Carl Edward Sagan :
(November 9, 1934 - December 20, 1996) was an American astronomer,  astrochemist, author, and highly successful popularizer of astronomy, astrophysics and other naturalsciences. He pioneered exobiolgy and promoted the Search for Extra-Terrestrial Intelligence (SETI). He was world-famous for writing popular science books and for co-writing and presenting the award-winning 1980 television series Cosmos:A Personal Voyage, which has been seen by more than 600 million people in over 60 countries, making it the most widely watched PBS program in history. Sagan is best known, however, for his research on the possibilities of extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan's capability to convey his ideas allowed many people to better understand the Cosmos — simultaneously emphasizing the value and worthiness of the human race, and the relative insignificance of the earth in comparison to the universe. Cosmos covered a wide range of scientific subjects including the origin of life and a perspective of our place in the universe.

Isaac Asminov described Sagan as one of only two people he ever met who were smarter than Asimov himself. The other was computer scientist and expert on artificial intelligence, Marvin Minsky. Sagan wrote frequently about religion and the relationship between religion and science, expressing his skepticism about many conventional conceptualizations of God. Sagan once stated, for instance, that "The idea that God is an oversized white male with a flowing beard, who sits in the sky and tallies the fall of every sparrow is ludicrous. But if by 'God' one means the set of physical laws that govern the universe, then clearly there is such a God. Sagan was a leader in the U.S. space program since its inception. From the 1950s onward, he worked as an adviser to NASA. One of his many duties during his tenure at the space agency included briefing the Apollo astronauts before their flights to the Moon. Sagan contributed to most of the robotic spacecraft missions that explored the solar system, arranging experiments on many of the expeditions. He conceived the idea of adding an unalterable and universal message on spacecraft destined to leave the solar system that could be understood by any extraterrestrial intelligence that might find it. Sagan assembled the first physical message that was sent into space: a gold-anodized plaque, attached to the space probe Pioneer 10, launched in 1972. Pioneer 11, also carrying the plaque, was launched the following year. He continued to refine his designs throughout his lifetime; the most elaborate message he helped to develop and assemble was the Voyager Golden Record that was

Sir Isaac Newton : FRS(January 4, 1643 – March 31, 1727 [OS: December 25,  1642 – March 20, 1726]) was an English physicist, mathematician, astronomer, natural philosopher, alchemist and theologian. His Philosophiæ Naturalis Principia Mathematica, published in 1687, is considered to be the most influential book in the history of science. In this work, Newton described universal gravitation and the three laws of motion, laying the groundwork for classical mechanics, which dominated the scientific view of the physical universe for the next three centuries and is the basis for modern engineering. Newton showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws by demonstrating the consistency between Kepler's laws of planetary motion and his theory of gravitation, thus removing the last doubts about heliocentrism and advancing the scientific revolution.

Albert Einstein  (14 March 1879 – 18 April 1955) was a German-born theoretical physicist. He is best known for his theory of relativity and specifically mass–energy equivalence, E = mc 2. Einstein received the 1921 Nobel Prize in Physics "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect."

Einstein's many contributions to physics include his special theory of relativity, which reconciled mechanics with electromagnetism, and his general theory of relativity, which extended the principle of relativity to non-uniform motion, creating a new theory of gravitation. His other contributions include relativistic cosmology, capillary action, critical opalescence, classical problems of statistical mechanics and their application to quantum theory, an explanation of the Brownian movement of molecules, atomic transition probabilities, the quantum theory of a monatomic gas, thermal properties of light with low radiation density (which laid the foundation for the photon theory), a theory of radiation including stimulated emission, the conception of a unified field theory, and the geometrization of physics.

Einstein published over 300 scientific works and over 150 non-scientific works. Einstein is revered by the physics community, and in 1999 Time magazine named him the "Person of the Century". In wider culture the name "Einstein" has become synonymous with genius. In 1905, while he was working in the patent office, Einstein had four papers published in the Annalen der Physik, the leading German physics journal. These are the papers that history has come to call the Annus Mirabilis Papers:

* His paper on the particulate nature of light put forward the idea that certain experimental results, notably the photoelectric effect, could be simply understood from the postulate that light interacts with matter as discrete "packets" (quanta) of energy, an idea that had been introduced by Max Planck in 1900 as a purely mathematical manipulation, and which seemed to contradict contemporary wave theories of light (Einstein 1905a). This was the only work of Einstein's that he himself called "revolutionary."
* His paper on Brownian motion explained the random movement of very small objects as direct evidence of molecular action, thus supporting the atomic theory. (Einstein 1905c)
* His paper on the electrodynamics of moving bodies introduced the radical theory of special relativity, which showed that the observed independence of the speed of light on the observer's state of motion required fundamental changes to the notion of simultaneity. Consequences of this include the time-space frame of a moving body slowing down and contracting (in the direction of motion) relative to the frame of the observer. This paper also argued that the idea of a luminiferous ether—one of the leading theoretical entities in physics at the time—was superfluous. (Einstein 1905d)
* In his paper on mass–energy equivalence (previously considered to be distinct concepts), Einstein deduced from his equations of special relativity what later became the well-known expression: E = mc2, suggesting that tiny amounts of mass could be converted into huge amounts of energy. (Einstein 1905e)

All four papers are today recognized as tremendous achievements—and hence 1905 is known as Einstein's "Wonderful Year". At the time, however, they were not noticed by most physicists as being important, and many of those who did notice them rejected them outright. Some of this work—such as the theory of light quanta—remained controversial for years. In 1915 had published his general theory of relativity in the form that is still used today. This theory explains gravitation as distortion of the structure of Space-Time by matter, affecting the inertial motion of other matter.   

Stephen William Hawking, CH, CBE, FRS, FRSA (born 8 January 1942) is a British theoretical physicist. Hawking is the Lucasian Professor of Mathematics at the University of Cambridge, and a Fellow of Gonville and Caius College, Cambridge. He is known for his contributions to the fields of cosmology and quantum gravity, especially in the context of black holes, and his popular works in which he discusses his own theories and cosmology in general.Hawking’s principal fields of research are theoretical cosmology and quantum gravity. In the late 10 bc, he and his Cambridge friend and colleague, Roger Penrose, applied a new, complex mathematical model they had created from Albert Einstein’s general theory of relativity. This led, in 1970, to Hawking proving the first of many singularity theorems; such theorems provide a set of sufficient conditions for the existence of a singularity in space-time. This work showed that, far from being mathematical curiosities which appear only in special cases, singularities are a fairly generic feature of general relativity. He supplied a mathematical proof, along with Brandon Carter, Werner Israel and D. Robinson, of John Wheeler’s “No-Hair Theorem” – namely, that any black hole is fully described by the three properties of mass, angular momentum, and electric charge. Hawking also suggested that, upon analysis of gamma ray emissions, after the Big Bang, primordial or mini black holes were formed. With Bardeen and Carter, he proposed the four laws of black hole mechanics, drawing an analogy with thermodynamics. In 1974, he calculated that black holes should thermally create and emit subatomic particles, known today as Hawking radiation, until they exhaust their energy and evaporate. In collaboration with Jim Hartle, Hawking developed a model in which the Universe had no boundary in space-time, replacing the initial singularity of the classical Big Bang models with a region akin to the North pole: One cannot travel North of the North pole, as there is no boundary there. While originally the no-boundary proposal predicted a closed Universe, discussions with Neil Turok led to the realisation that the no-boundary proposal is also consistent with a Universe which is not closed. Among Hawking’s many other scientific investigations, included are the study of: quantum cosmology, cosmic inflation, helium production in anisotropic Big Bang universes, large N cosmology, the density matrix of the universe, topology and structure of the universe, baby universes, Yang-Mills instantons and the S matrix; anti de Sitter space, quantum entanglement and entropy; the nature of space and time, including the arrow of time; spacetime foam, string theory, supergravity, Euclidean quantum gravity, the gravitational Hamiltonian; Brans-Dicke and Hoyle-Narlikar theories of gravitation; gravitational radiation, and wormholes. At a George Washington University lecture in honour of NASA's 50th anniversary, Prof. Hawking theorised on the existence of extraterrestrial life: "Primitive life is very common and intelligent life is fairly rare."

2 Lectures from the very Intelligent Stephen Hawkins 1)The Beginning of Time.
                                                                     & 2) Life in the Universe.
file:///C:/Users/legleich/Documents/sh%20life.pdf

From The Moon to the Earth

The Human Family Tree : The Evidence The Famous Fossil of "LUCY" Hominid Fossils The scientific community now generally agrees that between 5 and 8 million years ago there lived in Africa a hominoid which would ultimately give rise to the first hominids and later the members of the genus Homo. This period of time was during the end of the Miocence epoch, during which a drying period enveloped equatorial Africa. As a result of this drying, the Miocene forest began to shrink, forcing the apes living in the Miocene forest to begin to make the transition to a terrestrial way of live. Many of the genera of apes at the time likely became extinct during the transition, and those that made the transition to terrestrial life survived. The early apes that began to live on the emerging African savannah likely retained their aboreal abilities, being active on the savannah during the day to return to the trees at night. From at least one of these early terrestrial apes would evolve humankind as it is today. Ardipithecus ramidus Fossil evidence now indicates that the major event in the evolution of hominids from that point was not the immediate development of intelligence, which was thought in the Piltdown man hoax days. Rather, the single development which set hominids apart from our ape-like ancestors was the development of bipedality: an upright, two-legged walking style. This is shown simply by looking at the fossil record. The oldest known hominid, Ardipithecus ramidus, is dated at 4.4 million years and is a recent discovery, announced in September 1994. Although most remains so far are skull fragments (a skeleton which is 45% complete has been found but not been published on yet), indirect evidence suggests that it was possibly bipedal, but still having aboreal-dwelling characteristics. Australopithecus anamensis The next genus in the line of human evolution wass Australopithecus, which was definitely bipedal. The earliest known species of this genus is also a very recent discovery, being named in 1995, and is A. anamensis. It is dated to around 4.2 million years old, showing a very humanlike tibia, fibula, and humerus, although having a small and ape-like cranium. A. anamensis almost certainly represents the true beginnings of the human line and solidly shows that bipedality developed before greater intelligence. There are several models explaining why bipedality developed. Russell Tuttle, an anatomist and paleoanthropologist and the University of Chicago, has proposed that the earliest hominids who walked erect were in fact tree-dwelling primates who descended to the ground when the Miocene forest began to shrink, and those who were able to walk erect survived. Owen Lovejoy, on the other hand, argues that with the shrinking of the Miocene forest, the early forms of pseudo-hominids lived in the trees at night and were active on the savannah during the day. To carry food back that it would have found, it would have needed to be able to use its hands, thus encouraging bipedality. Whatever the cause of bipedality, it eventually led to the development of higher intelligence. Darwin's theory is that with the freed up hands that bipedality allows, hominids would be able to use tools, and the use of tools led to the development of greater intelligence. Australopithecus afarensis   The next hominid in the evolutionary line is A. afarensis, which existed between 3.9 and 3.0 million years agos. Afarensis had an apelike face with a low forehead, a bony ridge over the eyes, a flat nose, and no chin. They had protruding jaws with large back teeth, and their cranial capacity varied from 375 to 500 cc. Although the jaws and teeth are shaped between that of modern apes and humans, the pelvis and leg bones far more closely resemble those of modern man, leaving no doubt that they were bipedal. They were still slightly suited for trees, having longer and curved fingers and toes, but most scientists consider this to be evolutionary baggage. The type specimen for A. afarensis was discovered by Mary Leakey and is about 3.75 million years old. The most well known member of the species, however,   is Johanson and White's Lucy, who shows that at 3 million years hominids were completely bipedal. Her teeth were obviously in a transition stage between ape and human as well. Many other A. afarensis finds in the Hadar region of Ethiopia by Johanson and White contribute to the knowledge of the species. Also, afarensis is where the Laetoli footprints come in, because it was that species to which the footprints are attributed. Australopithecus africanus   Between 2 and 3 million years ago A. africanus appeared and was very similar to A. afarensis. The body size of africanus was slightly greater, as well as brain size, but the teeth and jaws were more similar to those of humans. The main fossil for this species is the "Taung baby" found by Raymond Dart in 1924. It consists of almost a full skull, the skull of an infant. A. afarensis and africanus are known as gracile australopithecines becuase of their light build. There are more robust Australopithecines as well. Australopithecus robustus A. robustus was similar to africanus, except with a larger and more robust skull and teeth. It existed between 2 and 1.5 million years ago. The average brain size is about 530 cc, and likely had a vegetarian diet due to its large grinding teeth. This species is not in the direct human lineage, but is rather a side branch that perhaps led to modern apes. Australopithecus boisei   A. boisei, once known as Zinjanthropus boisei, was also a robust australopithecine and was very similar to robustus. It existed between 2.1 and 1.1 million years ago and has a brain size similar to that of robustus. Although once thought to be by Louis Leakey, A. boisei is not in the human lineage either. So when did Homo arise, and what species of Australopithecines led to it? These questions are extremely controversial and are still not solidly resolved. Currently, one main interpretation is that A. afarensis was the link the the Homo genus, another that A. africanus led to Homo, and a third that Homo developed side by side with afarensis and africanus, arising from another species. Currently, evidence points to africanus as the link, but the truth is still being debated. Homo habilis   At this point in history (between 1.5 and 3 million years ago), there was a time in which 4 or 5 hominids likely were contemporaneous; it can be thought of as the great human experiment, with the result being a branching off of the human line. The first Homo likely lived alongside Australopithecines of several species. However, even this first Homo is being challenged - Homo habilis is said by some to be a form of australopithecine. However, the main thing that gives habilis its status is that evidence of tools have been found with him, hence its name, translated as "the human with ability". Habilis existed between 2.4 and 1.5 million years ago. The species is still primitive looking, but the teeth are smaller and the brain size is much larger thatn in australopithecines at 650 cc. The brain shape is also more humanlike and he likely was capable of rudimentary speech. The picture shown is of skull 1470, the most complete habilis skull ever found, found by Richard Leakey's team at Koobi Fora. Incidently, the stone tools made by habilis were a dramatic departure from what earlier hominids were able to do. This archaeological tradition, found in East and South Africa, is often known as the Olduwan Industry because many of the primitive stone tools found at Olduvai Gorge by Louis Leakey belonged to habilis. These tools were made by striking two pebbles together, leaving a crude edge along the fracture lines of the stone. The more advanced tools of the Olduwan industray, such as Chellean hand-axes, however, were the product of a more advance level of hominid, Homo erectus Homo erectus   Most paleontologists now believe that a second evolutionary pulse occurred around 1.9 million years ago that produced hominids with much larger brains, Homo erectus. <>were the first hominids to not just be human-like, but human. They were hunters, speculates Milford Wolpoff of the University of Michigan, and likely had the ability of some sort of speech, due to an enlarged Broca's area on their skulls. The face has protruding jaws, no chin, thick brow ridges, and a brain size ranging from 750 to 1225 cc. The skeletons are more robust than those of modern humans. Erectus likely had a very efficient walking style, and probably used fire as well. In addition, their stone tools are much better than those of habilis. Some of the most famous early archaeological finds were skeletal remains of Homo erectus, including the 1893 discovery "Java Man", the "Heidelberg Marn", the "Peking Man", and the "Turkana Boy" shown in the picture on the right. Erectus also turned out to be the creater of many of the stone tools and Chellean handaxes found at the Olduvai site by the Leakeys, the so-called "Chellean Man". Erectus was likely the first hominid to spread across the world, as the migrated to China by 800,000 years ago and to Europe by 500,000. However, by 300,000 years ago they were to be replaced by a new hominid - Homo Sapiens. Homo Sapiens There were several different types of this species that appeared onto the scene about 300,000 years ago, and perhaps the best known of this type is the emergence of   Homo sapiens neanderthalensis, which represent the final stage of human evolution prior to the reduction of the Mid-Pleistocene face and refinement of anatomy to result in modern Homo sapiens about 100,000 years ago. The Neanderthal is similar to erectus except having a larger brain of around 1,500 cc, slightly larger than modern humans. The tools they made in what is called the "Mousterian tradition" are more sophisticated than those of previous humans. They also bury their dead, something no earlier hominid ever did. There exists a huge debate today about whether or not Neanderthals are in the direct human line or a side branch because a very negative view exists about the Neanderthals. Due to some very poor early descriptions of skeletons, they are thought to be hunchbacked bent-legged animal-like idiots, but they were actually much more sophisticated than that (of course not as sophisticated as modern humans). What is certain, however, is that around 120,000 years ago at least, the modern Homo sapiens sapiens first appeared and lived contemporaneously with the Neanderthal for at least 90,000 years until the Neanderthal disappeared 30,000 years ago.   Modern humans have an average brain size of 1350 cc, with a sharply rising forehead, small eyebrow ridges or absent ones, a prominent chin, and a very gracile skeleton (although Texas Aggies may resemble a more Neanderthal looking version, being very robust with large eyebrow ridges). With the emergence of modern humans, tool kits became extremely sophisticated and cave paintings appeared in an advanced form. Cro-Magnon man is an example of modern human, living in Europe between 35,000 and 10,000 years ago, and was virtually identical to modern man, being skilled hunters, toolmakers, and cave artists. Within the last 100,000 years, a trend has existed towards smaller molars and decreased robustness. Thus, evolution has been ongoing, even within our species. Thus, it can be seen that Africa is truly the "cradle" of human life, being the major location for the transformation of hominids from early tree-dwellers to modern humans. Through archaeology, paleontology, taphonomy, and modern dating methods, archaeological discoveries are able to reveal to some extent the evolutionary trends and actions that have transpired over the past five million years. However, due to the inherent limitations to the Linnean classification system, such as where to draw the lines between species and genera, many debates still exist as to the relationship between different hominids, such as whether A. afarensis is the common ancestor between man an ape or A. africanus. However, new techniques and discoveries appear every day, so the future of African archaeology looks exciting and informative.