a negative charge just as large as the proton’s positive charge. 

An antiproton, however, is 1836 times as massive as a positron. It would take 
gamma rays or cosmic particles with 1836 times as much energy to form the 
proton-antiproton pair as would suffice for the electron-positron pair. Cosmic 
particles of the necessary energies existed but they were rare and the chance of 
someone being present with a particle detector just as a rare super-energetic 
cosmic particle happened to form a proton-antiproton pair was very small. 

The Bevatron began operation in 1954. 

Physicists had to wait until they had succeeded in designing particle accelerators 
that would produce enough energy to allow the creation of proton-antiproton 
pairs. This came about in the early 1950s when a device called the “Cosmotron” 
was built at Brookhaven National Laboratory in Long Island in 1952 and another 
called the “Bevatron” at the University of California in Berkeley in 1954. 

Using the Bevatron in 1956, Segre (the discoverer of technetium who had, by 
that time, emigrated to the United States), the American physicist Owen 
Chamberlain (1920- ), and others succeeded in detecting the antiproton. 

The antiproton was as unlikely to last as long as the positron was. It was 
surrounded by myriads of proton-containing nuclei and in a tiny fraction of a 
second it would encounter one. The antiproton and the proton also underwent 
mutual annihilation, but having 1836 times the mass, they produced 1836 times 
the energy that was produced in the case of an electron and a positron. 

There was even an “antineutron”, a particle reported in 1956 by the Italian- 
American physicist Oreste Piccioni (1915- ) and his co-workers. Since the 

neutron has no charge, the antineutron has no charge either, and one might 
wonder how the antineutron would differ from the neutron then. Actually, both 
have a small magnetic field. In the neutron the magnetic field is pointed in one 
direction with reference to the neutron’s spin; in the antineutron it is pointed in 
the other. 

Bubble chamber photograph of an antiproton annihilation. 

In 1965 the American physicist Leon Max Lederman (1922- ) and his co¬ 

workers produced a combination of an antiproton and an antineutron that 
together formed an “antideuteron”, which is the nucleus of antihydrogen-2. 

This is good enough to demonstrate that if antiparticles existed by themselves 
without the interfering presence of ordinary particles, they could form 
“antimatter”, which would be precisely identical with ordinary matter in every 
way except for the fact that electric charges and magnetic fields would be turned 

If antimatter were available to us, and if we could control the manner in which it 
united with matter, we would have a source of energy much greater and, perhaps, 
simpler to produce than would be involved in hydrogen fusion. 

To be sure, there is no antimatter on earth, except for the submicroscopic 
amounts that are formed by the input of tremendous energies. Nor does anyone 
know of any conceivable way of forming antimatter at less energy than that 
produced by mutual annihilation, so that we might say that mankind can never 
make an energy profit out of it—except that with the memory of Rutherford’s 
prediction that nuclear energy of any kind could never be tapped, one hesitates to 
be pessimistic about anything. 

The Unknown 

Physical theory makes it seem that particles and antiparticles ought to exist in 
the universe in equal quantities. Yet on earth (and, we can be quite certain, in the 
rest of the solar system and even, very likely, in the rest of the galaxy) protons, 
neutrons, and electrons are common, while antiprotons, antineutrons, and 
positrons are exceedingly rare. 

Could it be that when the universe was first formed there were indeed equal 
quantities of particles and antiparticles but that they were somehow segregated, 
perhaps into galaxies and “antigalaxies”? If so, there might occasionally be 
collisions of a galaxy and an antigalaxy with the evolution of vast quantities of 
energy as mutual annihilation on a cosmic scale takes place. 

There are, in fact, places in the heavens where radiation is unusually high in 
quantity and in energy. Can we be witnessing such enormous mutual 


Indeed, it is not altogether inconceivable that we may still have new types of 
forces and new sources of energy to discover. Until about 1900, no one 
suspected the existence of nuclear energy. Are we quite sure now that nuclear 
energy brings us to the end, and that there is not a form of energy more subtle 
still, and greater? 

In 1962, for instance, certain puzzling objects called “quasars” were discovered 
far out in space, a billion light-years or more away from us. Each one shines 
from 10 to 100 times as brilliantly as an entire ordinary galaxy does, and yet may 
be no more than a hundred-thousandth as wide as a galaxy. 

This is something like finding an object 10 miles across that delivers as much 
total light as 100 suns. 

It is very hard to understand where all that energy comes from and why it should 
be concentrated into so tiny a volume. Astronomers have tried to explain it in 
terms of the four interactions now known, but is it possible that there is a fifth 
greater than any of the four? 

If so, it is not impossible that eventually man’s restless brain may come to 
understand and even utilize it. 



See The First Reactor, another booklet in this series. 

12 ] 

See Nuclear Reactors and Nuclear Power Plants, companion booklets in this 

13 ] 

See Breeder Reactors, another booklet in this series. 

14 ] 

See Thorium—and the Third Fuel, another booklet in this series. 

15 ] 

See Controlled Nuclear Fusion, another booklet in this series. 


Inside Copyright © by Abelard-Shuman, Ltd., New York. Reprinted by 

front permission from Inside the Atom, Isaac Asimov, 1966. 



Basic Books 

Basic Laws of Matter (revised edition), Harrie S. W. Massey and Arthur R. 
Quinton, Herald Books, Bronxville, New York, 1965, 178 pp., $3.75. Grades 
7-9. A nontechnical presentation of atoms and the laws governing their 

Biography of Physics, George Gamow, Harper & Row, Publishers, New York, 
1961, 338 pp., $6.50 (hardback); $2.75 (paperback). Grades 9-12. A history of 
theoretical physics. 

Discoverer of X Rays: Wilhelm Conrad Roentgen, Arnulf K. Esterer, Julian 
Messner, New York, 1968, 191 pp., $3.50. Grades 7-10. This interesting 
biography includes a brief, but very helpful, pronouncing gazetteer of the 
German, Swiss, and Dutch names in the text. 

Ernest Rutherford: Architect of the Atom, Peter Kelman and A. Harris Stone, 
Prentice-Hall, Inc., Englewood Cliffs, New Jersey, 1969, 72 pp., $3.95. 
Grades 5-7. A well-done biography of this famous atomic scientist. Many of 
the drawings illustrate theoretical ideas very well for the elementary grades. A 
glossary is included. 

Enrico Fermi: Atomic Pioneer, Doris Faber, Prentice-Hall, Inc., Englewood 
Cliffs, New Jersey, 1966, 86 pp., $3.95. Grades 5-8. A biography of the man 
who built the first reactor. 

Giant of the Atom: Ernest Rutherford, Robin McKown, Julian Messner, New 
York, 1962, 191 pp., $3.50. Grades 7-12. The life and accomplishments of a 
great physicist. 

The History of the Atomic Bomb, Michael Blow, American Heritage 
Publishing Company, Inc., New York, 1968, 150 pp., $5.95. Grades 5-9. This 

sumptuously illustrated history provides an informative explanation of nuclear 
physics in addition to comprehensive coverage of the bomb’s development 
and use. 

Inside the Atom, Isaac Asimov, Abelard-Schuman, Ltd., New York, 1966, 197 
pp., $4.00. Grades 7-10. This comprehensive, well-written text explains 
nuclear energy and its applications. 

Madame Curie: A Biography, Eve Curie, translated by Vincent Sheean, 
Doubleday and Company, Inc., New York, 1937, 385 pp., $5.95 (hardback); 
$0.95 (paperback). Grades 9-12. This superb biography, which won the 1937 
National Book Award for Nonfiction, illustrates dramatically the full spectrum 
of Marie Curie’s life. 

Men Who Mastered the Atom, Robert Silverberg, G. P. Putnam’s Sons, New 
York, 1965, 193 pp., $3.49. Grades 7-9. Atomic energy history is told through 
the work of pioneer scientists from Thales to present-day researchers. 

The Neutron Story, Donald J. Hughes, Doubleday and Company, Inc., New 
York, 1959, 158 pp., out of print. Grades 7-9. A substantial and interesting 
account of neutron physics. 

Niels Bohr: The Man Who Mapped the Atom, Robert Silverberg, MacRae 
Smith Company, Philadelphia, Pennsylvania, 1965, 189 pp., $3.95. Grades 8- 
12. An exciting, suspenseful, and humorous biography of one of the pioneers 
in atomic energy. Includes a glossary and references. 

The Questioners: Physicists and the Quantum Theory, Barbara Lovett Cline, 
Crowell Collier and MacMillan, Inc., New York, 1965, 274 pp., $5.00 
(hardback); available in paperback with the title Men Who Made A New 
Physics: Physicists and the Quantum Theory, New American Library, Inc., 
New York, $0.75. Grades 9-12. An exceptionally well-delineated and 
personable account of the development of the quantum theory by physicists in 
the first quarter of this century. 

The Restless Atom, Alfred Romer, Doubleday and Company, Inc., New York, 
1960, 198 pp., $1.25. Grades 9-12. A stimulating nonmathematical account of 
the classic early experiments that advanced knowledge about atomic particles. 

Roads to Discovery, Ralph E. Lapp, Harper and Row, Publishers, New York, 

1960, 191 pp., out of print. Grades 10-12. Historical survey of nuclear physics 
beginning with Roentgen’s discovery of X rays and concluding with the 
discoveries of the rare elements. 

Secret of the Mysterious Rays: The Discovery of Nuclear Energy, Vivian Grey, 
Basic Books, Inc., Publishers, New York, 1966, 120 pp., $3.95. Grades 4-8. 
This outstanding history of nuclear research from Roentgen to Fermi is 
dramatically presented. The uncertainty of the unknown, the accidental 
discovery and the often lengthy and tedious research are woven in this story of 
scientists from around the world who pooled their knowledge and experience 
to unlock “the secrets of the mysterious rays”. 

Wilhelm Roentgen and the Discovery of X Rays, Bern Dibner, Franklin Watts, 
Inc., New York, 1968, 149 pp., $2.95. Grades 5-8. This detailed biography, 
illustrated with line drawings, historical photographs, and papers, is a fine 
addition to Watts’ “Immortals of Science” Series. 

Working with Atoms, Otto R. Frisch, Basic Books, Inc., New York, 1965, 96 
pp., $4.95. Grades 9-12. Dr. Frisch presents a history of nuclear energy 
research and provides experiments for the reader. He gives a personal account 
of the pioneering work in which he and Lise Meitner explained the splitting of 
uranium and introduced the term “nuclear fission”. 

Advanced Books 

An American Genius: The Life of Ernest Orlando Lawrence, Herbert Childs, 
E. P. Dutton and Company, Inc., New York, 1968, 576 pp., $12.95. This well- 
written, scientifically accurate, and very interesting biography captures the 
excitement of Lawrence’s life. Ernest Lawrence was the inventor of the 
cyclotron, a major member of the wartime atomic energy development, and 
the director of the Lawrence Radiation Laboratory. 

The Atom and Its Nucleus, George Gamow, Prentice-Hall, Inc., Englewood 
Cliffs, New Jersey, 1961, 153 pp., $1.25. A popular-level discussion of nuclear 
structure and the applications of nuclear energy. 

Atomic Energy for Military Purposes, Henry D. Smyth, Princeton University 
Press, Princeton, New Jersey, 1945, 308 pp., $4.00. A complete account of the 

wartime project that developed the first nuclear weapons and of the 
considerations that prompted their use. 

Atomic Quest, Arthur H. Compton, Oxford University Press, Inc., New York, 
1956, 370 pp., $7.95. A personal narrative of the research that led to the 
release of atomic energy on a useful scale by a scientist who played a 
principal part in the atomic bomb project during World War II. 

The Atomists ( 1805-1933 ), Basil Schonland, Oxford University Press, Inc., 
New York, 1968, 198 pp., $5.60. This book, which can be understood by 
anyone who has had a high school physics course, presents atomic theory 
development from Dalton through Bohr. It achieves a good balance between 
popular treatments and highly technical works without slighting the technical 

Atoms in the Family: My Life with Enrico Fermi, Laura Fermi, Chicago 
University Press, Chicago, Illinois, 1954, 267 pp., $5.00 (hardback); $2.45 
(paperback). Laura Fermi writes about her husband, Enrico Fermi, the 
physicist who led the group that built the first nuclear reactor. 

The Born-Einstein Letters: The Correspondence Between Albert Einstein and 
Max and Hedwig Born from 1916 to 1955, commentaries by Max Born, 
translated by Irene Born, Walker and Company, 1971, 240 pp., $8.50. These 
interesting letters reveal the scientific and personal lives of these two atomic 

Einstein: His Life and Times, Philipp Frank, Alfred A. Knopf, Inc., New York, 
1953, 298 pp., $6.95. A brilliant biography that reveals the richness of 
Einstein’s life and work and the tremendous impact he made upon physics. 

Enrico Fermi, Physicist, Emilio Segre, Chicago University Press, Chicago, 
Illinois, 1970, 288 pp., $6.95. This biography tells of Enrico Fermi’s 
intellectual history, achievements, and his scientific style. The scientific 
problems faced or solved by Fermi are explained in layman’s terms. Emilio 
Segre was a friend and scientific collaborator who worked with Fermi for 
many years. 

An Introduction to Physical Science: The World of Atoms (second edition), 
John J. G. McCue, The Ronald Press Company, New York, 1963, 775 pp., 
$9.50. This textbook was written for college humanities students. 

J. J. Thomson: Discoverer of the Electron, George Thomson, Doubleday and 
Company, Inc., New York, 1966, 240 pp., $1.45. This biography, written by J. 
J. Thomson’s son, describes his research at the famed Cavendish Laboratory 
in Cambridge, England. 

John Dalton and the Atom, Frank Greenaway, Cornell University Press, 
Ithaca, New York, 1966, 256 pp., $7.50. A biography for the general reader 
and the high school science student. Dalton is famous for his development of 
chemical combinations based on atomic theory. This provided the basis for 
modern structural theories of chemistry. 

John Dalton and the Atomic Theory: The Biography of a Natural Philosopher, 
Elizabeth C. Patterson, Doubleday and Company, Inc., New York, 1970, 320 
pp., $6.95 (hardback); $1.95 (paperback). The drama of Dalton’s life—his 
rigorous self-teaching, scientific work, and struggle to overcome class barriers 
in 19th century England—is well presented. Quotations from letters, diaries, 
and published works give a clear picture of Dalton’s atomic theory research 
and his time. 

Man-made Transuranium Elements, Glenn T. Seaborg, Prentice Hall, Inc., 
Englewood Cliffs, New Jersey, 1963, 120 pp., $6.95 (hardback); $2.95 
(paperback). The discovery, properties, and applications of elements heavier 
than uranium are considered in this book, which is designed as an introduction 
to the subject. Glenn Seaborg was co-discoverer of nine of the twelve 
transuranium elements. 

The Nature of Matter: Physical Theory from Thales to Fermi, Ginestra 
Amaldi, translated by Peter Astbury, Chicago University Press, Chicago, 
Illinois, 1966, 332 pp., $5.95. A nontechnical history of atomic energy. 

Niels Bohr: His Life and Work as Seen by His Friends and Colleagues, S. 
Rozental (Editor), John Wiley and Sons, Inc., New York, 1967, 355 pp., 
$5.95. An articulate and scholarly biography by the friends and co-workers of 
this outstanding atomic pioneer. 

Niels Bohr: The Man, His Science, and the World They Changed, Ruth Moore, 
Alfred A. Knopf, Inc., New York, 1966, 436 pp., $7.95. An interesting 
biography of one of the pioneers in the study of the internal structure of the 

Otto Hahn: My Life, Otto Hahn, translated by Ernest Kaiser and Eithne 
Wilkins, Herder and Herder, Inc., New York, 1970, 240 pp., $6.50. 
Autobiography of the man who discovered that the atom could be split. 

Otto Hahn: A Scientific Autobiography, Otto Hahn, Willy Ley, editor and 
translator, Charles Scribner’s Sons, New York, 1966, 320 pp., $9.95. Otto 
Hahn, winner of the 1944 Nobel Prize for his work in atomic fission, reviews 
the pioneer days in which a new science was created, and the role he played in 
its development. 

Physics and Beyond: Encounters and Conversations, Werner Heisenberg, 
translated by Arthur J. Pomerans, Harper and Row, Publishers, New York, 
1970, 247 pp., $7.95. Werner Heisenberg, a Nobel Prize physicist, presents his 
autobiography in the form of conversations with such men as Max Planck, 
Albert Einstein, Niels Bohr, Ernest Rutherford, Otto Hahn, and Enrico Fermi. 

Physics for Poets, Robert H. March, McGraw-Hill Book Company, New. 
York, 1970, 302 pp., $7.50. A physics textbook for nonscience students. The 
book covers certain developments of classical mechanics, relativity, and 
atomic and quantum physics. With this book the author won the 1971 
American Institute of Physics—U. S. Steel Foundation Science Writing Award 
in Physics and Astronomy. 

Sourcebook on Atomic Energy (third edition), Samuel Glasstone, Van 
Nostrand Reinhold Company, New York, 1967, 883 pp., $15.00. An excellent 
standard reference work, written for both scientists and the general public. 

The Swift Years: The Robert Oppenheimer Story, Peter Michelmore, Dodd, 
Mead and Company, New York, 1969, 273 pp., $6.95. Oppenheimer’s 
complex personality is delineated in this well-written biography. In the 
bibliography is a list of books that Oppenheimer felt “had done the most to 
shape his vocational attitude and philosophy of life”. 

The World of the Atom, 2 volumes, Henry A. Boorse and Lloyd Motz (Eds.), 
Basic Books, Inc., Publishers, New York, 1966, 1873 pp., $35.00. Contains 
the actual text of landmark documents in the history of atomic physics, each 
preceded by commentary that places it in the context of the discoverer’s 
personal life and in the conditions prevailing in science and in society in his 

Photo Credits 

Page The “Horsehead” Nebula in Orion. Hale Observatories. 




Author’s Jay K. Klein 

Contents Lick Observatory 

116 Samuel A. Goudsmit 

118 From Atoms in the Family: My Life With Enrico Fermi, Laura Fermi, 
1954. Copyright © by the University of Chicago Press. 

120 Top row, left, Institut fur Radium-forschung und Kemphysik, right, 
Lotte Meitner-Graff, middle row, left, Nobel Institute, right, Ernest 
Orlando Lawrence Berkeley Laboratory; bottom row, right, Ernest 
Orlando Lawrence Berkeley Laboratory, left, P. H. Abelson. 

123 Addison-Wesley Publishing Company 

130 Top, Ike Verne; bottom, Oak Ridge National Laboratory. 

132 & Letter and Roosevelt picture from the Franklin D. Roosevelt Library; 

133 Johan Hagemeyer. 

136 & Argonne National Laboratory 


141 U. S. Navy 

143 Right, Westinghouse Electric Corporation 

145 Argonne National Laboratory 

152 Lick Observatory 

155 Gulf Energy and Environmental Systems 

156 Los Alamos Scientific Laboratory 

158 Nobel Institute 

159 Left, C. D. Anderson; right, Nobel Institute. 

161 Ernest Orlando Lawrence Berkeley Laboratory 

★ U. S. GOVERNMENT PRINTING OFFICE: 1972 - 747-189/2 

The U. S. Atomic Energy Commission publishes this series of information 
booklets for the general public. These booklets explain the many uses of nuclear 

The booklets are listed below by subject category. 

General Interest 

WAS-009 Atomic Energy and Your World 

WAS-002 A Bibliography of Basic Books on Atomic Energy 

WAS-004 Computers 

WAS-008 Electricity and Man 

WAS-006 Nuclear Terms, A Glossary 

WAS-013 Secrets of the Past: Nuclear Energy Applications in Art and 

The Environment 

WAS-414 Nature’s Invisible Rays 
WAS-204 Nuclear Power and the Environment 


WAS-102 Atoms in Agriculture 
WAS-105 The Genetic Effects of Radiation 
WAS-107 Radioisotopes in Medicine 
WAS-109 Your Body and Radiation 


WAS-401 Accelerators 
WAS-403 Controlled Nuclear Fusion 
WAS-404 Direct Conversion of Energy 
WAS-416 Inner Space: The Structure of the Atom 
WAS-406 Lasers 

WAS-407 Microstructure of Matter 
WAS-411 Power from Radioisotopes 


WAS-303 The Atomic Fingerprint: Neutron Activation Analysis 
WAS-302 Cryogenics, The Uncommon Cold 
WAS-306 Radioisotopes in Industry 

Nuclear Reactors 

WAS-502 Atomic Power Safety 
WAS-513 Breeder Reactors 
WAS-503 The First Reactor 
WAS-505 Nuclear Power Plants 
WAS-507 Nuclear Reactors 
WAS-508 Radioactive Wastes 

Members of the general public may obtain free, single copies of six titles of their 
choice. Librarians and teachers may obtain free a complete set of the booklets. 
These requests should be made on school or library stationery. Those wishing to 
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booklets and inquiries on prices and availability should be directed to: 

USAEC—Technical Information Center, P. O. Box 62, Oak Ridge, TN 37830 

Comments are invited regarding this booklet and others in the series. 


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