Astronomy

Astronomy is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation). It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe.

Astronomy is one of the oldest sciences. Astronomers of early civilizations performed methodical observations of the night sky, and astronomical artifacts have been found from much earlier periods. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and even astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics. Since the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring and analyzing data, mainly using basic principles of physics. Theoretical astronomy is oriented towards the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the observational results, and observations being used to confirm theoretical results.

Amateur astronomers have contributed to many important astronomical discoveries, and astronomy is one of the few sciences where amateurs can still play an active role, especially in the discovery and observation of transient phenomena.

Old or even ancient astronomy is not to be confused with astrology, the belief system that claims that human affairs are correlated with the positions of celestial objects. Although the two fields share a common origin and a part of their methods (namely, the use of ephemerides), they are distinct.

Lexicology

The word astronomy literally means "law of the stars" (or "culture of the stars" depending on the translation) and is derived from the Greek αστρονομία, astronomia, from the words άστρον (astron, "star") and νόμος (nomos, "laws or cultures").

Use of terms "astronomy" and "astrophysics"

Generally, either the term "astronomy" or "astrophysics" may be used to refer to this subject. Based on strict dictionary definitions, "astronomy" refers to "the study of objects and matter outside the earth's atmosphere and of their physical and chemical properties" and "astrophysics" refers to the branch of astronomy dealing with "the behavior, physical properties, and dynamic processes of celestial objects and phenomena". In some cases, as in the introduction of the introductory textbook The Physical Universe by Frank Shu, "astronomy" may be used to describe the qualitative study of the subject, whereas "astrophysics" is used to describe the physics-oriented version of the subject. However, since most modern astronomical research deals with subjects related to physics, modern astronomy could actually be called astrophysics. Various departments that research this subject may use "astronomy" and "astrophysics", partly depending on whether the department is historically affiliated with a physics department, and many professional astronomers actually have physics degrees. Even the name of the scientific journal Astronomy & Astrophysics reveals the ambiguity of the use of the term.

History

Astronomy is the oldest of the natural sciences, dating back to antiquity, with its origins in the religious, mythological, and astrological practices of pre-history: vestiges of these are still found in astrology, a discipline long interwoven with public and governmental astronomy, and not completely disentangled from it until a few centuries ago in the Western World (see astrology and astronomy). Early astronomy involved observing the regular patterns of the motions of visible celestial objects, especially the Sun, Moon, stars and naked eye planets. An example of this early astronomy might involve a study of the changing position of the Sun along the horizon or the changing appearances of stars in the course of the year, which could be used to establish an agricultural or ritual calendar. In some cultures astronomical data was used for astrological prognostication.

Ancient astronomers were able to differentiate between stars and planets, as stars remain relatively fixed over the centuries while planets will move an appreciable amount during a comparatively short time.

In early times, astronomy only comprised the observation and predictions of the motions of objects visible to the naked eye. In some locations, such as Stonehenge, early cultures assembled massive artifacts that likely had some astronomical purpose. In addition to their ceremonial uses, these observatories could be employed to determine the seasons, an important factor in knowing when to plant crops, as well as in understanding the length of the year.

Before tools such as the telescope were invented early study of the stars had to be conducted from the only vantage points available, namely tall buildings, trees and high ground using the bare eye.

As civilizations developed, most notably in Mesopotamia, Greece, Egypt, Persia, Maya, India, China, and the Islamic world, astronomical observatories were assembled, and ideas on the nature of the universe began to be explored. Most of early astronomy actually consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, and the nature of the Sun, Moon and the Earth in the universe were explored philosophically. The Earth was believed to be the center of the universe with the Sun, the Moon and the stars rotating around it. This is known as the geocentric model of the universe.

A few notable astronomical discoveries were made prior to the application of the telescope. For example, the obliquity of the ecliptic was estimated as early as 1000 BC by the Chinese. The Chaldeans discovered that lunar eclipses recurred in a repeating cycle known as a saros. In the 2nd century BC, the size and distance of the Moon were estimated by Hipparchus.

During the Middle Ages, observational astronomy was mostly stagnant in medieval Europe, at least until the 13th century. However, observational astronomy flourished in the Islamic world and other parts of the world. Some of the prominent Arab astronomers, who made significant contributions to the science were Al-Battani and Thebit. Astronomers during that time introduced many Arabic names that are now used for individual stars.

Natural Science

In science, the term natural science refers to a rational approach to the study of the universe, which is understood as obeying rules or law of natural origin. The term natural science is also used to distinguish those fields that use the scientific method to study nature from the social sciences, which use the scientific method to study human behavior and society; and from the formal sciences, such as mathematics and logic, which use a different methodology.

History

Prior to the 17th century, the objective study of nature was known as natural philosophy. Over the next two centuries, however, a philosophical interpretation of nature was gradually replaced by a scientific approach using inductive methodology. The works of Sir Francis Bacon popularized this approach, thereby helping to forge the scientific revolution.

By the 19th century the study of science had come into the purview of professionals and institutions, and in so doing it gradually acquired the more modern name of natural science. The term scientist was coined by William Whewell in an 1834 review of Mary Somerville's On the Connexion of the Sciences. However the word did not enter general use until nearly the end of the same century.

According to a famous 1923 textbook Thermodynamics – and the Free Energy of Chemical Substances by the American chemist Gilbert N. Lewis and the American physical chemist Merle Randall, the natural sciences contain three great branches:

Aside from the logical and mathematical sciences, there are three great branches of natural science which stand apart by reason of the variety of far reaching deductions drawn from a small number of primary postulates – they are the mechanics, electrodynamics, and thermodynamics.

Disciplines of natural sciences

Astronomy

This discipline is the science of celestial objects and phenomena that originate outside the Earth's atmosphere. It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe. Astronomy includes the examination, study and modeling of stars, planets, comets, galaxies and the cosmos. Most of the information used by astronomers is gathered by remote observation, although some laboratory reproduction of celestial phenomenon has been performed (such as the molecular chemistry of the interstellar medium.)

While the origins of the study of celestial features and phenomenon can be traced back to antiquity, the scientific methodology of this field began to develop in the middle of the seventeenth century. A key factor was Galileo's introduction of the telescope to examine the night sky in more detail. The mathematical treatment of astronomy began with Newton's development of celestial mechanics and the laws of gravitation, although it was triggered by earlier work of astronomers such as Kepler. By the nineteenth century, astronomy had developed into a formal science with the introduction of instruments such as the spectroscope and photography, along with much improved telescopes and the creation of professional observatories.

Biology

This field encompasses a set of disciplines that examines phenomena related to living organisms. The scale of study can range from sub-component biophysics up to complex ecologies. Biology is concerned with the characteristics, classification and behaviors of organisms, as well as how species were formed and their interactions with each other and the natural environment.

The biological fiel ds of botany, zoology, and medicine date back to early periods of civilization, while microbiology was introduced in the 17th century with the invention of the microscope. However it was not until the 19th century that biology became a unified science; once scientists discovered commonalities between all living things it was decided they were best studied as a whole. Some key developments in the science of biology were the discovery of genetics; Darwin's theory of evolution through natural selection; the germ theory of disease and the application of the techniques of chemistry and physics at the level of the cell or organic molecule.

Modern Biology is divided into sub-disciplines by the type of organism and by the scale being studied. Molecular biology is the study of the fundamental chemistry of life, while cellular biology is the examination of the cell; the basic building block of all life. At a higher level, Physiology looks at the internal structure of organism, while ecology looks at how various organisms interrelate.

Chemistry

Constituting the scientific study of matter at the atomic and molecular scale, chemistry deals primarily with collections of atoms, such as gases, molecules, crystals, and metals. The composition, statistical properties, transformations and reactions of these materials are studied. Chemistry also involves understanding the properties and interactions of individual atoms for use in larger-scale applications. Most chemical processes can be studied directly in a laboratory, using a series of (often well-tested) techniques for manipulating materials, as well as an understanding of t he underlying processes. Chemistry is often called "the central science" because of its role in connecting the other natural sciences.

Early experiments in chemistry had their roots in the system of Alchemy, a set of beliefs combining mystic ism with physical experiments. The science of chemistry began to develop with the work of Robert Boyle, the discoverer of gas, and Antoine Lavoisier, who developed the theory of the Conservation of mass. The discovery of the chemical elements and the concept of Atomic Theory began to systematize this science, and researchers developed a fundamental understanding of states of matter, ions, chemical bonds and chemical reactions. The success of this science led to a complementary chemical industry that now plays a significant role in the world economy.

Earth science

Earth science (also known as geoscience, the geosciences or the Earth Sciences), is an all-embracing term for the sciences related to the planet Earth, including geology, geophysics, hydrology, meteorology, physical geography, oceanography, and soil science.

Although mining and precious stones have been human interests throughout the history of civilisation, their development into the sciences of economic geology and mineralogy did not occur until the 18th century. The study of the earth, particularly palaeontology, blossomed in the 19th century and the growth of other disciplines like geophysics in the 20th century led to the development of the theory of plate tectonics in the 1960s, which has had a similar impact on the Earth sciences as the theory of evolution had on biology. Earth sciences today are closely linked to climate research and the petroleum and mineral exploration industries.

Physics

Physics embodies the study of the fundamental constituents of the universe, the forces and interactions they exert on one another, and the results produced by these interactions. In general, the physics is regarded as the fundamental science as all other natural sciences utilize and obey the principles and laws set down by the field. Physics relies heavily on mathematics as the logical framework for formulation and quantification of principles.

The study of the principles of the universe has a long history and largely derives from direct observation and experimentation. The formulation of theories about the governing laws of the universe has been central to the study of physics from very early on, with philosophy gradually yielding to systematic, quantitative experimental testing and observation as the source of verification. Key historical developments in physics include Isaac Newton's theory of universal gravitation and classical mechanics, an understanding of electricity and it's relation to magnetism, Einstein's theories of special and general relativity, the development of thermodynamics, and the quantum mechanical model of atomic and subatomic physics.

The field of physics is extremely broad, and can include such diverse studies as quantum mechanics and theoretical physics to applied physics and optics. Modern physics is becoming increasingly specialized, where researchers tend to focus on a particular area rather than being "universalists" like Albert Einstein and Lev Landau, who worked in multiple areas.

Cross-disciplines

The distinctions between the natural science disciplines is not always sharp, and they share a number of cross-discipline fields. Physics plays a significant role in the other natural sciences, as represented by astrophysics, geophysics, physical chemistry and biophysics. Likewise chemistry is represented by such fields as biochemistry, geochemistry and astrochemistry.

A particular example of a scientific discipline that draws upon multiple natural sciences is environmental science. This field studies the interactions of physical, chemical and biological components of the environment, with a particular regard to the effect of human activities and the impact on biodiversity and sustainability. This science also draws upon expertise from other fields such as economics, law and social sciences.

A comparable discipline is oceanography, as it draws upon a similar breadth of scientific disciplines. Oceanography is sub-categorized into more specialized cross-displines, such as physical oceanography and marine biology. As the marine ecosystem is very large and diverse, marine biology is further divided into many subfields, including specializations in particular species.

There are also a subset of cross-disciplinary fields which, by the nature of the problems that they address, have strong currents that run counter to specialization. Put another way: In some fields of integrative application, specialists in more than one field are a key part of most dialog. Such integrative fields, for example, include nanoscience, astrobiology, and complex system informatics.

Mystery Creatures

Mysterious Sea Creatures Found
In Antarctic Waters

The return of the last of three Antarctic marine science research vessels marks the culmination of one of Australia's most ambitious International Polar Year projects, a census of life in the icy Southern Ocean known as the Collaborative East Antarctic Marine Census (CEAMARC).

Australia's Aurora Australis and collaborating vessels L'Astrolabe (France) and Umitaka Maru (Japan) have returned from the Southern Ocean, their decks overflowing with a vast array of ocean life including a number of previously unknown species collected from the cold waters near the East Antarctic land mass.

While the French and Japanese ships have been examining the mid and upper ocean environment over the past two months, Aurora Australis had her eyes fixed on the ocean floor, using both traditional and innovative sampling equipment to capture the diversity of life.

Aurora Australis voyage leader Dr Martin Riddle says that their expedition uncovered a remarkably rich, colourful and complex range of marine life in this previously unknown environment.

"Some of the video footage we have collected is really stunning – it's amazing to be able to navigate undersea mountains and valleys and actually see what the animals look like in their undisturbed state," he said.

"In some places every inch of the sea floor is covered in life. In other places we can see deep scars and gouges where icebergs scour the sea floor as they pass by. Gigantism is very common in Antarctic waters – we have collected huge worms, giant crustaceans and sea spiders the size of dinner plates.

"This survey establishes a point of reference to monitor the impact of environmental change in Antarctic waters. For example, ocean acidification, caused by rising atmospheric carbon dioxide levels, will make it harder for marine organisms to grow and sustain calcium carbonate skeletons.

"It is predicted that the first effects of this will be seen in the cold, deep waters of Antarctica. Our results provide a robust benchmark for testing these predictions."

CEAMARC Project Leader Dr Graham Hosie said that researchers are only beginning to understand the complex biodiversity that lies beneath the surface of the Southern Ocean and its importance in local, regional and global ecosystems.

"This research will help scientists understand how communities have adapted to the unique Antarctic environment. Our work also has wider applications, for example understanding fish community composition and structure is particularly important to explain the impacts of commercial trawling.

"Specimens collected will be sent to universities and museums around the world for identification, tissue sampling and bar-coding of their DNA. Not all of the creatures that we found could be identified and it is very likely that some new species will be recorded as a result of these voyages."

CEAMARC is part of the international Census of Antarctic Marine Life, coordinated by the Australian Antarctic Division, which will see some 16 voyages to Antarctic waters during this, the International Polar Year (2007-2009).

The Census of Antarctic Marine Life will survey the biodiversity of Antarctic slopes, abyssal plains, open water, and under disintegrating ice shelves. The census aims to determine species biodiversity, abundance and distribution and establish a baseline dataset from which future changes can be observed.

Adapted from materials provided by Australian Antarctic Division.
Glass-like animals known as tunicates are early colonisers of the sea floor.
(Credit: Antarctic Division)

Pseudoscience

Pseudoscience is defined as a body of knowledge, methodology, belief, or practice that is claimed to be scientific or made to appear scientific, but does not adhere to the scientific method, lacks supporting evidence or plausibility, or otherwise lacks scientific status. The term comes from the Greek root pseudo- (false or pretending) and "science" (from Latin scientia, meaning "knowledge"). An early recorded use was in 1843 by French physiologist François Magendie, who is considered a pioneer in experimental physiology.

As it is taught in certain introductory science classes, pseudoscience is any subject that appears superficially to be scientific or whose proponents state is scientific but nevertheless contravenes the testability requirement, or substantially deviates from other fundamental aspects of the scientific method. Professor Paul DeHart Hurd argued that a large part of gaining scientific literacy is "being able to distinguish science from pseudo-science such as astrology, quackery, the occult, and superstition". Certain introductory survey classes in science take careful pains to delineate the objections scientists and skeptics have to practices that make direct claims contradicted by the scientific discipline in question.

Beyond the initial introductory analyses offered in science classes, there is some epistemological disagreement about whether it is possible to distinguish "science" from "pseudoscience" in a reliable and objective way. The term itself has negative connotations, because it is used to indicate that subjects so labeled are inaccurately or deceptively portrayed as science. Accordingly, those labeled as practicing or advocating a "pseudoscience" normally reject this classification.

Pseudosciences have been characterised by the use of vague, exaggerated or untestable claims, over-reliance on confirmation rather than refutation, lack of openness to testing by other experts, and a lack of progress in theory development.

Background

The standards for determining whether a body of knowledge, methodology, or practice is scientific can vary from field to field. Within natural scientific method they involve agreed principles of reproducibility and intersubjective verifiability. Such principles aim to ensure that relevant evidence can be reproduced and/or measured given the same conditions, which allows further investigation to determine whether a hypothesis or theory related to given phenomena is both valid and reliable for use by others, including other scientists and researchers. It is expected that the scientific method will be applied throughout, and that bias will be controlled or eliminated, by double-blind studies, or statistically through fair sampling procedures. All gathered data, including experimental/environmental conditions, are expected to be documented for scrutiny and made available for peer review, thereby allowing further experiments or studies to be conducted to confirm or falsify results, as well as to determine other important factors such as statistical significance, confidence intervals, and margins of error.

In the mid-20th Century Karl Popper suggested the criterion of falsifiability to distinguish science from non-science. Statements such as "God created the universe" may be true or false, but no tests can be devised that could prove them false, so they are not scientific; they lie outside the scope of science. Popper subdivided non-science into philosophical, mathematical, mythological, religious and/or metaphysical formulations on the one hand, and pseudoscientific formulations on the other—though without providing clear criteria for the differences. He gave astrology and psychoanalysis as examples of pseudoscience, and Einstein's theory of relativity as an example of science. More recently, Paul Thagard (1978) proposed that pseudoscience is primarily distinguishable from science when it is less progressive than alternative theories over a long period of time, and the failure of proponents to acknowledge or address problems with the theory. Mario Bunge has suggested the categories of "belief fields" and "research fields" to help distinguish between science and pseudoscience.

Philosopher of science Paul Feyerabend has argued, from a sociology of knowledge perspective, that a distinction between science and non-science is neither possible nor desirable. Among the issues which can make the distinction difficult are that both the theories and methodologies of science evolve at differing rates in response to new data. In addition, the specific standards applicable to one field of science may not be those employed in other fields. Thagard also writes from a sociological perspective and states that "elucidation of how science differs from pseudoscience is the philosophical side of an attempt to overcome public neglect of genuine science."

Both the skeptics and the Brights movement, most prominently represented by Richard Dawkins, Mario Bunge, Carl Sagan and James Randi, consider all forms of pseudoscience to be harmful, whether or not they result in immediate harm to their adherents. These critics generally consider that the practice of pseudoscience may occur for a number of reasons, ranging from simple naïveté about the nature of science and the scientific method, to deliberate deception for financial or political gain. At the extreme, issues of personal health and safety may be very directly involved, for example in the case of physical or mental therapy or treatment, or in assessing safety risks. In such instances the potential for direct harm to patients, clients, the general public, or the environment may be an issue in assessing pseudoscience. (See also Junk science.)

The concept of pseudoscience as antagonistic to bona fide science appears to have emerged in the mid-19th century. Among the first recorded uses of the word "pseudo-science" was in 1844 in the Northern Journal of Medicine, I 387: "That opposite kind of innovation which pronounces what has been recognized as a branch of science, to have been a pseudo-science, composed merely of so-called facts, connected together by misapprehensions under the disguise of principles".

Identifying pseudoscience

A field, practice, or body of knowledge might reasonably be called pseudoscientific when it is presented as consistent with the accepted norms of scientific research; but it demonstrably fails to meet these norms, most importantly, in misuse of scientific method.

Subjects may be considered pseudoscientific for various reasons; Popper considered astrology to be pseudoscientific simply because astrologers keep their claims so vague that they could never be refuted, whereas Thagard considers astrology pseudoscientific because its practitioners make little effort to develop the theory, show no concern for attempts to critically evaluate the theory in relation to others, and are selective in considering evidence. More generally, Thagard stated that pseudoscience tends to focus on resemblances rather than cause-effect relations.

Science is also distinguishable from revelation, theology, or spirituality in that it claims to offer insight into the physical world obtained by "scientific" means. Systems of thought that derive from divine or inspired knowledge are not considered pseudoscience if they do not claim either to be scientific or to overturn well-established science.

Some statements and commonly held beliefs in popular science may not meet the criteria of science. "Pop" science may blur the divide between science and pseudoscience among the general public, and may also involve science fiction. Indeed, pop science is disseminated to, and can also easily emanate from, persons not accountable to scientific methodology and expert peer review.

If the claims of a given field can be experimentally tested and methodological standards are upheld, it is not "pseudoscience", however odd, astonishing, or counter-intuitive. If claims made are inconsistent with existing experimental results or established theory, but the methodology is sound, caution should be used; science consists of testing hypotheses which may turn out to be false. In such a case, the work may be better described as ideas that are not yet generally accepted.

The following have been proposed to be indicators of poor scientific reasoning.

Science Meaning

Science (from the Latin scientia, 'knowledge'), in the broadest sense, refers to any systematic knowledge or practice. In a more restricted sense, science refers to a system of acquiring knowledge based on the scientific method, as well as to the organized body of knowledge gained through such research.

Fields of science are commonly classified along two major lines:

* Natural sciences, which study natural phenomena (including biological life), and
* Social sciences, which study human behavior and societies.

These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being experimented for its validity by other researchers working under the same conditions.

Mathematics, which is sometimes classified within a third group of science called formal science, has both similarities and differences with the natural and social sciences. It is similar to empirical sciences in that it involves an objective, careful and systematic study of an area of knowledge; it is different because of its method of verifying its knowledge, using a priori rather than empirical methods. Formal science, which also includes statistics and logic, is vital to the empirical sciences. Major advances in formal science have often led to major advances in the physical and biological sciences. The formal sciences are essential in the formation of hypotheses, theories, and laws, both in discovering and describing how things work (natural sciences) and how people think and act (social sciences).

Science as discussed in this article is sometimes termed experimental science to differentiate it from applied science, which is the application of scientific research to specific human needs, though the two are often interconnected.

Philosophy of science

The philosophy of science seeks to understand the nature and justification of scientific knowledge. It has proven difficult to provide a definitive account of the scientific method that can decisively serve to distinguish science from non-science. Thus there are legitimate arguments about exactly where the borders are, leading to the problem of demarcation. There is nonetheless a set of core precepts that have broad consensus among published philosophers of science and within the scientific community at large.

Science is reasoned-based analysis of sensation upon our awareness. As such, the scientific method cannot deduce anything about the realm of reality that is beyond what is observable by existing or theoretical means. When a manifestation of our reality previously considered supernatural is understood in the terms of causes and consequences, it acquires a scientific explanation.

Resting on reason and logic, along with other guidelines such as parsimony (e.g., "Occam's Razor"), scientific theories are formulated and repeatedly tested by analyzing how the collected evidence (facts) compares to the theory. Some of the findings of science can be very counter-intuitive. Atomic theory, for example, implies that a granite boulder which appears a heavy, hard, solid, grey object is actually a combination of subatomic particles with none of these properties, moving very rapidly in space where the mass is concentrated in a very small fraction of the total volume. Many of humanity's preconceived notions about the workings of the universe have been challenged by new scientific discoveries. Quantum mechanics, particularly, examines phenomena that seem to defy our most basic postulates about causality and fundamental understanding of the world around us. Science is the branch of knowledge dealing with people and the understanding we have of our environment and how it works.

There are different schools of thought in the philosophy of scientific method. Methodological naturalism maintains that scientific investigation must adhere to empirical study and independent verification as a process for properly developing and evaluating natural explanations for observable phenomena. Methodological naturalism, therefore, rejects supernatural explanations, arguments from authority and biased observational studies. Critical rationalism instead holds that unbiased observation is not possible and a demarcation between natural and supernatural explanations is arbitrary; it instead proposes falsifiability as the landmark of empirical theories and falsification as the universal empirical method. Critical rationalism argues for the ability of science to increase the scope of testable knowledge, but at the same time against its authority, by emphasizing its inherent fallibility. It proposes that science should be content with the rational elimination of errors in its theories, not in seeking for their verification (such as claiming certain or probable proof or disproof; both the proposal and falsification of a theory are only of methodological, conjectural, and tentative character in critical rationalism). Instrumentalism rejects the concept of truth and emphasizes merely the utility of theories as instruments for explaining and predicting phenomena.

Scientific method

The scientific method seeks to explain the events of nature in a reproducible way, and to use these reproductions to make useful predictions. It is done through observation of natural phenomena, and/or through experimentation that tries to simulate natural events under controlled conditions. It provides an objective process to find solutions to problems in a number of scientific and technological fields. Often scientists have a preference for one outcome over another, and scientists are conscientious that it is important that this preference does not bias their interpretation. A strict following of the scientific method attempts to minimize the influence of a scientist's bias on the outcome of an experiment. This can be achieved by correct experimental design, and a thorough peer review of the experimental results as well as conclusions of a study.

Scientists use models to refer to a description or depiction of something, specifically one which can be used to make predictions that can be tested by experiment or observation. A hypothesis is a contention that has been neither well supported nor yet ruled out by experiment. A theory, in the context of science, is a logically self-consistent model or framework for describing the behavior of certain natural phenomena. A theory typically describes the behavior of much broader sets of phenomena than a hypothesis—commonly, a large number of hypotheses may be logically bound together by a single theory. A physical law or law of nature is a scientific generalization based on a sufficiently large number of empirical observations that it is taken as fully verified.

Science cannot claim absolute knowledge of nature or the behavior of the subject or of the field of study due to epistemological problems that are unavoidable and preclude the discovery or establishment of absolute truth. Unlike a mathematical proof, a scientific theory is empirical, and is always open to falsification, if new evidence is presented. Even the most basic and fundamental theories may turn out to be imperfect if new observations are inconsistent with them. Critical to this process is making every relevant aspect of research publicly available, which permits peer review of published results, and also allows ongoing review and repeating of experiments and observations by multiple researchers operating independently of one another. Only by fulfilling these expectations can it be determined how reliable the experimental results are for potential use by others.

Isaac Newton's Newtonian law of gravitation is a famous example of an established law that was later found not to be universal—it does not hold in experiments involving motion at speeds close to the speed of light or in close proximity of strong gravitational fields. Outside these conditions, Newton's Laws remain an excellent model of motion and gravity. Since general relativity accounts for all the same phenomena that Newton's Laws do and more, general relativity is now regarded as a more comprehensive theory.

Karl Popper denied the existence of evidence and of scientific method. Popper holds that there is only one universal method, the negative method of trial and error. It covers not only all products of the human mind, including science, mathematics, philosophy, art and so on, but also the evolution of life.

History of science

Well into the eighteenth century, science and natural philosophy were not quite synonymous, but only became so later with the direct use of what would become known formally as the scientific method. Prior to this time, the preferred term for the study of nature was natural philosophy, while English speakers most typically referred to the study of the human mind as moral philosophy. By contrast, the word "science" in English was still used in the 17th century to refer to the Aristotelian concept of knowledge which was secure enough to be used as a sure prescription for exactly how to do something. In this differing sense of the two words, the philosopher John Locke in An Essay Concerning Human Understanding wrote that "natural philosophy [the study of nature] is not capable of being made a science".

By the early 1800s, natural philosophy had begun to separate from philosophy, though it often retained a very broad meaning. In many cases, science continued to stand for reliable knowledge about any topic, in the same way it is still used in the broad sense (see the introduction to this article) in modern terms such as library science, political science, and computer science. In the more narrow sense of science, as natural philosophy became linked to an expanding set of well-defined laws (beginning with Galileo's laws, Kepler's laws, and Newton's laws for motion), it became more popular to refer to natural philosophy as natural science. Over the course of the nineteenth century, moreover, there was an increased tendency to associate science with study of the natural world (that is, the non-human world). This move sometimes left the study of human thought and society (what would come to be called social science) in a linguistic limbo by the end of the century and into the next.

Though the 19th century, many English speakers were increasingly differentiating science (meaning a combination of what we now term natural and biological sciences) from all other forms of knowledge in a variety of ways. The now-familiar expression “scientific method,” which refers to the prescriptive part of how to make discoveries in natural philosophy, was almost unused during the early part of the 19th century, but became widespread after the 1870s, though there was rarely totally agreement about just what it entailed. The word "scientist," meant to refer to a systematically-working natural philosopher, (as opposed to an intuitive or empirically-minded one) was coined in 1833 by William Whewell.Discussion of scientists as a special group of people who did science, even if their attributes were up for debate, grew in the last half of the 19th century. Whatever people actually meant by these terms at first, they ultimately depicted science, in the narrow sense of the habitual use of the scientific method and the knowledge derived from it, as something deeply distinguished from all other realms of human endeavor.

By the twentieth century, the modern notion of science as a special brand of information about the world, practiced by a distinct group and pursued through a unique method, was essentially in place. It was used to give legitimacy to a variety of fields through such titles as "scientific" medicine, engineering, advertising, or motherhood. Over the 1900s, links between science and technology also grew increasingly strong. By the end of the century, it is arguable that technology had even begun to eclipse science as a term of public attention and praise. Scholarly studies of science have begun to refer to "technoscience" rather than science of technology separately. Meanwhile, such fields as biotechnology and nanotechnology are capturing the headlines. One author has suggested that, in the coming century, "science" may fall out of use, to be replaced by technoscience or even by some more exotic label such as "techknowledgy."

Science All About

What is science?

Science is the concerted human effort to understand, or to understand better, the history of the natural world and how the natural world works, with observable physical evidence as the basis of that understanding¹. It is done through observation of natural phenomena, and/or through experimentation that tries to simulate natural processes under controlled conditions. (There are, of course, more definitions of science.)

Consider some examples. An ecologist observing the territorial behaviors of bluebirds and a geologist examining the distribution of fossils in an outcrop are both scientists making observations in order to find patterns in natural phenomena. They just do it outdoors and thus entertain the general public with their behavior. An astrophysicist photographing distant galaxies and a climatologist sifting data from weather balloons similarly are also scientists making observations, but in more discrete settings.

The examples above are observational science, but there is also experimental science. A chemist observing the rates of one chemical reaction at a variety of temperatures and a nuclear physicist recording the results of bombardment of a particular kind of matter with neutrons are both scientists performing experiments to see what consistent patterns emerge. A biologist observing the reaction of a particular tissue to various stimulants is likewise experimenting to find patterns of behavior. These folks usually do their work in labs and wear impressive white lab coats, which seems to mean they make more money too.

The critical commonality is that all these people are making and recording observations of nature, or of simulations of nature, in order to learn more about how nature, in the broadest sense, works. We'll see below that one of their main goals is to show that old ideas (the ideas of scientists a century ago or perhaps just a year ago) are wrong and that, instead, new ideas may better explain nature.

So why do science? I - the individual perspective

So why are all these people described above doing what they're doing? In most cases, they're collecting information to test new ideas or to disprove old ones. Scientists become famous for discovering new things that change how we think about nature, whether the discovery is a new species of dinosaur or a new way in which atoms bond. Many scientists find their greatest joy in a previously unknown fact (a discovery) that explains something problem previously not explained, or that overturns some previously accepted idea.

That's the answer based on noble principles, and it probably explains why many people go into science as a career. On a pragmatic level, people also do science to earn their paychecks. Professors at most universities and many colleges are expected as part of their contractual obligations of employment to do research that makes new contributions to knowledge. If they don't, they lose their jobs, or at least they get lousy raises.

Scientists also work for corporations and are paid to generate new knowledge about how a particular chemical affects the growth of soybeans or how petroleum forms deep in the earth. These scientists get paid better, but they may work in obscurity because the knowledge they generate is kept secret by their employers for the development of new products or technologies. In fact, these folks at Megacorp do science, in that they and people within their company learn new things, but it may be years before their work becomes science in the sense of a contribution to humanity's body of knowledge beyond Megacorp's walls.

Why do Science? II - The Societal Perspective

If the ideas above help explain why individuals do science, one might still wonder why societies and nations pay those individuals to do science. Why does a society devote some of its resources to this business of developing new knowledge about the natural world, or what has motivated these scientist to devote their lives to developing this new knowledge?

One realm of answers lies in the desire to improve people's lives. Geneticists trying to understand how certain conditions are passed from generation to generation and biologists tracing the pathways by which diseases are transmitted are clearly seeking information that may better the lives of very ordinary people. Earth scientists developing better models for the prediction of weather or for the prediction of earthquakes, landslides, and volcanic eruptions are likewise seeking knowledge that can help avoid the hardships that have plagued humanity for centuries. Any society concerned about the welfare of its people, which is at the least any democratic society, will support efforts like these to better people's lives.

Another realm of answers lies in a society's desires for economic development. Many earth scientists devote their work to finding more efficient or more effective ways to discover or recover natural resources like petroleum and ores. Plant scientists seeking strains or species of fruiting plants for crops are ultimately working to increase the agricultural output that nutritionally and literally enriches nations. Chemists developing new chemical substances with potential technological applications and physicists developing new phenomena like superconductivity are likewise developing knowledge that may spur economic development. In a world where nations increasingly view themselves as caught up in economic competition, support of such science is nothing less than an investment in the economic future.

Another whole realm of answers lies in humanity's increasing control over our planet and its environment. Much science is done to understand how the toxins and wastes of our society pass through our water, soil, and air, potentially to our own detriment. Much science is also done to understand how changes that we cause in our atmosphere and oceans may change the climate in which we live and that controls our sources of food and water. In a sense, such science seeks to develop the owner's manual that human beings will need as they increasingly, if unwittingly, take control of the global ecosystem and a host of local ecosystems.

Lastly, societies support science because of simple curiosity and because of the satisfaction that comes from knowledge of the world around us. Few of us will ever derive any economic benefit from knowing that the starlight we see in a clear night sky left those stars thousands and even millions of years ago, so that we observe such light as messengers of a very distant past. However, the awe, perspective, and perhaps even serenity derived from that knowledge is very valuable to many of us. Likewise, few of us will derive greater physical well-being from watching a flowing stream and from reflecting on the hydrologic cycle through which that stream's water has passed, from the distant ocean to the floating clouds of our skies to the rains and storms upstream and now to the river channel at which we stand. However, the sense of interconnectedness that comes from such knowledge enriches our understanding of our world, and of our lives, in a very valuable way. By understanding the stars in our sky and the rivers under our bridges, we better understand who we are and our place in the world. When intangible benefits like these are combined with the more tangible ones outlined above, it's no wonder that most modern societies support scientific research for the improvement of our understanding of the world around us.

How Research becomes Scientific Knowledge

As our friends at Megacorp illustrate, doing research in the lab or in the field may be science, but it isn't necessarily a contribution to knowledge. No one in the scientific community will know about, or place much confidence in, a piece of scientific research until it is published in a peer-reviewed journal. They may hear about new research at a meeting or learn about it through the grapevine of newsgroups, but nothing's taken too seriously until publication of the data.

That means that our ecologist has to write a paper (called a "manuscript" for rather old-fashioned reasons). In the manuscript she justifies why her particular piece of research is significant, she details what methods she used in doing it, she reports exactly what she observed as the results, and then she explains what her observations mean relative to what was already known.

She then sends her manuscript to the editors of a scientific journal, who send it to two or three experts for review. If those experts report back that the research was done in a methodologically sound way and that the results contribute new and useful knowledge, the editor then approves publication, although almost inevitably with some changes or additions. Within a few months (we hope), the paper appears in a new issue of the journal, and scientists around the world learn about our ecologist's findings. They then decide for themselves whether they think the methods used were adequate and whether the results mean something new and exciting, and gradually the paper changes the way people think about the world.

Of course there are some subtleties in this business. If the manuscript was sent to a prestigious journal like Science or Nature, the competition for publication there means that the editors can select what they think are only the most ground-breaking manuscripts and reject the rest, even though the manuscripts are all well-done science. The authors of the rejected manuscripts then send their work to somewhat less exalted journals, where the manuscripts probably get published but are read by a somewhat smaller audience. At the other end of the spectrum may be the South Georgia Journal of Backwater Studies, where the editor gets relatively few submissions and can't be too picky about what he or she accepts into the journal, and not too many people read it. For better or worse, scientists are more likely to read, and more likely to accept, work published in widely-distributed major journals than in regional journals with small circulation.

To summarize, science becomes knowledge by publication of research results. It then may become more general knowledge as writers of textbooks pick and choose what to put in their texts, and as professors and teachers then decide what to stress from those textbooks. Publication is critical, although not all publication is created equal. The more a newly published piece of research challenges established ideas, the more it will be noted by other scientists and by the world in general.

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Science and Change (and Miss Marple)

If scientists are constantly trying to make new discoveries or to develop new concepts and theories, then the body of knowledge produced by science should undergo constant change. Such change is progress toward a better understanding of nature. It is achieved by constantly questioning whether our current ideas are correct. As the famous American astronomer Maria Mitchell (1818-1889) put it, "Question everything".

The result is that theories come and go, or at least are modified through time, as old ideas are questioned and new evidence is discovered. In the words of Karl Popper, "Science is a history of corrected mistakes", and even Albert Einstein remarked of himself "That fellow Einstein . . . every year retracts what he wrote the year before". Many scientists have remarked that they would like to return to life in a few centuries to see what new knowlege and new ideas have been developed by then - and to see which of their own century's ideas have been discarded. Our ideas today should be compatible with all the evidence we have, and we hope that our ideas will survive the tests of the future. However, any look at history forces us to realize that the future is likely to provide new evidence that will lead to at least somewhat different interpretations.

Some scientists become sufficiently ego-involved that they refuse to accept new evidence and new ideas. In that case, in the words of one pundit, "science advances funeral by funeral". However, most scientists realize that today's theories are probably the future's outmoded ideas, and the best we can hope is that our theories will survive with some tinkering and fine-tuning by future generations.

We can go back to Copernicus to illustrate this. Most of us today, if asked on a street corner, would say that we accept Copernicus's idea that the earth moves around the sun - we would say that the heliocentric theory seems correct. However, Copernicus himself maintained that the orbits of the planets around the sun were perfectly circular. A couple of centuries later, in Newton's time, it became apparent that those orbits are ellipses. The heliocentric theory wasn't discarded; it was just modified to account for more detailed new observations. In the twentieth century, we've additionally found that the exact shapes of the ellipses aren't constant (hence the Milankovitch cycles that may have influenced the periodicity of glaciation). However, we haven't gone back to the idea of an earth-centered universe. Instead, we still accept a heliocentric theory - it's just one that's been modified through time as new data have emerged.

The notion that scientific ideas change, and should be expected to change, is sometimes lost on the more vociferous critics of science. One good example is the Big Bang theory. Every new astronomical discovery seems to prompt someone to say "See, the Big Bang theory didn't predict that, so the whole thing must be wrong". Instead, the discovery prompts a change, usually a minor one, in the theory. However, once the astrophysicists have tinkered with the theory's details enough to account for the new discovery, the critics then say "See, the Big Bang theory has been discarded". Instead, it's just been modified to account for new data, which is exactly what we've said ought to happen through time to any scientific idea.

Try an analogy: Imagine that your favorite fictional detective (Sherlock Holmes, Miss Marple, Nancy Drew, or whoever) is working on a difficult case in which the clues only come by fits and starts. Most detectives keep their working hypotheses to themselves until they've solved the case. However, let's assume that our detective decides this time to think out loud as the story unfolds, revealing their current prime suspect and hypothesized chronology of the crime as they go along. Now introduce a character who accompanies the detective and who, as each clue is uncovered, exclaims "See, this changes what you thought before - you must be all wrong about everything!" Our detective will think, but probably have the grace to not say, "No, the new evidence just helps me sharpen the cloudy picture I had before". The same is true in science, except that nature never breaks down in the last scene and explains how she done it.

Science and Knowledge

So what does all this mean? It means that science does not presently, and probably never can, give statements of absolute eternal truth - it only provides theories. We know that those theories will probably be refined in the future, and some of them may even be discarded in favor of theories that make more sense in light of data generated by future scientists. However, our present theories are our best available explanations of the world. They explain, and have been tested against, a vast amount of information.

Consider some of the information against which we've tested our theories:

We've examined the DNA, cells, tissues, organs, and bodies of thousands if not millions of species of organisms, from bacteria to cacti to great blue whales, at scales from electron microscopy to global ecology.

We've examined the physical behaviour of particles ranging in size from quarks to stars and at times scales from femtoseconds to millions of years.

We've characterized the 90 or so chemical elements that occur naturally on earth and several more that we've synthesized.

We've poked at nearly every rock on the earth's surface and drilled as much as six miles into the earth to recover and examine more.

We've used seismology to study the earth's internal structure, both detecting shallow faults and examining the behavior of the planet's core.

We've studied the earth's oceans with dredges, bottles, buoys, boats, drillships, submersibles, and satellites.

We've monitored and sampled Earth's atmosphere at a global scale on a minute-by-minute basis.

We've scanned outer space with telescopes employing radiation ranging in wavelength from infrared to X-rays, and we've sent probes to examine both our sun and the distant planets of our solar system.

We've personally explored the surface of our moon and brought back rocks from there, and we've sampled a huge number of meteorites to learn more about matter from beyond our planet.
We will do more in the centuries to come, but we've already assembled a vast array of information on which to build the theories that are our present scientific understanding of the universe.

This leaves people with a choice today. One option is to accept, perhaps with some skepticism, the scientific (and only theoretical) understanding of the natural world, which is derived from all the observations and measurements described above. The other option, or perhaps an other option, is to accept traditional understandings³ of the natural world developed centuries or even millenia ago by people who, regardless how wise or well-meaning, had only sharp eyes and fertile imaginations as their best tools.