Energy

"The most common way to describe entropy is as disorder... associated with things becoming more mixed, random and less ordered, but... the best way to think about entropy is as the tendency of energy to spread out. ...Most of the laws of physics work... the same... forwards or backwards in time. ...So how does this clear time dependence arise? ...[T]his is where Ludwig Boltzmann made an important insight. Heat flowing from cold to hot is not impossible, it's just improbable. ...In everyday solids there are about 100 trillion trillion atoms and even more energy packets, so heat flowing from cold to hot is just so unlikely that it never happens. ...[I]f the ...tendency is to spread out and for things to get messier, then how is it possible to have ...air conditioning, where the cold interior gets cooler and the hot exterior gets hotter? Energy is going from cold to hot, decreasing the entropy of the house. ...[T]his ...is only possible by increasing the entropy a greater amount ...at a power plant ...heating up the environment ...and creating waste heat in the fans and compressor [of the air conditioner]. ...How is there any structure left on earth? ...[I]f the earth were a the energy would spread out completely, meaning all life would cease, everything would decay and mix, and ...reach the same temperature. But luckily the earth is not a closed system, because we have the sun."

"The equations of Newtonian mechanics are reversible in time and Poincaré proved that if a mechanical system is in a given state it will return infinitely often to a state arbitrarily close to the given one. Zermelo deduced that the Second Law of Thermodynamics is impossible in a mechanical system. Boltzmann asserted that entropy increases almost always, rather than always. However he believed that Poincaré's result, although correct in theory, was in practice impossible to observe since the time before a system returns to near its original state was too long."

"Nernst's discovery was induced by the fact that even at room temperature entropy plays an astonishingly insignificant role in many chemical reactions."

"Carnot was... wrong about his perception of the steam engine, but... the essence... shone through... his fundamental misconception... that heat is a fluid—caloric—that flows from a hot reservoir [source] to a cold sink... [to] turn an engine... as [does] a waterwheel... by water. ...He ...considered heat ...neither created not destroyed as it flowed ...[H]e was able to prove ...efficiency of an idealized steam engine ...that ignores friction, leaks ...[etc.] is determined only by the temperatures of the ...source and ...sink ...independent of ...pressure and ...working substance [e.g., water, steam or air]. ...[T]he hot reservoir should be as hot as possible and the cold... as cold as possible. All other variables were fundamentally irrelevant."

"You should call it entropy, for two reasons. In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the second place, and more important, no one really knows what entropy really is, so in a debate you will always have the advantage."

"Rudolph Clausius... noticed a common feature of nature and had the stature... to publish [in 1850, Über die bewegende Kraft der Wärme (On the motive force of heat)] what others might think a simpleton's observation: heat does not flow from a cooler to a hotter body... [I]n this and subsequent papers he developed this... into a quantitative principle..."

"The quality of stored energy is measured by... entropy. ...[T]he lower the entropy the higher the quality."

"The concept of entropy was... rendered quantitatively precise by Rudolph Clausius in 1856... by defining the change... when energy is transferred to a system as heat. Specifically...Change\;in\;entropy = \frac{energy\;supplied\;as\;heat}{temperature\;at\;which\;the\;transfer\;occurs}[N]ote... temperature... is on the absolute scale..."

"The remarks on negative entropy have met with doubt and opposition from physicist colleagues. ...[I]f I had been catering for them alone I should have let the discussion turn on free energy instead. It is the more familiar notion... [b]ut seemed linguistically too near energy for... the average reader... the concept is a rather intricate one, whose relation to Boltzmann's order-disorder principle is less easy to trace... '[E]ntropy with a negative sign'... is not my invention. It... [is] precisely the thing on which Boltzmann's original argument turned."

"Clausius proposed... The entropy of an isolated system increases in any spontaneous change."

"I am standing on the threshold about to enter a room. ...I must make sure of landing on a plank travelling twenty miles a second around the sun—a fraction of a second too early or too late, the plank would be miles away. I must do this whilst hanging from a round planet head outward into space, and with a wind of aether... I ought really to look at the problem four-dimensionally as concerning the intersection of my world-line with that of the plank. Then again it is necessary to determine in which direction the entropy of the world is increasing in order to make sure that my passage over the threshold is an entrance, not an exit. Verily, it is easier for a camel to pass through the eye of a needle than for a scientific man to pass through a door. And whether... barn... or church door it might be wiser that he should consent to be an ordinary man... rather than wait til all the difficulties in... scientific ingress are resolved."

"Suppose we claim... heat flowing in the wrong direction, such as... ice forming in a glass of water... in an oven. ...Energy left the cool... water as heat, so the entropy went down. Because the temperature is low... in the denominator... that decrease in entropy is large. The same energy enters the hot region (...oven), so the entropy of that region increases. However... its temperature is high, [so] that increase in entropy is small. The net effect... a net decrease overall. ...[But] entropy never decreases, so heat cannot flow spontaneously... hot to cold..."

"I was interested in the concept introduced by Clausius, entropy.., (in addition to energy,) one of the most important variables of nature."

"The [Second] law is... used to predict whether a chemical reaction will run in one direction or another..."

"Boltzmann...was driven to his death by the inability of scientists... to come to terms with this profoundly simple insight."

"'[E]nergy supplied as heat' appears in the numerator of Clausius' expression, for the greater the energy... as heat, the greater... increase in disorder and therefore... entropy. The... temperature in the denominator fits... this analogy too... for a given supply of heat... [added to] a cool [little thermal motion] object... will introduce a... [relatively large] disturbance, corresponding to a big rise in entropy... [and the same heat added to a] hot [lots of thermal motion] object has relatively little effect, and the increase in entropy is small."

"Energy remains constant and entropy always grows and can never be reduced... the essence of the second law of thermodynamics... [i.e.,] the entropy of a system of bodies can... only increase."

"Except for action and entropy (which belongs to an entirely different class of physical conceptions) all the quantities prominent in pre-relativity physics refer to the three-dimensional sections which are different for different observers."

"It had become the regular outlook of science... that constellations are not to be taken seriously, until the constellation of entropy made a solitary exception. When we analyze the picture into a large number of particles of paints, we lose the aesthetic significance of the picture. The particles... go into the scientific inventory, and it is claimed that everything that there really was in the picture is kept. But this way of keeping... may be... losing ... The essence of a picture... is arrangement."

"I cannot read any significance into a physical world that is held... upside down. For that reason I am interested in entropy not only because it shortens calculations which can be made by other methods, but because it determines an orientation which cannot be found by other methods. ...[T]ime makes a dual entry and thus forms an intermediate link between the internal and the external. This is shadowed partially by the scientific world of primary physics (which excludes time's arrow), but fully when we... include entropy. ...[It] has generally been assumed that the object of the quest is to find out all that really exists. There is another quest... to find out all that really becomes."

"In the limiting case, [entropy] stays the same. If it increases.., the process is irreversible. If it remains the same.., the process is reversible... [i.e.,] you can let it run backwards."

"The discrimination between cause and effect depends on time's arrow and can only be settled by reference to entropy."

"[T]he conception associated with entropy... marked a reaction from the view that everything to which science must pay attention is discovered by a microscopic dissection of objects. ...[T]he centre of interest is shifted from the entities reached by the customary analysis (atoms, electric potentials, etc.) to qualities possessed by the system as a whole... The artist... resorts to an impressionist painting. ...[T]he physicist has found ...his impressionist scheme is just as much exact science and even more practical ...than his microscopic scheme."

"Entropy... was discovered and exalted because it was essential to practical applications of physics... But by it science has been saved from a fatal narrowness. ...[T]here would have been nothing to represent "becoming" in the physical world."

"Entropy was not in the same category as the other physical quantities ...and the extension ...was in a very dangerous direction. ...But entropy had secured a firm place in physics before it was discovered that it was a measure of the random element in arrangement. It was in great favour with the engineers. ...[A]t that time it was the general assumption that the Creation was the work of an engineer (not of a mathematician, as is the fashion nowadays)."

"Consciousness, besides detecting time's arrow, also roughly measures the passage of time. ...but is a bit of a bungler in carrying it out. ...Our consciousness somehow manages to keep ...record of the flight of time ...reading some kind of clock in the material brain ...a better analogy would be an entropy-clock ...primarily for measuring the rate of disorganisation of energy, and only roughly keeping pace with time. ...[I]n forming our ideas of duration and of becoming... [e]ntropy-gradient is... the direct equivalent of the time of consciousness in both... aspects. Duration measured by physical clocks (time-like interval) is only remotely connected."

"[T]he Kelvin statement is equivalent to... 'your engine will work only if you waste some energy'..."

"The third model regards mind as an information processing system. This is the model of mind subscribed to by cognitive psychologists and also to some extent by the ego psychologists. Since an acquisition of information entails maximization of negative entropy and complexity, this model of mind assumes mind to be an open system."

"Energy in the universe is constant and it can't be destroyed or created. [1st Law of Thermodynamics] ...You've got what's you've got. You've got entropy, which is a state of disorder, so things tend [from] order to disorder, but you're not going to destroy [the energy]. • Energy goes from organized and usable to disorganized and unusable, and it seeks equilibrium. That's the 2nd law and discusses entropy, which is just decay and disorder and death and destruction and... all that good stuff! All the happy stuff! When you get to be my age, you kind of look forward to it so it's not necessarily that bad. • Molecular motion stops, as does entropy, at . [3rd law] So when you get to absolute zero... nothing moves, which is why we can't really get there... because... we always take heat out of things by putting it into something else [at a lower temperature]... • Hot goes to cold. (Energy moves from higher temperature to lower temperature.) • High voltage goes to lower voltage. (Electrical current moves from high potential to low potential.) • High pressure goes to low pressure."

"The more closely we examine the association of entropy with "becoming" the greater do the obstacles appear. If entropy were one of the elementary indefinables of physics there would be no difficulty. Or if the moving on of time were something of which we were made aware through our sense organs there would be no difficulty. ...Suppose that we had to identify "becoming" with an electrical potential-gradient ...through the readings of a voltmeter."

"[S]uppose that we had to identify force with entropy-gradient. That would only mean that entropy-gradient is a condition which stimulates a nerve, which thereupon transmits an impulse to the brain, out of which the mind weaves its own peculiar impression of force. ...It is absurd to pretend that we are in ignorance of the nature of organisation in the external world in the same way that we are ignorant of the intrinsic nature of potential. It is absurd to pretend that we have no justifiable conception of "becoming"... That dynamical quality... has to do much more than pull the trigger of a nerve. ...a moving on of time is a condition of consciousness. ...It is the innermost Ego of all which is and becomes."

"We show that it is natural to introduce the concept of black-hole entropy as the measure of information about a black-hole interior which is inaccessible to an exterior observer. Considerations of simplicity and consistency, and dimensional arguments indicate that the black-hole entropy is equal to the ratio of the black-hole area to the square of the Planck length times a dimensionless constant of order unity. A different approach making use of the specific properties of Kerr black holes and of concepts from information theory leads to the same conclusion, and suggests a definite value for the constant."

"Suppose that we are asked to arrange the following in two categories— distance, mass, electric force, entropy, beauty, melody. [T]here are the strongest grounds for placing entropy alongside beauty and melody... Entropy is only found when the parts are viewed in association... [as are] beauty and melody. All three are features of arrangement. ...The reason why this [entropy] stranger can pass itself off among the aborigines of the physical world is... the language of arithmetic. It has... measure-number... at home in physics."

"When occurs, entropy has reached... maximum. If entropy can no longer grow.., no change can occur. This... I applied to physical-chemical and to radiation equilibria."

"{W}ith transportation, the zero-carbon future is basically this: Use electricity to run all the vehicles we can, and get cheap alternative fuels for the rest. In the first group are passenger cars and trucks, light and medium trucks, and buses. In the second group are long-distance trucks, trains, airplanes, and container ships."

"The path to zero carbon for heating actually looks a lot like the path for passenger cars: (1) electrify what we can, getting rid of natural gas water heaters and furnaces, and (2) develop clean fuels to do everything else."

"In most locations, your overall costs will go down if you get rid of an electric air conditioner and gas (or oil) furnace and replace both with an electric heat pump."

"The most effective tree-related strategy for climate change is to stop cutting down so many of the trees we already have."

"With agriculture . . . each year’s emissions of methane and nitrous oxide are the equivalent of more than 7 billion tons of carbon dioxide."

"There’s so much animal poop that it’s actually the second-biggest cause of emissions in agriculture, behind enteric fermentation."

"You already have a heat pump in your home . . . . It's called a refrigerator."

"[W]orldwide, crops take up less than half the nitrogen applied to farm fields. The rest runs off into ground or surface waters, causing pollution, or escapes into the air in the form of nitrous oxide . . . ."

"[W]e don’t have a practical way to make [the cement in concrete] without producing carbon."

"[C]ement . . . steel [and] plastics are cheap because fossil fuels are cheap."

"[In discussing solely cement, steel and plastics in this chapter] I'm leaving out fertilizer, glass, paper, aluminum, and many others. . . . We manufacture enormous amounts of materials, resulting in copious amounts of greenhouse gases, nearly a third of the 51 billion tons per year."

"Offshore wind holds a lot of promise . . . ."

"[T]he path to zero emissions in manufacturing looks like this: (1) Electrify every process possible. This is going to take a lot of innovation. (2) Get that electricity from a power grid that’s been decarbonized. This also will take a lot of innovation. (3) Use carbon capture to absorb the remaining emissions. And so will this. (4) Use materials more efficiently. Same."

"[W]e’re going to need much more clean electricity in the coming years. . . . [B]y 2050 . . . the world will need much more than three times the electricity we generate now."

"Deploying today’s renewables and improving transmission couldn’t be more important. . . . Unless we use large amounts of nuclear energy . . . every path to zero in the United States will require us to install as much wind and solar power as we can build and find room for. . . . [[w:Renewable energy in the United States#Potential resources|[M]ost countries aren’t as lucky as the United States when it comes to solar and wind resources]]. . . . That’s why, even as we deploy, deploy, deploy solar and wind, the world is going to need some new clean electricity inventions too."

"Just about everyone who’s alive now will have to adapt to a warmer world. As sea levels and floodplains change, we’ll need to rethink where we put homes and businesses. We’ll need to shore up power grids, seaports, and bridges. We’ll need to plant more mangrove forests . . . and improve our early-warning systems for storms."