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What the Unaided Eye Cannot SeeAwake!—2000 | August 22
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What the Unaided Eye Cannot See
TINY dust particles float unseen in the air. But then a shaft of sunlight streams through the window, and what had been invisible can suddenly be seen. The penetrating beam of light unmasks the particles to human vision.
Think further about visible light, which appears white or colorless to the unaided eye. What happens if sunlight shines at just the proper angle through droplets of water? The water serves as a prism, and we see a rainbow of beautiful colors!
Actually, objects around us reflect various wavelengths of light that our eyes see as color. Green grass, for example, does not of itself produce green light, but, rather, it absorbs all the wavelengths of visible light except green. The grass reflects the green wavelength back to our eyes. Thus, to our eyes the grass appears as green.
Aided by Man-Made Instruments
In recent years many things invisible to our unaided eyes have become visible by means of modern inventions. We can look through an ordinary microscope at a seemingly lifeless drop of water and discover that it is filled with all sorts of moving creatures. And a strand of hair, which to normal vision appears smooth and even, is seen to be rough and jagged. Very powerful microscopes can magnify objects one million times, the equivalent of enlarging a postage stamp to the size of a small country!
Now, with the use of even more powerful microscopes, researchers are provided with atom-scale contour images of surfaces. This gives them a view into what until quite recently was beyond the scope of human vision.
On the other hand, we may look up into the sky at night and see stars. How many? With the unaided eye, only a few thousand at most. But with the invention of the telescope nearly 400 years ago, people began to see many more. Then, in the 1920’s, a powerful telescope at the Mount Wilson Observatory revealed that there are galaxies beyond our own and that they too are filled with countless stars. Today, using sophisticated man-made means of probing the universe, scientists estimate that tens of billions of galaxies exist, many of which consist of hundreds of billions of stars!
It is truly amazing that telescopes have revealed that billions of stars, appearing as the Milky Way because of seemingly being so close together, are separated by incomprehensibly great distances. Similarly, powerful microscopes have helped the unaided eye to see that objects that appear to be solid are, in fact, composed of atoms that are primarily made up of empty space.
The Infinitesimally Small
The tiniest speck that can be seen under an ordinary microscope is composed of more than ten billion atoms! Yet, in 1897 it was discovered that the atom has tiny orbiting particles called electrons. In time, the nucleus of the atom, around which the electrons orbit, was found to consist of larger particles—neutrons and protons. The 88 different kinds of atoms, or elements, that occur naturally on earth are basically the same size, but they vary in weight because each has a progressively larger number of these three basic particles.
The electrons—in the case of the hydrogen atom, one single electron—whirl through space around the atom’s nucleus billions of times every millionth of a second, thus providing shape to the atom and causing it to behave as if it were solid. It would take nearly 1,840 electrons to equal the mass of a proton or a neutron. Both the proton and the neutron are about 100,000 times smaller than the entire atom itself!
To get some idea of how empty an atom is, try to visualize the nucleus of a hydrogen atom in relation to the atom’s orbiting electron. If that nucleus, consisting of a single proton, were the size of a tennis ball, its orbiting electron would be about two miles [3 km] away!
A report on the centennial celebrations of the discovery of the electron commented: “Few think twice about celebrating something no one has seen, which has no discernible size and yet has a measurable weight, an electric charge—and spins like a top. . . . Today no one questions the idea that things we can never see do exist.”
Even Tinier Objects
Atom-smashing machines, capable of hurling particles of matter at one another, now offer scientists a glimpse inside the nucleus of the atom. As a result, many particles with strange-sounding names are written about—positrons, photons, mesons, quarks, and gluons, to name but a few. All are invisible, even to the most powerful microscopes. But with such equipment as cloud and bubble chambers and scintillation counters, traces of their existence are observed.
Researchers now see what was once invisible. As they do, they are grasping the significance of what they believe are the four fundamental forces—gravity, electromagnetic force, and two subnuclear forces designated the “weak force” and the “strong force.” Some scientists pursue a quest for what is termed a “theory of everything,” which they hope will provide one comprehensible explanation of the universe, from the macroscopic to the microscopic.
What lessons can be learned from seeing what the unaided eye cannot? And based on what they have learned, what conclusions have many reached? The following articles provide answers.
[Pictures on page 3]
Images of nickel atoms (top) and platinum atoms
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Courtesy IBM Corporation, Research Division, Almaden Research Center
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Peering Into the Unseen—What Is Revealed?Awake!—2000 | August 22
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Peering Into the Unseen—What Is Revealed?
WHAT is accomplished when humans use new inventions to pull back the curtain, as it were, and see what they could not see before? Doing so can help determine with a degree of certainty what was formerly unknown.—See the box below.
It was once the common belief that the earth was the center of the universe. But then the use of the telescope showed that the planets, including the earth, are held in place in rotation around the sun. More recently, with the invention of powerful microscopes, humans have examined the atom itself and have seen how certain kinds of atoms combine with other kinds to form what are called molecules.
Consider the composition of a molecule of water, a substance essential to life. Because of their design, two atoms of hydrogen will combine in a unique way with a single atom of oxygen to form a molecule of water—billions of which are in each drop! What can we learn by examining a molecule of water and considering its behavior under different circumstances?
The Wonder of Water
Although individual drops of water seem very simple, water is an extremely complex substance. In fact, Dr. John Emsley, a science writer at Imperial College, in London, England, said that it is “one of the most investigated of all chemicals, but it is still the least understood.” New Scientist magazine stated: “Water is the most familiar liquid on Earth, but also one of the most mysterious.”
Dr. Emsley explained that despite the simple structure of water, “nothing is as complex in its behaviour.” For example, he said: “H20 should be a gas, . . . but it is a liquid. Moreover, when it freezes . . . , its solid form, ice, floats instead of sinking,” as would ordinarily be expected. Regarding this unusual behavior, Dr. Paul E. Klopsteg, a past president of the American Association for the Advancement of Science, observed:
“This appears as a remarkable design for sustaining aquatic life such as fishes. Think what would happen if water, as it cools to the freezing point, didn’t behave as described. Ice would form and keep forming until it occupied an entire lake, snuffing out all or most marine life.” Dr. Klopsteg said that this unexpected behavior of water is “evidence of a great and purposeful mind at work in the universe.”
According to New Scientist, researchers now think that they know the reason for this unusual behavior of water. They have developed the first theoretical model that accurately predicts the expansion of water. “The key to the mystery,” the researchers realized, “lay in the spacing of oxygen atoms within these structures.”
Isn’t that remarkable? A molecule that appears so simple challenges human comprehension. And to think that water makes up most of the weight of our body! Do you too see in the marvels of this molecule, of only three atoms of two elements, “evidence of a great and purposeful mind at work”? Yet, a molecule of water is extremely small and much less complex than many other molecules.
Molecules of Great Complexity
Some molecules are composed of thousands of atoms of many of the 88 elements that occur naturally on earth. For example, a molecule of DNA (short for deoxyribonucleic acid), which contains the coded information for the heredity of every living thing, can have millions of atoms of several elements!
Despite its unbelievable complexity, the DNA molecule is only 1/10,000,000 inch [0.0000025 mm] in diameter, far too small to be seen except with the aid of a powerful microscope. It was not until 1944 that scientists discovered that DNA determines the heredity of a person. This finding set off intensive research into this extremely complex molecule.
Yet, DNA and water are but two of the many kinds of molecules that go into the construction of things. And since there are many molecules that are found both in what is living and in what is nonliving, should we conclude that there is somehow just a simple step, or bridge, between what is alive and what is not?
For a long time, many people believed that to be the case. “The hope that increased biochemical knowledge would bridge the gap was specifically expressed by many authorities in the 1920s and 30s,” explained microbiologist Michael Denton. Yet, in time, what was actually discovered?
Life Is Special and Unique
Although scientists expected to find transitional intermediates, or a series of gradual steps, between what is living and what is not, Denton observed that the existence of a definite discontinuity was “finally established after the revolutionary discoveries of molecular biology in the early 1950s.” Relating a remarkable fact that has now become evident to scientists, Denton went on to explain:
“We now know not only of the existence of a break between the living and non-living world, but also that it represents the most dramatic and fundamental of all the discontinuities of nature. Between a living cell and the most highly ordered non-biological system, such as a crystal or a snowflake, there is a chasm as vast and absolute as it is possible to conceive.”
This does not mean that creating a molecule is easy. The book Molecules to Living Cells explains that “the synthesis of the small-molecule building blocks is complex in itself.” It adds, however, that making such molecules “is child’s play in comparison to what must have followed in order to generate the first living cell.”
Cells may exist by themselves as free-living organisms, such as bacteria, or they may function as part of a multicellular organism, such as a human. It would take 500 average-size cells to equal the size of the period at the end of this sentence. So it is not surprising that the functions of a cell are invisible to the unaided eye. What, then, is revealed by using a microscope to peer into a single cell in the human body?
The Cell—By Chance or Design?
First of all, a person cannot help but be amazed by the complexity of living cells. One science writer observed: “The normal growth of even the simplest living cell requires that tens of thousands of chemical reactions occur in coordinated fashion.” He asked: “How, within one tiny cell, can 20,000 reactions all be controlled at once?”
Michael Denton compared even the tiniest of living cells to “a veritable microminiaturized factory containing thousands of exquisitely designed pieces of intricate molecular machinery, made up altogether of one hundred thousand million atoms, far more complicated than any machine built by man and absolutely without parallel in the non-living world.”
Scientists remain baffled by the complexity of the cell, as The New York Times of February 15, 2000, noted: “The more biologists understand of living cells, the more daunting seems the task of figuring out everything they do. The average human cell is too small to be seen, yet at any moment up to 30,000 of its 100,000 genes may be flicking on or off, executing the cell’s housekeeping needs or responding to messages from other cells.”
The Times asked: “How can a machine so tiny and so intricate ever be analyzed? And even if by prodigious effort one human cell were ever completely understood, there are at least 200 different types in the human body.”
Nature magazine, in an article entitled “Real Engines of Creation,” reported the discovery of tiny motors within each cell of the body. These rotate to create adenosine triphosphate, the power source of cells. One scientist mused: “What can we do when we learn how to design and build molecular machine systems that are similar to the molecular systems we find in cells?”
Just think of the creative capacity of the cell! The amount of information contained within the DNA of just one cell of our body would fill about a million pages this size! More than that, each time a cell divides to create a new one, this same information is passed on to the new cell. How do you think each cell—all 100 trillion of them in your body—came to be programmed with this information? Did it happen by chance, or was a Master Designer responsible?
Perhaps you have reached the same conclusion that biologist Russell Charles Artist did. He said: “We are confronted with formidable, even insuperable, difficulties in trying to account for [the cell’s] beginning and, for that matter, its continued functioning, unless we maintain with reason and logic that an intelligence, a mind, brought it into existence.”
A Marvelous Order of Things
Years ago, Kirtley F. Mather, at the time professor of geology at Harvard University, reached the following conclusion: “We live in a universe, not of chance or caprice, but of Law and Order. Its Administration is completely rational and worthy of the utmost respect. Consider the marvelous mathematical scheme of nature that permits us to give consecutive atomic numbers to every element of matter.”
Let’s consider briefly that “marvelous mathematical scheme of nature.” Among the elementsa known to the ancients were gold, silver, copper, tin, and iron. Arsenic, bismuth, and antimony were identified by alchemists during the Middle Ages, and later during the 1700’s, many more elements were found. In 1863 the spectroscope, which can separate the unique band of colors that each element gives off, was used to identify indium, which was the 63rd element discovered.
At that time the Russian chemist Dmitry Ivanovich Mendeleyev concluded that the elements were not created haphazardly. Finally, on March 18, 1869, his treatise “An Outline of the System of the Elements” was read to the Russian Chemical Society. In it he declared: ‘I wish to establish some sort of system not guided by chance but by some sort of definite and exact principle.’
In this famous paper, Mendeleyev predicted: “We should still expect to discover many unknown simple bodies; for example, those similar to aluminum and silicon, elements with atomic weights of 65 to 75.” Mendeleyev left blank spaces for 16 new elements. When asked for proof for his predictions, he replied: “I have no need of proof. The laws of nature, unlike the laws of grammar, admit of no exception.” He added: “I suppose when my unknown elements are found, more people will pay us attention.”
That is exactly what occurred! “During the next 15 years,” explains Encyclopedia Americana, “the discovery of gallium, scandium and germanium, whose properties closely matched those predicted by Mendeleyev, established the validity of the periodic table and the fame of its author.” By the early part of the 20th century, all existing elements had been discovered.
Clearly, as research chemist Elmer W. Maurer noted, “this beautiful arrangement is hardly a matter of chance.” Of the possibility that the harmonious order of the elements is a matter of chance, professor of chemistry John Cleveland Cothran observed: “The post-prediction discovery of all of the elements whose existence [Mendeleyev] predicted, and their possession of almost exactly the properties he predicted for them, effectively removed any such possibility. His great generalization is never called ‘The Periodic Chance.’ Instead, it is ‘The Periodic Law.’”
A close study of the elements and how they fit together to form everything in the universe caused famous physicist P.A.M. Dirac, who was a professor of mathematics at Cambridge University, to say: “One could perhaps describe the situation by saying that God is a mathematician of a very high order, and He used very advanced mathematics in constructing the universe.”
Truly it is fascinating to peer into the unseen world of both infinitesimally tiny atoms, molecules, and living cells and mammoth galaxies of stars far beyond the range of unaided vision! The experience is humbling. How are you personally affected? What do you see reflected in these things? Do you see more than your physical eyes can see?
[Footnote]
a Fundamental substances that consist of atoms of only one kind. Only 88 elements occur naturally on earth.
[Box/Pictures on page 5]
Too Fast for the Eye to See
Since the movement of a galloping horse is so rapid, men in the 19th century debated whether, at any given moment, all of its hooves would be off the ground at the same time. Finally, in 1872, Eadweard Muybridge began photographic experiments that later settled the issue. He devised a technique for taking the first high-speed movies.
Muybridge lined up a series of 24 cameras spaced slightly apart. From each camera shutter, a string was stretched across the track, so that when the horse galloped along, it hit the strings and tripped the shutters. Analysis of the resulting photographs revealed that at times the horse was completely off the ground.
[Credit Line]
Courtesy George Eastman House
[Picture on page 7]
Why does frozen water float rather than sink?
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A DNA molecule is 1/10,000,000 inch [0.0000025 mm] in diameter, yet the information it contains would occupy a million pages
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Computerized model of DNA: Donald Struthers/Tony Stone Images
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In each body cell—all 100 trillion of them—tens of thousands of chemical reactions occur in coordinated fashion
[Credit Line]
Copyright Dennis Kunkel, University of Hawaii
[Pictures on page 9]
Russian chemist Mendeleyev concluded that the elements were not created haphazardly
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Courtesy National Library of Medicine
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