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swansont

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swansont last won the day on March 16

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About swansont

  • Birthday May 12

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    Washington DC region
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    Geocaching, cartooning
  • College Major/Degree
    PhD Atomic Physics Oregon State University
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    Physics
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    Physicist

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  1. The circumstances surrounding this and Hiroshima are hardly comparable.
  2. Klaus Fuchs. The Rosenbergs. And others. Also, your premise that Japan was beaten does not match the facts. They did not acknowledge it. They rejected the Potsdam terms. They did not surrender, even after the first bomb was dropped. Did they do their own Manhattan project equivalent, or did they use pilfered results? One thing about research is the time, money and effort you spend finding out things that don’t work. Subsequent efforts don’t have to expend resources chasing these down.
  3. Yes. I don’t think your post has a sold basis in fact.
  4. Assuming it would be economically feasible to retrieve these metals, I think the question this raises is what would happen if you could suddenly e.g. double the availability of these rare metals. IOW, are there efforts that are supply-constrained? If the new availability drove prices down, it’s possible that you’d come up with new products that aren’t currently viable owing to cost.
  5. The blocked light forms a cone (see the eclipse link for an example) s = r*theta s is the size of the block. theta is the angular size. r is the distance to the screen blocking the light.
  6. There are situations where this isn’t true, though it’s not truly thermal equilibrium - you can cool a sample of a dilute gas with lasers, with the axes being independent. One- and two-dimensional cooling can take place. The atoms equilibrate with the laser light. The photons don’t interact with each other, so the velocity profile in each dimension can be different. The atoms are dilute and move very slowly so they scatter much less often with each other than with the photons.
  7. In thermal equilibrium you can’t decouple these effects. You can’t create a situation where you have the translational motion without the non-translational motion.
  8. Have you ever noticed that e.g. a tree or house some distance away can block your view of things further away?
  9. If you want to block the whole star from all of earth, you need something the size of the earth. If you just want to block one person from seeing it, you need something roughly the size of someone’s face, though diffraction will mess with this. Arago’s spot means light will still be there. https://en.m.wikipedia.org/wiki/Arago_spot
  10. The size of the “light beam” is approximately the size of the source; even bigger, since over 4 LY you can’t ignore the divergence. Alpha Proxima is bigger than a few mm. The beam illuminates the whole earth, i.e. you could observe the star from any point on the surface unless earth itself is in the way. Diffraction means you need something bigger. Diffraction, and that the sun is bigger than the moon, and that the moon is some distance away. The light is not parallel. If you were closer to the moon, the dark spot would be bigger.
  11. This makes no sense. An angle, by definition, assumes a vertex, which is a point. The light from Proxima Centauri hitting the earth can be treated as parallel over such a short distance as the diameter of the earth. The angular size of the star is not the same as the divergence of light from it.
  12. Coxy123 banned as a sockpuppet of splodge and JustJoe
  13. These itemized topics look like math or computer questions.
  14. Yes you can copy and paste links, as long as they comply with the rules https://www.scienceforums.net/guidelines/ Rule 2.7 in particular, especially this part - “Links, pictures and videos in posts should be relevant to the discussion, and members should be able to participate in the discussion without clicking any links or watching any videos”
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