Atheism is, in the broadest sense, the absence of belief in the existence of deities. Less broadly, atheism is the rejection of belief. In an narrower sense, atheism is the position that there are no deities. Atheism is contrasted with theism, which, in its most general form, is the belief that at least one deity exists; the etymological root for the word atheism originated before the 5th century BCE from the ancient Greek ἄθεος, meaning "without god". In antiquity it had multiple uses as a pejorative term applied to those thought to reject the gods worshiped by the larger society, those who were forsaken by the gods, or those who had no commitment to belief in the gods; the term denoted a social category created by orthodox religionists into which those who did not share their religious beliefs were placed. The actual term atheism emerged first in the 16th century. With the spread of freethought, skeptical inquiry, subsequent increase in criticism of religion, application of the term narrowed in scope.
The first individuals to identify themselves using the word atheist lived in the 18th century during the Age of Enlightenment. The French Revolution, noted for its "unprecedented atheism," witnessed the first major political movement in history to advocate for the supremacy of human reason; the French Revolution can be described as the first period where atheism became implemented politically. Arguments for atheism range from the philosophical to historical approaches. Rationales for not believing in deities include arguments that there is a lack of empirical evidence, the problem of evil, the argument from inconsistent revelations, the rejection of concepts that cannot be falsified, the argument from nonbelief. Nonbelievers contend that atheism is a more parsimonious position than theism and that everyone is born without beliefs in deities. Although some atheists have adopted secular philosophies, there is no one ideology or set of behaviors to which all atheists adhere. Since conceptions of atheism vary, accurate estimations of current numbers of atheists are difficult.
According to global Win-Gallup International studies, 13% of respondents were "convinced atheists" in 2012, 11% were "convinced atheists" in 2015, in 2017, 9% were "convinced atheists". However, other researchers have advised caution with WIN/Gallup figures since other surveys which have used the same wording for decades and have a bigger sample size have reached lower figures. An older survey by the British Broadcasting Corporation in 2004 recorded atheists as comprising 8% of the world's population. Other older estimates have indicated that atheists comprise 2% of the world's population, while the irreligious add a further 12%. According to these polls and East Asia are the regions with the highest rates of atheism. In 2015, 61 % of people in China reported; the figures for a 2010 Eurobarometer survey in the European Union reported that 20% of the EU population claimed not to believe in "any sort of spirit, God or life force". Writers disagree on how best to define and classify atheism, contesting what supernatural entities are considered gods, whether it is a philosophic position in its own right or the absence of one, whether it requires a conscious, explicit rejection.
Atheism has been regarded as compatible with agnosticism, has been contrasted with it. A variety of categories have been used to distinguish the different forms of atheism; some of the ambiguity and controversy involved in defining atheism arises from difficulty in reaching a consensus for the definitions of words like deity and god. The plurality of wildly different conceptions of God and deities leads to differing ideas regarding atheism's applicability; the ancient Romans accused Christians of being atheists for not worshiping the pagan deities. This view fell into disfavor as theism came to be understood as encompassing belief in any divinity. With respect to the range of phenomena being rejected, atheism may counter anything from the existence of a deity, to the existence of any spiritual, supernatural, or transcendental concepts, such as those of Buddhism, Hinduism and Taoism. Definitions of atheism vary in the degree of consideration a person must put to the idea of gods to be considered an atheist.
Atheism has sometimes been defined to include the simple absence of belief. This broad definition would include newborns and other people who have not been exposed to theistic ideas; as far back as 1772, Baron d'Holbach said. George H. Smith suggested that: "The man, unacquainted with theism is an atheist because he does not believe in a god; this category would include the child with the conceptual capacity to grasp the issues involved, but, still unaware of those issues. The fact that this child does not believe in god qualifies him as an atheist." Implicit atheism is "the absence of theistic belief without a conscious rejection of it" and explicit atheism is the conscious rejection of belief. For the purposes of his paper on "philosophical atheism", Ernest Nagel contested including mere absence of theistic belief as a type of atheism. Graham Oppy classifies as innocents those who never considered the question because they lack any understanding of what a god is. According to Oppy, these could be one-month-old babies, humans with severe traumatic brain injuries, or patients with advanced dementia.
Philosophers such as Antony Flew and Michael Martin have contrasted positive (st
Religion is a cultural system of designated behaviors and practices, worldviews, sanctified places, ethics, or organizations, that relates humanity to supernatural, transcendental, or spiritual elements. However, there is no scholarly consensus over what constitutes a religion. Different religions may or may not contain various elements ranging from the divine, sacred things, faith, a supernatural being or supernatural beings or "some sort of ultimacy and transcendence that will provide norms and power for the rest of life". Religious practices may include rituals, commemoration or veneration, festivals, trances, funerary services, matrimonial services, prayer, art, public service, or other aspects of human culture. Religions have sacred histories and narratives, which may be preserved in sacred scriptures, symbols and holy places, that aim to give a meaning to life. Religions may contain symbolic stories, which are sometimes said by followers to be true, that have the side purpose of explaining the origin of life, the universe, other things.
Traditionally, faith, in addition to reason, has been considered a source of religious beliefs. There are an estimated 10,000 distinct religions worldwide, but about 84% of the world's population is affiliated with one of the five largest religion groups, namely Christianity, Hinduism, Buddhism or forms of folk religion; the religiously unaffiliated demographic includes those who do not identify with any particular religion and agnostics. While the religiously unaffiliated have grown globally, many of the religiously unaffiliated still have various religious beliefs; the study of religion encompasses a wide variety of academic disciplines, including theology, comparative religion and social scientific studies. Theories of religion offer various explanations for the origins and workings of religion, including the ontological foundations of religious being and belief. Religion is derived from the ultimate origins of which are obscure. One possible interpretation traced to Cicero, connects lego read, i.e. re with lego in the sense of choose, go over again or consider carefully.
The definition of religio by Cicero is cultum deorum, "the proper performance of rites in veneration of the gods." Julius Caesar used religio to mean "obligation of an oath" when discussing captured soldiers making an oath to their captors. The Roman naturalist Pliny the Elder used the term religio on elephants in that they venerate the sun and the moon. Modern scholars such as Tom Harpur and Joseph Campbell favor the derivation from ligare bind, connect from a prefixed re-ligare, i.e. re + ligare or to reconnect, made prominent by St. Augustine, following the interpretation given by Lactantius in Divinae institutiones, IV, 28; the medieval usage alternates with order in designating bonded communities like those of monastic orders: "we hear of the'religion' of the Golden Fleece, of a knight'of the religion of Avys'". In the ancient and medieval world, the etymological Latin root religio was understood as an individual virtue of worship in mundane contexts. In general, religio referred to broad social obligations towards anything including family, neighbors and towards God.
Religio was most used by the ancient Romans not in the context of a relation towards gods, but as a range of general emotions such as hesitation, anxiety, fear. The term was closely related to other terms like scrupulus which meant "very precisely" and some Roman authors related the term superstitio, which meant too much fear or anxiety or shame, to religio at times; when religio came into English around the 1200s as religion, it took the meaning of "life bound by monastic vows" or monastic orders. The compartmentalized concept of religion, where religious things were separated from worldly things, was not used before the 1500s; the concept of religion was first used in the 1500s to distinguish the domain of the church and the domain of civil authorities. In the ancient Greece, the Greek term threskeia was loosely translated into Latin as religio in late antiquity; the term was sparsely used in classical Greece but became more used in the writings of Josephus in the first century CE. It was used in mundane contexts and could mean multiple things from respectful fear to excessive or harmfully distracting practices of others.
It was contrasted with the Greek word deisidaimonia which meant too much fear. The modern concept of religion, as an abstraction that entails distinct sets of beliefs or doctrines, is a recent invention in the English language; such usage began with texts from the 17th century due to events such the splitting of Christendom during the Protestant Reformation and globalization in the age of exploration, which involved contact with numerous foreign cultures with non-European languages. Some argue that regardless of its definition, it is not appropriate to apply the term religion to non-Western cultures. Others argue that using religion on non-western cultures distorts what people believe; the concept of religion was formed in the 16th and 17th centuries, despite the fact that ancient sacred texts like the Bible, the Quran, others did not have a word or a concept of religion in the original languages and neither did the peopl
Eugenie Carol Scott is an American physical anthropologist, a former university professor and educator, active in opposing the teaching of young Earth creationism and intelligent design in schools. From 1986 to 2014, Scott served as the Executive Director of the National Center for Science Education, a nonprofit science education organization supporting teaching of evolutionary science. Since 2013, Scott has been listed on their Advisory Council. Scott holds a Ph. D. in biological anthropology from the University of Missouri. A biologist, her research has been in skeletal biology. Scott serves on the Board of Trustees of Americans United for Separation of State. Scott grew up in Wisconsin and first became interested in anthropology after reading her sister's anthropology textbook. Scott received BS and MS degrees from the University of Wisconsin–Milwaukee, followed by a PhD from the University of Missouri, she joined the University of Kentucky as a physical anthropologist in 1974, shortly thereafter attended a debate between her mentor James A. Gavan and the young Earth creationist Duane Gish, which piqued her interest in the creation-evolution controversy.
She taught at the University of Colorado and at California State University, Hayward. Her research work focused on medical anthropology, skeletal biology. In 1980, Scott worked to prevent creationism from being taught in the public schools of Lexington, Kentucky. Scott was appointed the executive director of the National Center for Science Education in 1987, the year in which requiring the teaching of creation science in American public schools was deemed illegal by the Supreme Court in Edwards v. Aguillard. Scott announced that she would be retiring from this position by the end of 2013, doing so on 6 January 2014, her place was taken by Ann Reid. Scott was brought up in Christian Science by her mother and grandmother but switched to a congregational church under the influence of her sister. Scott describes herself as a nontheist. In 2003, the San Francisco Chronicle reported that, "Scott describes herself as atheist but does not discount the importance of spirituality." In 2003 she was one of the signatories to the third humanist manifesto and Its Aspirations.
Scott is an expert on creationism and intelligent design. Her book Evolution vs. Creationism: An Introduction was published by Greenwood Press in 2004 and in paperback by the University of California Press in 2005. Niles Eldredge wrote the foreword in the first edition. A second edition of the book was published in 2008 and in paperback in 2009; the foreword to this edition was written by John E. Jones III, the presiding judge in the Kitzmiller v. Dover court case, she co-edited with Glenn Branch the 2006 anthology Not in Our Classrooms: Why Intelligent Design is Wrong for Our Schools. In 2006 Jon D. Miller and Shinji Okamoto had a brief article published in Science entitled "Public Acceptance of Evolution", an analysis of polling on the acceptance of evolution from the last 20 years in the United States and compared to other countries. Turkey had the lowest acceptance of evolution in the survey, with the United States having the next-lowest, though the authors saw a positive in the higher percentage of Americans who are unsure about evolution, therefore "reachable" for evolution.
David Berlinski, a fellow at the Discovery Institute, describes Scott as an opponent "who is sent out to defend Darwin". Scott prefers to see herself as "Darwin's golden retriever". Scott has been profiled in The New York Times, Scientific American, The Scientist, the San Francisco Chronicle, the Stanford Medical Magazine, she has had been interviewed for Science & Theology News, CSICOP, Church & State and Point of Inquiry. She has commentary published by Metanexus Institute. Scott has taken part in numerous debates on Fox News. In 2004, Scott represented the National Center for Science Education on the Showtime television show Penn & Teller: Bullshit!, on the episode titled "Creationism", where she offered philosophical views about the creationist and intelligent design movements. In 2005, Scott and other NCSE staff served as scientific and educational consultants for the plaintiffs in the Kitzmiller v. Dover Area School District case regarding the teaching of intelligent design in public schools.
Judge John Jones ruled in favor of the plaintiffs. Scott said that "we won decisively" and "in triplicate," and "we had the better case." About the merits of the case, she said, "Within evolutionary biology, we argue about the details... and the mechanisms," but "we don't argue about whether living things descended with modification from common ancestors, what biological evolution is all about.... The Dover School Board wanted students to doubt whether evolution had taken place." 2009 The Stephen J Gould Prize awarded by the Society for the Study of Evolution "to recognize individuals whose sustained and exemplary efforts have advanced public understanding of evolutionary science and its importance in biology and everyday life in the spirit of Stephen Jay Gould." 2009 The Fellows Medal awarded by the California Academy of Sciences. The award is the Academy's highest honor, awarded in recognition of a recipient's notable contributions to one or more of the natural sciences. 2010 The Public Welfare Medal awarded by the U.
S. National Academy of Sciences "in recognition of distinguished contributions in the application of science to the public welfare." It is the most prestigious honor. 2012 The Richard Dawkins Award presented by the Atheist Alliance of America "to individuals it judges to have raised the
The Big Bang theory is the prevailing cosmological model for the observable universe from the earliest known periods through its subsequent large-scale evolution. The model describes how the universe expanded from a high-density and high-temperature state, offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background, large scale structure and Hubble's law. If the observed conditions are extrapolated backwards in time using the known laws of physics, the prediction is that just before a period of high density there was a singularity, associated with the Big Bang. Physicists are undecided whether this means the universe began from a singularity, or that current knowledge is insufficient to describe the universe at that time. Detailed measurements of the expansion rate of the universe place the Big Bang at around 13.8 billion years ago, thus considered the age of the universe. After its initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, simple atoms.
Giant clouds of these primordial elements coalesced through gravity forming early stars and galaxies, the descendants of which are visible today. Astronomers observe the gravitational effects of dark matter surrounding galaxies. Though most of the mass in the universe seems to be in the form of dark matter, Big Bang theory and various observations seem to indicate that it is not made out of conventional baryonic matter but it is unclear what it is made out of. Since Georges Lemaître first noted in 1927 that an expanding universe could be traced back in time to an originating single point, scientists have built on his idea of cosmic expansion; the scientific community was once divided between supporters of two different theories, the Big Bang and the Steady State theory, but a wide range of empirical evidence has favored the Big Bang, now universally accepted. In 1929, from analysis of galactic redshifts, Edwin Hubble concluded that galaxies are drifting apart. In 1964, the cosmic microwave background radiation was discovered, crucial evidence in favor of the Big Bang model, since that theory predicted the existence of background radiation throughout the universe before it was discovered.
More measurements of the redshifts of supernovae indicate that the expansion of the universe is accelerating, an observation attributed to dark energy's existence. The known physical laws of nature can be used to calculate the characteristics of the universe in detail back in time to an initial state of extreme density and temperature. In 1922, Russian mathematician Alexander Friedmann proposed on theoretical grounds that the universe is expanding, rederived independently and observationally confirmed soon afterwards by Belgian astronomer and Catholic priest Georges Lemaître in 1927 Lemaître proposed what became known as the "Big Bang theory" of the creation of the universe calling it the "hypothesis of the primeval atom".: in his paper Annales de la Société Scientifique de Bruxelles under the title "Un Univers homogène de masse constante et de rayon croissant rendant compte de la vitesse radiale des nébuleuses extragalactiques", he presented his new idea that the universe is expanding and provided the first observational estimation of what is known as the Hubble constant.
What will be known as the "Big Bang theory" of the origin of the universe, he called his "hypothesis of the primeval atom" or the "Cosmic Egg". American astronomer Edwin Hubble observed that the distances to faraway galaxies were correlated with their redshifts; this was interpreted to mean that all distant galaxies and clusters are receding away from our vantage point with an apparent velocity proportional to their distance: that is, the farther they are, the faster they move away from us, regardless of direction. Assuming the Copernican principle, the only remaining interpretation is that all observable regions of the universe are receding from all others. Since we know that the distance between galaxies increases today, it must mean that in the past galaxies were closer together; the continuous expansion of the universe implies that the universe was denser and hotter in the past. Large particle accelerators can replicate the conditions that prevailed after the early moments of the universe, resulting in confirmation and refinement of the details of the Big Bang model.
However, these accelerators can only probe so far into high energy regimes. The state of the universe in the earliest instants of the Big Bang expansion is still poorly understood and an area of open investigation and speculation; the first subatomic particles to be formed included protons and electrons. Though simple atomic nuclei formed within the first three minutes after the Big Bang, thousands of years passed before the first electrically neutral atoms formed; the majority of atoms produced by the Big Bang were hydrogen, along with helium and traces of lithium. Giant clouds of these primordial elements coalesced through gravity to form stars and galaxies, the heavier elements were synthesized either within stars or during supernovae; the Big Bang theory offers a comprehensive explanation for a broad range of observed phenomena
Pseudoscience consists of statements, beliefs, or practices that are claimed to be both scientific and factual, but are incompatible with the scientific method. Pseudoscience is characterized by contradictory, exaggerated or unfalsifiable claims; the term pseudoscience is considered pejorative because it suggests something is being presented as science inaccurately or deceptively. Those described as practicing or advocating pseudoscience dispute the characterization; the demarcation between science and pseudoscience has scientific implications. Differentiating science from pseudoscience has practical implications in the case of health care, expert testimony, environmental policies, science education. Distinguishing scientific facts and theories from pseudoscientific beliefs, such as those found in astrology, alternative medicine, occult beliefs, religious beliefs, creation science, is part of science education and scientific literacy. Pseudoscience can cause negative consequences in the real world.
Antivaccine activists present pseudoscientific studies that falsely call into question the safety of vaccines. Homeopathic remedies with no active ingredients have been promoted as treatment for deadly diseases; the word pseudoscience is derived from the Greek root pseudo meaning false and the English word science, from the Latin word scientia, meaning "knowledge". Although the term has been in use since at least the late 18th century the concept of pseudoscience as distinct from real or proper science seems to have become more widespread during the mid-19th century. Among the earliest uses of "pseudo-science" was in an 1844 article in the Northern Journal of Medicine, issue 387: That opposite kind of innovation which pronounces what has been recognized as a branch of science, to have been a pseudo-science, composed of so-called facts, connected together by misapprehensions under the disguise of principles. An earlier use of the term was in 1843 by the French physiologist François Magendie.
During the 20th century, the word was used pejoratively to describe explanations of phenomena which were claimed to be scientific, but which were not in fact supported by reliable experimental evidence. From time-to-time, the usage of the word occurred in a more formal, technical manner in response to a perceived threat to individual and institutional security in a social and cultural setting. Philosophers classify types of knowledge. In English, the word science is used to indicate the natural sciences and related fields, which are called the social sciences. Different philosophers of science may disagree on the exact limits – for example, is mathematics a formal science, closer to the empirical ones, or is pure mathematics closer to the philosophical study of logic and therefore not a science? – but all agree that all of the ideas that are not scientific are non-scientific. The large category of non-science includes all matters outside the natural and social sciences, such as the study of history, religion and the humanities.
Dividing the category again, unscientific claims are a subset of the large category of non-scientific claims. This category includes all matters that are directly opposed to good science. Un-science includes pseudoscience, thus pseudoscience is a subset of un-science, un-science, in turn, is subset of non-science. Pseudoscience is differentiated from science because – although it claims to be science – pseudoscience does not adhere to accepted scientific standards, such as the scientific method, falsifiability of claims, Mertonian norms. A number of basic principles are accepted by scientists as standards for determining whether a body of knowledge, method, or practice is scientific. Experimental results should be verified by other researchers; these principles are intended to ensure experiments can be reproduced measurably given the same conditions, allowing further investigation to determine whether a hypothesis or theory related to given phenomena is valid and reliable. Standards require the scientific method to be applied throughout, bias to be controlled for or eliminated through randomization, fair sampling procedures, blinding of studies, other methods.
All gathered data, including the experimental or environmental conditions, are expected to be documented for scrutiny and made available for peer review, allowing further experiments or studies to be conducted to confirm or falsify results. Statistical quantification of significance and error are important tools for the scientific method. During the mid-20th century, the philosopher Karl Popper emphasized the criterion of falsifiability to distinguish science from nonscience. Statements, hypotheses, or theories have falsifiability or refutability if there is the inherent possibility that they can be proven false; that is, if it is possible to conceive of an argument which negates them. Popper used astrology and psychoanalysis as examples of pseudoscience and Einstein's theory of relativity as an example of science, he subdivided nonscience into philosophical, mythological and metaphysical formulations on one hand, pseudoscientific formulations on the other, though he did not provide clear criteria for the differences.
Another example which shows the distinct need for a claim to be f
The Creation of Adam
The Creation of Adam is a fresco painting by Italian artist Michelangelo, which forms part of the Sistine Chapel's ceiling, painted c. 1508–1552. It illustrates the Biblical creation narrative from the Book of Genesis in which God gives life to Adam, the first man; the fresco is part of a complex iconographic scheme and is chronologically the fourth in the series of panels depicting episodes from Genesis. The image of the near-touching hands of God and Adam has become iconic of humanity; the painting has been reproduced in countless parodies. Michelangelo's Creation of Adam is one of the most replicated religious paintings of all time. In 1505 Michelangelo was invited back to Rome by the newly elected Pope Julius II, he was commissioned to build the Pope's tomb, to include forty statues and be finished in five years. Under the patronage of the Pope, Michelangelo experienced constant interruptions to his work on the tomb in order to accomplish numerous other tasks. Although Michelangelo worked on the tomb for 40 years, it was never finished to his satisfaction.
It is located in the Church of S. Pietro in Vincoli in Rome and is most famous for his central figure of Moses, completed in 1516. Of the other statues intended for the tomb, two known as the Rebellious Slave and the Dying Slave, are now in the Louvre. During the same period, Michelangelo painted the ceiling of the Sistine Chapel, which took four years to complete. According to Condivi's account, working on the building of St Peter's Basilica, resented Michelangelo's commission for the Pope's tomb and convinced the Pope to commission him in a medium with which he was unfamiliar, in order that he might fail at the task. Michelangelo was commissioned to paint the Twelve Apostles on the triangular pendentives that supported the ceiling, cover the central part of the ceiling with ornament. Michelangelo persuaded Pope Julius to give him a free hand and proposed a different and more complex scheme, representing the Creation, the Fall of Man, the Promise of Salvation through the prophets, the genealogy of Christ.
The work is part of a larger scheme of decoration within the chapel which represents much of the doctrine of the Catholic Church. The composition stretches over 500 square metres of ceiling, contains over 300 figures. At its centre are nine episodes from the Book of Genesis, divided into three groups: God's Creation of the Earth. On the pendentives supporting the ceiling are painted twelve men and women who prophesied the coming of Jesus. Among the most famous paintings on the ceiling are The Creation of Adam and Eve in the Garden of Eden, the Deluge, the Prophet Jeremiah and the Cumaean Sibyl. God is depicted as an elderly white-bearded man wrapped in a swirling cloak while Adam, on the lower left, is nude. God's right arm is outstretched to impart the spark of life from his own finger into that of Adam, whose left arm is extended in a pose mirroring God's, a reminder that man is created in the image and likeness of God. Another point is that God's finger are not touching, it gives the impression that God, the giver of life, is reaching out to Adam who has yet to receive it.
Many hypotheses have been formulated regarding the identity and meaning of the twelve figures around God. According to an interpretation, first proposed by the English art critic Walter Pater and is now accepted, the person protected by God's left arm represents Eve, due to the figure's feminine appearance and gaze towards Adam, the eleven other figures symbolically represent the souls of Adam and Eve's unborn progeny, the entire human race; this interpretation has been challenged on the grounds that the Catholic Church regards the teaching of the pre-existence of souls as heretical. The figure behind God has been suggested to be the Virgin Mary, the personified human soul, or "an angel of masculine build"; the Creation of Adam is thought to depict the excerpt "God created man in His own image, in the image of God He created him". The inspiration for Michelangelo's treatment of the subject may come from a medieval hymn, "Veni Creator Spiritus", which asks the'finger of the paternal right hand' to give the faithful speech.
Michelangelo's main source of inspiration for his Adam in his Creation of Adam may have been a cameo showing a nude Augustus Caesar riding sidesaddle on a Capricorn. This cameo is now at Northumberland; the cameo used to belong to cardinal Domenico Grimani who lived in Rome while Michelangelo painted the ceiling. Evidence suggests that Grimani were friends; this cameo offers an alternative theory for those scholars who have been dissatisfied with the theory that Michelangelo was inspired by Lorenzo Ghiberti's Adam in his Creation of Adam. Several hypotheses have been put forward about the meaning of The Creation of Adam's original composition, many of them taking Michelangelo's well-documented expertise in human anatomy as their starting point. In 1990 in Anderson, Indiana physician Frank Meshberger noted in the Journal of the American Medical Association that the background figures and shapes portrayed behind the figure of God appeared to be an anatomically accurate picture of the human brain.
On close examination, borders in the painting correlate with m
The Universe is all of space and time and their contents, including planets, stars and all other forms of matter and energy. While the spatial size of the entire Universe is unknown, it is possible to measure the size of the observable universe, estimated to be 93 billion light years in diameter. In various multiverse hypotheses, a universe is one of many causally disconnected constituent parts of a larger multiverse, which itself comprises all of space and time and its contents; the earliest scientific models of the Universe were developed by ancient Greek and Indian philosophers and were geocentric, placing Earth at the center of the Universe. Over the centuries, more precise astronomical observations led Nicolaus Copernicus to develop the heliocentric model with the Sun at the center of the Solar System. In developing the law of universal gravitation, Isaac Newton built upon Copernicus' work as well as observations by Tycho Brahe and Johannes Kepler's laws of planetary motion. Further observational improvements led to the realization that the Sun is one of hundreds of billions of stars in the Milky Way, one of at least hundreds of billions of galaxies in the Universe.
Many of the stars in our galaxy have planets. At the largest scale galaxies are distributed uniformly and the same in all directions, meaning that the Universe has neither an edge nor a center. At smaller scales, galaxies are distributed in clusters and superclusters which form immense filaments and voids in space, creating a vast foam-like structure. Discoveries in the early 20th century have suggested that the Universe had a beginning and that space has been expanding since and is still expanding at an increasing rate; the Big Bang theory is the prevailing cosmological description of the development of the Universe. Under this theory and time emerged together 13.799±0.021 billion years ago and the energy and matter present have become less dense as the Universe expanded. After an initial accelerated expansion called the inflationary epoch at around 10−32 seconds, the separation of the four known fundamental forces, the Universe cooled and continued to expand, allowing the first subatomic particles and simple atoms to form.
Dark matter gathered forming a foam-like structure of filaments and voids under the influence of gravity. Giant clouds of hydrogen and helium were drawn to the places where dark matter was most dense, forming the first galaxies and everything else seen today, it is possible to see objects that are now further away than 13.799 billion light-years because space itself has expanded, it is still expanding today. This means that objects which are now up to 46.5 billion light-years away can still be seen in their distant past, because in the past when their light was emitted, they were much closer to the Earth. From studying the movement of galaxies, it has been discovered that the universe contains much more matter than is accounted for by visible objects; this unseen matter is known as dark matter. The ΛCDM model is the most accepted model of our universe, it suggests that about 69.2%±1.2% of the mass and energy in the universe is a cosmological constant, responsible for the current expansion of space, about 25.8%±1.1% is dark matter.
Ordinary matter is therefore only 4.9% of the physical universe. Stars and visible gas clouds only form about 6% of ordinary matter, or about 0.3% of the entire universe. There are many competing hypotheses about the ultimate fate of the universe and about what, if anything, preceded the Big Bang, while other physicists and philosophers refuse to speculate, doubting that information about prior states will be accessible; some physicists have suggested various multiverse hypotheses, in which our universe might be one among many universes that exist. The physical Universe is defined as all of their contents; such contents comprise all of energy in its various forms, including electromagnetic radiation and matter, therefore planets, stars and the contents of intergalactic space. The Universe includes the physical laws that influence energy and matter, such as conservation laws, classical mechanics, relativity; the Universe is defined as "the totality of existence", or everything that exists, everything that has existed, everything that will exist.
In fact, some philosophers and scientists support the inclusion of ideas and abstract concepts – such as mathematics and logic – in the definition of the Universe. The word universe may refer to concepts such as the cosmos, the world, nature; the word universe derives from the Old French word univers, which in turn derives from the Latin word universum. The Latin word was used by Cicero and Latin authors in many of the same senses as the modern English word is used. A term for "universe" among the ancient Greek philosophers from Pythagoras onwards was τὸ πᾶν, tò pân, defined as all matter and all space, τὸ ὅλον, tò hólon, which did not include the void. Another synonym was ho kósmos. Synonyms are found in Latin authors and survive in modern languages, e.g. the German words Das All and Natur for Universe. The same synonyms are found in English, such as everything, the cosmos, the world (as in the many-worlds interpr