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Eise

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Eise last won the day on June 8

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490 Beacon of Hope

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About Eise

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    Primate

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  • Location
    the old world
  • Favorite Area of Science
    Physics, Astronomy
  • Biography
    University degree philosophy, subsidary subject physics
  • Occupation
    Database administrator, a bit of Linux too

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  1. I think Joigus made an excellent job here. Not giving the absolute, technical correct explanation, but trying to pickup from the estimated level where the questioner stands. Joigus presented the Einstein Equation, which really has (kind of) the form he presents. On one side stands a mathematical description of the curvature of spacetime ("Geometry"), and on the other side the possible sources of that curvature ("Matter"). Maybe one could say that "Geometry = Gravity" is a postulate of general relativity, but is definitely not the Einstein Equation itself.
  2. You must distinguish between the many different contributions E made to physics. But I assume you mean relativity: special- and general relativity. For special relativity, the time was ripe for its discovery. Several physicists before (Fitzgerald, Lorentz, Poincaré, and several others) already guessed the correct formulas. It was even Poincaré that called the Lorentz transformations that way. But Fitzgerald and Lorentz used more or less ad hoc assumptions to derive them, e.g to explain the null result of the Michelson-Morley experiment. Poincaré's views already circled around the concept
  3. No, no, this is not the way it works. Say you are mining real, physical gold. That also costs a lot of energy (and labour). If you can't earn those costs back with the gold you are selling on the market, you would consider to close the mine. With Bitcoin it is the same: your mining costs energy, infrastructure (especially powerful computers). But then, if you have created a new Bitcoin, you go to the market with it. If your costs were $15'000, and the Bitcoin is worth $20'000 at the moment you have earned $5'000. But if the Bitcoin is $10'000, you have to accept a loss. And you might cons
  4. More or less. But I think I should wait for MPMin's reaction. You see, if you introduce too technical details, there is the risk of a 'conceptual overload'. Either MPMin understands what I mean, or (s)he asks more detailed questions him (her?) self. You see, sometimes my toes curve, not due to space curvature, but because I see that a curious beginner gets confronted with all kinds of technical details that he cannot see through. So this is a didactic principle of mine: try to connect as much as possible to the level of understanding that the questioner has. This risk is exactly shown her
  5. No. 'Flat' means that e.g. parallel lines stay parallel, no matter how far you compare their distance between them. Best example is two light beams. When these do not converge or diverge, the universe is flat. It is difficult to imagine how a positive curved universe can be infinite because it is closed in itself, like the surface of a sphere. But with negative curvature and flat space that problem does not arise. Just take care that the universe seems to be flat on average. Locally, due to mass and energy, the flat universe can be curved.
  6. Recently Ethan Siegel has an article about it: starts with a bang.
  7. I am not a CC expert either, but I picked up, that also financial transactions cost a lot of energy. AFAIK this is because enough of the delocalised blockchains must confirm the transaction before it is definite. Googling I found this comparison: From here.
  8. Yep. It is called gravitational redshift.
  9. This makes no sense. We know 'Newton' is not valid for velocities that are comparable with light speed. So at one side you apply 'Newton' (E = 1/2mv^2), on the other side you apply relativity by saying that the speed of light is speed limit. You need to use relativity from the beginning, and then you will see that a proton accelerated to 7 TeV flies just a tiny fraction slower than c.
  10. In addition to MigL comment on time dilation: at the event horizon of a black hole time dilation for an observer on a big distance goes to infinity. That means the frequency of an EM wave goes to zero, and the remote observer will not see any EM radiation.
  11. See it this way: getting out of a gravitational field costs energy. Objects with mass lose kinetic energy, which means they slow down. Light also has energy, but it is not dependent on its speed, because it always has the same speed. But the energy of light is related to its frequency. So light 'loses frequency', which means its frequency goes down, i.e. it becomes redder. Now imagine a light beam with less energy than needed to get out of the gravity field. It would have no energy anymore, which for a wave simply means it does not exist anymore. At the event horizon EM radiation just has not
  12. Ethan Siegel in 'Start with a Bang': Why You Should Doubt ‘New Physics’ From The Latest Muon g-2 Results It throws doubt about the correctness of the theoretical calculation of the value of g-2. So there might not be a discrepancy between experiment and theory, because the calculation is not rock solid. But hey, how many articles appeared with new physics explaining neutrinos traveling faster than light? Hundreds? But it was an experimental error. This time I set my bets on a wrong calculation.
  13. Of course, I forgive you: even stronger, anyone can correct my English. Wasn't it you who said you wanted to know English perfectly, at least on your deathbed? As long as the stream of the discussion is not disturbed, any correction is welcome. You know, there are so many ways that the same, or nearly the same (especially in none English ears) sounds can be written in English. My favourite is the [i:]: peace piece pee release receive retrieve But life, live, and yes, lose and loose are difficult too to remember. But I try to improove! The one
  14. Don't expect too much from me... Ethics never was a main topic for me. I would say, as any sensible person, just the risk of giving capital punishment to an innocent should be reason enough to refrain from it. And AFAIK deterrence seldom works. So I think incarceration might be the best solution, in the first place simply because we put somebody away who has proven to be dangerous, in the second place we, i.e. society must attach consequences to people who do not want to play by the rules. However, if a society does not take the chance to rehabilitate the offender, it is not much us
  15. Then the world is absurd. See a ball and feathers falling in vacuum:
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