query: According to the second law of  thermodynamics such a planetary machine can never exist."

positive: Thermodynamic equilibrium Thermodynamic equilibrium is an axiomatic concept of thermodynamics . It is an internal state of a single thermodynamic system , or a relation between several thermodynamic systems connected by more or less permeable or impermeable walls . In thermodynamic equilibrium there are no net macroscopic flows of matter or of energy , either within a system or between systems . In a system in its own state of internal thermodynamic equilibrium , no macroscopic change occurs . Systems in mutual thermodynamic equilibrium are simultaneously in mutual thermal , mechanical , chemical , and radiative equilibria . Systems can be in one kind of mutual equilibrium , though not in others . In thermodynamic equilibrium , all kinds of equilibrium hold at once and indefinitely , until disturbed by a thermodynamic operation . In a macroscopic equilibrium , almost or perfectly exactly balanced microscopic exchanges occur ; this is the physical explanation of the notion of macroscopic equilibrium .   A thermodynamic system in its own state of internal thermodynamic equilibrium has a spatially uniform temperature . Its intensive properties , other than temperature , may be driven to spatial inhomogeneity by an unchanging long range force field imposed on it by its surroundings .   In non-equilibrium systems , by contrast , there are net flows of matter or energy . If such changes can be triggered to occur in a system in which they are not already occurring , it is said to be in a metastable equilibrium .   Though it is not a widely named law , it is an axiom of thermodynamics that there exist states of thermodynamic equilibrium . The second law of thermodynamics states that when a body of material starts from an equilibrium state , in which portions of it are held at different states by more or less permeable or impermeable partitions , and a thermodynamic operation removes or makes the partitions more permeable and it is isolated , then it spontaneously reaches its own new state of internal thermodynamic equilibrium , and this is accompanied by an increase in the sum of the entropies of the portions .

positive: Black hole A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing -- not even particles and electromagnetic radiation such as light -- can escape from inside it . The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole . The boundary of the region from which no escape is possible is called the event horizon . Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it , no locally detectable features appear to be observed . In many ways a black hole acts like an ideal black body , as it reflects no light . Moreover , quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation , with the same spectrum as a black body of a temperature inversely proportional to its mass . This temperature is on the order of billionths of a kelvin for black holes of stellar mass , making it essentially impossible to observe .   Objects whose gravitational fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace . The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916 , although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958 . Black holes were long considered a mathematical curiosity ; it was during the 1960s that theoretical work showed they were a generic prediction of general relativity . The discovery of neutron stars sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality .   Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle . After a black hole has formed , it can continue to grow by absorbing mass from its surroundings . By absorbing other stars and merging with other black holes , supermassive black holes of millions of solar masses may form . There is general consensus that supermassive black holes exist in the centers of most galaxies .   Despite its invisible interior , the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light . Matter that falls onto a black hole can form an external accretion disk heated by friction , forming some of the brightest objects in the universe . If there are other stars orbiting a black hole , their orbits can be used to determine the black hole 's mass and location . Such observations can be used to exclude possible alternatives such as neutron stars . In this way , astronomers have identified numerous stellar black hole candidates in binary systems , and established that the radio source known as Sagittarius A * , at the core of our own Milky Way galaxy , contains a supermassive black hole of about 4.3 million solar masses .   On 11 February 2016 , the LIGO collaboration announced the first observation of gravitational waves ; because these waves were generated from a black hole merger it was the first ever direct detection of a binary black hole merger . On 15 June 2016 , a second detection of a gravitational wave event from colliding black holes was announced .

positive: Second law of thermodynamics The second law of thermodynamics states that the total entropy of an isolated system can only increase over time . It can remain constant in ideal cases where the system is in a steady state ( equilibrium ) or undergoing a reversible process . The increase in entropy accounts for the irreversibility of natural processes , and the asymmetry between future and past .   Historically , the second law was an empirical finding that was accepted as an axiom of thermodynamic theory . Statistical thermodynamics , classical or quantum , explains the microscopic origin of the law .   The second law has been expressed in many ways . Its first formulation is credited to the French scientist Sadi Carnot in 1824 , who showed that there is an upper limit to the efficiency of conversion of heat to work in a heat engine .

positive: Thermodynamics Thermodynamics is a branch of physics concerned with heat and temperature and their relation to energy and work . The behavior of these quantities is governed by the four laws of thermodynamics , irrespective of the composition or specific properties of the material or system in question . The laws of thermodynamics are explained in terms of microscopic constituents by statistical mechanics . Thermodynamics applies to a wide variety of topics in science and engineering , especially physical chemistry , chemical engineering and mechanical engineering .   Historically , thermodynamics developed out of a desire to increase the efficiency of early steam engines , particularly through the work of French physicist Nicolas Léonard Sadi Carnot ( 1824 ) who believed that engine efficiency was the key that could help France win the Napoleonic Wars . Scottish physicist Lord Kelvin was the first to formulate a concise definition of thermodynamics in 1854 which stated , `` Thermo-dynamics is the subject of the relation of heat to forces acting between contiguous parts of bodies , and the relation of heat to electrical agency . ''   The initial application of thermodynamics to mechanical heat engines was extended early on to the study of chemical compounds and chemical reactions . Chemical thermodynamics studies the nature of the role of entropy in the process of chemical reactions and has provided the bulk of expansion and knowledge of the field . Other formulations of thermodynamics emerged in the following decades . Statistical thermodynamics , or statistical mechanics , concerned itself with statistical predictions of the collective motion of particles from their microscopic behavior . In 1909 , Constantin Carathéodory presented a purely mathematical approach to the field in his axiomatic formulation of thermodynamics , a description often referred to as geometrical thermodynamics .

negative: Brownian ratchet In the philosophy of thermal and statistical physics , the Brownian ratchet or Feynman-Smoluchowski ratchet is a thought experiment about an apparent perpetual motion machine first analysed in 1912 by Polish physicist Marian Smoluchowski and popularised by American Nobel laureate physicist Richard Feynman in a physics lecture at the California Institute of Technology on May 11 , 1962 , during his Messenger Lectures series The Character of Physical Law in Cornell University in 1964 and in his text The Feynman Lectures on Physics as an illustration of the laws of thermodynamics . The simple machine , consisting of a tiny paddle wheel and a ratchet , appears to be an example of a Maxwell 's demon , able to extract useful work from random fluctuations ( heat ) in a system at thermal equilibrium in violation of the second law of thermodynamics . Detailed analysis by Feynman and others showed why it can not actually do this .

negative: Thermodynamic operation A thermodynamic operation is an externally imposed manipulation or change of connection or wall between a thermodynamic system and its surroundings . An externally imposed change in the state of the surroundings of a system can usually be regarded as a virtual thermodynamic operation . It may usually be analyzed as due to changes in the walls that separate the systems in the surroundings . It is assumed in thermodynamics that the operation is conducted in ignorance of any pertinent microscopic information .   A thermodynamic operation requires a contribution from an animate agency , or at least an independent external agency , that does not come from the passive or inanimate properties of the systems . Perhaps the first expression of the distinction between a thermodynamic operation and a thermodynamic process is in Kelvin 's statement of the second law of thermodynamics : `` It is impossible , by means of inanimate material agency , to derive mechanical effect from any portion of matter by cooling it below the temperature of the surrounding objects . '' A sequence of events that occurred other than `` by means of inanimate material agency '' would entail an action by an animate agency , or at least an independent external agency . Such an agency could impose some thermodynamic operations . For example , those operations might create a heat pump , which of course would comply with the second law . A Maxwell 's demon conducts an extremely idealized and naturally unrealizable kind of thermodynamic operation .   An ordinary language expression for a thermodynamic operation is used by Edward A. Guggenheim : `` tampering '' with the bodies .

negative: Zeroth law Zeroth law may refer to :   The Zeroth law of thermodynamics  The Zeroth law of robotics

negative: Zeroth law of thermodynamics The zeroth law of thermodynamics states that if two thermodynamic systems are each in thermal equilibrium with a third , then they are in thermal equilibrium with each other . Accordingly , thermal equilibrium between systems is a transitive relation .   Two systems are said to be in the relation of thermal equilibrium if they are linked by a wall permeable only to heat and they do not change over time . As a convenience of language , systems are sometimes also said to be in a relation of thermal equilibrium if they are not linked so as to be able to transfer heat to each other , but would not do so if they were connected by a wall permeable only to heat .   The physical meaning of the law was expressed by Maxwell in the words : `` All heat is of the same kind '' . For this reason , another statement of the law is `` All diathermal walls are equivalent '' .   The law is important for the mathematical formulation of thermodynamics , which needs the assertion that the relation of thermal equilibrium is an equivalence relation . This information is needed for a mathematical definition of temperature that will agree with the physical existence of valid thermometers .

negative: Third law of thermodynamics The third law of thermodynamics is sometimes stated as follows , regarding the properties of systems in equilibrium at absolute zero temperature :   At absolute zero ( zero kelvin ) , the system must be in a state with the minimum possible energy , and the above statement of the third law holds true provided that the perfect crystal has only one minimum energy state . Entropy is related to the number of accessible microstates , and for a system consisting of many particles , quantum mechanics indicates that there is only one unique state ( called the ground state ) with minimum energy . If the system does not have a well-defined order ( if its order is glassy , for example ) , then in practice there will remain some finite entropy as the system is brought to very low temperatures as the system becomes locked into a configuration with non-minimal energy . The constant value is called the residual entropy of the system .   The Nernst -- Simon statement of the third law of thermodynamics concerns thermodynamic processes at a fixed , low temperature :   Here a condensed system refers to liquids and solids .   A classical formulation by Nernst ( actually a consequence of the Third Law ) is :  It was proven in 2017 by Masanes and Oppenheim .   There also exists a formulation of the Third Law which approaches the subject by postulating a specific energy behavior :

negative: Carnot's theorem (thermodynamics) Carnot 's theorem , developed in 1824 by Nicolas Léonard Sadi Carnot , also called Carnot 's rule , is a principle that specifies limits on the maximum efficiency any heat engine can obtain . The efficiency of a Carnot engine depends solely on the difference between the hot and cold temperature reservoirs .   Carnot 's theorem states :  All heat engines between two heat reservoirs are less efficient than a Carnot heat engine operating between the same reservoirs .  Every Carnot heat engine between a pair of heat reservoirs is equally efficient , regardless of the working substance employed or the operation details .   The formula for this maximum efficiency is   where TC is the absolute temperature of the cold reservoir , TH is the absolute temperature of the hot reservoir , and the efficiency is the ratio of the work done by the engine to the heat drawn out of the hot reservoir .   Based on modern thermodynamics , Carnot 's theorem is a result of the second law of thermodynamics . Historically , however , it was based on contemporary caloric theory and preceded the establishment of the second law .

negative: Reflections on the Motive Power of Fire Reflections on the Motive Power of Fire and on Machines Fitted to Develop that Power is a book published in 1824 by French physicist Sadi Carnot .   The 118-page book 's French title was Réflexions sur la puissance motrice du feu et sur les machines propres à développer cette puissance . It is a significant publication in the history of thermodynamics about a generalized theory of heat engines .   The book is considered the founding work of thermodynamics . It contains the preliminary outline of the second law of thermodynamics . Carnot stated that motive power is due to the fall of caloric ( heat ) from a hot to a cold body .   The work was unnoticed until 1834 when French mining engineer Émile Clapeyron put it on a graphical footing in his Memoir on the Motive Power of Heat . Through Clapeyron 's paper , German physicist Rudolf Clausius learned of Carnot 's theory of heat and through a modification of Carnot 's suppositions on heat , Clausius put the second law in mathematical form with his introduction of the concept of entropy .   By 1849 , thermo-dynamic , as a functional term , was used in William Thomson 's paper An Account of Carnot 's Theory of the Motive Power of Heat .   The Reflections contain a number of principles such as the Carnot cycle , the Carnot heat engine , Carnot 's theorem , thermodynamic efficiency . Similar to how the Reflections was the precursor to the second law , English physicist James Joule 's 1843 paper Mechanical equivalent of heat was the precursor to the first law of thermodynamics .   Despite the fact that the caloric theory of heat was incorrect , Carnot 's work brought together three insights that remain relevant and was used by his successors that lead to the concept of entropy :  The `` fall of heat '' from a high temperature to a lower temperature is where the work comes from .  Analyzing a cycle , rather than an open system , is the correct way to analyze a heat engine .  The concept of a reversible process .

negative: History of perpetual motion machines The history of perpetual motion machines dates back to the Middle Ages . For millennia , it was not clear whether perpetual motion devices were possible or not , but modern theories of thermodynamics have shown that they are impossible . Despite this , many attempts have been made to construct such machines , continuing into modern times . Modern designers and proponents sometimes use other terms , such as `` overunity '' , to describe their inventions .

negative: Chemical thermodynamics Chemical thermodynamics is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics . Chemical thermodynamics involves not only laboratory measurements of various thermodynamic properties , but also the application of mathematical methods to the study of chemical questions and the spontaneity of processes .   The structure of chemical thermodynamics is based on the first two laws of thermodynamics . Starting from the first and second laws of thermodynamics , four equations called the `` fundamental equations of Gibbs '' can be derived . From these four , a multitude of equations , relating the thermodynamic properties of the thermodynamic system can be derived using relatively simple mathematics . This outlines the mathematical framework of chemical thermodynamics .

negative: Conservation of energy In physics , the law of conservation of energy states that the total energy of an isolated system remains constant -- it is said to be conserved over time . Energy can neither be created nor destroyed ; rather , it transforms from one form to another . For instance , chemical energy can be converted to kinetic energy in the explosion of a stick of dynamite . In technical terms , conservation of energy can be rigorously proven by the Noether theorem to be a direct consequence of continuous time translation symmetry .   A consequence of the law of conservation of energy is that a perpetual motion machine of the first kind can not exist . That is to say , no system without an external energy supply can deliver an unlimited amount of energy to its surroundings . For equations of motion which do not have time translation symmetry , the conservation of energy may not be able to be defined . Examples include curved spacetimes in general relativity or time crystals in condensed matter physics .

negative: Debra Searles Debra Searles is the professional name for an Australian theoretical chemist whose married name is Debra Bernhardt . She is best known for her contributions towards understanding the Fluctuation Theorem . This theorem shows the Second law of thermodynamics and the Zeroth law of thermodynamics can be derived mathematically rather than postulated as laws of Nature .

negative: T-symmetry T-symmetry or time reversal symmetry is the theoretical symmetry of physical laws under the transformation of time reversal :   Although in restricted contexts one may find this symmetry , the observable universe itself does not show symmetry under time reversal , primarily due to the second law of thermodynamics . Hence time is said to be non-symmetric , or asymmetric , except for equilibrium states when the second law of thermodynamics predicts the time symmetry to hold .  However , quantum noninvasive measurements are predicted to violate time symmetry even in equilibrium , contrary to their classical counterparts , although it has not yet been experimentally confirmed .   Time asymmetries are generally distinguished as among those intrinsic to the dynamic physical laws , those due to the initial conditions of our universe , and due to measurements .  The T-asymmetry of the weak force is of the first kind ,  The T-asymmetry of the second law of thermodynamics is of the second kind , while  The T-asymmetry of the noninvasive measurements is of the third kind .

negative: Newton's laws of motion Newton 's laws of motion are three physical laws that , together , laid the foundation for classical mechanics . They describe the relationship between a body and the forces acting upon it , and its motion in response to those forces . More precisely , the first law defines the force qualitatively , the second law offers a quantitative measure of the force , and the third asserts that a single isolated force does n't exist . These three laws have been expressed in several different ways , over nearly three centuries , and can be summarised as follows :   The three laws of motion were first compiled by Isaac Newton in his Philosophiæ Naturalis Principia Mathematica ( Mathematical Principles of Natural Philosophy ) , first published in 1687 . Newton used them to explain and investigate the motion of many physical objects and systems . For example , in the third volume of the text , Newton showed that these laws of motion , combined with his law of universal gravitation , explained Kepler 's laws of planetary motion .

negative: Clausius–Duhem inequality The Clausius -- Duhem inequality is a way of expressing the second law of thermodynamics that is used in continuum mechanics . This inequality is particularly useful in determining whether the constitutive relation of a material is thermodynamically allowable .   This inequality is a statement concerning the irreversibility of natural processes , especially when energy dissipation is involved . It was named after the German physicist Rudolf Clausius and French physicist Pierre Duhem .

negative: Carnot cycle The Carnot cycle is a theoretical thermodynamic cycle proposed by Nicolas Léonard Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s . It provides an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work , or conversely , the efficiency of a refrigeration system in creating a temperature difference ( e.g. refrigeration ) by the application of work to the system . It is not an actual thermodynamic cycle but is a theoretical construct .   Every single thermodynamic system exists in a particular state . When a system is taken through a series of different states and finally returned to its initial state , a thermodynamic cycle is said to have occurred . In the process of going through this cycle , the system may perform work on its surroundings , thereby acting as a heat engine . A system undergoing a Carnot cycle is called a Carnot heat engine , although such a `` perfect '' engine is only a theoretical construct and can not be built in practice . However , a microscopic Carnot heat engine has been designed and run .   Essentially , there are two systems at temperatures Th and Tc ( hot and cold respectively ) , which are so large that their temperatures are practically unaffected by a single cycle . As such , they are called `` heat reservoirs '' . Since the cycle is reversible , there is no generation of entropy during the cycle ; entropy is conserved . During the cycle , an arbitrary amount of entropy ΔS is extracted from the hot reservoir , and deposited in the cold reservoir . Since there is no volume change in either reservoir , they do no work , and during the cycle , an amount of energy ThΔS is extracted from the hot reservoir and a smaller amount of energy TcΔS is deposited in the cold reservoir . The difference in the two energies ( Th-Tc ) ΔS is equal to the work done by the engine .

negative: Loschmidt's paradox Loschmidt 's paradox , also known as the reversibility paradox , irreversibility paradox or Umkehreinwand , is the objection that it should not be possible to deduce an irreversible process from time-symmetric dynamics . This puts the time reversal symmetry of ( almost ) all known low-level fundamental physical processes at odds with any attempt to infer from them the second law of thermodynamics which describes the behaviour of macroscopic systems . Both of these are well-accepted principles in physics , with sound observational and theoretical support , yet they seem to be in conflict ; hence the paradox .

negative: Internal energy In thermodynamics , the internal energy of a system is the energy contained within the system , excluding the kinetic energy of motion of the system as a whole and the potential energy of the system as a whole due to external force fields . It keeps account of the gains and losses of energy of the system that are due to changes in its internal state .   The internal energy of a system can be changed by transfers of matter or heat or by doing work . When matter transfer is prevented by impermeable containing walls , the system is said to be closed . Then the first law of thermodynamics states that the increase in internal energy is equal to the total heat added plus the work done on the system by its surroundings . If the containing walls pass neither matter nor energy , the system is said to be isolated and its internal energy can not change . The first law of thermodynamics may be regarded as establishing the existence of the internal energy .   The internal energy is one of the two cardinal state functions of the state variables of a thermodynamic system .

negative: Thermodynamic system A thermodynamic system is the material and radiative content of a macroscopic volume in space , that can be adequately described by thermodynamic state variables such as temperature , entropy , internal energy and pressure . Usually , by default , a thermodynamic system is taken to be in its own internal state of thermodynamic equilibrium , as opposed to a non-equilibrium state . The thermodynamic system is always enclosed by walls that separate it from its surroundings ; these constrain the system . A thermodynamic system is subject to external interventions called thermodynamic operations ; these alter the system 's walls or its surroundings ; as a result , the system undergoes thermodynamic processes according to the principles of thermodynamics . ( This account mainly refers to the simplest kind of thermodynamic system ; compositions of simple systems may also be considered . )   The thermodynamic state of a thermodynamic system is its internal state as specified by its state variables . In addition to the state variables , a thermodynamic account also requires a special kind of quantity called a state function , which is a function of the defining state variables . For example , if the state variables are internal energy , volume and mole amounts , that special function is the entropy . These quantities are inter-related by one or more functional relationships called equations of state , and by the system 's characteristic equation . Thermodynamics imposes restrictions on the possible equations of state and on the characteristic equation . The restrictions are imposed by the laws of thermodynamics .   According to the permeabilities of the walls of a system , transfers of energy and matter occur between it and its surroundings , which are assumed to be unchanging over time , until a state of thermodynamic equilibrium is attained . The only states considered in equilibrium thermodynamics are equilibrium states . Classical thermodynamics includes equilibrium thermodynamics . It also considers : ( a ) systems considered in terms of cyclic sequences of processes rather than of states of the system ; such were historically important in the conceptual development of the subject ; and ( b ) systems considered in terms of processes described by steady flows ; such are important in engineering .   In 1824 Sadi Carnot described a thermodynamic system as the working substance ( such as the volume of steam ) of any heat engine under study . The very existence of such thermodynamic systems may be considered a fundamental postulate of equilibrium thermodynamics , though it is only rarely cited as a numbered law . According to Bailyn , the commonly rehearsed statement of the zeroth law of thermodynamics is a consequence of this fundamental postulate .   In equilibrium thermodynamics the state variables do not include fluxes because in a state of thermodynamic equilibrium all fluxes have zero values by postulation . Equilibrium thermodynamic processes may of course involve fluxes but these must have ceased by the time a thermodynamic process or operation is complete bringing a system to its eventual thermodynamic state . Non-equilibrium thermodynamics allows its state variables to include non-zero fluxes , that describe transfers of matter or energy or entropy between a system and its surroundings .

negative: Equilibrium thermodynamics Equilibrium Thermodynamics is the systematic study of transformations of matter and energy in systems in terms of a concept called thermodynamic equilibrium . The word equilibrium implies a state of balance . Equilibrium thermodynamics , in origins , derives from analysis of the Carnot cycle . Here , typically a system , as cylinder of gas , initially in its own state of internal thermodynamic equilibrium , is set out of balance via heat input from a combustion reaction . Then , through a series of steps , as the system settles into its final equilibrium state , work is extracted .   In an equilibrium state the potentials , or driving forces , within the system , are in exact balance . A central aim in equilibrium thermodynamics is : given a system in a well-defined initial state of thermodynamic equilibrium , subject to accurately specified constraints , to calculate , when the constraints are changed by an externally imposed intervention , what the state of the system will be once it has reached a new equilibrium . An equilibrium state is mathematically ascertained by seeking the extrema of a thermodynamic potential function , whose nature depends on the constraints imposed on the system . For example , a chemical reaction at constant temperature and pressure will reach equilibrium at a minimum of its components ' Gibbs free energy and a maximum of their entropy .   Equilibrium thermodynamics differs from non-equilibrium thermodynamics , in that , with the latter , the state of the system under investigation will typically not be uniform but will vary locally in those as energy , entropy , and temperature distributions as gradients are imposed by dissipative thermodynamic fluxes . In equilibrium thermodynamics , by contrast , the state of the system will be considered uniform throughout , defined macroscopically by such quantities as temperature , pressure , or volume . Systems are studied in terms of change from one equilibrium state to another ; such a change is called a thermodynamic process .   Ruppeiner geometry is a type of information geometry used to study thermodynamics . It claims that thermodynamic systems can be represented by Riemannian geometry , and that statistical properties can be derived from the model . This geometrical model is based on the idea that there exist equilibrium states which can be represented by points on two-dimensional surface and the distance between these equilibrium states is related to the fluctuation between them .

negative: Heat death of the universe The heat death of the universe is a plausible ultimate fate of the universe in which the universe has diminished to a state of no thermodynamic free energy and therefore can no longer sustain processes that increase entropy . Heat death does not imply any particular absolute temperature ; it only requires that temperature differences or other processes may no longer be exploited to perform work . In the language of physics , this is when the universe reaches thermodynamic equilibrium ( maximum entropy ) .   If the topology of the universe is open or flat , or if dark energy is a positive cosmological constant ( both of which are supported by current data ) , the universe will continue expanding forever and a heat death is expected to occur , with the universe cooling to approach equilibrium at a very low temperature after a very long time period .   The hypothesis of heat death stems from the ideas of William Thomson , 1st Baron Kelvin , who in the 1850s took the theory of heat as mechanical energy loss in nature ( as embodied in the first two laws of thermodynamics ) and extrapolated it to larger processes on a universal scale .

negative: Philosophy of thermal and statistical physics The philosophy of thermal and statistical physics is that part of the philosophy of physics whose subject matter is classical thermodynamics , statistical mechanics , and related theories . Its central questions include : What is entropy , and what does the second law of thermodynamics say about it ? Does either thermodynamics or statistical mechanics contain an element of time-irreversibility ? If so , what does statistical mechanics tell us about the arrow of time ?

negative: Isolated system In physical science , an isolated system is either of the following :   a physical system so far removed from other systems that it does not interact with them .  a thermodynamic system enclosed by rigid immovable walls through which neither matter nor energy can pass .   Though subject internally to its own gravity , an isolated system is usually taken to be outside the reach of external gravitational and other long-range forces .   This can be contrasted with what ( in the more common terminology used in thermodynamics ) is called a closed system , being enclosed by selective walls through which can pass energy as heat or work , but not matter ; and with an open system , which both matter and energy can enter or exit , though it may have variously impermeable walls in parts of its boundaries .   An isolated system obeys the conservation law that its total energy -- mass stays constant . Most often , in thermodynamics , matter and energy are treated as separately conserved .   Because of the requirement of enclosure , and the near ubiquity of gravity , strictly and ideally isolated systems do not actually occur in experiments or in nature . Though very useful , they are thus hypothetical concepts only .   Classical thermodynamics is usually presented as postulating the existence of isolated systems . It is also usually presented as the fruit of experience . Obviously , no experience has been reported of an ideally isolated system .   It is , however , the fruit of experience that some physical systems , including isolated ones , do seem to reach their own states of internal thermodynamic equilibrium . Classical thermodynamics postulates the existence of systems in their own states of internal thermodynamic equilibrium . This postulate is a very useful idealization .   In the attempt to explain the idea of gradual approach to thermodynamic equilibrium after a thermodynamic operation , with entropy increase according to the second law of thermodynamics , Boltzmann 's H-theorem used equations which assumed a system ( for example , a gas ) was isolated . That is , all the mechanical degrees of freedom could be specified , treating the enclosing walls simply as mirror boundary conditions . This led to Loschmidt 's paradox . If , however , the stochastic behavior of the molecules and thermal radiation in real enclosing walls is considered , then the system is in effect in a heat bath . Then Boltzmann 's assumption of molecular chaos can be justified .   The concept of an isolated system can serve as a useful model approximating many real-world situations . It is an acceptable idealization used in constructing mathematical models of certain natural phenomena ; e.g. , the planets in the Solar System , and the proton and electron in a hydrogen atom are often treated as isolated systems . But from time to time , a hydrogen atom will interact with electromagnetic radiation and go to an excited state .   Sometimes people speculate about `` isolation '' for the universe as a whole , but the meaning of such speculation is doubtful .

negative: Irreversible process In science , a process that is not reversible is called irreversible . This concept arises frequently in thermodynamics .   In thermodynamics , a change in the thermodynamic state of a system and all of its surroundings can not be precisely restored to its initial state by infinitesimal changes in some property of the system without expenditure of energy . A system that undergoes an irreversible process may still be capable of returning to its initial state ; however , the impossibility occurs in restoring the environment to its own initial conditions . An irreversible process increases the entropy of the universe . However , because entropy is a state function , the change in entropy of the system is the same whether the process is reversible or irreversible . The second law of thermodynamics can be used to determine whether a process is reversible or not .   All complex natural processes are irreversible . The phenomenon of irreversibility results from the fact that if a thermodynamic system , which is any system of sufficient complexity , of interacting molecules is brought from one thermodynamic state to another , the configuration or arrangement of the atoms and molecules in the system will change in a way that is not easily predictable . A certain amount of `` transformation energy '' will be used as the molecules of the `` working body '' do work on each other when they change from one state to another . During this transformation , there will be a certain amount of heat energy loss or dissipation due to intermolecular friction and collisions ; energy that will not be recoverable if the process is reversed .   Many biological processes that were once thought to be reversible have been found to actually be a pairing of two irreversible processes . Whereas a single enzyme was once believed to catalyze both the forward and reverse chemical changes , research has found that two separate enzymes of similar structure are typically needed to perform what results in a pair of thermodynamically irreversible processes .

negative: Digital probabilistic physics Digital probabilistic physics is a branch of digital philosophy which holds that the universe exists as a nondeterministic state machine . The notion of the universe existing as a state machine was first postulated by Konrad Zuse 's book Rechnender Raum . Adherents hold that the universe state machine can move between more and less probable states , with the less probable states containing more information . This theory is in contrast to digital physics , which holds that the history of the universe is computable and is deterministically unfolding from initial conditions .   The fundamental tenets of digital probabilistic physics were first explored at great length by Tom Stonier in a series of books which explore the notion of information as existing as a physical phenomenon of the universe . According to Stonier , the arrangement of atoms and molecules which make up physical objects contains information , and high-information objects such as DNA are low-probability physical structures . Within this framework , civilization itself is a low-probability construct maintaining its existence by propagating through communication . Stonier 's work has been unique in considering information as existing as a physical phenomenon , being broader than as an application to the domain of telecommunications .   To distinguish the probability of the physical state of the molecules from the probability of the energy distribution of thermodynamics , the term extropy was appropriated to define the probability of the atomic configuration , as opposed to the entropy . Thus , in thermodynamics , a ` coarse-grain ' set of partitions is defined which groups together similar microscopically different states and in digital probabilistic physics the specific microscopic state probability is considered alone . The extropy is defined to be the self-information of the Markov chain describing the physical system .   The extropy of a system in bits associated with the Markov chain configuration whose outcome has probability is :     Within this philosophy , the probability of the physical system does not necessarily change with the deterministic flow of energy through the atomic framework , but rather moves into a lesser probability state when the system goes through a bifurcating transition . Examples of this include Bernoulli cell formation , quantum fluctuations in a gravitational field causing gravitational precipitation points , and other systems moving through unstable self-amplifying state transitions .

negative: Atmospheric thermodynamics Atmospheric thermodynamics is the study of heat-to-work transformations ( and their reverse ) that take place in the earth 's atmosphere and manifest as weather or climate . Atmospheric thermodynamics use the laws of classical thermodynamics , to describe and explain such phenomena as the properties of moist air , the formation of clouds , atmospheric convection , boundary layer meteorology , and vertical instabilities in the atmosphere . Atmospheric thermodynamic diagrams are used as tools in the forecasting of storm development . Atmospheric thermodynamics forms a basis for cloud microphysics and convection parameterizations used in numerical weather models and is used in many climate considerations , including convective-equilibrium climate models .

negative: Fluctuation theorem The fluctuation theorem ( FT ) , which originated from statistical mechanics , deals with the relative probability that the entropy of a system which is currently away from thermodynamic equilibrium ( i.e. , maximum entropy ) will increase or decrease over a given amount of time . While the second law of thermodynamics predicts that the entropy of an isolated system should tend to increase until it reaches equilibrium , it became apparent after the discovery of statistical mechanics that the second law is only a statistical one , suggesting that there should always be some nonzero probability that the entropy of an isolated system might spontaneously decrease ; the fluctuation theorem precisely quantifies this probability .

negative: Heat death paradox Formulated in 1862 by Lord Kelvin , Hermann von Helmholtz and William John Macquorn Rankine , the heat death paradox , also known as Clausius 's paradox and thermodynamic paradox , is a reductio ad absurdum argument that uses thermodynamics to show the impossibility of an infinitely old universe .   This paradox is based upon the classical model of the universe in which the universe is eternal . Clausius 's paradox is a paradox of paradigm . It was necessary to amend the fundamental ideas about the universe , which brought about the change of the paradigm . The paradox was solved when the paradigm was changed .   The paradox was based upon the rigid mechanical point of view of the Second principle of thermodynamics postulated by Rudolf Clausius according to which heat can only be transferred from a warmer to a colder object . If the universe was eternal , as claimed in the classical stationary model of the universe , it should already be cold .   Any hot object transfers heat to its cooler surroundings , until everything is at the same temperature . For two objects at the same temperature as much heat flows from one body as flows from the other , and the net effect is no change . If the universe were infinitely old , there must have been enough time for the stars to cool and warm their surroundings . Everywhere should therefore be at the same temperature and there should either be no stars , or everything should be as hot as stars .   Since there are stars and the universe is not in thermal equilibrium it can not be infinitely old .   The paradox does not arise in Big Bang or Steady State cosmology . In Big Bang cosmology , the current age of the universe is not old enough to have reached equilibrium ; while in a Steady State system , sufficient hydrogen is replenished or regenerated continuously to allow for a constant average density and preventing stars from running down .

negative: Work output In physics , work output is the work done by a simple machine , compound machine , or any type of engine model . In common terms , it is the energy output , which for simple machines is always less than the energy input , even though the forces may be drastically different .   In thermodynamics , work output can refer to the thermodynamic work done by a heat engine , in which case the amount of work output must be less than the input as energy is lost to heat , as determined by the engine 's efficiency .

negative: Kirchhoff's law of thermal radiation See also Kirchhoff 's laws ( disambiguation ) for other laws named after Gustav Kirchhoff .   In heat transfer , Kirchhoff 's law of thermal radiation refers to wavelength-specific radiative emission and absorption by a material body in thermodynamic equilibrium , including radiative exchange equilibrium .   A body at temperature radiates electromagnetic energy . A perfect black body in thermodynamic equilibrium absorbs all light that strikes it , and radiates energy according to a unique law of radiative emissive power for temperature , universal for all perfect black bodies . Kirchhoff 's law states that :   For a body of any arbitrary material emitting and absorbing thermal electromagnetic radiation at every wavelength in thermodynamic equilibrium , the ratio of its emissive power to its dimensionless coefficient of absorption is equal to a universal function only of radiative wavelength and temperature . That universal function describes the perfect black-body emissive power .   Here , the dimensionless coefficient of absorption ( or the absorptivity ) is the fraction of incident light ( power ) that is absorbed by the body when it is radiating and absorbing in thermodynamic equilibrium .   In slightly different terms , the emissive power of an arbitrary opaque body of fixed size and shape at a definite temperature can be described by a dimensionless ratio , sometimes called the emissivity , the ratio of the emissive power of the body to the emissive power of a black body of the same size and shape at the same fixed temperature . With this definition , Kirchhoff 's law states :   For an arbitrary body emitting and absorbing thermal radiation in thermodynamic equilibrium , the emissivity is equal to the absorptivity .   In some cases , emissive power and absorptivity may be defined to depend on angle , as described below . The condition of thermodynamic equilibrium is necessary in the statement , because the equality of emissivity and absorptivity often does not hold when the material of the body is not in thermodynamic equilibrium .   Kirchhoff 's law has another corollary : the emissivity can not exceed one ( because the absorptivity can not , by conservation of energy ) , so it is not possible to thermally radiate more energy than a black body , at equilibrium . In negative luminescence the angle and wavelength integrated absorption exceeds the material 's emission , however , such systems are powered by an external source and are therefore not in thermodynamic equilibrium .

negative: Reactionless drive A reactionless drive is a device producing motion without the exhaust of a propellant . A propellantless drive is not necessarily reactionless when it constitutes an open system interacting with external fields ; but a reactionless drive is a particular case of a propellantless drive as it is a closed system presumably in contradiction with the law of conservation of momentum and often considered similar to a perpetual motion machine . The name comes from Newton 's third law , which is usually expressed as , `` for every action , there is an equal and opposite reaction . '' A large number of infeasible devices , such as the Dean drive , are a staple of science fiction particularly for space propulsion . To date , no reactionless device has ever been validated under properly controlled conditions .

negative: Adiabatic wall In thermodynamics , an adiabatic wall between two thermodynamic systems does not allow heat or matter to pass across it .   In theoretical investigations , it is sometimes assumed that one of the two systems is the surroundings of the other . Then it is assumed that the work transferred is reversible within the surroundings , but in thermodynamics it is not assumed that the work transferred is reversible within the system . The assumption of reversibility in the surroundings has the consequence that the quantity of work transferred is well defined by macroscopic variables in the surroundings . Accordingly , the surroundings are sometimes said to have a reversible work reservoir .   Along with the idea of an adiabatic wall is that of an adiabatic enclosure . It is easily possible that a system has some boundary walls that are adiabatic and others that are not . When some are not adiabatic , then the system is not adiabatically enclosed , though adiabatic transfer of energy as work can occur across the adiabatic walls .   The adiabatic enclosure is important because , according to one widely cited author , Herbert Callen , `` An essential prerequisite for the measurability of energy is the existence of walls that do not permit the transfer of energy in the form of heat . '' In thermodynamics , it is customary to assume a priori the physical existence of adiabatic enclosures , though it is not customary to label this assumption separately as an axiom or numbered law .

negative: Exergy efficiency Exergy efficiency ( also known as the second-law efficiency or rational efficiency ) computes the efficiency of a process taking the second law of thermodynamics into account .