studiot

Well I have a major disagreement with the claim I have emboldened. This is a fine example of what two experts (+1 each) have been trying to tell you. You do not know enough to understand exactly what they are saying to you. The energy level has exactly zero bearing on the direction of heat flow. This is a simple case of. If A > then B heat flows from A to B. If A = B no heat flows.

I can't see why anyone should give you a negative rep for these questions so I have reversed them. +1 also to exchem for introducing some scientific sanity here. I am suprised you are only offering these oversimplistic responses to someone who is perhaps a youngster trying to understand climate change. @CrystalMagic To answer you questions and offer some further information about the subject. The fundamental driver for the average surface temperature of the Earth is the balance between energies reaching the Earth, energies leaving the Earth and energies being transported within the Earth. None of these three energy flows have ever been constant. As a result there have been periods when the Earth's surface has been warmer than at present and also colder than at present, both on average. Climate is the result of the fact that the average surface temperature is the average of a very uneven distribution of temperature and also the three energy flows. Climate is the response by the Earth's fluid environments (Atmosphere and Ocean) to this uneven distribution towards evening this out. The processes of climate are affected by many factors including the two you have asked about. The last major volcanic eruption, Krakatoa in 1883, cooled the Earth for about a decade becasue the dust released in the atmosphere reflected back some solar energy before it reached the surface. And yes, as sensei says there were bigger and better eruption a long time ago. As to your second question, yes the Earth has warmed and cooled many times before the present as the actual prevailing position of that energy balance shifts. The shifts occur over periods of hundreds of years, thousands of years as well as the millions sensei mentioned. We are currently in a period between two much colder periods commonly called ice ages. Please indicate if you have further interest when you reply.

So what about my shadow ? That occupies points where, by definition, nothing happens. And the shadow is made of nothing, again by definition. Also if you are going to claim that the points are but abstract and only come into existence when something happens then you also need to establish whether or not the points and their nature depend in any way upon the something that happens. A real can of worms.

Some are some are not. I think Seth was referring to those that are. You should listen to him and answer his questions properly. He is/was a pretty good engineer. I don't any response to his question about the working fluid. The term 'working fluid' has a particular meaning to an engineer and may be imaginary or representational depending upon the configuration of the machine. This is because Carnot and the 2nd Law refer to a working fluid undergoing a cyclic process. They do not apply directly to non cyclic processes This is of fundamental importance and would be asked by any engineer working on a heat engine.

So you haven't really shown that they 'don't exist' - whatever that means. I don't know of any human who has tried and failed to move from one 'real ' point to another through the empty space between them, where you seem to claim there are no points. As a matter of interest two different scientific definitions of the word 'event' have been introduced in this thread. One is the Physics (relativistic) definition which means point in space, occupied or not and regardless of 'whether anything happens there ' The other is the statistics definition which seems to fit how you intend to use the word. This does indeed define points in 'event space' as an individual instance of something happening. Event space is by nature discrete, though we postulate underlying abstract continuous spaces in some cases.

Perhaps if you could elaborate further we could explain. What sort of line on each representation do you mean ? You realise that the mapping from one to the other may result in a straight line becoming curved and vice-versa ? Also it depends upon just how long the lines are.

Are you suggesting that the peoples in Australia did not come from 'the African Cradle' ? As a matter of interest you map appears to show that man never reached India ? Only half a mistake really. The nomads of the steppes pushed both east and west, and into south northern India at one time or another. It's just that the older cultures in India and China were stronger and better at resisting that the weaker cultures in Europe.

If it doesn't exist, how can you identify it to demonstrate that it doesn't exist ? Further how can you tell that nothing happens there ? These are really similar questions to those Genady has already put. Indeed so, but Riemann has already taken that into account. Translation from German by Spivak, adapted by McCleary. So was the birth of Topology and topological manifolds.

I am aware of the work of Prigogine and of Szilard. But I am not aware that anyone has proven the need for either deletion or the actual physical embodyment of mathematics. As far as I am concerned, the Mathematics existes and existed quite independently of any physical use or discovery. I do not support the suggestion that symbols written say 1000 years ago should be erased or deleted, otherwise the equations of entropy that I write today, or even just conceive of but not write down, would somehow become unbalanced. In my opinion they are totally unconnected. But we are getting further and further from the OP question which was about large numbers and my observation that since there are no limits to the number of point in a region of space we can assign a different number to each one without limit. We simply need to follow a Peano curve 1,2,3,4,5... to accomplish this. Since one one the basic tenets of number theory is that we can take any number proposed as the largest and increase it by various means. We can repeat this indefinitely. Each repetition we will uniquely identify a new largest 'number'.

I don't follow your objection. Please elaborate, perhaps with an example or two. As regards units, since entroy difference refers to the difference between states in a space it follows that any system that possesses multiple states can have an entropy, defined by multiplying the statistical entropy of the states (which is a pure number) by the units of those states.

Thermodynamic entropy is indeed a function of energy (and temperature) It has units (dimensions) of energy per degree K. Information entropy is dimensionless. Probably the most interesting distinction is given by Caratheodory in his version of the 2nd Law. As far as I know, Information entropy admits no such restriction on the states and consequently does not require the second law. Clearly since it it not directly concerned with energy it does not require the first law either. Another commonly mixed up pair of terms is information and meaning. Take the letters in alpha order A D E M N O R S Form one of the 1024 (with replacement) possible 10 letter 'words'and you have a 1 in 1024 chance of getting RANDOMNESS. How many more have meaning ? This is rather like the difference in economics between price, cost and value or worth.

I have no quarrel with proper capitalism. But I don't see how your reply to my post you quoted has anything to do with my point. As regard value, here is a parable about value. Due to Stafford Beer. Take 1lb of apples. Something of intrinsic worth in its own right. Give it to a top chef and he will turn it into something worth significantly more. Give it instead to an ill suited work experience person who may well loose all of its original value let alone add to it, in the mess they make.

Well as I understand the Aboriginals in Australia they are some of the most (or perhaps longest) undisturbed humans on the planet. Yet the maps show they are quite different from the Polynesians, Maoris and South American indigenous peoples. Yet Australia (the nearest parts) is thousands of miles closer to SE asia than New Zealand or most of the pacific islands. So why did they not get to Australia first or even at all ?

I wouldn't until I knew what sort of entropy you were talking about. It is unfortunate that the same word (ie entropy) is used for both phenomena, unlike my example which clearly distinguishes. Beltrami has a good discussion of different sorts of 'entropy' in his book What is Random ? Chance and order in Mathematics and Life.

You surely can and I agree Seth deserves one. See below to make your choice of like (blue) or upvote (green) . The only restrictions are that new members are restricted to 5 posts in their first 24 hours to prevent spambombers.

NASA considers Pluto to be a Planet and says so many times in this article. https://solarsystem.nasa.gov/planets/dwarf-planets/pluto/in-depth/ There was discussion of the status of Pluto presented in their New Horizon's video, which as I recall, came down on the side of planet, dwarf or otherwise. Of course if we discount dwarf planets as being planets the not only are we not speaking English, but we must also discount giant planets , such as Jupiter. What a daft situation.

This doesn't prove anything, but does rule some hypotheses out. I don't think the South American hypothesis is disproven. Note the maps refer to 'before the european expansion'.

I note this was moved to Mathematics, not Physics. I have noted before that just because two physical phenomena follow the same mathematical models does not imple any connection between them. For example the voltage transfer characteristic of an FET follows a square law, as does the trajectory of a ballistic object on Earth. Yet I can see no connection between these phenomena. Information entropy and thermodynamic entropy have the same disconnection. I can't agree with that. Phase change at constant temperature is purely entropy drive but the macrostate is definitely significantly affected.

Which all goes to show that we have several 'best guesses' about the spread but are finding substaintial new evidence all the time and these guesses are in a state of constant revision. It is important to acknowledge when we don't know enough.

Which means they are not subject to energy constraints. How much energy is required to provide a perfect shadow in some region ? Yet every point (and there is an infinity of such points) is 'in shadow'.

Nice one Moon. +1

OK so they are not planets, they are dwarf planets. How much did the snouts at the trough receive for that leap forward in science ? Can I have a similar amount for reclassifying the tortoise shell as a partial shell ?

That was not my understanding from the results of the New Horizon's spaceprobe.

Please elaborate. Also our word for planet come from the ancient Greek meaning 'wanderer'. These referred to heavenly objects that did not track nightly across the sky the way the remote stars do, but moved in an apparently erratic way. There are many objects in the sky that do this and in the clear middle eastern skies more can readily be seen. So it depends upon what your poets meant by planets.

These are interesting ideas, I hadn't heard of the neadethalis v sapiens comments. But the coastline theory doesn't stand up well to close examination.