Recent content by Jackissimus

  1. J

    B Why does Lithium fission produce energy?

    Hi, a simple question from an amateur: Why does Lithium fission produce energy instead of consuming it? (https://www.world-nuclear.org/information-library/current-and-future-generation/lithium.aspx) I always thought that fission of heavy elements produces energy, and fusion of light elements...
  2. J

    I Quantum Tunneling in an STM: ELI5 Requested

    Right, that actually makes sense, the voltage used was not very high, just a couple of volts. The topography is reconstructed from the current map as the tip is raster scanned above the surface (about 50nm high) BTW. Right, so the main difference is that classically the voltage would have to be...
  3. J

    I Quantum Tunneling in an STM: ELI5 Requested

    In an STM, you image the surface topography by tunnelling electrons from the metallic tip to the conductive surface, while measuring the current. I have worked with these instruments before and I never understood why does one need a quantum explanation for this. Wouldn't the electron jump to...
  4. J

    What's the point of Escape Velocity?

    Ok guys, I gave it some more thought and I think I got it. What you are saying is that as my rocket is flying away from Earth, the deceleration rate gets smaller and smaller and it converges to a certain number, which for escape velocity would be 0km/s. If I would fly a rocket at 13.2km/s from...
  5. J

    What's the point of Escape Velocity?

    Yep, the Voyagers are leaving our system right now for example, they had enough speed to reach the Heliopause, but that doesn't necessarily mean they won't come back. They most likely won't, because they will encounter another star that will pull them in, but they didn't need to reach escape...
  6. J

    What's the point of Escape Velocity?

    If you send a rocket away from the Earth at 11km/s, the rocket will slow down gradually. The speed will get to 10km/s, then 9km/s, due to gravitational pull. The deceleration rate will get lower and lower, but it will stop the vehicle and then turn it around, because there is a constant...
  7. J

    What's the point of Escape Velocity?

    Hi everyone and thanks for this great forum! I don't understand how is calculating escape velocity important to space travel. I think I am right to say that you can never really escape the gravity of a body. However far your rocket goes, be it 400km or 14 billion light years and making the...
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