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

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Thermodynamic equilibrium <=SEP=> 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 .

Black hole <=SEP=> 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 .

Second law of thermodynamics <=SEP=> 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 .

Thermodynamics <=SEP=> 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 .