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Time and black holes

  1. Jul 6, 2009 #1
    Hello everyone, before I start, I just want to say I feel a little out of place here. I am not a student of physics or cosmology, and I am definitely not a professional at anything scientific. I am an artist and going to school for Industrial design. I have always been fascinated with Science, and understand it, but lack the mathematical ability to pursue any scientific field, I just have a talent for creativity and a mostly A.D.D. wired brain...I do have some thoughts though on physics I want to share with people and ask questions and all, but I don’t have anyone to really talk about it with. Most people get lost when I start talking about these things so hopefully you guys can help me more on this, and even though I might not know much mathematically, I hope maybe creatively I can give you some lead for current and future scientists. With that said......

    I understand that black holes warp space/time around them. Here is my question or pitch or whatever...what if the larger black holes at the very center of galaxies not only warp space and time...but actually create time throughout their galaxy. Thus the spinning motion of galaxies is time being created by their black holes in their center of the galaxy. So every second that goes by could not occur if it wasn’t for the massive black hole that spins our galaxy around. SO.....



    I know it might sound dumb of me to even write this, it's probably something that someone already thought about, but it’s something that has been on my mind for a while...let me know what you think.
     
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  3. Jul 7, 2009 #2

    malawi_glenn

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    woo another "creative" person who thinks and hope that he can inspire scientists...

    All massive objects "warp" space-time...

    We actually know why galaxies spin, so there is no need for you to even mention this insane idea...
     
  4. Jul 7, 2009 #3
    your right about the spin part, i almost completely forgot about dark matter and all that...but if massive objects warp space-time, then dont you think they have an influence in the way we percieve time itself? especially a massive object with a Huge gravitational pull like a central black hole...

    and as for the whole creative person thing, sorry...didnt mean to hurt your feelings, im not implying that im smarter or that you cant think creatively...I just think if a right brain and a left brain working together would benifit everyone instead of holding on to you arrogance and completely dismissing me because of your personal opinions. But hey, its cool...Im here to learn.
     
  5. Jul 7, 2009 #4

    sylas

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    Learning is good. What was rather surreal was the phrase:
    I hope maybe creatively I can give you some lead for current and future scientists

    I don't think it is particularly arrogant or inappropriate to note that you have not a hope in hades of giving any lead to scientists. That's not an insult to you, and it should not prevent you at all from going on with the honourable task of learning more about things for yourself. It's not about you, particularly, but about how science works and what it takes to actually give credible leadership in science. If you really don't understand that, then that's one of the things you still have to learn.

    Your initial post is rather incoherent. It's not that you aren't "smart", but that you have not yet learned nearly enough about the subject.

    Good luck with your endeavors, seriously. But forget about giving leadership, unless you are wanting to take up science as a career.

    Cheers -- sylas
     
  6. Jul 7, 2009 #5

    mabey i said it wrong and thats fine I accept that. But I do not want to take leadership, just learn more about these things, and if some idea come up in my head, its ok if you shoot it down, just explain to me what you know wo i can better understand. and even though i am not taking science up as a career I want to keep it as a hobby, im a person who wants to know about the world he lives in and not stay blind to it. so help. thats all, and ill keep asking and throwing out my dumb opinion and ideas so you can teach me more and help me understand better, thats the whole point of why I signed in to this forum, to talk to people who know, because not to many people around me do.
     
  7. Jul 7, 2009 #6

    malawi_glenn

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    if you are here to learn, ask - don't come up with your own "ideas"... we do not post our own ideas here (read the forum rules).

    And yes, massive objects to infect time, no-one has said anything else?
     
  8. Jul 7, 2009 #7

    sylas

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    Good for you; and don't be put off the learning part of your project! If you'll take some advice, at this point it is going to be more useful to you to sort out other people's ideas than to make speculations of your own. Ungrounded speculations are a poor basis for useful questions.

    The short answer to your speculation in the original post is "definitely not". Time is not "created by" black holes, and the motions of stars in a galaxy depend only on the total mass, regardless of whether it is in the form of a black hole or not. For example... if by some magic our Sun was compressed to a black hole, the boundary of the "hole" would be about 3 kilometers across; but the orbit of the Earth would be unaffected.

    Cheers -- sylas

    PS. Hi malawi glenn. Uh... "infect time"? I guess you mean "influence time". Glenn is right that massive objects (not only black holes) will alter the passage of time. But they don't "create time", whatever that might mean.
     
  9. Jul 7, 2009 #8

    malawi_glenn

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    Sorry, English is not my native language and I very tired now - yes "infect" is a very bad choice of words LOL thank you for the correction :-)

    Now to the OP, WHAT DO you want to learn? We can surley help you to get into the correct direction, do you want to learn about galaxies? Black holes?
     
  10. Jul 7, 2009 #9
    I have a question along these lines about what causes the spinning of galaxies. of course it's gravity that makes planets orbit stars and stars orbit galaxies but what causes all that spinning? why desnt everything just drift aimlessly through the cosmos? I understand why hurricanes on earth spin in a certain direction because of the coriolis effect (spelled it wrong didnt I?) so is there some cosmic coriolis effect that causes a hydrogen cloud to start spinning as it condenses to form a star and planetary acretion disk?

    I once asked why does the earth rotate on it's axis and somone said well who's axis do you want it to rate on? :P



    P.S. to the OP, be careful of those 'time' questions. ;)
     
  11. Jul 7, 2009 #10

    malawi_glenn

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    It is just a consequence of gravitational attraction and conservation of angular momentum, and the equations of motion in general relativity: even if you put a gas cloud in totally rest it would create an accretion disk.

    And even without taken into account general relativity, we will have spiralling, since all gas clouds that we know of have started with some inhomogeneous velocity distribution, and as it contracts, its angular velocity will increase (c.f. ice skate dancers when they draw in their arms against their body)

    So, the spiraling are due to two things, initial conditions with conservation of angular momentum and equations of motion in general relativity.
     
  12. Jul 7, 2009 #11
    ah ok, that makes sense. So that would work for whole galaxies also , as well as solar systems
     
  13. Jul 8, 2009 #12

    malawi_glenn

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    yes, consider the solar system, staring from a gas cloud with some small initial velocity distribution (due to thermal fluctuations, gravity fluctuations from nerby stars and the initial velocity distribution it got when being ejected from the supernova or stellar wind. Actually, it is believed that a star must disturb the cloud gravitationally in order to initiate the collapse - just as the planets orbint around the sun at different pace, so do stars orbiting around the galaxy), then contracting due to gravity -> increasing temperature and angular velocity. Sun forms in the hottest centre, and planets around it. Everything (except the intrinsic rotation of venus) is rotation in the same direction.
     
  14. Jul 8, 2009 #13
    why the exception for Venus?
     
  15. Jul 8, 2009 #14

    malawi_glenn

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    why? don't you know that it rotates around it's own axis in the opposite direction as compared with all the other planets? Also, its day is longer than its year, the explanation at hand is that it was hit/(strongly influenced) by a gravitational object in the young solar system (similar as we think that the moon of the earth was "created")
     
  16. Jul 8, 2009 #15

    everything about this subject, how do massive bodies influence time.
    how would earths orbit remain uneffected if by some crazy reason the sun became a black hole.

    would time be slower or almost stop if one traveled outside of a galaxy or far enought away from a massive object? theoretically, or would it remain the same?
     
  17. Jul 8, 2009 #16

    malawi_glenn

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    Massive objects influence time due to curving space-time, time and space is "two sides of each coin" in Einstein's Theory of Relativity. The "strength" of the curving is proportional to the "Energy-momentum tensor" in Einsteins Field Equations. Given a mass distribution we can solve for the metric/geometry of space time and then calculate time dilation.

    The only thing we would notice here on earth if the sun was replaced by a BH with same mass is that it would be night all the time due to no light from the sun ;-) A BH does not "pull" stronger than other gravitational bodies, only "inside" the black hole there is any difference

    (inside in this context means inside it's so called Schwarzchild radius and since the Schwarchild radius of a body with mass as the sun is approx 2km, earth will not notice that the sun turned to a BH, or well, this is over course, but the finite size of the sun has like an impact of i think the 0.001% level when we theoretically calculate the earth orbit as compared with if the sun was treated as a point mass...)

    Now let us turn to WHY it is called Special/General RELATIVITY. You ask if time would move slower if one travelled faaaar away from a massive object. According to WHOM? One will always percept time in the same pace, but since we are dealing with a relativistic theory, observers will not agree on how fast time goes.

    For instance, consider an observer standing on earth, and an observer on the moon. Since the moon has lighter mass, time will go at a different pace as COMPARED with earth. So consider two men on earth, synchronizing their clocks then one of them go to the moon for 1year. The two observers clocks will not agree when they meet again on earth, but one second for the guy on the moon will be percepted as one second - nothing strange he thinks.
     
  18. Jul 9, 2009 #17

    Back to Venus for a second. So it was originally spinning the same direction of the other planets but got reversed because of an impactor. If the spinning of the sun and planets is caused by the conservation of angular momentum like a skater pulling in the arms. So why do all the planets spin in the same direction? Why not random directions? and do they spin in the same direction as the sun? on their axes I mean, not the orbits.

    relativity question. if the observer on the earth peered through a telescope would he see the clock on the moon running slower than his on earth? and the guy on the moon would he see his clock running faster or slower than the one he sees when he looks back at the earth? guess I'm getting off topic of the thread. maybe I should go google time dilation
     
  19. Jul 9, 2009 #18

    malawi_glenn

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    Yes they do, and why should they be random?! think about it, the gas cloud rotated in certain direction and then all orbits will of course spin in the same direction...

    The conservation of angular momentum just means that the angular velocity increases as radius decreases. This argument is not logically linked to the one above, the above argument is the observational evidence that solar systems do form from a primordial rotating gas cloud-> the planets orbit in the same direction around the sun and so on.

    Yes they spin in same direction too, except venus.

    Yes they would, one has actually made such experiment with high-precision clocks, one in an air-plane 12 000km above ground where gravity field is weaker than on ground, and one clock on the ground -> the difference is exactly the one we should find using Einsteins equations.
     
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