Science Vs Christians

"We can imagine that this complicated array of moving things which constitutes "the world" is something like a great chess game being played by the gods, and we are observers of the game. We do not know what the rules of the game are; all we are allowed to do is to watch the playing. Of course, if we watch long enough, we may eventually catch on to a few of the rules. The rules of the game are what we mean by fundamental physics..." -Richard Feynman. http://vimeo.com... Stephen Hawking's Universe- The Story of Everything (2010). Our Current views on the motion of bodies date back to Galileo and Newton. Previously, views on the motion of bodies dated back to Aristotle. Sir Issac Newton wondered, why do objects move, why do they stop, and why things fall to the earth. Newton, claimed it hit him when an apple fell from a tree. He proposed that objects are pulled by a force in which he called gravity. This was the start of a revolution in science. http://touch.dailymotion.com... Stephen Hawking's Grand Design- The Key To The Cosmos Aristotle stated that the natural state of a body was at rest, and that it only moved if driven by force. This followed that a heavy body should fall at a higher velocity than a lighter one, because it would have a greater pull to the earth. Furthermore, he proposed the laws of the universe could be worked out by thought, and observation was not necessary. As a result, those who accepted the Aristotelian tradition never bothered to see whether bodies of different weights did fall at different rates of speed. However, Galileo Galilei, demonstrated this belief to be inaccurate with an experiment. To explain, he rolled balls of different weights down a smooth slope, and found the bodies increase their speed at the same rate. galileo.phys.virginia.edu/classes/109N/lectures/michelson.html http://galileoandeinstein.physics.virginia.edu... In this experiment, Galileo found, that a body will increase it's velocity per distance fallen: X=(a*t")/2. These measurements were used by Newton as a basis in his laws of motion. In 1687, Newton made a publication, "Principia Mathematica" in which he stated that a body not acted on by any force, moves in the same direction at the same velocity. However, when acted on by a force, a body will change it's speed proportional to the force. In addition, he discovered that every body attracts every other body with a force that is proportional to the mass of each body. Therefore, it was governed by a few concepts, the mass of the objects and their distance apart. http://www.physicsclassroom.com... http://plato.stanford.edu... An example would be provided by a car: the greater the engine power, the greater the acceleration, but the heavier the car, the smaller the acceleration for the same engine. On the other hand, a lead weight would fall faster than a feather, but only because it is slowed down by air resistance: F grav-F air/m2=a. Concurrently, David R Scott demonstrated that a feather and a lead weight does fall at the same rate on the moon, where there is no air resistance. Therefore, a heavier body will have twice the force of gravity pulling: F grav=(G*m1*m2)/d", but will also have twice the mass. According to Newton's second law, these two effects will cancel each other, so the acceleration will be the same in all cases: F grav/m2=(G*m1)/d"=a. http://m.youtube.com... Newton's laws of gravity would predict the motion of bodies within our solar system with great accuracy. To emphasize, his law states that the gravitational attraction of a star is exactly one fourth that of a similar star half the distance. On the other hand, if the law were that the gravitational attraction of a star, decreased or increased more rapidly with distance, the orbits of planets would not be elliptical, would spiral in to the sun, or escape it's orbit within the solar system. However, this new view of absolute rest did not set well with Newton. To explain, his measurements indicated that one could not give an event an absolute position in space. Furthermore, Newton believed in an absolute God, and refused to accept the implications of his own laws. Both Aristotle and Newton believed in absolute time. To explain, they believed two individuals could unambiguously measure the interval between two events and reach the same measurement. Furthermore, space and time were not yet connected as we now understand it to be. Eleven years earlier than Newton's publication in 1676, Danish astronomer Ole Christensen Roemer, observed that the moons did not orbit around Jupiter at a constant rate, as one might expect. Furthermore, he noticed the lunar eclipses of Jupiter appeared much later the further our distance from Jupiter. Thus, he argued that light travels at a high but finite speed. http://micro.magnet.fsu.edu... Roemer's measurements indicated that light travels at 140,000 miles per second. However, a proper theory of the propagation of light did not come until 1865, when British physicist James Clerk Maxwell began to study a strange realm of science, the connection between electricity and magnetism. Furthermore, he succeeded in unifying the partial theories used to describe the forces of electricity and magnetism. For Maxwell, it was quite simple, move a magnet toward a wire and you will cause electricity to flow through the wire. Put electricity through a wire and it will act like a magnet and deflect a compass. He connected electricity, magnetism, and light in a few simple equations, known as Maxwell's laws. http://www.askamathematician.com... These laws govern everything from the Auroras that dance across the night sky to the modern electrical and communications technology that powers the planet. Maxwell's equations predicted that there could be wavelike disturbances in the combined electromagnetic fields, and these would travel at high speeds, like ripples in a pond. To emphasize, if the wavelength of these waves is a meter or more, they are radio waves, microwaves are a few centimeters, visible light forty to eighty millionths of a centimeter, and even shorter wavelengths are known as gamma rays. He soon concluded that light was also an electromagnetic wave. In addition, Maxwell's theory predicted that radio or light waves should travel at a certain fixed speed. However, Newton's theory had gotten rid of the idea of absolute rest, so if light was supposed to travel at a fixed speed, one would have to say what that fixed speed was relative to. This lead to the experiment by Albert Michelson and Edward Morley in 1887. To explain, they predicted that just as water waves are waves that travel in water, and sound waves are waves that travel through a medium, light waves are waves that travel through something in which they called, "luminiferous ether". If this were true, then it should effect the speed of light, and it should be measurable. However, during the experiment, they found no difference in the speed of light no matter which direction they looked. As a result, they concluded that this ether does not exist, and were embarrassed to report they had been wrong. But, this was one of the most important mistakes in the history of science. http://galileoandeinstein.physics.virginia.edu... In 1905, Albert Einstein pointed out in his paper, called relativity, that the idea of ether was unnecessary, providing one was willing to abandon the idea of absolute time. To emphasize, he proposed that the laws of science should be the same for all freely moving observers. To explain, Einstein, developed a thought experiment, he asked, "If I were running along side a beam of light, what I would see?" It would only make since traveling at approximately 186,000 miles per second, a beam of light would appear stationary. Later he found that if he was traveling at the speed of light, it would appear to dash away at the speed of light relative to his own point of view. He imagined a train from two points of view, on the train, and a stationary position from outside the train. The observer on the train observes the light on the train car reaching the end of the car at the speed of light. However, a viewer from the trackside see's the end of the train moving toward the beam of light, therefore has a smaller distance to travel. As a result, this idea had some remarkable consequences, most notably the equivalence of mass and energy, and the law that nothing may travel faster than the speed of light. To explain why, the energy which an object has due to it's motion will add to it's mass, thus making it harder to increase it's speed. Therefore, an object would never reach the speed of light, because by then it's mass would have become infinite, and it would take an infinite amount of energy to get there. http://www.pitt.edu... The special Theory of Relativity was very successful in explaining that the speed of light appears the same to all observers, but it was inconsistent with the Newtonian theory of gravity. To explain, Newton's theory of gravity explained that objects are attracted with a force dependent on the distance between them. Finally, in 1915, he developed what is known as the general theory of relativity. To emphasize, he suggested that spacetime is not flat, as previously assumed: it is curved, or "warped", by the distribution of mass and energy in it. In addition, gravity can be thought of as a hole in a body of water that stretches out forever, this hole would cause water to drain away effecting anything that falls within its distortion. Furthermore, light too would be effected by the distortion in spacetime which was confirmed later by Arthur Eddington in 1919. "It followed from the special theory of relativity that mass and energy are both but different manifestations of the same thing -- a somewhat unfamiliar conception for the average mind. Furthermore, the equation E is equal to m c-squared, in which energy is put equal to mass, multiplied by the square of the velocity of light, showed that very small amounts of mass may be converted into a very large amount of energy and vice versa. The mass and energy were in fact equivalent, according to the formula mentioned above. This was demonstrated by Cockcroft and Walton in 1932, experimentally."- Einstein http://www.aip.org... Another prediction of general relativity is that time should appear to run slower near a point of gravity, such as the earth. To explain why, there is a relation between the energy of light and it's frequency: the greater the energy, the higher the frequency. As light travel upward, it loses energy and it's frequency goes down. To someone high up, it would appear that everything below was taking longer to happen, and vice versa. 1962, a pair if very accurate clocks were mounted at the top and bottom of a water tower, and was found to run at two different speeds, in agreement with general relativity. The difference in the speed of clocks at different heights above the earth is now of considerable practical importance, with the advent of very accurate navigation systems based on signals from satellites. If one ignores the predictions of general relativity, the positions that one calculated would be wrong by several miles. http://www.phys.unsw.edu.au... Before 1915, space and time were thought of as a fixed arena which events took place, but which was not affected by what happened in it. Concurrently, this was true even of the special theory of relativity. To emphasize, bodies moved, forces attracted and repelled, but time and space simply continued, unaffected. However, according to the general theory of relativity, space and time are dynamic quantities: when a body moves or a force acts, it affects the curvature of spacetime- and in turn, the structure of spacetime affects the way in which bodies move and forces act. In conclusion, space and time not only affects, but is also affected by everything that occurs in the universe. Therefore, the old idea of an essentially unchanging universe that could have existed, could continue to exist, was forever replaced by the notion of dynamic, expanding universe that seemed to begun a finite time ago, and that might end at a finite time in the near future. The Expanding universe. Most stars are visible to the naked eye within a few hundred lights years from us. In fact, these stars appear spread all over the night sky, but are particularly concentrated in one band, which we call the Milky Way. As long ago as 1750, some astronomers suggested that the appearance of the Milky Way could be explained if most of the visible stars lie in a single disklike configuration, one example of what we now call a spiral galaxy. Only a few decades later, the astronomer Sir William Herschel confirmed this idea by painstakingly cataloging the positions and distances of vast numbers of stars. Our modern picture of the universe dates back to only 1924, when American astronomer Edwin Hubble demonstrated that ours was not the only galaxy. Instead, there were many others, with vast tracts of empty space between them. In order to prove this, he needed to determine the distances to these galaxies, which are so far away. However, Hubble was forced to use indirect methods to measure the distances. For example, the brightness of a star depended on two factors, how much light it radiates (it's luminosity), and it's distance from us. For nearby stars, we can measure their apparent brightness and their distance, therefore we can work out their luminosity. On the other hand, if we knew the luminosity of stars in other galaxies, we could work out their distance by measuring their apparent brightness. Hubble noted that certain types of stars always have the same luminosity when they are near enough for us to measure; therefore, he argued, if we found such stars in another galaxy, we could assume they had the same luminosity- and so calculated the distance to that galaxy. If we could do this for a number of stars in the same galaxy, and our calculations always gave the same distance, we could be fairly confident of our estimate. Using this method, Hubble worked out the distances to nine different galaxies. With modern telescopes, we have determined, some hundred thousand million galaxies, each containing some hundred thousand million stars. Stars are so far away that they appear to be just pin points in the sky, and we cannot determine their size or shape. So how can we tell different types of stars apart? For the vast majority of stars, there is only one character feature that we can " the color of their light. Newton discovered that if light from the sun pass through a triangular-shaped piece of glass, called a prism, it breaks up into it's component color (it's spectrum) as in a rainbow. By focusing on an individual star or galaxy, one can similarly observe the spectrum of the light from that star or galaxy. Different stars have different spectra, but relative brightness of different colors is always exactly what one would expect to find in the light emitted by an object that is glowing red hot. The light emitted by any opaque object that is glowing red hot has a characteristic spectrum that depends on it's temperature " a thermal spectrum. This means we can tell a star's temperature from the spectrum of it's light. Moreover, we find that very specific colors from the star's spectra, and these missing colors may vary from star to star. Since we know that each chemical element absorbs a characteristic set of very specific colors, by matching these to those that are missing from a star's spectrum, we can determine exactly which elements are present in the star's atmosphere. In the 1920's, when astronomers began to look at the spectra of stars in other galaxies, they found something most peculiar: there were the same characteristic sets of missing colors as for stars in our own galaxy, but they were all shifted toward the red end of the spectrum. Visible light consist of fluctuations, or waves, in the electromagnetic field. The wavelength of light is extremely small, ranging from four to seven millionths of a metre. The different wavelengths of light are what the human eye sees as different colors, the longest wavelengths appearing at the red end of the spectrum and the shortest wavelengths at the blue end. Now imagine a source of light at a constant distance from us, such a star, emitting waves of light at a constant wavelength. Obviously, the wavelength of waves we receive will be the same as the wavelength at which they are emitted. Suppose now that the source of light starts moving toward us. When the source the next wave crest it will be nearer to us, so the distance between waves crests will be smaller than when the star was stationary. This means the wavelength we receive is shorter, than when the star was stationary. Correspondingly, if the source is moving away from us, the wavelengths we receive will be longer. In the case of light, therefore this means stars moving away from us, will have their spectra shifted toward the red end of the spectrum (red shifted) and those moving toward us will have their spectra blue shifted. This relationship between wavelengths and speed, which is called the Doppler effect, is an everyday experience. Imagine your standing on a race track and a car passes you by, you might notice the pitch of the engine increases as it approaches you and decreases as it passes you by. The behavior of light or radio waves is similar. Indeed, the police make use if the Doppler effect to measure the speed of cars by measuring the wavelength of pulses of radio waves reflected off of them. In the following years, Hubble spent his time cataloging the distances of other galaxies, and observing their spectra. At that time, people expected the galaxies to be moving around quite randomly, and so expected to find as many blue-shifted spectra as red-shifted ones. It was quite a surprise, therefore, to find that most galaxies appeared red shifted: nearly all were moving away from us (recession). More surprising still was the finding Hubble published in 1929: even the size of a galaxy's distance from us. Or, in other words, the farther a galaxy is, the faster it is moving away! And that meant the universe could not be static, as everyone had previously thought, but is in fact expanding between the different is growing all the time. The discovery that the universe is expanding was one of the great intellectual revolutions of the twentieth century. With hindsight, it is easy to wonder why no one had thought of it before. Newton, and others, should have realized that a static universe would soon start to contract under the influence of gravity. But supposed instead that the universe was expanding. If it was expanding fairly slowly, the force of gravity would cause it to stop expanding and then to start contracting. However, if it was expanding at a more critical rate, gravity would never be strong enough to stop it, and the universe would expand forever. This is a bit like what happens when one fires a rocket upward from the surface of the earth. If it has a fairly low speed, gravity will eventually stop the rocket and it will start falling back. On the other hand, if it has more than a certain critical speed (about seven miles per second) gravity will not be strong enough to pull it back, so it will keep going away forever. This behavior of the universe could have been predicted from newton's theory of gravity at any time in the nineteenth century, or even the late seventh centuries. Yet so strong was the belief in a static universe that it persisted into the early twentieth century. Even Einstein, when he formed the general theory of relativity in 1915, was so sure that the universe had to be static that he modified his theory to make it possible, introducing the so-called cosmological constant into his equations. Einstein introduced a new, "antigravity" force, which unlike other forces, did not come from any particular force but was built in to the very fabric of spacetime. He claimed that spacetime had a built in tendency to to expand, and this could be made to balance exactly the attraction of all the universe, so that a static universe would result. Only one man, it seems, was willing to take general relativity at face value, and while Einstein and other physicists were looking for ways to avoid general relativity's predictions of a non-static universe, the Russian physicist and mathematician. Alexander Friedmann instead set out explaining it. Friedmann made two very simple assumptions about the universe: that the universe looks identical in whichever direction we look, and this would be true if we were observing the universe anywhere else. From these two ideas alone, Friedmann showed that we should not expect the universe to be static. In fact, in 1922, several years before Edwin Hubble's discovery, Friedmann predicted exactly what Hubble found. http://www.atnf.csiro.au... The assumption that the universe looks exactly the same in every direction is clearly not true in reality. For example, as we have seen, the other stars form a distinct band of light across the night sky, called the Milky Way. But if we look at distant galaxies, there seems to be more or less the same number of them. So the universe does seem to be roughly the same in every direction, provided one views it on a large scale compared to the distances between them, and ignores the differences on small scales. For a long time, this was sufficient justification for Friedmann's assumptions " as a rough approximation to the real universe. But more recently, a lucky accident uncovered the fact that Friedmann's assumptions is in fact a remarkably accurate description of our universe. In 1965, two American physicists at Telephone Laboratories in New Jersey, Arno Penzias and Robert Wilson, were testing a very sensitive microwave detector. Penzias and Wilson were worried when their detector was picking up more noise than it ought to. First they discovered bird droppings in their detector and checked for other possible malfunctions, but soon ruled these out. They knew that any noise from in the atmosphere would be stronger when the detector was not pointing straight up than when it was, because light rays travel through much more atmosphere when received from horizon than when received from directly overhead. The extra noise was the same which ever direction the detector was pointing, so it must come from outside the atmosphere. It was the same day and night and throughout the year, even though the earth was rotating on it's axis and orbiting around the sun. This showed that the radiation must come from beyond the Solar System, and even from beyond the galaxy, as otherwise it would vary as the movement of earth pointed the detector in different directions. In fact, we know that radiation must have traveled to us across most of the observable universe, and since it appears to be the same in different directions, the universe must also be the same in every direction, if only on a large scale. We know that whichever direction we look, the noise never varies by more than a tiny fraction: so Penzias and Wilson had unwittingly stumbled across a remarkably accurate confirmation of Friedman's first assumption. However because the universe is not exactly the same in every direction, but only on average on a large scale, the microwaves can not be exactly the same in every direction either. There have to be slight variations between different directions. These were first detected in 1992 by the Cosmic Background Explorer satellite, or COBE, at a level of about one part in a hundred thousand. Small as these variations are they are very important. At roughly the same time as Penzias and Wilson were investigating noise in their detector, two American physicists at a nearby Princeton University, Bob Dicke and Jim Peebles, were also taking an interest in microwaves. They were working on a suggestion, made by George Gamow (once a student of Alexander Friedmann), that the early universe should have been very hot and dense, glowing white hot. Dicke and Peebles argued that we should still be able to see a glow of the early universe, because light from very distant parts of it would only just be reaching us now. However, the expansion of the universe meant that this light should be so greatly red-shifted that it appear to us as microwave radiation. Dicke and Peebles were preparing to look for this when Penzias and Wilson heard about their work and realized they had already found it. For this, Penzias and Wilson was awarded the Nobel prize in 1978. Now at first sight, all this evidence that the universe looks the same in whichever direction we look might suggest there is something special about our place in the universe. In particular, it might seem that if we observe all of the other galaxies to be moving away from us, then we must be at the center of the universe. There is, however, an alternate explanation: the universe universe might look the same in every direction from any galaxy, too. This as we have seen, was Friedmann's second assumption.However we have no evidence to verify Friedmann's second assumption- it is commonly accepted on the ground of modesty. Based on these assumptions, he predicted exactly what Edwin Hubble found in 1924. Friedmann's model can be compared to a balloon with a number of spots painted on it being steadily blown up- as the balloon expands, the distance between any two spots increase, but no spot can be said to be the center of expansion. In Friedmann's model the galaxies were also moving apart proportional to the distance between them. Thus, the red shift of a galaxy should be proportional to it's distance from us- exactly what Hubble found. Despite the success of his model and his prediction of Hubble's observation, Friedmann's work remained largely unknown in the West until similar models were discovered in 1935 by American physicist Howard Robertson and British mathematician Arthur Walker, In response to Hubble's discovery of the uniform expansion of the universe. Although Friedmann found only one, there are three models that obey: 1) The universe is expanding sufficiently slowly that the gravitation between the different galaxies causes expansion to slow down and eventually stop- thus the universe would eventually collapse. In this model, space is bent in on itself, like the surface of the earth (and is therefore finite in extent). 2) It is expanding so rapidly that the gravitation can never stop it. In this model, space is bent like the surface of a saddle (and is therefore infinite). 3) The universe is expanding just fast enough to avoid recollapse. In this model, space is flat (and therefore space is also infinite). But which model describes our universe? Will the universe stop expanding and start contracting, or will it expand forever? To answer this question we need to know the present rate of expansion of the universe and it's present average density. If the density is less than a certain critical value, determined by the rate of expansion, the gravitational attraction will be too weak to halt the expansion. If the density is greater than the critical value, gravity will stop the expansion at some point in the future and cause the universe to recollapse. We can determine the present rate of expansion by measuring the velocities at which other galaxies are moving away from us, using the Doppler's effect. This can be done very accurately. However, the distance to the galaxies are not very well known because we can only measure them indirectly. So all we know is the universe is expanding by between 5% and 10% every thousand million years. However, our uncertainty about the present average density of the universe is even greater. If we add up all the stars that we can see in our galaxy and other galaxies, the total is less than one hundredth of the amount required to halt the expansion of the universe, even for the lowest estimate of the rate of expansion. Our galaxy and other galaxies, however, must contain a large amount of "dark matter" that we cannot see directly, but which we know must be there because of the influence of it's gravitational attraction on the orbits of stars in the galaxies. Moreover, most galaxies are found in clusters, and we can similarly infer the presence of yet more dark matter in between the galaxies in these clusters by it's effects on the motion of galaxies. When we add up all this dark matter, we still only get about one tenth of the amount required to halt expansion. However we can not exclude the possibility that there might be some other form of matter, distributed almost uniformly throughout the universe, that we have not yet detected and might still raise the average density of the universe up to the critical value needed to halt the expansion. The present evidence therefore suggests that the universe will probably expand forever, but all we can really be sure of is that if the universe is going to recollapse, it won't do so for at least anther ten thousand million years, since it has already been expanding for at least that long. This should not unduly worry us: by that time, unless we have colonized beyond the Solar System, mankind will long since have died out, extinguished along with our sun! All of the Friedmann solutions have the feature that at some time in the past (between ten and twenty thousand million years ago) the distance between neighboring galaxies must have been zero. At that time, which we call the big bang, the density of the universe and the curvature of space-time would have to be infinite. Because mathematics cannot really handle infinite numbers, this means that the general theory of relativity (on which Friedmann's solutions are based) predicts that there is a point in the universe where the theory itself breaks down. Such a point is an example of what mathematicians call a singularity. In fact, all our theories of science are formulated on the assumption that space time is flat, so they break down at the singularity, where curvature of space time is infinite. This means one could not use them to determine what would happen afterwards, because predictability would break down at the big bang. Correspondingly, if, as if the case, we know only what has happened since the big bang, we cannot determine what happened beforehand. As far as we are concerned, events before the big bang can have no consequences, so they should not form part of a scientific model of the universe. We should therefore cut them out of the model and say that time had a beginning at the big bang. Many people do not like the idea that time has a beginning, probably because it smacks of divine intervention. There were therefore a number of attempts to avoid the conclusion that there had to be a big bang. The proposal that gained widest support was called the steady state theory. It was suggested in 1948 by two refugees from Nazi-occupied Austria, Hermann Bondi and Thomas Gold, together with a Briton, Fred Hoyle, who had worked with them on the development of radar during the war. The idea was that as galaxies moved away from each other, new galaxies were continually forming in the gaps in between, from new matter that was being continually created. The universe would therefore look roughly the same at all times as well at all points of space. The steady state theory required a modification of general relativity to allow for the continual creation of matter, but the rate that was involved was so low that it was not in conflict with experiment. The theory was a good scientific theory, in the sense it was simple and it made definite predictions that could be tested by observation. One of these predictions was that a number of galaxies or similar objects in any given volume of space should be the same wherever and whenever we look in the universe. In the late 1950's and early 1960's a survey of sources of radio waves from outer space was carried out at Cambridge by a group of astronomers led by Martin Ryle (who had also worked with Bond I, Gold, and Hoyle on radar during the war). The Cambridge group showed that most of the radio sources must lie outside our galaxy (indeed many of them could be identified with other galaxies) and also that there were many more weak sources than strong one's. They interpreted the weak sources as being the more distant ones, and the stronger ones as being nearer. Then there appeared to be less common sources per unit volume of space for the nearby sources than for the distant ones. This could mean that we are at the center of a great region in the universe in which the sources are fewer than elsewhere. Alternatively, it could mean that the sources were more numerous in the past, at the time that the radio waves left on their journey to us, than they are now. Either explanation contradicted the predictions of the steady state theory. Moreover, the discovery of the microwave radiation by Penzias and Wilson in 1965 also indicated that the universe must have been much more denser in the past. The steady state theory therefore had to be abandoned. Another theory, in response to Friedman's model stated that not everything had to go back to a single point but really close together. However this model was supported by Friedman's expanding universe. In 1965 British mathematician and physicist, Roger Penrose showed that a star collapsing under it's gravity is trapped in a region who's surface eventually shrinks to zero size. And, since the surface of the region shrinks to zero, so too it's volume. All of the matter in the star will be compressed to a region of zero volume, so the density of matter and the curvature of space-time becomes infinite. His theorem had shown that any star must end in a singularity; the time reverse argument showed that any Friedmann-like expanding universe must have begun with a singularity. Aristotle believed that all of matter in the universe was made up of four basic elements- earth air, fire, and water. These elements were acted upon by two forces; gravity, and levity. In addition he believed that matter was continuous, that is, one could cut a piece of matter into smaller and smaller bits without limit. On the other hand, the Greeks, such as Democritus, held that matter was inherently made up of large numbers of Atoms. (Meaning "indivisible" to the Greeks.) For Centuries the arguments continued without supporting evidence on either side. Later, in 1803 British chemist and physicist John Dalton pointed out that the fact that chemical compounds always combined in certain proportions could be explained by the grouping together of atoms to form units called molecules. However, this argument was not settled in favor of atomists until 1905, by Albert Einstein. Before his paper on special relativity (not to be confused with the general theory of relativity) Einstein pointed out that what was called the Browning motion- the irregular random motion of small particles of dust suspended in liquid- could be explained as the effects of atoms of the liquid colliding with liquid particles. By this time there were already suspicions that these atoms were not, after all, indivisible. Four notable figures, known for the discovery of various subatomic particles are listed with attachments available. Trinity College, J.J. Thomson. http://www.biography.com... 1911, Ernest Rutherford. http://www.biography.com... Cambridge, James Chadwick. http://www-outreach.phy.cam.ac.uk... Before 1969, it was thought that protons and neutrons were elementary. However, experiments indicated that, they too were made up of smaller particles- called quarks. Caltech physicist Murray Gell-Mann. https://the-history-of-the-atom.wikispaces.com... http://m.particleadventure.org... So the question is: What are the truly elementary particles, the basic building blocks from which everything is made? Since the wavelength of light is much larger than the size of an atom, we cannot hope to "look" at the parts of an atom in the ordinary way. Quantum physics tells us that all particles are in fact waves, and the higher the energy of a particle, the smaller the wavelength of the corresponding wave. (http://www.pitt.edu...). So the best answer we can give to our question depends on how high energy a particle we have at our disposal, because this determines how small a length scale we can look. These particles are measured in units called electron volts. (https://www.princeton.edu...). In the nineteenth century, when the only particles that people knew how to use were the low energies of a few electron volts generated by chemical reactions such as burning, it was thought that atoms were the smallest units. In Rutherford's experiment, the alpha-particles had energies of millions of electron volts. More recently, we have learned how to use electromagnetic fields to give particles of at first millions and then thousands of millions of electron volts. And so we know that particles that were thought to be "elementary" are, in fact, made up of smaller particles. Using wave/particle duality, everything in the universe, including light and gravity, can be described in terms of particles. These particles have a property called spin. One way to think of spin is to imagine the particles spinning on it's axis. However this can be misleading, because quantum mechanics tells us that particles do not have any well-defined axis. (http://spinningparticles.com...). The matter particles obey what is called the Pauli's exclusion principle. This was first discovered in 1925 by Australian physicist Wolfgang Pauli- for which he received the Nobel prize in 1945. (http://chemwiki.ucdavis.edu...). A proper theory of the electron and other 1/2 spin particles did not come until 1928, proposed by Paul Dirac. (http://www.nobelprize.org...), and ( http://www.pha.jhu.edu...). We now know that every particle has an antiparticle, with which it can annihilate. In quantum physics, the forces or interactions between matter particles are all supposed to be carried by particles of integer spin" 0, 1, or 2, which, as we see, give rise to forces between the matter particles. What happens is that a matter particle, such as an electron or a quark, emits a force carrying particle. The recoil from this emission changes the velocity of the matter particle. This collision changes the velocity of the second particle, just as if there had been a force between the two matter particles. It is an important property of the force carrying particles that they do not obey the exclusion principle. This means that there is no limit to the number that can be exchanged, and so they can give rise to a strong force. However, if the force carrying particles have a high mass, it will be difficult to produce and exchange them over large distances. So the force they carry will only have a short range. On the other hand, if the force-carrying particles have no mass of their own, the forces will be long range. For more information see http://hyperphysics.phy-astr.gsu.edu... http://hubblesite.org... https://www.princeton.edu... http://hyperphysics.phy-astr.gsu.edu... http://grandunificationtheory.org.... http://m.youtube.com... http://whystringtheory.com...