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Showing content with the highest reputation on 02/04/23 in all areas

  1. Perhaps "upper bound" are the words to look for here? It definitely sets a theoretical upper bound in terms of energy obtained to energy invested ratio, having nothing to do with time --how long the machine is running, as you pointed out before--, or with whether the machine will eventually stop or keeps going forever --as Swansont pointed out. Because the Carnot cycle is defined in terms of state variables --due to all intermediate states beeing equilibrium ones-- and because an ideal gas has no internal mechanism to hide energy other that its pressure, volume, and temperature, no matter how many contraptions or intermediate complications we introduce, this upper bound cannot be overcome. The dynamics of this discussion does remind me of that of a Carnot engine, with a reservoir full of an inexhaustible resource, and the corresponding sink that can take any amount of such resource without in any way changing its state.
    2 points
  2. BH falling into object or the other way around is a matter of reference frame. The thing about small Schwarzschild radius --in comparison to falling object-- is a question about tidal forces (gradients of gradients or second-order derivatives.) When object is very close to centre of gravitational attraction, it's no longer possible to consider local inertial system as such, due to second-order effects (second order derivatives.) I'm sure you know about this --from what I can infer. You're either an expert on this or a person so knowledgeable that not even an expert could tell the difference.
    1 point
  3. @Tom Booth here is an example where the scientists probe at the limits of applicability: ... Source: https://www.nature.com/articles/nphys3518.pdf (I do not wish to take the discussion off topic, we discuss the case of Carnot limit for macroscopic engines. Just wanted to share in case there is any interest in papers discussing limits of applicability in the context of Studiots comment.)
    1 point
  4. In the realm of ethics, it would seem that caring is of lesser importance than what actions we take or facilitate others in taking. I can virtuously broadcast how much I care about ecological and climatic changes over the next couple generations, but if I keep serving beef or pork at every meal and driving an Escalade everywhere I go and sitting with my wife in a 2500 square foot propane-heated house with a heavily irrigated quarter acre of bluegrass lawn, then my caring has minimal ethical component. The duty of care is to implement those worthy concerns I have in remedial actions. This action would also mean that passing on wealth to the next generation is more likely to succeed, since ecological and climatic catastrophes seem likely to destroy wealth. Ergo, joining in on a beneficial approach at the societal level can also yield benefit at the familial level. For some, the latter motivates the former.
    1 point
  5. I've just found this, but wouldn't know why that's the case: (My emphasis). From: https://en.wikipedia.org/wiki/C/2022_E3_(ZTF) Maybe you can make something out from this.
    1 point
  6. I recall trying to run my stirling engine on a hot day. I put it on a mug of hot water and it would barely run - too much friction. When I put ice cubes on the top plate, it ran pretty well. Since the source of heat was the same, the only way this could be the case is if I was converting more heat to work - the efficiency increased.
    1 point
  7. Yes, it’s indeed not different from EM waves. What is different though is the way gravitational waves interact with one another, and with any background curvature that might be present.
    1 point
  8. Disgust over things which spread illness and disease (like spitting, coughing, nose picking, and scrotal scratching) makes good sense in social groups where for centuries even a small cut or stubbed toe could (and rather often did) lead to infection and death. Disgust over OTHER PEOPLE happening to prefer intimacy with more similarly gendered partners does NOT help prevent the spread of illness and disease. You are a free man with a free mind and are equally free to feel disgust over any ridiculous damned thing you want, but let’s please drop the charade and stop pretending it serves some higher evolutionary purpose when it’s felt toward non-heterosexuals just for being who they are and loving who they love.
    1 point
  9. No one has ever been banned for having a difference of opinion with another poster. And you convince others to your point of view with a robust argument; not complaints. Why not just drop it and concentrate on your posts; not complaining about others' ?
    1 point
  10. You are focusing on the part about being right or wrong; which are not against the rules. We are all here to learn. I've been wrong lots of times, as I'm sure you have; allow others the same courtesy. And referring to someone as a 'moron' is against the rules; even if as a choice between troll or moron.
    1 point
  11. What are the same are the speed of light (in a vacuum) and the speed of gravity waves. Gravity waves are not gravity itself, but more like ripples traveling through the gravitational field. Put another way, you can't have gravitational waves without there already being a gravitational field, but you can have a gravitational field without gravitational waves. Light interacts with the gravitational field, which is "already there" As already mentioned, light has no "rest mass". However, it still can interact gravitationally. While in Newtonian physics you need mass to do so, under our more recent understanding of gravity(General Relativity), mass is just one factor that can contribute to gravity. Energy is another, and light does have energy.
    1 point
  12. Personal theories must be backed up with evidence and you should expect to be challenged. “hostile agenda” has to be more than your say-so There isn’t one; it was not directed at an individual.
    0 points
  13. An ISRAELI CORPORATION You have two cows. They come with guns. Move you to a dusty cowshed and take your cows. Then they bulldoze your cowshed and when you protest, they shoot you for being a terrorist. Then American taxpayers pay to replace the bullets. Then end times. https://www.scienceforums.net/topic/35130-political-humor/page/17/#comment-1228505 (post content from other thread added by moderator for context) The joke takes a swipe at Israeli hardline policy, seems like. Maybe not the greatest joke, but I would not want to start downvoting jokes. Am counteracting the DV, not because I agree with all the premise of the joke but because I like this thread being one thread where people feel accepted to make weird or even smelly transgressive attempts at political humor. (one can also Google "Palestinian olive trees destroyed" for further research on what triggers such jokes - quite the eye opener!)
    -1 points
  14. An ISRAELI CORPORATION You have two cows. They come with guns. Move you to a dusty cowshed and take your cows. Then they bulldoze your cowshed and when you protest, they shoot you for being a terrorist. Then American taxpayers pay to replace the bullets. Then end times.
    -3 points
  15. Your exaggeration of my theory is false. Babies aren't born believing in democracy or capitalism or communism or Christianity or Islam or Judaism or science or any other cultural belief system. Again, only your exaggeration is false. Got some mommy issues, princess? Those theories are politically motivated propaganda.
    -4 points
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