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Showing content with the highest reputation on 01/17/22 in Posts

  1. I loved "Longitude"! Sobel made more sense out of navigation, timekeeping and related topics than anything else I've read. I second BC's recommendation.
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  2. If I can add another...a book entitled "Longitude" by Dava Sobel...a story about solving the greatest scientific problem of the time, and the carpenter that took up the challenge creating the first working chronometer that could be used at sea on an unstable surface, and away from any observational land forms. His name was John Harrison. The problem was monumental and the cause of many tragedies at sea in that age of Oceanic exploration. So much so that King George 111 offered prizes and rewards worth millions today. Even the great Sir Isacc Newton thought it impossible. Another great and learned read.
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  3. Three guys walk into a bar. A witness on the sidewalk says, "ouch, that must have hurt!"
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  4. I'll have another go. The spinning propeller is designed to that there is a pressure difference between the front and rear surfaces, and that's what gives thrust, in any propeller. Now consider the spinning propeller with no wind. Yes, there is a pressure difference, and therefore a resultant force on the propeller. So there is a forward thrust on the vehicle. BUT, it's not enough to drive the vehicle forwards, because of drag and friction losses. So in still air, the vehicle when running at speed would slow down and stop. But now consider the spinning propeller with a following wind. The air from the propeller meets the following wind, and you get a greater pressure build up, all the way back to the propeller. So in this case, there is a greater pressure difference front to rear on the propeller blade, than in the no-wind case. So with a following wind, even if it's slower than the vehicle speed, you will still get more thrust on the propeller blades, than in no wind. So instead of slowing to a stop, the vehicle can accelerate. So it's the back up pressure that's giving the extra thrust. So even though the wind is not keeping up with the vehicle, it's still providing energy, through the raised back up pressure. The kinetic energy of the wind is being transferred through all of the tiny collisions, between the propeller air molecules, and the wind air molecules. So the wind slows, and the vehicle accelerates.
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  5. Yes, I was one of the participants, arguing strongly that Jesus more probably existed than not. I am missing reference here to the fact that Paul mentions meeting Peter and Jesus' brother James (in a letter that is considered genuine), and that James is also mentioned by a few (two, if I correctly remember) historians in the Roman age. There is also the strange fact that according to one gospel Jesus was simply born in Nazareth, but in Luke there is the complicated history where Joseph and Maria had to go from Nazareth to Bethlehem, obvious bending history to get it in sync with the prediction that said the Messiah would be born in Bethlehem. Such a bending would not be necessary if the story was a myth from the beginning. Most classical historians agree that the evidence hints at a real existence of Jesus. But 'hints' does not mean 'proves'. Read e.g. Bart Ehrman, Did Jesus really exist?. But the picture of who Jesus really was, is very different from how he is pictured by (modern) Christianity. He seems to have been an apocalyptic preacher, expecting to see the 'youngest day' (the Apocalypse) on Earth (not in heaven!) in his own lifetime, or at least very soon. I will not repeat every argument here, there are many posts of me in that thread.
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  6. From time to time people ask why the US immigration forms ask you if you plan to over throw the government by force. People laugh at this- after all- any actual revolutionary would simply lie about it. The point of the question is that, if it tuns out that you were planning a coup, the government can throw you out of the country for providing misleading information on your visa application. That's it; no court needed- no appeal. The thing that most people fail to recognise is that it's a general rule. If you get caught lying they kick you out. It's one of the more sensible things the US govt does. Most countries will do it, if they have the slightest reason not to want you in their territory. And Djokovic did not fill in the paperwork correctly. What did he expect to happen? I heard he intends to participate via Zoom.
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  7. My wife just stopped and said, ”You weren’t even listening were you?” I thought… “That’s a pretty weird way to start a conversation.”
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