Danijel Gorupec

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About Danijel Gorupec

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  1. Danijel Gorupec

    First real Black Hole image - 10 April 2019

    How can an event horizon ring? Isn't time stopped at the event horizon, and thus for an outside observer it should remain unchangeable? I don't even understand how it can grow.
  2. Danijel Gorupec

    First real Black Hole image - 10 April 2019

    Thanks beecee, hopefully this weekend I find time to read in more details (both links seem interesting, yet difficult for me). Anyway, after a quick look at the links, it seems to me that this BH observation might mean more for the theory of accretion disks than for the theory of black holes themselves.
  3. Danijel Gorupec

    First real Black Hole image - 10 April 2019

    I have few additional questions about the photography: Any idea what is the approx. mass of the accretion disk relative to the black hole mass? Should I expect it to be 'paper-thin' (like Sautrn's rings) or does it have a substantial thickness? What is the density of the accretion disk near its 'middle' region - like that of water? Or more? Or less? What do colors/shades on the photo show - radiation intensity or radiation wavelength?
  4. Danijel Gorupec

    First real Black Hole image - 10 April 2019

    Great photo - thanks. Accretion disk! I thought it is some sort of occultation that was imaged (I assumed this because of all the talk regarding the shape of its shadow)... If it is accretion disk, then I guess it is lucky that it is angled the way to show us the black middle.
  5. Danijel Gorupec

    First real Black Hole image - 10 April 2019

    What is the size of the black thing? I couldn't find this data in the link provided by Strange. What is the source of the background microwave radiation? Seems huge.
  6. Danijel Gorupec

    Energetically favorable configuration

    Actually yes; thank you. It introduces the concept of 'evolution of energy' which I find more intuitive than the 'energetically favorable configuration'. But I guess there is some misalignment in your answer and my question - you are talking about 'energetically favorable process', while I ask for 'energetically favorable configuration'. I can guess, from your answer, that the 'energetically favorable configuration' could mean that a system reached a state where there is no more net evolution of energy - could this be right? (Yes, I had to write 'isolated system' instead of 'closed system' - I guess i my language we use the same term for both things).
  7. Danijel Gorupec

    Are AI abilities limitless?

    AI is limited by laws of physics - it cannot do God-like things, if this is what you had in mind. Maybe there are other limitations that we are not aware of (for example, maybe extreme intelligence is not stable in single personality - maybe personalities spontaneously split. I don't think it is like that, but I don't know of any proof against it.) Edit: typo
  8. Danijel Gorupec

    Energetically favorable configuration

    A quickie... What does the term 'energetically favorable configuration' means? Does it have any strict meaning at all? One might say, for example: "magnetic domains will set into an energetically favorable configuration" (but my question is general, not about magnetic domains in ferromagnetic materials). (If it means 'lowest possible energy' then I guess that closed systems cannot have 'energetically favorable configuration' as the energy there is conserved)
  9. Danijel Gorupec

    SFN Slogan

    Not the topic her, but yes, it does bother me. It seems that people are associating atheism with these prominent and men - but, sadly, mostly to the aggressive part of their image... I noticed that I started to feel bad about revealing my own atheism, or if I am forced to reveal, I quickly say "atheist, but not anti-theist".
  10. Danijel Gorupec

    SFN Slogan

    Hmm... but isn't it that you should be explaining this to new forum visitors? They will be judging this forum by its quotation choice. They will judge that this is a fighting forum and will take the fighting stance (some of them happily and readily). They won't make their judgement by what is quoted, but by who said it.... This is the practical side of my reasoning against the quote. Yes, I know I am exaggerating (very few people will actually read the quote... and if we also write the author's name in a very fine print...)
  11. Danijel Gorupec

    SFN Slogan

    If this can be done, it would be much better But my advice to the owner of the forum remains the same.
  12. Danijel Gorupec

    SFN Slogan

    True... but my point is something else... Even if author is all perfect (which I think is not) and even if its quote is polite, reasonable and beautiful (which I think it is), this still is not enough... as long as there is a large group of people who might be offended by the choice, we should refrain from forcing it. Even if this large group of people is all wrong... That was my point. (I am not being a coward, I just think that SFN is not that kind of forum; not an anti-theist forum... not a fighting forum, but just a discussion forum... but this is only how I see the SFN, other members might have other ideas.) Agreed (but I did use it intentionally, because I am skeptical about how much good did Hitchens do for me. I am not sure if I feel comfortable calling myself an atheist if this is enough to evoke a fight-or-flight response in other people.)
  13. Danijel Gorupec

    SFN Slogan

    And this is exactly why I would advice against... The quotation itself is mild and nice, but its author is some sort of atheist god of war.
  14. Danijel Gorupec

    Energy contained in the magnetic field

    Yes, but I don't know how much is this 10^11 estimation reliable. Also, it might be the density figure within the magnetar's body (wikipedia is not clear about it). It is also very unlikely that our magnetar will be perfectly aligned to make optimal conditions for our measurements. That's why I opted for the more conservative 10^10 value. Another obstacle, I think, is that the physical size of the field is way too small - several tens of kilometers in diamter. How much would an occultation from such a small object last - a fraction of a second? I guess it is too small to make measurement, but I actually don't know.
  15. Danijel Gorupec

    Energy contained in the magnetic field

    I understand the method, great! In fact, it occurs to me that even one single light source, passing slowly through the magnetic field, can be used - its light should, if conditions are preferable, display larger wobbling amplitude as it approaches the magnetar's surface. This actually could provide some mass-energy distribution information. Edit: I still think, however, that our instruments cannot do it - eight orders of magnitude, calculated by Swansont, seems as a too large obstacle.