Black Holes .

Discussion in 'Astronomy, Exobiology, & Cosmology' started by river, Aug 11, 2019.

Thread Status:
Not open for further replies.
  1. DaveC426913 Valued Senior Member

    Messages:
    14,675
    1. Not all galaxies have black holes at their centre.
    2. Black holes are not merely mathematical constructs. Nor are they merely theory. We have plenty of evidence - including images.
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Janus58 Valued Senior Member

    Messages:
    2,152
    If two black holes form close enough to each other they will start off orbiting each other. The action of this orbiting causes the system to emit gravitational radiation, the energy for which comes from the orbital pair*, and they spiral in towards each other. The energy emitted by gravitational radiation is proportional to the frequency of the radiation and that frequency is determined by the orbital period of the BHs, as the orbits shrink, the periods get shorter that the intensity of the gravitational radiation bleeds of orbital energy faster, shrinking the orbit... The shrinking of the orbits start off slowly but gets faster and faster, during the last moments, the black holes are orbiting so fast that they produce a "chirp" of gravitational radiation ( it was this chirp that was strong enough to be detected by LIGO.

    * The earth does it too, but because its orbital period is a year long, the radiation is very weak and only results in the Earth's orbit shrinking by the width of a proton per orbit.
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. river

    Messages:
    14,698
    If , is theoretical .
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. river

    Messages:
    14,698
    1) why not ?

    2) what images ?
     
  8. Write4U Valued Senior Member

    Messages:
    14,733
  9. DaveC426913 Valued Senior Member

    Messages:
    14,675
    Why should they?

    Please Register or Log in to view the hidden image!

     
  10. Janus58 Valued Senior Member

    Messages:
    2,152
    Since LIGO actually detected the gravitational waves generated by such an event, It isn't just theoretical.
    The "If" here is of the same usage as in "If you have a group of 367 people, there will be at least two people that share the same Birthday (month and day). There is nothing "theoretical" about being able to gather together a group of 367 people. The 'If' in this sentence has nothing to do with the likely-hood of the existence of people or their affinity to gather in large groups. In either case, you could have just as easily used "When" rather than "if", and not changed the intent of the sentence. " If I go to the store, I need to buy bread" Doesn't imply doubt on whether stores do or not exist or assumes that I may never go to one in my lifetime.
    Trying to support your case by picking on a particular word used in a sentence and applying an overly narrow meaning to it just makes you look desperate or foolish.
     
  11. JJM Registered Senior Member

    Messages:
    355
    Some bh's are impact momentum spheroids as produced by collision, friction,and the state of motion. Either one or in combination with each other.
     
  12. sculptor Valued Senior Member

    Messages:
    6,964
    black holes---wormholes?
    if so
    where to?
     
  13. DaveC426913 Valued Senior Member

    Messages:
    14,675
    This has been conjectured, but there's no evidence or model to support it.
     
  14. paddoboy Valued Senior Member

    Messages:
    26,023
    Don't ever let the idiocy of river throw you off. BH's are as confirmed now as other scientific theories are such as the BB, SR/GR are. The evidence is overwhelming.
    Wormholes while certainly being allowed for by GR, are as yet to be observed.
    Some though have theorised spacetime forming a wormhole of sorts, via a ERB at the center of BH's and what we now call the singularity. The singularity as was once defined by infinite spacetime curvature and density, is not thought to be viable, but certainly a singularity as defined by the failure of our laws of physics and GR, is still on the cards. This would mean a surface of sorts at or just below the quantum/Planck level where these laws fail us. So probably no wormhole, or singularity as defined by infinite qualities, but a mass/energy in an unknown conglomerate state.
     
  15. davewhite04 Valued Senior Member

    Messages:
    4,884
    Of course it is.

    [/quote]

    What word did you pick?
     
  16. davewhite04 Valued Senior Member

    Messages:
    4,884
    All I see here is a bunch of Know-nothing's pretending to know something and ganging up on an inquisitive mind. River will reach enlightenment, all you bullies never will.
     
  17. paddoboy Valued Senior Member

    Messages:
    26,023
    What word did you pick?[/QUOTE]
    Well since so far we have had around 14 or so discoveries of gravitational waves, that all just happened to match templates of various size and mass, and since we have now also taken a photo with the EHT of a BH, it is far more then any theory you choose to contemplate. It is a scientific theory which continues to gain in certainty. But of course you may have some evidence of your own to show it is something else? That something else by the way, going on what observational data we do have, would be far more weird and strange then what you and river apparently see a BH as.

    Please Register or Log in to view the hidden image!

    From one know nothing to another, there is nothing wrong with any inquisitive mind...there is nothing wrong with asking questions, but there is sadly plenty wrong in being a gullible fool and accepting what any kook will tell you, particularly when it concerns anal probing Aliens, ghosts, goblins, Santa, and fairies at the bottom of your garden. That is the result of a mind that simply has never matured.
     
  18. davewhite04 Valued Senior Member

    Messages:
    4,884
    You've said nothing of value. Considering we are talking about science and a theory it is a given we use theory, why would we want to write "scientific theory" instead? Why do you think scientists are employed to study this exact theory full time and paid?
     
  19. DaveC426913 Valued Senior Member

    Messages:
    14,675
    When river - or anyone else - is inquisitive, I try to indulge that as best as I can. I did that for the first half of this thread, when river was asking questions.

    river in particular tends to ask about two questions and then start making declarations.

    Examples:
    'All galaxies have black holes at their centre'. This is demonstrably false.
    'Since no one can tell me what the "essence" of a black hole is, it is only a mathematical construct'. Doubly demonstrably false.

    What we uphold here are science and facts. What we discourage is ignorant anti-science trolling.

    You'll notice, by the way, that this thread - while ostensibly a hard science topic - is posted in Free Thoughts. That's because river has been banned from posting in the science forums by the moderators for habitual trolling.
     
  20. davewhite04 Valued Senior Member

    Messages:
    4,884
    That is your problem. You think facts exist.
     
  21. DaveC426913 Valued Senior Member

    Messages:
    14,675
    Your problem is that you're anti-science.

    Why come to a science forum - unless it's to troll?
     
    paddoboy likes this.
  22. paddoboy Valued Senior Member

    Messages:
    26,023
    Because a scientific theory unlike any application of what you may call a theory in every day life, is the highest accolade any scientific model can have. A scientific theory is always open for change, improvement, modification, or simply scrubbing...a scientific theory also continues to gain in certainty over time, and as it continues to make correct predictions. eg; GR told us 100 years ago about gravitational waves....That has despite your misgivings gained in certainty now....The theory of the evolution of life and the BB have gained so much certainty that even the Catholic church recognises both. For the Catholic church though, that's where it ends...they blindly put it down to the work of some deity....science on the other hand, keeps searching and making more and more observations in an attempt to arrive at an evidenced based answer. https://en.wikipedia.org/wiki/Scientific_theory
     
  23. davewhite04 Valued Senior Member

    Messages:
    4,884
    You think I'm anti-science? What give you that idea?
     
Thread Status:
Not open for further replies.

Share This Page