studiot

I think you have some misunderstandings of your own here.

I don't see this as a quantum issue. That was also why I chose a mass of 1kg (got it right this time ) - to avoid the issue of the body being a single sub atomic particle. In any event temperature does not play well as a quantum variable. I asked the question "Where does the radiation energy go?" and now I am asking where does it come from? It comes by reducing the vibrations of the particles that comprise the body. These are held by bonding forces that are electrostatic in nature. And we know that electrostatic forces are many times stronger than gravitational ones. So I suggest there will not be a relativistic gravitational effect in this universe, leading to an expansion, although there will be a near negligible gravitation effect on the radiation leaving the body. Can anyone else see anything further that can be extracted from this scenario?

T There's no right answer here or else everyone is right. swansont was (as usual) really quick off the mark and happened to put what I was thinking about in his spoiler. I was thinking that the body would start to radiatiate as a black body within its universe. The radiation couldn't leave the universe because of the isolation. My first thought was that it would cool to absolute zero if one could wait long enough but on second thoughts life is more complicated. But where will the radiation go? Into the empty surroundings I suppose. This will raise the background temperature of the otherwise empty surroundings a fraction, rather like the background in our own universe. The loss of energy from the body will also cool the body somewhat. So there will be an ever diminishing temperature differential between the body and its surroundings, so it will cool at an ever decreasing rate and never actually reach absoulte zero. The cooling will be asymptotic to some low temperature above zero, where a balance exists between the cooling radiation and warming radiation from the background. This is rather like the discharge of a capacitor over time. My comment about the link to cosmology is "doesn't this look rather like the big bang in many ways?' Others may have equally valid (or even better) ideas.

Thanks it's already much better and someone else is concurrently watching HD video over my broadband as well as my use, whereas it's been solo all day here till now.

I am not trying to hide trick information here. Sensei, So let us assume there is no radioactivity in play - say the mass is iron. Carrock, there is nothing to prevent thermal radiation is there. I did say that test universe was isolated, not the mass. MacSwell, I am not looking for accurate numbers just ballpark. Thank everyone for answering and hope you will continue to discuss, I hope the question is stimulating - it has relevance in cosmology - I am interested in the physical arguments you would employ to arrive at a conclusion.

Is there gender prejudice inScience and Technology? http://www.bbc.co.uk/news/av/world-41502661/100-women-i-transitioned-and-lost-my-male-privilege

The BBC view purporting to show that mass shootings are increasing in the USA. http://www.bbc.co.uk/news/av/world-us-canada-41474594/las-vegas-how-us-mass-shootings-are-getting-worse

Sorry a body of one kilogramme mass.

Yes, I've had the 'bad gateway' and I've also found that other sites are not acting like this. The problem occurs on ( fully up to date) Firefox on an older PC and also on Bing on a fully uptodate windows 10 machine. If I for instance clcik on to move from page 2 to page 3 on a thread I see the timer circling with the word 'connecting' dosplayed. I also see 'waiting for scienceforums.net quite often for upt to 30 seconds in the activity box in the bottom right, along with the waiting for google ads, etc etc .

A 1k body is totally isolated in its own universe. What is its temperature, consistent with the laws of Physics?

Well this is a good test of who actually understands the basic laws of physics and knows how to apply them - and who doesn't. It is inappropriate here so I am starting a new thread offering a brain teaser question on the application of the Laws of Thermodynamics and associated laws.

Of all members, no one is more vociferous than you in correcting folks who use popular expressions in place of proper Scientific Statements. I also felt this thread was beginning to take on a witchhunt appearance, which is over the top against a young lad who has read to many superman comics. He (hopefully) just needs nudging in the right direction of proper science and scientific expression.

Rubbish, the Laws of Thermodynamics do not forbid Perpetual Motion. They forbid Perpetual Motion Machines. Or perhaps you think the Kinetic Theory incorrect? Or perhaps the Law of Conservation of Momentum?

When the latest forum format was introduced, for all its many faults, it was not slow. For the past few weeks SF have been interminable waits between moving to another page or responding to simple questions like hovering the mouse over the who is online list.

"A body will continue in its state of motion (or rest) (indefinitely) in its right line unless acted upon by. etc...." I my view that is a pretty clear requirement, It also offers conditions when it is not true. I meant to say before there is a difference between perpetual motion and a pertual motion machine. although I did indicate that a machine outputs work. It is true to say that no machine is possible that outputs work with neither input nor direct conversion from another form of energy. Or to put the Second Law in its original form, heat cannot be continuously converted into work with no other effect in the universe.

It would be a good idea for you to find out what is meant by the words you are using before embarking on this quest. Do you know what is perpetual motion, becuase perpetual motion itself is not only not forbidden by the Laws of Physics, it is required in appropriate circumstances. (Newton's First Law). However constructing a P.M. machine, even in theory, is an entirely different ball game. Do you know what a machine is? Originally it was a device for "putting work into a convenient form" - It does not change the amount of work required. With the discovery of further forms of energy it came to mean a device for transforming energy from one form into another. Formally this became the Science of Thermodynamics and from this it was realised first that "You can't get something for nothing" which lead to the idea ( and prohibition of) a Perpertual Motion Machine of the First Kind, which is a device that does exactly that. It produces energy with no input. Further development lead to proposals for more sophisticated machines that did not create something from nothing, but did output useful work directly from heat energy. These were called a P.M. Machine of the Second Kind. This was then discovered to be also impossible and a heirarchy of forms of energy was established to explain why.

You might find this book of interest. https://www.amazon.com/Thermodynamics-Earth-Planets-Alberto-Pati-f1o/dp/0521896215 It should be accessible to anyone with high school maths and explains things as it goes along.

I suppose it's about whether the mathematical concepts which are used have a physical meaning or not. When you proof a mathematical concept with a physical meaning then proof in math and science are the same thing. You have the density matrices, metrics... Perhaps you could explain to me how this is an answer to either my question directly to yourself or to the original post? Either the 'proof' is the same in Mathematics and Physics or it is not. You seemed to me to be asserting that it is the same so I asked for confirmation since My OP operates from the premise that it is not the same and furthermore I offered one example of difference. I do not claim it is the only example.

So you were just guessing.

Where do you know this from? Is your position that there is no difference between 'proof' in Mathematics and 'proof' in Science? The example I gave arises because Mathematics is built on axioms and propositions, proof is a process of verification of the consistency of any proposition with what precedes it in the structure. Scientists do not have this absolute luxury since there may be a scientific phenomenon beyond their knowledge that negates their prediction. As a result of this scientific 'proof' is really about the verification of a prediction.

I don't think you can generalise about the subject at all, some are good, some are bad. Though I do think CharonY has nailed the basis of a good popsci book. Authors are like the general population at large. A percentage have a good grounding in Science, others offer second hand knowledge from what they ahve been told, yet others just bullshit along. Whatever their background some naturally want to tell a story ( the narrative of CharonY) and these provide many examples of superbly interesting and entertaining tests. Others just churn the handle, and it shows. Very often the publisher relies on heavy promotion to boost this brand of author so these are unfortunately the ones in the public eye. Most of us will have a main area of expertise, and may then welcome something a bit lighter in scientific areas that are peripheral to us individually. I know I do. Geology is such a subject for me and I find that unless I am actually working to BS CP 2001 (Site Investigations) the dry pedantry of the geological language tiresome. But I also like to be able to trust the author and I find that popularising books by recognised professors such as Mike Benton can bring the subject alive. But it is also true for fiction that Jane Austen leaves me cold but i have read and reread C S Forrester books many times. Yet others find that Austen was a great author. So, I imagine, it also goes with popsci. Others will have a different opinion

Mark, Since discussion of fields is both offtopic here but of great general interest I have started a new thread for you to ask field qustions.

In any feedback control system the sensor should be as close as possible to the business end of the device. Having the sensor up by the fan is counterproductive as it will respond to changes close to the fan before these have any effect on the boring machine end. So any desired change in airflow at the boring machine end will effectively be short circuited. You said your tubes were a couple of kilometres long so the latency in the control system will need to be designed to prevent this happening. 3MW is a big fan.

Yes, the dehumidifier is a scaled down version of the industrial plant I mentioned. True, the device has apparently to be different from that which someone else has already made.

No I did not miss the sometimes. But since you made a statement, conditional on the sometimes, I asked about the times when that holds true. Since I offered two mutually exclusive possibilities (the third not said being a combination) the reply "In no way" is puzzling to say the least. I am sorry we are havng such trouble communicating, but I certainly can't agree that discoveries deal with the known. Surely that is a self contridiction? How is something a discovery if it is already known? I stand by my scenarios, perhaps some examples might help? 1 )Van Leeuwenhoek discovered something no man had ever seen or had any idea existed. He named these things 'animalcules'. He was the first man to see microscopic organisms. 2) Galileo dropped two cannon balls from the tower of Pisa to see which one would land first. A test between two different theories. I am sure I could find many many more examples.