Atomic World

Nuclear scientists have given us the Bomb. Now they are reaching for the answer to life itself

HOWARD W. BLAKESLEE January 1 1947

Atomic World

Nuclear scientists have given us the Bomb. Now they are reaching for the answer to life itself

HOWARD W. BLAKESLEE January 1 1947

Atomic World

Nuclear scientists have given us the Bomb. Now they are reaching for the answer to life itself

HOWARD W. BLAKESLEE

IN SIZE you are about midway between a star and one of the three types of particles that form atoms. You are made entirely of these three particles and so is the star.

Science cannot tell you what your intelligence is made of, or your spirit, or your soul. But it can show you that your flesh and bone is not entirely what it looks to be*.

All physical matter, science is now convinced, is really a form of energy.

Matter can be changed into energy and energy into matter, but energy appears to be the basic substance of all creation.

In laboratories scientists have seen energy changing into bits of matter, and the atomic bomb has removed all doubts as to whether matter can change into energy. The actual amount of matter that changed’ into energy to destroy most of Hiroshima was less than the size of a penny.

Only one tenth of one per cent of each splitting* atom changed into energy. And only a small proportion of the atoms in the explosive metal split, so that the amount of uranium or plutonium brought together to get as much as the weight of one penny to explode was necessarily a fairly large number of pounds.

All matter is made of atoms. But what is an atom? How can “solid flesh” or solid anything else be composed of minute particles whirling throdgh space?

In the answers to these questions lies the“se«ret”of the atomic bomb— and better spark plugs, the development of strange new medicines—and better gasoline for your car. Pursuing the course opened by our growing knowledge of what the world is made of, science is exploring vast new fields of research and reaching toward a solution to the mystery of life itself.

Atomic Patterns

I^ACH atdm is made of electrons,

-A protons and neutrons. The electrons and protons carry electrical charges, usually negative for electrons and positive for protons.

All atoms are formed in exactly the same patterns. They are like the solar system, where the sun is the centre and the earth and the otlier planets revolve around it, at great distances.

In atoms this sun is a knot of protons and neutrons, bound tightly together in the centre. The planets are electrons, circulating at distances that are nearly 100,000 times the diameter of the central nucleus.

That’s not all that’s surprising about the make-up of these atoms. Protons and neutrons are each a little more than 1,800 times heavier than electrons. Yet they are so tightly pressed together in the atomic nucleus that they occupy perhaps less space than a single electron. Because of the weight of these protons and neutrons 99% of the mass of any atom is concentrated in its nucleus.

It is fhis nucleus that splits in the bomb explosion. This nucleus is the goal at which science has «— quite literally—been shooting for much of the present century in quest of atomic energy. Atomic is a misnomer. It is really nuclear energy.

Nuclear energy was first noted in the rays of

radium. These rays come from the nuclei of radium and other atoms. The splitting of uranium was the second step in discovering how to get nuclear energy. What the third step is to be no scientist now knows.

Discovery of the atom and its structure involved the work of many scientists over a period of many years. Electrons were the first of the three particles to be found. They appeared in the vacuum tubes designed by Sir William Crookes in 1879. In a way this tube was the forerunner of present neon lights.

Electrons Always the Same

THE CROOKES tube emitted particles too small to be seen with microscopes, but they revealed their presence and nature by the light they caused in part of the tube, and in the way that they would turn a tiny wheel by striking its vanes, as water turns a wheel.

These particles were electrically charged, the charges were negative and the particles could be drawn from any form of matter, in a variety of

ways. Electrons appeared when matter was heated or when it was hit by X-rays. Some metals produced electrons merely when light fell upon them.

Then a stunning fact was observed. Whatever kind of matter they came from, electrons were always the same. That meant they were a universal constituent of matter.

Twenty years after this the second of the three particles was found by Lord Rutherford, at one time a professorat McGill University. He placed radium close to various chemical elements so that the elements were hit by one of the rays of radium. This ray was a stream of heavy bits of matter known as alpha particles. From these bits a new particle appeared, much heavier than an electron, and positively charged. These new particles were named protons. They, too, could be obtained from any form of matter, and it was evident that they also were universal building blocks.

But electrons and protons did not fully account for the weights or the behavior of atoms. After a lapse of about 10 more years, another Englishman, Sir James Chadwick, in 1932 discovered the missing member of the trio. This was the neutron, which has no electrical charge. This particle also was found to be emitted by all the chemical elements.

With the finding of the neutron, the picture of the structure of atoms, and hence of the building blocks of the entire material universe, became reasonably complete. The study of neutrons led directly, seven years later, to discovery of nuclear fission of uranium, and six years after that to the atomic bomb.

Although tiny, the presence of these three atomic particles is verified by unaided eyesight. They appear in the fog of the cloud chamber, an invention of an Englishman, JProf. C. T. R. Wilson. You look into a small metal box, its top covered with glass, like a showcase. A hidden piston expands the air, causing instant formation of fog in the box. An atomic particle, even a lightweight electron, passing through this fog, causes droplets of water to condense in its trail, like the vapor trails of high-flying war planes. The trail remains a moment easily visible. Each kind of particle leaves a

distinct and identifying type of trail.

Dwarfing Gravity

WITH THIS and other apparatus an atomic world has come into man’s view. Surprising facts are numerous. Most astonishing is the force that binds together the heavy particles—the protons and neut rons—in the nuclei of atoms. This force has been variously estimated. The low estimate is a million times greater than the force of gravitation. The high is a multiple of gravitation expressed by the figure “one” followed by 36 zeros.

Another remarkable fact is that all the atoms are nearly the same size, despite. the fact that the lightest in weight, hydrogen, consists of only two particles, one proton and one electron, while uranium, the heaviest natural atom, contains 92 electrons, 92 protons and 146 neutrons. The present explanation is that the binding force compresses the heavy particles to nearly the same diameter as a single particle.

Protons and neutrons

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can be shot like bullets at atoms. When either of these heavy particles hits a nucleus under the right circumstances the striking particle remains there. Whereupon the struck atom changes into a different, chemical element. This is transmutation. Platinum becomes gold and gold becomes mercury. Carbon changes into nitrogen and nitrogen into oxygen.

That is to say, the difference between the carbon in your finger and the gold in your ring is solely in the number of particles forming each. In nature there are only 92 recognized chemical elements Always, the difference between them is in the number of particles they contain. This same rule is true of the new atoms which scientists are making.

There is another strange thing. These particles, when they travel, move in wave motions. They act like waves. Their wave vibrations are exceedingly rapid. Protons have a vibration estimated as a million times faster than the vibrations of light.

All these fundamental particles are so small that they penetrate solid matter easily The reason is that each atom is mostly empty space in the eyes of particles so small. Shooting stars fly through the space between earth and other planets and seldom hit anything. The atomic particles travel through matter much like shooting stars through space.

Light, heat, X-rays and the gamma rays of radium and of other radioactive atoms also travel with a wave motion. But these immaterial rays are divided into separate packets, as if each packet of light was also a particle. These packets are called quanta.

The word “quanta” describes the amount of energy in each packet. Identical quanta of energy are associated with electrons, protons and neutrons. These quanta are like the pounds and ounces of a grocery store. It takes 16 avoirdupois ounces to make one pound —never 15, and never 17. When the particles of matter combine, or when light, heat and other forms of energy interact with .solid particles, the transaction is always done in quanta. If, for example, 16 quanta of energy, whether they are in particles or in waves of light, are needed in forming an atom of hydrogen, then 17 quanta or 15 quanta never will make hydrogen.

The packets or quanta of light are called photons. These photons are not miniature solar systems, like the atoms. Yet the packets of light have one resemblance to the sun and planets. The bits of light are spinning. This spin of light Is so strong that very small particles, floating in the air, in a beam of sunlight, will sometimes move with a minute, corkscrew motion. They apparently get that motion from being bumped by the spinning photons of light.

New Atoms, New Answers

The nuclei of atoms also appear to he spinning, much as the sun turns on its axis. The spin of one of these nuclei has been measured. This Is deuterium, the heavy hydrogen that forms heavy water. This nucleus appears to be shaped like a football standing on end. Like the spinning earth, or the sun, this deuterium nucleus has a north and a south magnetic pole.

Finally, in some manner not well understood, magnetism is always present both in the quanta of light and in atomic particles.

These conceptions of the nature of

the atomic worlc^ have led to many practical results. For one thing it is possible now to make atoms that do not exist in nature. * Nearly 500 of these have been produced. They include the new heavy metals, neptunium, plutonium, umerisium and curium. Plutonium makes bombs, and is in present prospects the largest future source of atomic power. The uses of the other three are unkown.

Among the new atoms are radioactive carbon, sulphur, iron, phosphorus iodine and calcium. All these substances in nonradioactive form are important in living tissues, especially those of man. Made radioactive they can be “traced” through the body, revealing bodily processes. Thus iron is useful for studying anaemia, phosphorus for the study of bone, muscle, the liver and the small intestines. Iodine is useful for studying the thyroid gland, and the new radioactive form has been used to cure the disease known as toxic goitre. Carbon is the foundation of human tissues. Without calcium nerves go to pieces and hones are starved.

Do Tricks in Cold

These and other new radioactive atoms are going more and more into use to learn about some of the puzzles of life, such as the reasons for growth, and why growth stops at the right time, instead of permitting one hand to grow as big as a barrel. Another Is the now unknown reason why people grow old, and especially why some persons age prematurely.

There is hope that the radioactive atoms may assist in solving the riddle of the process called photosynthesis, by which the green coloring matter of plants uses the energy of sunlight and the carbon dioxide and water in the plant tissues, to produce the starches and sugars that are the basis of all food.

In industry the radioactive atoms trace impurities, leaks, the flow of liquids and of gases and the unseen vibration of moving parts. They make it possible to look inside steel and other metals. They permit more exact determination of minute quantities of chemicals to improve both metals and plastics. One of them, carbon from the Oak Ridge, Term., atomic ovens, is useful for studying cracking processes in making gasoline and improving the quality of motor fuel.

Spark plugs impregnated with polonium, a naturally radioactive metal, make for easier starting in cold weather. The radioactive rays build up bridges of ionized air for the electrical spark to jump across.

Electronics, plastics and many of the advances in chemistry and metallurgy have com«* in part from the new knowledge of the atomic world and its electrical behavior.

During the war electric light bulbs were made that retain their light long after the current is switched off. Remove one of these bulbs from its socket when lighted, and put it in your pocket. It will continue to give bright light for 10 to 20 minutes, no matter where you go-

Construction of these bulbs is based on what is likely to be the lighting of the future. Theÿ are coated inside with phosphor crystals, that continue to glow after an exposure to light. Electric lights of this kind already give more light for the same amount of current than do hot filaments. Phosphor crystals occur in nature, and are made synthetically.

One of the forms of energy that is made of quanta, or separate packages, is heat. For that reason, among others, the study of extreme cold, close to absolute zero, has been important.

Absolute zero is the term u;cd to describe the condition where there is no heat. It is 459.6 degrees below zero F.

fleat emanates from atoms. The faster atoms vibrate, the greater their heat. Wherever there is heat there is also turmoil in atoms and the atomic particles forming them.

Hut at close to absolute zero atoms lose most of ibis turmoil. They approach the highest possible state of orderliness in atoms. Some results of this orderliness are amazing. Liquid helium, if cooled to 2.19 degrees above absolute zero, climbs vertically up the walls of a glass vessel. The guess has been made that gravitation is still at work, hut that the almost dead helium atoms are picked up by the atoms in glass, because these latter are warmer than the helium and have enough energy left to act as elevators. Hut why the atoms in glass should become elevators is not clear. In rising, the dying helium atoms go in the direction of more warmth.

In extreme cold copper becomes stronger than steel, while still retaining its pliability, but steel becomes brittle as glass.

A thin film of silver on glass, enough to he opaque at ordinary temperatures, becomes transparent at about 260 degrees below zero’ F. An explana tion is that the extreme cold slows the movement of the electrons circling about the silver atomic nuclei. The electrons move so much slower that light gets through.

Some metals, particularly tin, lead and mercury, lose all their electrical resistance at close to absolute zero. At about one degree above absolute zero, electricity appears to remain in a wire, like water left standing in a hose, without motion. In this way electric current has been bottled up for days in a strand of wire. When the wire was warmed the electricity flowed out normally. There did not seem to have been any loss in storage.

This extremely low temperature is far too expensive to use to make cold lines for transmitting electricity. However, it is a fact that all the electricity produced by Niagara Falls powerhouses could he transmitted all the way to San Francisco through a single lead wire no thicker than a spider web if it were cold enough. And there would be ho appreciable loss of electricity en route. Ordinary high-power lines transmit electricity economically only a few hundred miles because of the losses.

Kept On Ice

If space ships should become feasible, then temperatures where electricity stands like water in a pipe might he available on the shady side of the ship.

These studies of extreme cold have revived the old idea of suspended animation. If living cells are cooled down almost instantly to nearly 200 below zero, many of them live indefinitely. Ninety-eight per cent of yeast cells have survived, to continue living after being warmed up; 70% of red blood corpuscles have survived. Sperm of frogs and seeds have lived, and the seeds afterward grew into normal plants.

With artificial insemination liecoming important in human reproduction, it has tx-en suggested that a great man’s seed might be preserved by cold for use in a long-distant future. The idea probably has more force in artificial insemination of cattle, which already is important for breeding stock which produces more milk and meat.

Suspended animation for any living thing except the most minute by quick chilling, however, seems impossible, because the entire cooling has to be done at a rate of at least 100 degrees

drop in tissue temperature per second. Slower chilling kills. rI i,e warmup has also to proceed at a similar rapid rate to prevent death during thawing. Large bodies cannot he either cooled or warmed so rapidly.

Water when frozen by this method becomes vitreous. It remains perfectly clear. Hut it becomes about as hard as steel.

Cosmic Hailstones

lí human eyes could magnify things by 10 million times, you would see something that looks like perpetual hail. This hail would be cosmic rays. The cosmic hail falls on the earth without change, day and night, and is simply a shower of electrons, protons and neutrons. Sometimes there is a cosmic hailstone that appears to be a combination of these particles.

One thing is different about the particles that appear as cosmic rays— namely their speed of travel and their energies. These cosmic particles sometimes drive so fast they would penetrate 75 feet of lead. They reach sea level in large numbers, and some drive deeply into the earth or into the oceans.

About 10 of these rays pass through each human being every second of time. In your body one of the rays may tear apart millions of your personal molecules. That is harmless, because one speck of dust contains more molecules by a million times than there are people on the earth.

It would do no good to raise an umbrella against these rays. If the umbrella were lead, the rays from above would knock apart so many lead atoms that the particles from these broken atoms would literally deluge your body.

The air and huge buildings filter out many of these cosmic hailstones. Under one of New York City’s 34-story skyscrapers, in a* vault 45 feet below ground, the rays were reduced to about 45 per minute. This vault had a 16inch steel ceiling.

The nuclear physicists do not know the origin of these rays, except that they come from outside the earth’s atmosphere. Hut they use the rays to get more information about the behavior and nature of the atomic particles. Among the cosmic particles one has been found that is about two or three hundred times heavier than an electron. It is about one third the weight of a proton or a neutron.

These medium-weight cosmic hailstones have been named mesotrons, or mesons. They are unusual in several ways. They appear for only a few millionths of a second and then vanish. Apparently they re-enter an atom. Some have tremendous energies or speeds. One measurement recorded a mesotron with an estimated energy of one trillion electron volts. That is 5,000 times more than the energy emitted by each atom of splitting atomic bomb metal.

One theory suggests that the mesons may he the missing links between matter and energy. That is, they are momentarily particles of matter created out of energy let loose from an atomic nucleus. After a few millionths of a second they re-enter some atom and are reconverted into energy.

A mesotron moving very fast has a longer life than one moving slowly. This increase Is about one third in life span. In actual time that third is not much, since it is still only a few millionths of a second.

According to Einstein’s theory time is different at extremely high speeds than at the slow speeds common on earth. These fast-moving, longer-life mesotrons may be an example of what Einstein’s theory means.

'i hese st rer an effects of speed appear to oc of what the world is made of. To get LÍ at evidence it is necessary to go to the heavens and the stars. 'I he Milky Way is a whirling, cartwheel mass of stars known as a spiral nebula, and the earth is part of that mass. Telescopes counted about 75 million similar spiral nebulae, each aboutas big as the Milky Way. And the end is not in sight.

Man and the earth, as part of this creation, are continuously in highspeed motion. Man and earth are flying at about 18 miles a second around the sun. They are also travelling, along with the sun, toward the southern constellation Swordfish at about 130 miles a second. And still faster, they are moving at about 170 miles a second as part of the rotating motion of the whole Milky Way.

Mass or weight increases with speed. That is apparent in the smash of a rifle bullet. The bullet is actually heavier at the moment of impact than it is at rest. Hut a rifle bullet is very slow compared with the three speeds of the earth. All the billions of stars and nebulae, everything in creation, in fact, is travelling at speeds like those of the earth. In all cases their weights, or masses, like those of the earth are made partly of the fast motion.

Consequently gravitation is dependent on speed, since gravitation varies with mass. Nowhere in the universe is it possible to measure precisely any one of these speeds or any one of the resulting masses. Because man’s own platform is moving, he cannot make a true weight or speed measurement for anything outside the earth. These things he cannot measure are called the absolute velocities and masses. He can measure only relative velocities and masses.

To fit this high-speed creation, Einstein rewrote the mathematics of gravitation, and so created the theory of general relativity. Newton’s laws apply on earth, where gravitation is weak. They do not apply completely elsewhere where gravitational forces are different.

Picture Still Incomplete

Some remarkable ideas appeared from the new theory of gravitational laws. Such as: a clock moving very

fast keeps different time from one moving slowly. And a measuring rod travelling at very high speed becomes shorter than when it is going at low speed. These two ideas have not been proved yet, although some experimente indicate that the time at high speed really is different. But other things, almost as incredible, that arose from Einstein’s equations, have been demonstrated. One of these is the equivalence of mass and energy, that made the atomic bomb.

This picture of the physical world is still incomplete. Some unifying principle has escaped detection. But if mass and energy are equivalent, it is likely there is a link between them. What Ls this link? Einstein thinks it is gravitation and the electromagnetic fields that fill all of known space. He suggests that these two fields combine in some manner to form the physical world of matter.

Quite recently the brilliant English mathematician, P. A. M. Dirac, came up with a mathematical proposal that seemed to show that electrons and protons are particles with no size whatever, but with weight and with electrical charges.

If thus paradox is true, that something material can have no size, yet possess weight, then the mysterious forces that hold atomic nuclei together can be explained. This force is simply

ordinary gravitation, which Ls so immensely strong because particles with no size could get as closely together as the particles in a nucleus * are known to be.

Our minds can hardly conceive of something with weight but no size. Yet it is not a great stretch of imagination to accept this view. For the three primary particles already are so very tiny that imagination cannot

really conceive anything so small. So it is not much of an effort to say—well, they have no size at all. Furthermore, these three particles appear to change to and fro from mass to energy and back again. So perhaps Dirac has put his finger on one more of the realities.

Certainly there is some unifying principle between matter and energy, and certainly man’s physical body is part of that unity. ★