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Thread: Falling through the event horizon

  1. #1 Falling through the event horizon 
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    Here are some questions for all you black hole experts.

    If a hapless traveler falls into a black hole, is there any way for him to tell whether he has crossed the event horizon? I have read the that the equivalency principle states that nothing special happens when you cross it; all local laws of physics remain the same.

    If this is true, can the traveler still receive electomagnetic radiation from outside the event horizon after he crosses it? If not, wouldn't the winking out of all external stars would be a pretty good indication that the event horizon has been crossed?

    On the other hand, if an observer inside the event horizon can see the outside, how will it be Doppler shifted? Remember, to an outside observer, time comes to a standstill as the traveler approaches the event horizon. Would that mean that the traveler would see blue shifted light from the outside? Would outside events appear to speed up as he approaches the horizon? Would he see the entire history of the universe flash before his eyes right before he crosses the point of no return? Is so, what happens next? Or would he see nothing notable as he crosses?


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  3. #2 Re: Falling through the event horizon 
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    Quote Originally Posted by geo_man
    Here are some questions for all you black hole experts.

    If a hapless traveler falls into a black hole, is there any way for him to tell whether he has crossed the event horizon? I have read the that the equivalency principle states that nothing special happens when you cross it; all local laws of physics remain the same.

    If this is true, can the traveler still receive electomagnetic radiation from outside the event horizon after he crosses it? If not, wouldn't the winking out of all external stars would be a pretty good indication that the event horizon has been crossed?

    On the other hand, if an observer inside the event horizon can see the outside, how will it be Doppler shifted? Remember, to an outside observer, time comes to a standstill as the traveler approaches the event horizon. Would that mean that the traveler would see blue shifted light from the outside? Would outside events appear to speed up as he approaches the horizon? Would he see the entire history of the universe flash before his eyes right before he crosses the point of no return? Is so, what happens next? Or would he see nothing notable as he crosses?
    There is not problem with electromagnetic radiation crossing the event horizon from the outside to the inside. However, nothing goes from inside to the outside.

    You are tryiing to apply simply analogies to black hole physics, which is dominated by extreme curvature and can only be explained using general relativity.

    A local observer crossing the event horizon will experience nothing special. As he proceeds further into the interior, things get a bit more exotic and he will experience extreme tidal forces due to the high curvature of spacetime therein. Those forces will eventually pull him apart. He will be completely unable to communicate with those outside the event horizon.

    You might want to take a look at Black Holes and Time Warps by Kip Thorne. It is a pretty good book for the non-specialist.


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  4. #3 Re: Falling through the event horizon 
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    Quote Originally Posted by DrRocket
    You might want to take a look at Black Holes and Time Warps by Kip Thorne. It is a pretty good book for the non-specialist.
    +1

    I've read it twice. Very accessible.
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  5. #4 Re: Falling through the event horizon 
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    Here are some questions for all you black hole experts.

    If a hapless traveler falls into a black hole, is there any way for him to tell whether he has crossed the event horizon?
    Yes there is. If traveler has a small black hole aboard, he can .... need to think
    some more.
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  6. #5  
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    Time stands still at the event horizon, at least from the perspective of any outside observer attempting to look in, so the moment before you reach it is the last time your clock ever advances. Presumably, that means you wouldn't experience anything after crossing over. You'd be frozen (not like ice frozen, but not moving.)
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  7. #6  
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    There's a difference between being frozen, and appearing frozen to an outside observer.
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  8. #7  
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    Quote Originally Posted by kojax
    Time stands still at the event horizon, at least from the perspective of any outside observer attempting to look in, so the moment before you reach it is the last time your clock ever advances. Presumably, that means you wouldn't experience anything after crossing over. You'd be frozen (not like ice frozen, but not moving.)
    This is just plain wrong.
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  9. #8 Re: Falling through the event horizon 
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    Quote Originally Posted by geo_man
    Here are some questions for all you black hole experts.

    If a hapless traveler falls into a black hole, is there any way for him to tell whether he has crossed the event horizon?
    No, when a outside observer looks at small black hole moving towards a black hole,
    he sees the small black hole expanding, but observer moving with the small
    black hole does not see it expanding.


    I have read the that the equivalency principle states that nothing special happens when you cross it; all local laws of physics remain the same.

    If this is true, can the traveler still receive electomagnetic radiation from outside the event horizon after he crosses it? If not, wouldn't the winking out of all external stars would be a pretty good indication that the event horizon has been crossed?
    Well of course, if you look around. "Local" means you don't look around.



    On the other hand, if an observer inside the event horizon can see the outside, how will it be Doppler shifted? Remember, to an outside observer, time comes to a standstill as the traveler approaches the event horizon. Would that mean that the traveler would see blue shifted light from the outside? Would outside events appear to speed up as he approaches the horizon? Would he see the entire history of the universe flash before his eyes right before he crosses the point of no return?
    That's right.
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  10. #9 Re: Falling through the event horizon 
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    Quote Originally Posted by jartsa



    On the other hand, if an observer inside the event horizon can see the outside, how will it be Doppler shifted? Remember, to an outside observer, time comes to a standstill as the traveler approaches the event horizon. Would that mean that the traveler would see blue shifted light from the outside? Would outside events appear to speed up as he approaches the horizon? Would he see the entire history of the universe flash before his eyes right before he crosses the point of no return?
    That's right.
    thats a really good one, I hadn't read or even thought of that before! Very interesting..........
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  11. #10 Re: Falling through the event horizon 
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    Quote Originally Posted by fatman57
    thats a really good one, I hadn't read or even thought of that before! Very interesting..........
    You two deserve each other.
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  12. #11  
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    To see why the above is wrong, and to see why the book above was referenced, you guys should go here and read the prologue from the "Look Inside" feature.

    http://www.amazon.co.uk/reader/03336...der_0333639693


    Roughly around page 32 is where discussion about Arnold the robot really addresses the errors in reasoning above (you can read from the beginning all the way to page 64 for free).
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  13. #12  
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    Quote Originally Posted by inow
    To see why the above is wrong, and to see why the book above was referenced, you guys should go here and read the prologue from the "Look Inside" feature.

    http://www.amazon.co.uk/reader/03336...der_0333639693


    Roughly around page 32 is where discussion about Arnold the robot really addresses the errors in reasoning above (you can read from the beginning all the way to page 64 for free).
    Does Kip Thorne think gravitational time dilation is not an absolute thing??
    That is a common misconception among laymen. :-D

    No, Kip Thorne says it really takes a long time for light to travel up.
    Why does it not take a long time to travel down? Maybe Kip Thorne
    did not come to think about that question.

    Oh yes Kip Thorne says light struggles on uphill. Then probably downhill
    should be easy going for light. So maybe an uphill takes a long time,
    while a downhill takes a short time. Well that's how a layman would think.
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  14. #13  
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    Alright. Now I am starting to get very confused.

    http://en.wikipedia.org/wiki/Gravita..._time_dilation



    * t0 is the proper time between events A and B for a slow-ticking observer within the gravitational field,
    * tf is the coordinate time between events A and B for a fast-ticking observer at an arbitrarily large distance from the massive object (this assumes the fast-ticking observer is using Schwarzschild coordinates, a coordinate system where a clock at infinite distance from the massive sphere would tick at one second per second of coordinate time, while closer clocks would tick at less than that rate),
    * G is the gravitational constant,
    * M is the mass of the object creating the gravitational field,
    * r is the radial coordinate of the observer (which is analogous to the classical distance from the center of the object, but is actually a Schwarzschild coordinate),
    * c is the speed of light, and
    * r0 = 2GM / c2 is the Schwarzschild radius of M. If a mass collapses so that its surface lies at less than this radial coordinate (or in other words covers an area of less than 4πG2M2 / c4), then the object exists within a black hole.
    My understanding is that, if two satellites with internal clocks are launched into space, and one is allowed to orbit the sun as far away as Mercury for a year (as measured from Earth), and the other is allowed to orbit the Sun as far out as Venus for a year (as measured from Earth), and then both return home to Earth, we would find that the clock in the satellite that orbited closer to the Sun had measured less time to have passed.

    Taken to the extreme, the clock inside satellite that was allowed to orbit a black hole at the Schwartzchild radius for a year, and then returned to Earth (We'll say a wizard magically teleports it back to Earth)..... would not measure any time to have passed at all. None.
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  15. #14 Re: Falling through the event horizon 
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    Quote Originally Posted by DrRocket
    Quote Originally Posted by fatman57
    thats a really good one, I hadn't read or even thought of that before! Very interesting..........
    You two deserve each other.
    lol - if I could guaruntee a job doing it then I would happily think about black holes all day and would hopefully stumble accross that one as my understanding unfolds but I am afraid I have to work at other things buddy, even though a black hole would be far more interesting..................
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  16. #15  
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    Quote Originally Posted by jartsa
    Does Kip Thorne think gravitational time dilation is not an absolute thing??
    That is a common misconception among laymen. :-D

    No, Kip Thorne says it really takes a long time for light to travel up.
    Why does it not take a long time to travel down? Maybe Kip Thorne
    did not come to think about that question.

    Oh yes Kip Thorne says light struggles on uphill. Then probably downhill
    should be easy going for light. So maybe an uphill takes a long time,
    while a downhill takes a short time. Well that's how a layman would think.
    Uhhmm... What?!?
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  17. #16  
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    Quote Originally Posted by DrRocket
    Quote Originally Posted by kojax
    Time stands still at the event horizon, at least from the perspective of any outside observer attempting to look in, so the moment before you reach it is the last time your clock ever advances. Presumably, that means you wouldn't experience anything after crossing over. You'd be frozen (not like ice frozen, but not moving.)
    This is just plain wrong.
    It's his speciality. He's really good at it.
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    Black Hole is just the densest gravitons, itís not a hole... itís a sphere.

    Worm Hole is the theoretical 4D, worm hole is a hole.
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    Quote Originally Posted by In infinity
    Black Hole is just the densest gravitons, itís not a hole... itís a sphere.

    Worm Hole is the theoretical 4D, worm hole is a hole.
    Grubby scientists donít want you to know this.
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  20. #19  
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    Quote Originally Posted by inow
    Quote Originally Posted by jartsa
    Does Kip Thorne think gravitational time dilation is not an absolute thing??
    That is a common misconception among laymen. :-D

    No, Kip Thorne says it really takes a long time for light to travel up.
    Why does it not take a long time to travel down? Maybe Kip Thorne
    did not come to think about that question.

    Oh yes Kip Thorne says light struggles on uphill. Then probably downhill
    should be easy going for light. So maybe an uphill takes a long time,
    while a downhill takes a short time. Well that's how a layman would think.
    Uhhmm... What?!?
    I'm just addressing errors in reasoning in Kip Thornes book.
    To learn how it really works, read what geo_man said.
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  21. #20  
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    Geo_man - A random teenager on an internet forum with no formal training.
    Kip_Thorne - An established theoretical physicist at CalTech who has been publishing for years and working with the biggest names and teaching graduate and post graduate students for decades.

    You want me to disregard Thorne and listen to Geo_man... asserting that Thorne is wrong with no reasoning why or how or where.

    This is not an argument from authority thing, but a common sense thing, and I offer you the following response:

    Uhm... No.
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  22. #21  
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    Quote Originally Posted by inow
    Geo_man - A random teenager on an internet forum with no formal training.
    Kip_Thorne - An established theoretical physicist at CalTech who has been publishing for years and working with the biggest names and teaching graduate and post graduate students for decades.

    You want me to disregard Thorne and listen to Geo_man... asserting that Thorne is wrong with no reasoning why or how or where.

    This is not an argument from authority thing, but a common sense thing, and I offer you the following response:

    Uhm... No.
    Nope. It is my authority that should make you believe that Thorne is wrong and
    geo_man is right, when I tell you that geo_man is right.
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  23. #22  
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    What authority?
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  24. #23  
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    Quote Originally Posted by MagiMaster
    What authority?
    The authority of a retarded person over a more retarded person. How's that?
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    So, Black Holes and light are a little bit different than common sense would think:

    Light gains speed in an uphill, and loses speed in a downhill.

    Which causes everything to get trapped and to freeze in an event horizon.
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  26. #25  
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster
    What authority?
    The authority of a retarded person over a more retarded person. How's that?
    Sorry. I don't recognize that authority.

    Quote Originally Posted by jartsa
    So, Black Holes and light are a little bit different than common sense would think:

    Light gains speed in an uphill, and loses speed in a downhill.

    Which causes everything to get trapped and to freeze in an event horizon.
    It's not even that simple. Light is the same speed everywhere, everywhen. This causes things to appear to freeze when they hit the event horizon (sort of) from an outside viewpoint.
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  27. #26  
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    Quote Originally Posted by MagiMaster
    It's not even that simple. Light is the same speed everywhere, everywhen. This causes things to appear to freeze when they hit the event horizon (sort of) from an outside viewpoint.
    Can you explain to me how same speed of light everywhere causes things appearing to freeze on event horizon?
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  28. #27  
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    Quote Originally Posted by Ophiolite
    Quote Originally Posted by DrRocket
    Quote Originally Posted by kojax
    Time stands still at the event horizon, at least from the perspective of any outside observer attempting to look in, so the moment before you reach it is the last time your clock ever advances. Presumably, that means you wouldn't experience anything after crossing over. You'd be frozen (not like ice frozen, but not moving.)
    This is just plain wrong.
    It's his speciality. He's really good at it.

    How do you interpret gravitational time dilation then? I think the difference between your clock slowing down and you slowing down is mostly semantic. If your clock stops, then you stop. You don't perceive yourself to stop, of course, but the whole universe will have succumbed to heat death before the next tick of your clock, so does it really matter whether you know you are frozen in time?


    Another way to describe it would be to say that, from your perspective, events happening outside the black hole will appear to be moving faster and faster until their apparent speed reaches infinity. That might be more of a blue shift effect than a "real" effect, depending on how you look at it, but the fact remains that as light approaches infinite blue shift, the data it contains appears to arrive faster and faster.

    It's like if a starship moving at .5 C approaching Earth were to broadcast a TV program toward Earth. Not only would the signal have a shorter wavelength than normal, but upon decoding that signal, you would find that all the characters on the screen were moving and talking at a much faster rate than normal (assuming that you decode it in real time, as fast as your receiving it). If you were near the event horizon of a black hole and had special optics that allowed you to see the massively blue shifted light as it arrived, you would see billions of years worth of events transpiring in the blink of an eye. If you fell into the event horizon, then those billions of years of activity would appear to transpire even faster than the blink of an eye. They would be perfectly instant.
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  29. #28  
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster
    It's not even that simple. Light is the same speed everywhere, everywhen. This causes things to appear to freeze when they hit the event horizon (sort of) from an outside viewpoint.
    Can you explain to me how same speed of light everywhere causes things appearing to freeze on event horizon?
    Actually, no I can't. That's a question of general relativity, and I don't understand the details well enough to try and explain them to someone else.

    Ok, I'm also not 100% sure that it's just the constant speed of light causing that effect, but I do know that that's one of the two assumptions of special relativity from which length contraction and time dilation are derived.
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  30. #29  
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    Quote Originally Posted by MagiMaster
    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster
    It's not even that simple. Light is the same speed everywhere, everywhen. This causes things to appear to freeze when they hit the event horizon (sort of) from an outside viewpoint.
    Can you explain to me how same speed of light everywhere causes things appearing to freeze on event horizon?
    Actually, no I can't. That's a question of general relativity, and I don't understand the details well enough to try and explain them to someone else.

    Ok, I'm also not 100% sure that it's just the constant speed of light causing that effect, but I do know that that's one of the two assumptions of special relativity from which length contraction and time dilation are derived.
    General relativity and special relativity are quite a bit different in the way that they look at things. Special relativity turns out to be the local version of general relativity -- you can think of it as either general relativity without gravity or as general relativity on the tangent space.

    The critical difference is that in special relativity you have reference frames that are global, and so it makes sense in principle to compare two clocks at different spatial locations. In general relativity you do not have that luxury. All that you can do is compare two clocks at a single spatial location -- or in other words you can compare the time measured on two world lines at point of intersection in spacetime. This means that in general relativity you do not have any global notion of time, which creates all sorts of problems for cosmologists who need one.

    In any case, the notion of gravitational time dilation is something that comes with the general theory and not with the special theory and hence requires a bit more than just the invariance of the speed of light.

    But that is not the real problem It has been amply demonstrated that NO ONE can explain ANYTHING to jartsa, and furthermore it is equally clear that it is not worth the effort to try.
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  31. #30 Re: Falling through the event horizon 
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    Quote Originally Posted by geo_man
    Here are some questions for all you black hole experts.

    If a hapless traveler falls into a black hole, is there any way for him to tell whether he has crossed the event horizon? I have read the that the equivalency principle states that nothing special happens when you cross it; all local laws of physics remain the same.

    If this is true, can the traveler still receive electomagnetic radiation from outside the event horizon after he crosses it? If not, wouldn't the winking out of all external stars would be a pretty good indication that the event horizon has been crossed?

    On the other hand, if an observer inside the event horizon can see the outside, how will it be Doppler shifted? Remember, to an outside observer, time comes to a standstill as the traveler approaches the event horizon. Would that mean that the traveler would see blue shifted light from the outside? Would outside events appear to speed up as he approaches the horizon? Would he see the entire history of the universe flash before his eyes right before he crosses the point of no return? Is so, what happens next? Or would he see nothing notable as he crosses?
    Hi Geo, stop the bus, you make many valid points on vexed questions which
    some have fixed views on. For my part, these questions have been asked before,
    but I feel are due to some reconsideration. Number one, the the traveller would
    not be pulled apart by gravitational forces, that is a myth, he is in free fall for
    one, the other is he governed by the laws of space time and gravity.
    You are correct Geo, to the outside observer our traveller would appear stationary when at the event horizon and falling in. The thing to remember here is,
    the event horizon is still a theory, an attempt to explain what we, as yet,do not understand. All we know for now, is that our known laws of physics break down
    in the proximity of a black hole, can we, for once, leave aside conjecture and
    find a way of reconciling quantum mechanics with newtonion physics.
    nokton
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  32. #31 Re: Falling through the event horizon 
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    Quote Originally Posted by nokton
    Hi Geo, stop the bus, you make many valid points on vexed questions which
    some have fixed views on. For my part, these questions have been asked before,
    but I feel are due to some reconsideration. Number one, the the traveller would
    not be pulled apart by gravitational forces, that is a myth, he is in free fall for
    one, the other is he governed by the laws of space time and gravity.
    You are correct Geo, to the outside observer our traveller would appear stationary when at the event horizon and falling in. The thing to remember here is,
    the event horizon is still a theory, an attempt to explain what we, as yet,do not understand. All we know for now, is that our known laws of physics break down
    in the proximity of a black hole, can we, for once, leave aside conjecture and
    find a way of reconciling quantum mechanics with newtonion physics.
    nokton
    1. The traveler would indeed be pulled apart in the interior of a large blackk hole, desppite the fact that he would be in free fall. This is because of the extreme curvature of spacetime which results in a large tidal force -- the gradient is so high that the gravitational force at his head is much smaller than the force at this feet (falling feet first) and the result is a stretching that would pull him apart. This does not happen at the event horizon but later on in the interior.

    2. The theory of general relativity and the application to black holes are pretty well understood so long as one considers only regions somewhat distant from the center which is known to be singular. So, in particular the theory covers quite adequately what goes on near the event horizon. Where it breaks down is deep in the intnerior. Singularities are not well understood from a physical perspective and the general thought is that it will take a unified theory of gravity and quantum theory to adequately address that situation.

    3. It is quite well known that quantum mechanics replaces Newtonian mechanics and that no reconciliation is needed. What is needed is a reconciliation of quantum mechanics with general relativity. Newtonian mechanics is pretty much useless when one is interested in black holes and their structure, which are a rather unique prediction of GR.

    4. The event horizon is not a theory. In fact it is apparent that you do not understand what is meant by the term "theory" when used in the context of physics. A theory is a mathematical construct that has significant predictive power and has been substantiated by a body of experimental evidence. The main theories of modern physics are general relativity, the electroweak theory and quantum chromodynamics. The latter two are quantum field theories while the former is a deterministic theory of gravity, space and time based on Riemannian geometry. One incompatibility is that GR is deterministic while the quantum field theories are stochastic.

    4a. It appears that you are using the word "theory" as a synomym for "conjecture" which is not correct in the context of physics. The event horizon is most certainly not a conjecture. See for instance The Mathematical Theory of Black Holes by Chandrasekhar or Gravitation by Misner, Thorne and Wheeler.

    5 Outr known laws of physics do not necessarily break down in the proximity of a black hole, depending on what you mean by "black hole". They are quite adequate near the event horizon for instance. They do apparently break down near the singularity, which is where one presumably needs a unified theory of gravity and quantum mechanics.
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    Quote Originally Posted by MagiMaster
    Actually, no I can't.
    ...
    Ok, I'm also not 100% sure that it's

    Well done. See how discussion with me makes you wiser.




    So, light stops at event horizon. So we can guess vacuums permeability and permittivity
    are very large near event horizon. We could say that is the reason light stops.
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    Quote Originally Posted by jartsa
    So, light stops at event horizon.
    No, it doesn't. And also... Relative to whom/what? You may as well be asking all of us "what's the difference between a duck?" You are failing to regard the necessity of relativity with your comments, and you continue to post in ways which suggest you are a fool, a moron, or a paste eater... Granted, those are not mutually exclusive descriptors.
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    There is an interesting question: when light stops at the event horizon, then
    relative to what does it stands still?.

    Well, obviously relative to the Black Hole.

    But how about a spinning Black Hole?

    Kip Thorne tells us about this in page 52, last paragraph: Kolob circles a Black Hole
    that spins 270 spins per second, Kolob making 270 circles per second, and being
    unable to change the 270 circles per second.

    (probably the calculations are correct in the book)
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    Quote Originally Posted by jartsa
    There is an interesting question: when light stops at the event horizon, then...
    Your premise is flawed. Light doesn't stop. It travels at consistent speed. It travels at c... and it does so in all frames. Given this, the rest of your post is rendered moot.
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    I wonder would light be reflected if the change in light's speed is abrupt, like
    in case of a very small Black Hole?
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    Quote Originally Posted by jartsa
    I wonder would light be reflected if the change in light's speed is abrupt, like
    in case of a very small Black Hole?
    As mentioned in the post immediately preceding yours, as well as in countless others... Light does not change speed, hence again rendering your question wholly moot.
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    Quote Originally Posted by inow
    As mentioned in the post immediately preceding yours, as well as in countless others... Light does not change speed, hence again rendering your question wholly moot.

    Yes, you have said it couple of times.



    What if we build a capacitor in that high permittivity space
    I mentioned earlier? Capacitance of a capacitor is proportional
    to permittivity, as we remember from the schoolbook.

    Or we can lower a charged capacitor into a gravity well. Energy of a capacitor
    decreases as permittivity increases, as we remember from our textbook.
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  40. #39  
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    Quote Originally Posted by jartsa
    Quote Originally Posted by inow
    As mentioned in the post immediately preceding yours, as well as in countless others... Light does not change speed, hence again rendering your question wholly moot.

    Yes, you have said it couple of times.



    What if we build a capacitor in that high permittivity space
    I mentioned earlier? Capacitance of a capacitor is proportional
    to permittivity, as we remember from the schoolbook.

    Or we can lower a charged capacitor into a gravity well. Energy of a capacitor
    decreases as permittivity increases, as we remember from our textbook.
    Well, I certaily can't answer that question, since you seem to have made it up whole cloth. Nowhere in any of the current theories of physics does it describe the area around a black hole as having a high permittivity.

    Also, I don't much appreciate you taking my comments out of context, much less chopping up my sentences to make them say what you want. :x

    I think I'm going to have to agree with DrRocket here. You don't seem to be here to learn, only to push your agenda.
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    Hey inow let's try to not be stubborn for awhile

    Now we take a light clock in witch light bounces million times per second.

    Now this clock itself makes couple of bounces. This causes light to
    make fewer bounces compared to non-bouncing light clock.
    This is called time dilation.

    Now we lower slowly a light clock into a gravity well. Then we pull the clock back.
    This dipping into a well causes light to make fewer bounces compared to light in a
    non-dipping clock. This is called time dilation.

    Now you can see in the second case the same slowing of bouncing
    of light as in the first case, but without the compensating extra traveling.

    And that is how light slows down.

    Maybe I should try to say it in more nerdy way:
    The local speed of light is lower lower as seen by an observer that is
    on an upper location. Sounds like gibberish.
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    Quote Originally Posted by jartsa
    Sounds like gibberish.
    Yep.

    There is a good reason for that.
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    Quote Originally Posted by jartsa
    Hey inow let's try to not be stubborn for awhile
    You should try it yourself once in a while.

    Either you know you don't understand this stuff and you're just writing in a fashion that makes it seem like you think you do, or you don't understand that you don't understand and you're just stubborn. Either way, it will be impossible to convince anyone you're right, since you're not.
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    Quote Originally Posted by MagiMaster
    You should try it yourself once in a while.

    Either you know you don't understand this stuff and you're just writing in a fashion that makes it seem like you think you do, or you don't understand that you don't understand and you're just stubborn. Either way, it will be impossible to convince anyone you're right, since you're not.


    Seems I am the best Black Hole expert this forum has to offer:-D
    Questions about Black Holes?


    What would MagiMaster like to discuss about?
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    Jartsa, maybe you should spend some effort trying to explain why you are right, and why the rest of us should believe you, instead of just stating your ideas as fact, and then acting like you are being persecuted every time someone casts doubt on them.
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    Quote Originally Posted by kojax
    Jartsa, maybe you should spend some effort trying to explain why you are right, and why the rest of us should believe you, instead of just stating your ideas as fact, and then acting like you are being persecuted every time someone casts doubt on them.
    What kind of stuff should I be saying?



    How about this: first you ask a question then I answer the question. Do you have a question about permittivity of space near a Black Hole?
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    Quote Originally Posted by jartsa

    What kind of stuff should I be saying?
    How about stuff that is consistent with both well-known physical principles and basic logic ? That would be both unusual for you and quite refreshing for everyone else.
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    Quote Originally Posted by jartsa
    Quote Originally Posted by kojax
    Jartsa, maybe you should spend some effort trying to explain why you are right, and why the rest of us should believe you, instead of just stating your ideas as fact, and then acting like you are being persecuted every time someone casts doubt on them.
    What kind of stuff should I be saying?



    How about this: first you ask a question then I answer the question. Do you have a question about permittivity of space near a Black Hole?
    How about this. Where does the idea that black holes change the permittivity of space come from? Or, what evidence do you have to support that theory? Or at least where's the math?
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    Quote Originally Posted by jartsa

    How about this. Where does the idea that black holes change the permittivity of space come from? Or, what evidence do you have to support that theory? Or at least where's the math?
    Apparently it comes from you. Do you have any idea, any scintilla of an idea,a what you are talking about ?

    The theory of black holes comes from general relativity. The math is available in Gravitation by Misner, Thorne and Wheeler or in The Mathematical Theory of Black Holes by Chandrasekhar. Take your pick. There are other sources, but these are two of the best. You might also be intereested in The large-scale structcure of spacetime by Hawking and Ellis for a nice discussion of singularities.
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    Quote Originally Posted by MagiMaster

    How about this. Where does the idea that black holes change the permittivity of space come from? Or, what evidence do you have to support that theory? Or at least where's the math?
    Well, not very good. "Why are you so dumb?" is not a good question either.

    Here are some better questions:
    Can you tell some more about ....?
    Does this not contradict ... ?


    Now I try to explain something.

    In relativity we have "frames". Sometimes we say two frames are
    very much different frames. Typically time is different in different frames.

    Now one case where two frames are different is when one frame is near
    a black hole and another one is not. And one thing that is different in these
    frames is time.

    Are you still following and agreeing? Is this a new idea or an old idea?












    ..
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  51. #50  
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    DrRocket, that one was a bit misquoted.

    Anyway,

    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster

    How about this. Where does the idea that black holes change the permittivity of space come from? Or, what evidence do you have to support that theory? Or at least where's the math?
    Well, not very good. "Why are you so dumb?" is not a good question either.

    Here are some better questions:
    Can you tell some more about ....?
    Does this not contradict ... ?


    Now I try to explain something.

    In relativity we have "frames". Sometimes we say two frames are
    very much different frames. Typically time is different in different frames.

    Now one case where two frames are different is when one frame is near
    a black hole and another one is not. And one thing that is different in these
    frames is time.

    Are you still following and agreeing? Is this a new idea or an old idea?

    ..
    Err, how exactly were any of my questions calling you dumb?

    Let me rephrase those.
    - What inspired this idea?
    - What math do you have to support this?
    - What evidence do you have to support this?

    And what you said about frames is nothing special. It follows from the definition of a frame and from gravitational time dilation. (Also, by definition, if two frames weren't different, they'd be the same frame.)
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    Quote Originally Posted by MagiMaster

    And what you said about frames is nothing special. It follows from the definition of a frame and from gravitational time dilation. (Also, by definition, if two frames weren't different, they'd be the same frame.)


    So we continue.

    This is a good physics problem, isn't it? :
    A clock hand is 10 cm long. It makes 60 turns per hour. Calculate
    the speed of the tip of the clock hand.


    Is this a valid physics problem? :
    The aforementioned clock is lowered into a gravity well, so that
    clock's time becomes 0.5 * time in the frame that the clock was
    before the lowering. Calculate the speed of the tip of the clock hand
    in the frame that the clock was before the lowering.
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    Yes, it's a valid physics problem, but depending on how much precision you're looking for, the answer is either going to be uninstructively simple, or very difficult to work out.

    (Also, you seem to be avoiding my questions, even though you asked for them in the first place.)
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    Quote Originally Posted by MagiMaster
    Yes, it's a valid physics problem, but depending on how much precision you're looking for, the answer is either going to be uninstructively simple, or very difficult to work out.

    (Also, you seem to be avoiding my questions, even though you asked for them in the first place.)
    I'll answer your questions later.


    If we replace the tip of a clock hand with a photon in this problem,
    the speed of the photon will be 150000 km/s, is this right?
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    No. The speed of a photon is always (about) 300,000 km/s. Instead, you'll get a photon moving at lightspeed with half the energy.

    I told you the previous problem would either be uninstructively simple or very difficult. It seems you've taken the simple case and tried to apply the results to the difficult case. It doesn't work.
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    Quote Originally Posted by MagiMaster
    No. The speed of a photon is always (about) 300,000 km/s. Instead, you'll get a photon moving at lightspeed with half the energy.

    I told you the previous problem would either be uninstructively simple or very difficult. It seems you've taken the simple case and tried to apply the results to the difficult case. It doesn't work.
    Tell me more about difficult case, is redshift involved somehow,
    and how does it work?
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    Quote Originally Posted by jartsa
    Quote Originally Posted by kojax
    Jartsa, maybe you should spend some effort trying to explain why you are right, and why the rest of us should believe you, instead of just stating your ideas as fact, and then acting like you are being persecuted every time someone casts doubt on them.
    What kind of stuff should I be saying?



    How about this: first you ask a question then I answer the question. Do you have a question about permittivity of space near a Black Hole?
    Explain what evidence exists for this permitivity. Religion says: "I will give you lots of details so long as you just blindly believe me that I am right. " They then go on to write some very long books (Bible, Koran, ...etc.)

    Science says: "I am right and I can prove it." You're not talking like science right now.

    Quote Originally Posted by MagiMaster
    No. The speed of a photon is always (about) 300,000 km/s. Instead, you'll get a photon moving at lightspeed with half the energy.

    I told you the previous problem would either be uninstructively simple or very difficult. It seems you've taken the simple case and tried to apply the results to the difficult case. It doesn't work.

    This is always true according local time. However, if you were standing outside of a gravity well, and you placed a mirror deep inside that gravity well..... say 300million meters away from you (C is ~300 million meters/sec, not ~300 million km/sec), and then emitted a pulse of light toward that mirror, you would notice that it took longer than 2 seconds for that pulse to come back to you.

    This is because you are not measuring according to the beam of light's local time. You are measuring according to your own local time. According to your own local time, the beam of light did slow down.
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster
    No. The speed of a photon is always (about) 300,000 km/s. Instead, you'll get a photon moving at lightspeed with half the energy.

    I told you the previous problem would either be uninstructively simple or very difficult. It seems you've taken the simple case and tried to apply the results to the difficult case. It doesn't work.
    Tell me more about difficult case, is redshift involved somehow,
    and how does it work?
    The difficult case is that the end of the clock hand is moving in circles, which complicates things as you try to speed it up to relativistic speeds. (Basically, there's a limit on how fast you can turn things in a circle before you end up breaking your clock.)

    Quote Originally Posted by kojax
    Quote Originally Posted by jartsa
    Quote Originally Posted by kojax
    Jartsa, maybe you should spend some effort trying to explain why you are right, and why the rest of us should believe you, instead of just stating your ideas as fact, and then acting like you are being persecuted every time someone casts doubt on them.
    What kind of stuff should I be saying?



    How about this: first you ask a question then I answer the question. Do you have a question about permittivity of space near a Black Hole?
    Explain what evidence exists for this permitivity. Religion says: "I will give you lots of details so long as you just blindly believe me that I am right. " They then go on to write some very long books (Bible, Koran, ...etc.)

    Science says: "I am right and I can prove it." You're not talking like science right now.

    Quote Originally Posted by MagiMaster
    No. The speed of a photon is always (about) 300,000 km/s. Instead, you'll get a photon moving at lightspeed with half the energy.

    I told you the previous problem would either be uninstructively simple or very difficult. It seems you've taken the simple case and tried to apply the results to the difficult case. It doesn't work.

    This is always true according local time. However, if you were standing outside of a gravity well, and you placed a mirror deep inside that gravity well..... say 300million meters away from you (C is ~300 million meters/sec, not ~300 million km/sec), and then emitted a pulse of light toward that mirror, you would notice that it took longer than 2 seconds for that pulse to come back to you.

    This is because you are not measuring according to the beam of light's local time. You are measuring according to your own local time. According to your own local time, the beam of light did slow down.
    I said 300,000, not 300,000,000. (300,000,000 meters = 300,000 kilometers anyway.)

    Also, how are you measuring 300 million meters anyway? The only way would be to place it where light would take 2 seconds to bounce back.
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    Quote Originally Posted by kojax

    Explain what evidence exists for this permitivity. Religion says: "I will give you lots of details so long as you just blindly believe me that I am right. " They then go on to write some very long books (Bible, Koran, ...etc.)

    Science says: "I am right and I can prove it." You're not talking like science right now.

    By the way, science does not say "I am right and I can prove it."
    Science says "I say it works like this, and you can't prove me wrong"
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    I was supposed to answer some MagiMasters questions, so here it is now:

    - What inspired this idea?
    What idea, I don't have ideas, this thing is not my thing, and it's not an inspired thing.


    - What math do you have to support this?
    now that's a very very very lame question, I'm just amazed of the lameness
    here's some math: permittivity1 > permittivity2 <=> c1 < c2
    here is a physics formula:
    1/ c = permittivity of free space*permeability of free space


    - What evidence do you have to support this?
    I have two answers: 1: none 2: I write my evidence myself
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    Quote Originally Posted by jartsa
    Quote Originally Posted by kojax

    Explain what evidence exists for this permitivity. Religion says: "I will give you lots of details so long as you just blindly believe me that I am right. " They then go on to write some very long books (Bible, Koran, ...etc.)

    Science says: "I am right and I can prove it." You're not talking like science right now.

    By the way, science does not say "I am right and I can prove it."
    Science says "I say it works like this, and you can't prove me wrong"
    No, science says "This is theory predicts observations accurately."

    Quote Originally Posted by jartsa
    I was supposed to answer some MagiMasters questions, so here it is now:

    - What inspired this idea?
    What idea, I don't have ideas, this thing is not my thing, and it's not an inspired thing.


    - What math do you have to support this?
    now that's a very very very lame question, I'm just amazed of the lameness
    here's some math: permittivity1 > permittivity2 <=> c1 < c2
    here is a physics formula:
    1/ c = permittivity of free space*permeability of free space


    - What evidence do you have to support this?
    I have two answers: 1: none 2: I write my evidence myself
    *facepalm*

    *facepalm repeatedly*

    *massive double facepalm*



    Ok. Despite the caption on that picture, I'll try using words.

    1) If it's not your idea, who's is it?

    2) You do realize that all of physics is built on, and out of, math? Newtonian mechanics, for example, is basically one equation () that explains how gravity was previously thought to work. The same is true of everything in physics. There is no physics without the math.

    3) If you have no evidence, then you have no theory, just a conjecture. All science cares about is having a good mathematical formula that can predict new observations, and that is shown by gathering evidence that it does just that.
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    Quote Originally Posted by kojax
    Alright. Now I am starting to get very confused.

    http://en.wikipedia.org/wiki/Gravita..._time_dilation



    * t0 is the proper time between events A and B for a slow-ticking observer within the gravitational field,
    * tf is the coordinate time between events A and B for a fast-ticking observer at an arbitrarily large distance from the massive object (this assumes the fast-ticking observer is using Schwarzschild coordinates, a coordinate system where a clock at infinite distance from the massive sphere would tick at one second per second of coordinate time, while closer clocks would tick at less than that rate),
    * G is the gravitational constant,
    * M is the mass of the object creating the gravitational field,
    * r is the radial coordinate of the observer (which is analogous to the classical distance from the center of the object, but is actually a Schwarzschild coordinate),
    * c is the speed of light, and
    * r0 = 2GM / c2 is the Schwarzschild radius of M. If a mass collapses so that its surface lies at less than this radial coordinate (or in other words covers an area of less than 4πG2M2 / c4), then the object exists within a black hole.
    My understanding is that, if two satellites with internal clocks are launched into space, and one is allowed to orbit the sun as far away as Mercury for a year (as measured from Earth), and the other is allowed to orbit the Sun as far out as Venus for a year (as measured from Earth), and then both return home to Earth, we would find that the clock in the satellite that orbited closer to the Sun had measured less time to have passed.

    Taken to the extreme, the clock inside satellite that was allowed to orbit a black hole at the Schwartzchild radius for a year, and then returned to Earth (We'll say a wizard magically teleports it back to Earth)..... would not measure any time to have passed at all. None.
    the second you enter a black hole all time stops.....the oposite of traveling at the speed of light....i believe that all timelines and dimensions are available the second you enter the black hole....to me..time is the folding of the next higher dimension...and mass is the tool that unfolds it
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    So we have conjecture1: time runs slower in lower places
    And we have conjecture2: time just seems to run slower in lower places

    One of these conjectures is a bad one, while one is good.

    Now how to decide which is which?

    Well, we start by thinking about information transfer by radio from a lower place
    to an upper place. We see that if receiver receives information at slow rate
    but sender sends information at normal rate, then information needs to go
    into a temporary storage. When the broadcasting is going on the storage
    is filling up, so the size of the storage needed is from zero to infinity,
    depending on how long the filling up continues. We can see that the space
    between sender and receiver does not meet these requirements for
    information storage. There doesn't seem to be a suitable information
    storage place.

    And this is the fault in conjecture2. It doesn't work.

    This has been a lesson in 1: gravitational time dilation 2: conjectures in science
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    Quote Originally Posted by MagiMaster

    I said 300,000, not 300,000,000. (300,000,000 meters = 300,000 kilometers anyway.)

    Oh. Sorry. I should have looked more closely before "correcting".


    Also, how are you measuring 300 million meters anyway? The only way would be to place it where light would take 2 seconds to bounce back.
    Couldn't you use triangulation?

    Place two telescopes a few km apart, aim them at the object holding the mirror, and measure the difference in the angles. Then calculate the distance from that.

    Quote Originally Posted by jartsa
    So we have conjecture1: time runs slower in lower places
    And we have conjecture2: time just seems to run slower in lower places

    One of these conjectures is a bad one, while one is good.

    Now how to decide which is which?
    You do realize that formal experiments have been carried out, don't you, by sending clocks inside of satellites to areas with different amounts of gravity and leaving them there long enough to observe this effect?




    Well, we start by thinking about information transfer by radio from a lower place
    to an upper place. We see that if receiver receives information at slow rate
    but sender sends information at normal rate, then information needs to go
    into a temporary storage. When the broadcasting is going on the storage
    is filling up, so the size of the storage needed is from zero to infinity,
    depending on how long the filling up continues. We can see that the space
    between sender and receiver does not meet these requirements for
    information storage. There doesn't seem to be a suitable information
    storage place.
    If both sender and receiver are inside the same gravitational field, then the sender sends at a rate exactly as slow as the receiver. There is no difference in transmission/receiving rates.

    And, even if the sender were sending faster than the receiver can receive all that would happen is something called a "blue shift", and this is a well understood phenomenon. (It's the basis for police radar guns that are used to catch speeders.)
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    Quote Originally Posted by kojax
    ....
    Kojax your job here would be to engage your brain and try to reason through what
    you read, while reading what I wrote.
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    Quote Originally Posted by kojax
    Quote Originally Posted by MagiMaster

    I said 300,000, not 300,000,000. (300,000,000 meters = 300,000 kilometers anyway.)

    Oh. Sorry. I should have looked more closely before "correcting".


    Also, how are you measuring 300 million meters anyway? The only way would be to place it where light would take 2 seconds to bounce back.
    Couldn't you use triangulation?

    Place two telescopes a few km apart, aim them at the object holding the mirror, and measure the difference in the angles. Then calculate the distance from that.
    The problem with triangulation is that angles don't add up to 180 in areas where space is curved (everywhere really), but the effect is tiny except in areas like black holes. The end result of all of this is that you'll always measure light as movinig at c while distance and time change.

    Quote Originally Posted by jartsa
    Quote Originally Posted by kojax
    ....
    Kojax your job here would be to engage your brain and try to reason through what
    you read, while reading what I wrote.
    It's really hard to take what you write seriously after your math comment. Also, it's no one's job to understand what you write. It's your job to write stuff people can understand.
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    Dr Rocket,
    Thanks for your input. Would take issue with you on my concept
    of theory. Theory is supposition or a system of ideas intended to explain something, conjecture is an opinion or conclusion based upon incomplete
    information. Neither has any basis in fact.
    You attempt to describe to me the dynamics within a black hole within the
    so called event horizon, so called by you, tidal forces. Tell me about what
    you mean by tidal forces, and
    what parameters you are alluding to? You speak of a sngularity at the centre,
    you have no concept of any singularity, nor any evidence of it. You make
    believe you know and understand what is beyond your comprehension.
    nokton.
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    Quote Originally Posted by nokton
    Dr Rocket,
    Thanks for your input. Would take issue with you on my concept
    of theory. Theory is supposition or a system of ideas intended to explain something, conjecture is an opinion or conclusion based upon incomplete
    information. Neither has any basis in fact.
    You attempt to describe to me the dynamics within a black hole within the
    so called event horizon, so called by you, tidal forces. Tell me about what
    you mean by tidal forces, and
    what parameters you are alluding to? You speak of a sngularity at the centre,
    you have no concept of any singularity, nor any evidence of it. You make
    believe you know and understand what is beyond your comprehension.
    nokton.
    You obviously don't understand what the word theory means, nor do you seem to realize that you're describing yourself better than you are DrRocket.
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  69. #68  
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    Quote Originally Posted by nokton
    Dr Rocket,
    Thanks for your input. Would take issue with you on my concept
    of theory. Theory is supposition or a system of ideas intended to explain something, conjecture is an opinion or conclusion based upon incomplete
    information. Neither has any basis in fact.
    You attempt to describe to me the dynamics within a black hole within the
    so called event horizon, so called by you, tidal forces. Tell me about what
    you mean by tidal forces, and
    what parameters you are alluding to? You speak of a sngularity at the centre,
    you have no concept of any singularity, nor any evidence of it. You make
    believe you know and understand what is beyond your comprehension.
    nokton.
    In science, there are two important words: "Theory", and "Hypothesis"..... and a few other terms like "supposition" and "guess", but scientists don't do a lot of those second two.

    A "Theory" means it has been confirmed to within a reasonably large probability to be true. "Hypothesis" is the word for things that really haven't been confirmed but which are thought to have the potential to be confirmed once more evidence becomes available. )

    As for the tidal thing: it's not that difficult to understand. Even using just Newtonian gravity, the force is equal to g*M*m/R^2. That means every distance from the center has a different force. Further away the force is weaker than nearby. In a normal gravity like here on planet Earth that difference is too small to matter. Near a black hole, though, ..... well..... imagine if Super Man grabbed for feet and started swinging you around in circles faster and faster until your legs broke and your feet came off your body, and he's just standing there holding your severed feet. That's what a large "difference in acceleration" means.

    Now... Superman is a nice guy and he probably wouldn't do that, ... but I think you get my point....?
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    Quote Originally Posted by MagiMaster


    It's really hard to take what you write seriously after your math comment. Also, it's no one's job to understand what you write. It's your job to write stuff people can understand.

    You'd never admit if you understood something I said.

    What's your opinion about Kojax's teachings about gravitational time dilation?
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  71. #70  
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster


    It's really hard to take what you write seriously after your math comment. Also, it's no one's job to understand what you write. It's your job to write stuff people can understand.

    You'd never admit if you understood something I said.

    What's your opinion about Kojax's teachings about gravitational time dilation?
    What kojax said in his previous post seems reasonable, but I don't think I'd quite call anything he's said in this thread as "teachings about gravitational time dilation." Other than that, I've already responded to kojax.

    BTW, I'm mostly understood what you said, and I've understood that what you've said is wrong.
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    The rest of us are just waiting for him to stop evading the questions put to him, or for him to leave.
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    Quote Originally Posted by inow
    The rest of us are just waiting for him to stop evading the questions put to him, or for him to leave.

    That would require him to understand the questions or to have somewhere to go. Don't hold your breath.
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    MagiMaster said this a while ago:

    Actually, no I can't. That's a question of general relativity, and I don't understand the details well enough to try and explain them to someone else.

    Ok, I'm also not 100% sure that it's just the constant speed of light causing that effect, but I do know that that's one of the two assumptions of special relativity from which length contraction and time dilation are derived.

    Then I quoted MagiMaster like this:
    No I can't .... I'm not sure


    And then MagiMaster had a problem with my way of quoting him.
    Well let me explain: I thought that I cut the idle stuff and left the good part.


    So now I am getting to what I want to say:

    Do you MagiMaster understand general relativity or not?
    You said there that you understand, right? Except the details.
    No wait, you understand the details too, but not well enough
    to explain the details?
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  75. #74  
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    Quote Originally Posted by jartsa
    MagiMaster said this a while ago:

    Actually, no I can't. That's a question of general relativity, and I don't understand the details well enough to try and explain them to someone else.

    Ok, I'm also not 100% sure that it's just the constant speed of light causing that effect, but I do know that that's one of the two assumptions of special relativity from which length contraction and time dilation are derived.

    Then I quoted MagiMaster like this:
    No I can't .... I'm not sure


    And then MagiMaster had a problem with my way of quoting him.
    Well let me explain: I thought that I cut the idle stuff and left the good part.
    And you wonder why I have a problem with that?

    Quote Originally Posted by jartsa
    So now I am getting to what I want to say:

    Do you MagiMaster understand general relativity or not?
    You said there that you understand, right? Except the details.
    No wait, you understand the details too, but not well enough
    to explain the details?
    I certainly don't claim to be an expert. I understand the principal (bending of 4D space-time) and I know what it's range of validity is (pretty much everything that isn't quantum-scale, black holes or the big bang). I know what math you'd need to understand the theory properly (tensors, specifically the stress-energy tensor), but I don't know how to use tensors (I've never really needed them, but if I had a few days and a good reference, I could probably figure them out).

    I don't know enough details to do actual calculations. I don't know enough to teach someone how it works, since I'd likely introduce errors into their understanding.

    Basically, I know enough to know when I don't know something. I don't think you can say that much.
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    SADLY! There is no point in our "looking" for anything inside black holes. As you approach a black hole, the increasing gravitational field makes time tick more slowly. So, for an external oberver, anything inside would "form" to the observer after an INFINATE ammount of time had passed.
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    Quote Originally Posted by quantumboy
    SADLY! There is no point in our "looking" for anything inside black holes. As you approach a black hole, the increasing gravitational field makes time tick more slowly. So, for an external oberver, anything inside would "form" to the observer after an INFINATE ammount of time had passed.
    More to the point, light inside the event horizon cannot get out so you cannot see inside. That is why it is called a BLACK hole.
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    Quote Originally Posted by MagiMaster

    I certainly don't claim to be an expert. I understand the principal (bending of 4D space-time) and I know what it's range of validity is (pretty much everything that isn't quantum-scale, black holes or the big bang). I know what math you'd need to understand the theory properly (tensors, specifically the stress-energy tensor), but I don't know how to use tensors (I've never really needed them, but if I had a few days and a good reference, I could probably figure them out).

    I don't know enough details to do actual calculations. I don't know enough to teach someone how it works, since I'd likely introduce errors into their understanding.

    Basically, I know enough to know when I don't know something. I don't think you can say that much.

    You just think your understanding is error free.
    MY understanding on the other hand is error free.
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  79. #78  
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster

    I certainly don't claim to be an expert. I understand the principal (bending of 4D space-time) and I know what it's range of validity is (pretty much everything that isn't quantum-scale, black holes or the big bang). I know what math you'd need to understand the theory properly (tensors, specifically the stress-energy tensor), but I don't know how to use tensors (I've never really needed them, but if I had a few days and a good reference, I could probably figure them out).

    I don't know enough details to do actual calculations. I don't know enough to teach someone how it works, since I'd likely introduce errors into their understanding.

    Basically, I know enough to know when I don't know something. I don't think you can say that much.

    You just think your understanding is error free.
    MY understanding on the other hand is error free.
    Your understanding is non-existent.
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  80. #79  
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    Quote Originally Posted by DrRocket
    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster

    I certainly don't claim to be an expert. I understand the principal (bending of 4D space-time) and I know what it's range of validity is (pretty much everything that isn't quantum-scale, black holes or the big bang). I know what math you'd need to understand the theory properly (tensors, specifically the stress-energy tensor), but I don't know how to use tensors (I've never really needed them, but if I had a few days and a good reference, I could probably figure them out).

    I don't know enough details to do actual calculations. I don't know enough to teach someone how it works, since I'd likely introduce errors into their understanding.

    Basically, I know enough to know when I don't know something. I don't think you can say that much.

    You just think your understanding is error free.
    MY understanding on the other hand is error free.
    Your understanding is non-existent.
    Jartsa, if you actually understood what you were saying then you would be able to describe it in detail, at least well enough so that one of us could add math to it. Then, once you've nailed it down to something specific, it can be compared with experimental results to see if it matches.
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  81. #80  
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster

    I certainly don't claim to be an expert. I understand the principal (bending of 4D space-time) and I know what it's range of validity is (pretty much everything that isn't quantum-scale, black holes or the big bang). I know what math you'd need to understand the theory properly (tensors, specifically the stress-energy tensor), but I don't know how to use tensors (I've never really needed them, but if I had a few days and a good reference, I could probably figure them out).

    I don't know enough details to do actual calculations. I don't know enough to teach someone how it works, since I'd likely introduce errors into their understanding.

    Basically, I know enough to know when I don't know something. I don't think you can say that much.

    You just think your understanding is error free.
    MY understanding on the other hand is error free.
    Those kind of statements only demonstrate a lack of understanding. (And where did I ever claim my understanding is error free?)
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  82. #81  
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    Quote Originally Posted by MagiMaster
    (And where did I ever claim my understanding is error free?)
    It's what you think.

    This is what you don't think:
    "It would have been better to not learn
    this stuff at all, because the teacher was likely to
    introduce errors into my understanding".
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  83. #82  
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster
    (And where did I ever claim my understanding is error free?)
    It's what you think.

    This is what you don't think:
    "It would have been better to not learn
    this stuff at all, because the teacher was likely to
    introduce errors into my understanding".
    And how exactly do you know what I think? (You're digging yourself into an awfully deep hole here.)

    I know for sure that my understanding is not error-free. I'd bet that none of my teachers understanding is 100% error-free either, but their understanding is much better than mine (and their errors are probably of a different nature), so I can still learn from them.

    More importantly than any of that though is having enough understanding to know where the gaps in my knowledge are. I am not affraid or embarrased to say "I don't know" when I really don't.
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  84. #83 knowledge 
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    MagiMaster, you one of a kind, you can put up your hand and say, I do not know.
    I wish science was awash with people like you. So much respect for science is
    lost by ordinary people because of the contradictions among scientists who would
    rather prevaricate than just say, I do not know.
    Nokton.
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    And to what field of science does that apply? Sure as hell not physics or mathematics.

    Quote Originally Posted by MagiMaster
    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster
    (And where did I ever claim my understanding is error free?)
    It's what you think.

    This is what you don't think:
    "It would have been better to not learn
    this stuff at all, because the teacher was likely to
    introduce errors into my understanding".
    And how exactly do you know what I think? (You're digging yourself into an awfully deep hole here.)

    I know for sure that my understanding is not error-free. I'd bet that none of my teachers understanding is 100% error-free either, but their understanding is much better than mine (and their errors are probably of a different nature), so I can still learn from them.

    More importantly than any of that though is having enough understanding to know where the gaps in my knowledge are. I am not affraid or embarrased to say "I don't know" when I really don't.
    And at the same time also have the understanding and ability to see what you do, in fact, know.

    Special relativity is about where my understanding drops off, and general relativity I only know in concept (I couldn't give any details, nor solve any in depth problems regarding GR.) I know, like MM, what I do not understand.

    Quote Originally Posted by jartsa
    You just think your understanding is error free.
    MY understanding on the other hand is error free.
    This was the single greatest quote by jartsa and I feel is the best example for why he does not belong here.
    Wise men speak because they have something to say; Fools, because they have to say something.
    -Plato

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  86. #85 Re: knowledge 
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    Quote Originally Posted by nokton
    MagiMaster, you one of a kind, you can put up your hand and say, I do not know.
    I wish science was awash with people like you. So much respect for science is
    lost by ordinary people because of the contradictions among scientists who would
    rather prevaricate than just say, I do not know.
    Nokton.
    It's been shown in numerous studies that the ability to assess gaps in your knowledge is proportional to your knowledge in general. Most scientists will tell you they don't know if you ask a question they really don't know about.

    In fact, that's why science in general has such a reputation for weasling. Scientists say things like, "if string theory is correct, we might can explain the big bang," or "we don't really know what dark energy is, but we know it's out there." This kind of talk comes from trying to be precise about what we do and don't know, but to lay people, it just comes across as unsure.
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    Quote Originally Posted by MagiMaster

    More importantly than any of that though is having enough understanding to know where the gaps in my knowledge are. I am not affraid or embarrased to say "I don't know" when I really don't.

    Well maybe I am insane.

    So does this important thing protect from insanity? Or how is it important?
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    Yes. I would say that it probably does protect from certain forms of insanity.

    Really though. Can you honestly not see why it's important to know when you don't know something?
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    Quote Originally Posted by MagiMaster
    Yes. I would say that it probably does protect from certain forms of insanity.

    Really though. Can you honestly not see why it's important to know when you don't know something?

    You were bragging how scientific you are. While jartsa is ..... what?

    I'm asking here for more information about how you are better than me,
    because you know that you don't know ... whatever that is that you know
    that you don't know.
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  90. #89  
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    Quote Originally Posted by Arcane_Mathematician
    fact, know.

    Special relativity is about where my understanding drops off, and general relativity I only know in concept (I couldn't give any details, nor solve any in depth problems regarding GR.) I know, like MM, what I do not understand.
    And I'm not too concerned about truly understanding GR in depth, because I think that when GR and QM finally square off and have their great showdown, QM is going to be the one to emerge victorious. (I don't know how yet. It's just what I think will happen.) In order to believe GR, you've got to believe that there is a lot of invisible matter and energy out there, and ..... generally once a theory starts postulating a lot of totally unobservable phenomena, .... it's on its way to actually failing.

    I'm not trying to give Jartsa ammunition, though. His description of his idea is so vague that he might as well be theorizing that a bunch of magical unicorns cause gravity for all the use we can make of it.
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  91. #90  
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    Quote Originally Posted by jartsa

    Well maybe I am insane.
    Delusional at the very least.
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster
    Yes. I would say that it probably does protect from certain forms of insanity.

    Really though. Can you honestly not see why it's important to know when you don't know something?

    You were bragging how scientific you are. While jartsa is ..... what?

    I'm asking here for more information about how you are better than me,
    because you know that you don't know ... whatever that is that you know
    that you don't know.
    You seem to be very confused, or very malicious. I can't tell. Either way, you keep putting words in my mouth and misrepresenting what I've said.

    I haven't been bragging and I haven't said I'm better than you. What I've said is that I recognize when I'm presented with a question I don't know the answer to and that that's an important skill you seem to lack.

    Quote Originally Posted by kojax
    Quote Originally Posted by Arcane_Mathematician
    fact, know.

    Special relativity is about where my understanding drops off, and general relativity I only know in concept (I couldn't give any details, nor solve any in depth problems regarding GR.) I know, like MM, what I do not understand.
    And I'm not too concerned about truly understanding GR in depth, because I think that when GR and QM finally square off and have their great showdown, QM is going to be the one to emerge victorious. (I don't know how yet. It's just what I think will happen.) In order to believe GR, you've got to believe that there is a lot of invisible matter and energy out there, and ..... generally once a theory starts postulating a lot of totally unobservable phenomena, .... it's on its way to actually failing.

    I'm not trying to give Jartsa ammunition, though. His description of his idea is so vague that he might as well be theorizing that a bunch of magical unicorns cause gravity for all the use we can make of it.
    Dark matter and dark energy are not part of GR. They are just names for things we've calculated must exist (in some form) but we don't know what they really are. GR does not say these things exist, just our observations of the universe.
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    Quote Originally Posted by MagiMaster

    I recognize when I'm presented with a question I don't know the answer to

    And then you say:
    I know but I can't tell




    Here is one case:

    Me:
    Can you explain to me how same speed of light everywhere causes things appearing to freeze on event horizon?

    You:
    Actually, no I can't. That's a question of general relativity, and I don't understand the details well enough to try and explain them to someone else.



    There is not any "I don't know the answer to your question" there.
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    So that isn't close enough to an "I don't know" for you? Let me be a bit more explicit then. I don't know enough about general relativity to answer that question with any degree of certainty.
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    Quote Originally Posted by MagiMaster
    So that isn't close enough to an "I don't know" for you? Let me be a bit more explicit then. I don't know enough about general relativity to answer that question with any degree of certainty.

    No this is not "I don't know".
    Well, maybe this specific case is not the right place for "I don't know"



    Now I found one thing you said that sounds goofy:
    Basically, there's a limit on how fast you can turn things in a circle before you end up breaking your clock.

    So let me ask you: Do you actually know that thing above? Is there a limit?
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    So this event horizon ... every event horizon resides at the same
    very low altitude, right?
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    Quote Originally Posted by jartsa
    Quote Originally Posted by MagiMaster
    So that isn't close enough to an "I don't know" for you? Let me be a bit more explicit then. I don't know enough about general relativity to answer that question with any degree of certainty.

    No this is not "I don't know".
    Well, maybe this specific case is not the right place for "I don't know"



    Now I found one thing you said that sounds goofy:
    Basically, there's a limit on how fast you can turn things in a circle before you end up breaking your clock.

    So let me ask you: Do you actually know that thing above? Is there a limit?
    That is a question that can be answered with special relativity. Basically, since velocity addition isn't linear, the tip of the rotating arm begins to experience something like drag (it isn't dragging against anything though) which puts stress on the arm. This stress would be infinite if the tip reached light speed, but since every material will break at some finite stress, it never gets that far. And yes, I could do the math to say what speed a given arm could withstand.

    Quote Originally Posted by jartsa
    So this event horizon ... every event horizon resides at the same
    very low altitude, right?
    No. Look up the Schwartzchild radius. The radius is directly proportional to its mass.
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    Quote Originally Posted by MagiMaster
    That is a question that can be answered with special relativity. Basically, since velocity addition isn't linear, the tip of the rotating arm begins to experience something like drag (it isn't dragging against anything though) which puts stress on the arm. This stress would be infinite if the tip reached light speed, but since every material will break at some finite stress, it never gets that far. And yes, I could do the math to say what speed a given arm could withstand.
    In part the answer to this is that special relativity precludes the existence of rigid bodies, whic in turn precludes the outer point of the rotating arm from reaching c.
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  99. #98  
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    Quote Originally Posted by MagiMaster

    Quote Originally Posted by kojax
    Quote Originally Posted by Arcane_Mathematician
    fact, know.

    Special relativity is about where my understanding drops off, and general relativity I only know in concept (I couldn't give any details, nor solve any in depth problems regarding GR.) I know, like MM, what I do not understand.
    And I'm not too concerned about truly understanding GR in depth, because I think that when GR and QM finally square off and have their great showdown, QM is going to be the one to emerge victorious. (I don't know how yet. It's just what I think will happen.) In order to believe GR, you've got to believe that there is a lot of invisible matter and energy out there, and ..... generally once a theory starts postulating a lot of totally unobservable phenomena, .... it's on its way to actually failing.

    I'm not trying to give Jartsa ammunition, though. His description of his idea is so vague that he might as well be theorizing that a bunch of magical unicorns cause gravity for all the use we can make of it.
    Dark matter and dark energy are not part of GR. They are just names for things we've calculated must exist (in some form) but we don't know what they really are. GR does not say these things exist, just our observations of the universe.
    Those calculations were made using GR. That means GR is making the prediction. Whenever you use a theory in making a calculation, whatever your calculation predicts is what the theory predicts. Without Dark Matter, the rotational speed of most Galaxies would be inexplicable. GR predicts that they will move at one speed, but we observe them to move at another, and Dark Matter is merely being introduced as an Ad hoc adjustment to make observation compatible with theory.

    I see little difference between the "evil demons make things fall" theory of gravity and the GR + Dark Matter theory. Neither of them can be compared against observation. No matter how fast or slow you see a galaxy rotating, you can always make your predictions match observation just by adding or subtracting Dark Matter.
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    Quote Originally Posted by MagiMaster
    No. Look up the Schwartzchild radius. The radius is directly proportional to its mass.
    Every event horizon resides at the same pretty large depth, right?
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    Quote Originally Posted by kojax
    Quote Originally Posted by MagiMaster

    Quote Originally Posted by kojax
    Quote Originally Posted by Arcane_Mathematician
    fact, know.

    Special relativity is about where my understanding drops off, and general relativity I only know in concept (I couldn't give any details, nor solve any in depth problems regarding GR.) I know, like MM, what I do not understand.
    And I'm not too concerned about truly understanding GR in depth, because I think that when GR and QM finally square off and have their great showdown, QM is going to be the one to emerge victorious. (I don't know how yet. It's just what I think will happen.) In order to believe GR, you've got to believe that there is a lot of invisible matter and energy out there, and ..... generally once a theory starts postulating a lot of totally unobservable phenomena, .... it's on its way to actually failing.

    I'm not trying to give Jartsa ammunition, though. His description of his idea is so vague that he might as well be theorizing that a bunch of magical unicorns cause gravity for all the use we can make of it.
    Dark matter and dark energy are not part of GR. They are just names for things we've calculated must exist (in some form) but we don't know what they really are. GR does not say these things exist, just our observations of the universe.
    Those calculations were made using GR. That means GR is making the prediction. Whenever you use a theory in making a calculation, whatever your calculation predicts is what the theory predicts. Without Dark Matter, the rotational speed of most Galaxies would be inexplicable. GR predicts that they will move at one speed, but we observe them to move at another, and Dark Matter is merely being introduced as an Ad hoc adjustment to make observation compatible with theory.

    I see little difference between the "evil demons make things fall" theory of gravity and the GR + Dark Matter theory. Neither of them can be compared against observation. No matter how fast or slow you see a galaxy rotating, you can always make your predictions match observation just by adding or subtracting Dark Matter.
    Tou don't need GR for this. Newtonian models are quite sufficient to reveal the anomaly that resulted in the dark matter hypothesis.
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