by Mike Bennett
Beta particles are high-energy electrons. They also have a relatively short range in air, and can again be blocked by using relatively thin shielding materials. They are also hazardous, as if they are sufficiently energetic they have the capacity to ionise the materials within our bodies, again causing permanent damage.
The third broad category is gamma decay. Gamma rays are very high-frequency energetic electromagnetic waves. They are extremely penetrating and are very difficult to shield against. Depending on the energy of the gamma emissions, as a rule of thumb it takes around one inch of solid lead shielding to attenuate the received gamma ray dose rate by one order of magnitude. This means that powerful gamma ray sources need very thick and heavy shielding in order to get the dose rates on the outside of the shielding down to acceptable levels.
Gamma rays are not absorbed into the body, but pass straight through it, striking our molecules on the way. As you know, humans are made up mostly of water which is H2O. Gamma rays are capable of splitting a water molecule into free radicals. This means that free hydrogen and oxygen atoms will be produced. These will then recombine, but not necessarily back into water. A free radical of oxygen can combine with an existing water molecule within the body to produce H2O2 (hydrogen peroxide), which is toxic.
In addition to the creation of toxic substances within our bodies, long-term damage can be caused when radiation strikes our DNA chains. As the reader will know, DNA is the biological blueprint of how the various cells within the body are constructed. As a good deal of the tissue within the body is continually being regenerated, the damaged DNA chains can cause cancerous tissues to grow. This long-term effect of radiation can result in people developing many types of cancer years after they were actually exposed to the radiation.
One of the key components used in some exotic science today is an isotope known as sodium 22. Sodium is a member of the alkali metals group, and is therefore highly reactive. There are twenty known isotopes of sodium, with atomic weights ranging from 18 to 37, although all of the higher atomic weight isotopes decay very rapidly and can only exist for a fraction of a second. Sodium 22 is chemically akin to the only stable sodium isotope, sodium 23, that we all eat as common salt in the form of NaCl (sodium chloride). However, sodium isotopes all have nuclei containing eleven protons. Sodium 22 is a very special and unusual isotope, because it emits particles called positrons, and as a result the element changes to neon 22. Positrons are actually antielectrons, or in layman’s language antimatter. When matter and antimatter meet, they annihilate each other and release very large amounts of energy in the process.
Now that we have got the school lesson out of the way, we can begin to discuss the history of science.
CHAPTER 2
In order to gain an appreciation of how science has progressed up until modern times, I am now including a discussion covering the most significant and groundbreaking achievements in this field. Due to the ever-increasing rate of growth in our knowledge as the years have progressed, I am splitting this discussion into three separate sections.
The current section will deal with pioneering developments prior to 1930. This is because when Adolf Hitler became Chancellor of Germany in 1933, he banned the teaching and research of all ideas developed by Albert Einstein, as he considered this to be Jewish physics. German scientists therefore had to think in totally new directions, and as a result a series of major breakthroughs in many fields of physics and science were made.
The next section then deals with developments in science from the 1930s until the 1970s. I chose the 1970s as this was the time when I studied physics at university. This chapter will include advancements up until the time at which I graduated. It will also include information regarding the quite amazing achievements of the German scientists prior to and during World War II, together with many of the subsequent developments made by both Allied and Soviet scientists after they had access to this technological treasure trove.
The final of these three sections in the development of science covers the 1970s up to the present day. Developments in the fields of science, physics, engineering and astronomy during this period have been quite breathtaking, and I hope that the achievements that we discuss will be as fascinating to the reader as they are to me.
When looking at the early era of scientific developments I will start with Leonardo Da Vinci. Prior to Da Vinci, most of the early work was philosophy which is outside the scope of this book. He was born in Vinci, Italy in 1452, and in my opinion was one of the most talented men who ever lived. He was an extremely accomplished painter, sculptor, mathematician, engineer, astronomer, architect, musician, writer, botanist, anatomist, geologist, cartographer, and the list goes on.
Everyone knows about the priceless works of art that he created, including the Mona Lisa and the Last Supper, but I will limit our discussion to his scientific achievements.
Da Vinci had no formal education in mathematics or Latin, and most of his peer group at the time tended to ignore him. He was more of an observational scientist, but had a huge talent for making accurate theoretical deductions from the information that he collected. His engineering achievements however were quite remarkable.
His journals included a large number of practical inventions, and most people now believe that if the materials and manufacturing capabilities that we have today had existed in the 15th century, many of his inventions could have been successfully turned into working machines.
It appears from the content of his journals that he was planning a series of papers to be published on a variety of subjects. While Leonardo’s experimentation followed clear scientific methods, a recent and exhaustive analysis by Capra of Leonardo as a scientist argues that he was a fundamentally different kind of scientist from Galileo, Newton and many of the other scientists who followed him in that, as a Renaissance Man, his theorising and his hypothesising integrated the arts and particularly painting.
During his lifetime Leonardo was valued as an engineer. In a letter to Ludovico il Moro he claimed to be able to create all sorts of machines both for the protection of a city and for siege. When he fled to Venice in 1499, he found employment as an engineer, and devised a system of moveable barricades to protect the city from attack.
He also had a scheme for diverting the flow of the Arno River, a project on which Niccolò Machiavelli also worked. Leonardo’s journals include a vast number of inventions, both practical and impractical. They include musical instruments, hydraulic pumps, reversible crank mechanisms, finned mortar shells and a steam cannon.
In 1502, Leonardo produced a drawing of a single span 720 foot (220 metre) bridge as part of a civil engineering project for Ottoman Sultan Bayezid II of Constantinople. The bridge was intended to span an inlet at the mouth of the Bosporus known as the Golden Horn. Bayezid did not pursue the project because he believed that such a construction was impossible. Leonardo’s vision was resurrected in 2001 when a smaller bridge based on his design was successfully constructed in Norway.
For much of his life, Leonardo was fascinated by the phenomenon of flight, and he produced many studies of the flight of birds, including his 1505 Codex on the Flight of Birds, as well as plans for several flying machines as mentioned earlier. The British television station Channel Four commissioned a documentary that was titled Leonardo’s Dream Machines, broadcast in 2003. Leonardo’s designs for machines such as a parachute and a giant crossbow were interpreted, constructed and then tested. Some of those designs proved a success, whilst others fared less well when tested practically.
As our knowledge of science progressed, many pioneers in this area had a very hard time. The fate of people who upset the status quo can be precarious, but this has been happening for centuries.
Galileo is often credited with inventing the telescope. However, the first recorded reference to a telescope-type device was in a patent filed by a Dutch lens maker called Hans Lippershey in 1608. The patent was entitled “for seeing things far away as if they were nearby”.
Galileo made improvements to this original design, and in 1609 constructed the first modern optical telescope that we are all familiar with today.
This then ushered in an era with many very intelligent and competent people who spent many years studying the night sky. Subsequently a new breed of astronomers declared that the Earth was not at the centre of the universe, and in fact we were within a solar system with the sun at its centre. This immensely important discovery was proven after years of meticulous observation and mathematical analysis.
Unfortunately for many of them, they were burned alive at the stake, as their observations and conclusions contradicted the teachings of certain religious groups at the time.
The same fate befell the first explorers who announced that the Earth was not in fact flat, but spherical. It seems that some religious groups need to be dragged kicking and screaming into every successive century when scientific proof contradicts the beliefs that they preach. This has not only happened in the distant past, but still goes on today.
The man who first developed spectacles (eyeglasses) was also brutally murdered. His crime was trying to improve on God’s perfect design, which was totally unacceptable to some religious leaders at the time. It is lucky that this type of ignorance is on the decline today, as otherwise all of our doctors and cancer surgeons would probably be burned at the stake as well.
I am not trying to put down religion at all. I personally am not a religious man, but I do know right from wrong, good from evil, and I respect people who hold religious values. I believe that I became confused about religion when I was about eight or nine years old. My mother was a Quaker, and my sister and I were required to attend Quaker meetings every Sunday. They are not like most other religious services. In the meeting room, chairs are positioned in concentric circles around a central table with flowers.
All of the children had to sit in the outer circles and were forbidden from speaking. Occasionally one or two of the senior adult members would stand up and say something, but otherwise we would all sit in silence for an hour. At the time, I could see no difference between a Quaker meeting and the punishment of a school detention, but I think that every religion has its own individual way of expressing their beliefs.
CHAPTER 3
Following the work of Leonardo Da Vinci, the next major pioneer of scientific discovery was Nicolaus Copernicus. He was a Polish scientist born in 1473. Copernicus was a Renaissance astronomer and mathematician, and was the first scientist who recognised that the sun was at the centre of our solar system, and the universe did not revolve around the Earth.
In 1551, he published a series of astronomical tables that astronomers and astrologists of the time adopted, and his ideas quickly superseded those that had previously been accepted.
His work on heliocentric theory was revolutionary at the time, and the main points of his discoveries are summarised below, although some of his theories were later found to be incorrect.
1. There is no one centre of all the celestial circles or spheres.
2. The centre of the Earth is not the centre of the universe, but only of the lunar sphere.
3. All the spheres revolve about the sun as their midpoint.
4. The ratio of the Earth’s distance from the sun to the height of the firmament (outermost celestial sphere containing the stars) is so much smaller than the ratio of the Earth’s radius to its distance from the sun that the distance from the Earth to the sun is imperceptible in comparison with the height of the firmament.
5. Whatever motion appears in the firmament arises not from any motion of the firmament, but from the Earth’s motion. The Earth, together with its circumjacent elements, performs a complete rotation on its fixed poles in a daily motion, while the firmament and the highest heaven abide unchanged.
6. What appear to us as motions of the sun arise not from its motion, but from the motion of the Earth and our sphere, with which we revolve about the sun like any other planet. The Earth has, then, more than one motion.
7. The apparent retrograde and direct motion of the planets arises not from their motion but from the Earth’s. The motion of the Earth alone, therefore, suffices to explain so many apparent inequalities in the heavens.
Luckily for Copernicus, he died in 1543 before the news of his work reached the Catholic Inquisition. Others who later expanded on his discoveries were not so lucky. It would be about another seventy years before any further major advancement was made in this field.
Tycho Brahe was a Danish nobleman, although he was born in Sweden in 1546. He is recognised for his accurate and comprehensive astronomical and planetary observations. At about the same time, another great mathematician and astrologer named Giordano Bruno was born in Italy in 1548. Brahe made important contributions by devising the most precise instruments available, before the invention of the telescope, for observing the heavens. Brahe made his observations from an island in the sound between Denmark and Sweden called Hveen. Brahe’s instruments allowed him to determine more precisely than had previously been possible the detailed motions of the planets. In particular, Brahe compiled extensive data on the planet Mars, which would later prove crucial to Kepler in his formulation of the laws of planetary motion, because it would be sufficiently precise to demonstrate that the orbit of Mars was not a circle but an ellipse.
The most important scientific contributions of Brahe were as follows:
1. He made the most precise observations that had yet been made by devising the best instruments available before the invention of the telescope.
2. His observations of planetary motion, particularly that of Mars, provided the crucial data for later astronomers like Kepler to construct our present model of the Solar System.
3. He made observations of a supernova (a new star, as he then thought) in 1572. We now know that a supernova is an exploding star, not a new star. This was a “star” that appeared suddenly where none had been seen before, and was visible for about eighteen months before fading from view. Since this clearly represented a change in the sky, prevailing opinion held that the supernova was not really a star, but some local phenomenon in the atmosphere. One must remember that the heavens were supposed to be unchanging in the Aristotelian view. Brahe’s meticulous observations showed that the supernova did not change position with respect to the other stars (no parallax). Therefore, it was a real star, not a local object. This was early evidence against the immutable nature of the heavens, although Brahe did not interpret the absence of parallax for stars correctly, as we discuss below.
4. Brahe made careful observations of a comet in 1577. By measuring the parallax for the comet, he was able to show that the comet was further away than the moon. This contradicted the teachings of Aristotle, who had held that comets were atmospheric phenomena. “Gases burning in the atmosphere” was a common explanation among Aristotelians. As for the case of the supernova, comets represented an obvious change in a celestial sphere that was supposed to be unchanging. Furthermore, it was very difficult to ascribe uniform circular motion to a comet.
5. He made the best measurements that had yet been made in the search for stellar parallax. Upon finding no parallax for the stars, he correctly concluded that either
a) the Earth was motionless at the centre of the universe, or
b) the stars were so far away that their parallax was too small to measure.
Not for the only time in human thought, a great thinker formulated a pivotal question correctly, but then made the wrong choice of possible answers. Brahe did not believe that the stars could possibly be so far away, and so concluded that the Earth was the centre of the universe and that Copernicus was wrong.
6. Brahe proposed a model of the Solar System that was intermediate between the Ptolemaic and Copernican models (it had the Earth at the centre). It proved to be incorrect, but was the most widely accepted model of the Solar System for a time.
Brach also made many other contributions to astronomy, and during his flamboyant life he lost par
t of his nose in a duel. He finally died in 1601 after his bladder burst.
Tycho Bruno also affirmed that the universe was homogeneous, and that essentially the same physical laws would operate everywhere, although the use of that term is anachronistic. For Bruno, space and time were both infinite. There was no room in his stable and his permanent universe theory for the Christian notions such as Divine Creation and the Last Judgement.
In Bruno’s model, the sun was simply one more star, and the stars all suns, each with their own planets. Bruno saw a solar system of a sun/star with planets as the fundamental unit of the universe. All these planets constituted an infinite number of inhabited worlds, a philosophical position known as cosmic pluralism.
According to Bruno, an infinite God necessarily created an infinite universe, formed of an infinite number of solar systems, separated by vast regions full of Aether. This was because he believed that empty space could not exist. Bruno had not yet arrived at the concept of a galaxy.
Bruno believed that comets were part of stars, and not, as other people maintained at the time, divine instruments or heavenly messengers. Each comet was a world, a permanent celestial body, formed of the four basic elements. Bruno’s cosmology is marked by infinitude, homogeneity and isotropy, with planetary systems distributed evenly throughout. Bruno believed that matter followed an active animistic principle. This is the most dramatic respect in which Bruno’s cosmology differs from a modern scientific understanding of the universe.
During the late 16th century, and throughout the 17th century, Bruno’s ideas were held up for ridicule, debate, or inspiration. Bruno’s true, if partial, vindication would have to wait for the implications and impact of Newtonian cosmology.
Bruno’s overall contribution to the birth of modern science is still controversial. Some scholars follow Frances Yates, stressing the importance of Bruno’s ideas about the universe being infinite and lacking geocentric structure as a crucial cross-point between the old and the new. Others see Bruno’s idea of multiple worlds as a forerunner of Everett’s many worlds interpretation of quantum mechanics. However, Bruno’s ground-breaking ideas were not well received by the Catholic church.
