Friday, November 27, 2009

X-rays and Truth

One distant memory of my childhood involves visits to the shoe store. Many such establishments had shoe-fitting fluoroscopes. These machines sent X-rays through shoe, flesh, and bone. Live images were transmitted to a fluorescent screen and we were able to see the digits of our toes wiggling. Purportedly, these fascinating machines helped the shoe salesman achieve a proper fit for the wearer. I’ll confess to being more highly interested in the novelty of seeing the internal structure of my feet--live, and in motion. These machines no doubt helped sell footwear, but the same purpose could have been achieved with simple measurements.

X-rays were discovered by Wilhelm Roentgen in 1895. My paternal grandparents were teenagers; my maternal grandparents were already busy raising their first eight children on the Great Plains of Oklahoma. X-rays were so named because so much was unknown about them. Knowledge of electromagnetic radiation--its potential and its hazards--was in its earliest stages. Medical personnel were quick to apply the technology to aid in discovering internally embedded objects, reveal fractures, and treat injured soldiers on the battlefield. It was soon discovered that X-rays also had downside potential.

The shortest-wave, highest frequency areas of the electromagnetic spectrum, such as X-rays, also have the highest energy. This means they are able to penetrate a wide variety of bodies. X-rays are able to ionize atoms and molecules in living things by detaching electrons, leaving charged ions to wreak tissue damage in large enough doses. Returning to our introductory example, fluoroscopes were recognized as potentially dangerous, and they vanished from shoe stores shortly after mid-century.

Preachers could use many object lessons from the scientific realm, particularly lessons concerning the penetrating qualities of radiation and its ability to reveal otherwise obscured truth. Medical personnel, in particular, need to discover truth about conditions in our bodies in order to effect appropriate treatment. X-rays and other types of penetrating radiation reveal not only the truth about internal bodily conditions, but are also effective in treatment of some of those conditions. For example, in proper doses they are able to destroy harmful tissue, such as cancer cells.

Luke 12:2 speaks explicitly about the revelation of truth in our spiritual, conscious existence: “There is nothing concealed that will not be disclosed, or hidden that will not be made known.” God’s desire is that this existence be healthy: “Surely you desire truth in the inner parts; you teach me wisdom in the inmost place” (Psalm 51:6, NIV). God’s truth discovery methods, therefore, also have a dimension of treatment for undesirable conditions.

We are created as physical beings as well as spiritual beings in God’s image. These two realms are intertwined. Since the scientific revolution, and, in particular, in the last 150-200 years mankind has been gifted with knowledge as never before in the preceding hundreds of centuries. That this knowledge has been made accessible is a cause for celebration and wonder

Tuesday, November 24, 2009

Life Sustaining Flood

How do we react to a flood? Of course, it would depend on which type of flood we are talking about. I refer again to the flood of electromagnetic radiation arriving at earth’s doorstep each moment of our lives. The more we understand it, the more it appears God has ordered all things for the existence and benefit of man. Consider the flood of natural radiation ever present since the beginning.

The matter in our universe generates a constant stream of electromagnetic radiation: gamma rays, x-rays, ultraviolet, visible light, infrared, microwaves, and radio waves. In nature, these radiations rain down on our planet from multiple objects in our surroundings, our solar system, and the distant universe.

Most invisible short-wave, high energy radiation from outer space--gamma rays, x-rays, and ultraviolet--is filtered out by our atmosphere before reaching us. For that, we are thankful. We are shielded from potentially dangerous radiation. But this radiation is visible to cameras on space vehicles orbiting outside our atmosphere. We are able, therefore, to use such information to help us gain detailed knowledge of our universe--its structure, its function, and its origin.

Lower energy, longer wave radiation such as visible light, infrared, microwaves, and radio waves, penetrate our delicate atmospheric barrier. What a treasure trove of beauty, fascination, and life sustaining energy comes with it! We observe our beautiful sun, moon, and stars by visible light with our naked eye. We also use visible light telescopes to reveal countless additional stars, galaxies, and nebulae. Visible light and short wave infrared are easily transmitted from the sun through our atmosphere, and then absorbed or reflected by objects on earth. Finally, we see images around us and bask in the reflected warmth produced by long wave infrared. Earth temperature is maintained at a life-sustaining level.

Longer than light waves, microwaves bombard earth from every direction in outer space. These microwaves (cosmic microwave background radiation--CMBR) are left-over relics from the incredible Big Bang creation event. What about naturally-produced radio waves? Planet Jupiter, the Sun, and other bodies emit radiation in various radio frequencies. To be sure, these radio signals do not produce music or speech, but are merely “noise,” because they are not generated by intelligent beings.

Electromagnetic waves are part of God’s creative design features enabling man to develop and sustain our modern civilization. Scientists have discovered how to harness them in ways unimaginable a few centuries ago. Electromagnetic waves, however, were plentiful in the environment long before man’s birth on this planet.

Tuesday, November 17, 2009

Invisible but Real

Before discussing the reality of another portion of the invisible electromagnetic spectrum, I’ll ask my readers to join me on a field trip.

Some of the most memorable field trips with my science classes were visits to the museums of the Franklin/Sterling Hill area of northern New Jersey. At the Sterling Hill Mining Museum we walked through old mine tunnels of eons-old crystallized limestone interlaced with the leftovers of commercial minerals recovered during mining operations of long ago. I recall having a sense of strange reverence while walking through 1800 feet of cool, dark mine shafts in the bowels of the earth. Comparing human history with the age of these rocks, these rocks are about 20,000 times older.

The geological complexity of this area provides us with well over 300 different minerals, several dozen of which are found nowhere else in the world. We considered one room at the Franklin Mineral Museum to be one of the highlights of our visit. In ordinary light, we entered a long room--the fluorescent room--with a fairly ordinary array of rocks displayed behind large glass panels. But these rocks were different. Before us was one of the world’s foremost fluorescent mineral collections.

Upon first entering the “fluorescent room” the guide spoke about the minerals while the visible overhead lights were shining. Ultraviolet (UV) light (invisible wavelengths shorter than visible violet) was also shining on the display. At a given moment, the overhead visible lights were turned off. The many specimens of fluorescent minerals, however, continued to glow with a pleasing variety of different hues and brightness. The 1960s crowd may have called such a display “psychedelic.”

What explains the fluorescence? Electrons in the atoms are forced unnaturally to different “energy levels” by the UV light. As those electrons return to their normal energy levels, they emit visible light of a different wavelength--a visible wavelength this time. J.J. Thomson and other 19th century scientists described moving electrical charges as the source of all electromagnetic radiation. Moving electrons generate oscillating electric fields.

Invisible ultraviolet waves come in various wavelengths and have other effects apart from making certain minerals fluoresce. Some cause sunburn; others are beneficial to the body in measured quantities. Certain wavelengths have a germicidal function. The atmosphere filters out most UV coming from outer space.

Spiritual applications and object lessons abound. In fluorescence, the mineral’s source of energy to emit visible light is outside of itself. This reminds us of a similar term often used in scripture: power. In dozens of scripture passages, the power source for righteous living is outside of ourselves. God the Creator is the external source of the Christian’s power to achieve conversion and lead a righteous life.

Thursday, November 12, 2009

And There Was Light

When we flip on a light switch, wonderful things happen. In a subjective sense, our path is illuminated and objects become visible. But in a scientific sense we must explain the events in more complex terms. In our last three posts, we’ve spoken about the wonders of electromagnetic waves. We could also speak of those waves as packets of energy called photons.

White light bulbs emit thousands of different wavelengths together. The longest and shortest of them do not differ in wavelength very much. The tiny difference, however, is vitally important. A prism is able to separate the wavelengths. The longest of them (about 1/40,000 inch) impact our eyes and brain and we see “red.” We see the shortest (about 1/70,000 inch) as “violet.” The in-between wavelengths are seen as orange, yellow, green, and blue.

At the speed light travels--300,000 km/sec--trillions of these waves strike our eyes each second. When we see an object giving off red light, or appearing red, we are really seeing light which has a frequency of 430 trillion hertz (Hz). Violet colored objects emit light with a frequency of 750 trillion Hz. Other colors fall between these frequency values. Scientists use Hz to indicate the number of waves passing a given point per second. Therefore, when we observe red light or a red object, 430 trillion electromagnetic waves pass into our eyes each second.

We do not comprehend such enormous numbers. At the 1962 Seattle World’s Fair, I viewed the display of one million silver dollars. Even with that visual aid, one million was difficult to grasp. A trillion (a million million) is certainly beyond our comprehension, whether in respect to waves of light entering our eyes each second, or as a figure to quantify our national debt. Scientists have determined wavelengths and their frequency with great precision.

Visible light falls between the wavelength range described above. In our environment, there are uncountable different wavelengths longer than these; uncountable billions of wavelengths are even shorter. These longer and shorter wavelengths exist abundantly all around us, but they are all invisible to humans. Our very existence would be impossible without them.

The imagery of light in scripture is beautiful and bountiful. Science knowledge in the 21st century helps us extend our applications of such imagery. “I am the Light of the world” refers to the spiritual illumination provided by Jesus Christ and is a metaphor for salvation. The created light in Genesis enabled man to inspect the glorious works of God. Physical light often accompanied the presence of Deity.

Our current knowledge of light evokes a sense of wonder at the glory of our created order. We may visually observe the beauty and function of the physical creation and the life forms it supports, producing reverent worship. While contemplating all this, we may use human terms to exclaim simply, “God had great ideas!”

Friday, November 6, 2009

A Spectrum of Possibilities

Science terms or definitions are necessary, but knowing a definition and understanding a subject are sometimes not the same. With that disclaimer, I’ll offer this definition of the electromagnetic spectrum (EMS). The electromagnetic spectrum is the complete range of possible wavelengths of electromagnetism, from longest to shortest.

Imagine the length of a long piece of string to represent the distance between electromagnetic waves. We could cut the string in any fractional length we choose, and continue to divide the string into smaller and smaller pieces. In theory, there is no limit to how short the pieces of string could be cut or how many pieces we could cut. It’s also possible to make longer and longer pieces of string by tying on additional pieces. Down the road we wind up with an infinitely large number of string pieces of many different lengths. Likewise, possible wavelengths of electromagnetism are virtually infinite.

Electromagnetic waves include radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. These range in length from many kilometers to only trillionths of a centimeter. In the following brief primer on electromagnetic waves, we will use radio waves as an illustration. The length of waves in the radio band of the EMS varies over a wide range.

All electromagnetic waves are described in terms of packages of electromagnetic energy (photons) traveling at 300,000 km/sec. They are described according to wave length--the distance between the waves. In addition, they are described according to frequency--hertz (symbol Hz)--the number of waves passing a given point per second. All AM radio stations broadcast on the “medium wave” band of the radio portion of the EMS. At the 300,000 km/sec speed, an AM radio station at 600 on the dial sends out 600,000 waves, or photons, per second. It is said, therefore, to have a frequency of 600 kHz (600,000 Hz). Your radio receiver detects them and converts the information in the waves to audible, intelligible sound. Wavelengths of the 600 kHz AM station--the distance between one wave and the next--are about one-half kilometer.

My personal fondness for investigating the EMS may more aptly be described as astonished fascination. In lighter moments I have stated that when this created order ends and the New Creation begins (Revelation 3:12; Revelation 21), I would like to discover, directly from the Creator of this present order, more mysteries of the EMS I did not understand. Included in the questions would be why different waves have such a markedly different effect on man, our equipment, and our environment, when the only physical difference between them is a difference in wavelength. In many cases, that difference is unimaginably small.

The only electromagnetic wave mentioned specifically in the Bible is light, a topic for another post. The scientific knowledge of our day enriches our appreciation of scripture’s spiritual imagery concerning light.

Monday, November 2, 2009

Timeline Trivia

One of my pastimes is personal family genealogical research. I enjoy pinpointing family events and connecting them with people and dates in history. Which family life spans overlapped those of famous people? Who was living when certain historic events occurred? What family member was alive, for example, when a certain scientific discovery was made?

My maternal grandfather was born just before the Civil War and died a few weeks after my birth. He was alive, therefore, in 1864 when brilliant physicist James Clerk Maxwell (1831-1879) developed his famous theory of electromagnetism which unified many observations of scientists who lived in previous decades.

Maxwell’s theory explained waves of electric and magnetic energy traveling at right angles to each other and to their direction of travel. I asked my students to imagine a tiny “package” of magnetism, the invisible force surrounding their childhood magnetic toys which attracted or repelled each other. They also imagined “packages” of electric force which, when pulsing through a copper wire, could deflect the needle of a nearby compass. By this, students were able to visualize the intrinsic relationship between electricity and magnetism.

The students needed to imagine these “packages” racing off through space. Through his equations, Maxwell calculated that the speed of these “packages” (waves) should be about 300,000 km/sec (186,000 mi/sec). Since light was known to travel at that speed, he correctly theorized that light was an electromagnetic wave. And he predicted that scientists would later be able to generate them artificially. Radio waves were first produced by Heinrich Hertz in 1886.

How are these waves produced? Another giant of science was J.J. Thomson (1856-1940). He was alive until 1940, several years after my birth. In 1897, this Nobel Prize winner discovered electrons: tiny negatively-charged particles present in all matter. In the late 19th century, Thomson and others realized that when electric or magnetic fields change position, or oscillate, electromagnetic waves are generated. As the atoms in all the objects around us vibrate constantly with kinetic energy, the electrons in them also oscillate. What is the result? The electrons and the magnetic fields around them also oscillate. Electromagnetic waves are produced.

My grandfather raised his older children on the prairies of Oklahoma during the late 19th century. His older children knew nothing of radio, microwaves, infra-red, the electromagnetic nature of visible light, ultraviolet, X-rays, and gamma rays. Discoveries and applications of electromagnetic waves were in their infancy. And yet, they feared God deeply. With respect to our fear of God, what impact does our present knowledge have on us?