StringJunky Posted January 10, 2015 Share Posted January 10, 2015 That's not very fair. I put my time and effort into giving you informative responses, and I'd like to think I've been very patient. I can't help if you aren't willing to learn. You have been unreasonably patient. You can lead a man to a book but you can't make him think. 4 Link to comment Share on other sites More sharing options...
JohnSSM Posted January 10, 2015 Author Share Posted January 10, 2015 How many times did i have to state and restate that there is a radius, at which a certain mass can create the effects of a BH? I did the same thing with BH and supernova that you did to me...I denied what i knew was real until you gave proof, so that you could prove to me that your proof was as good as mine..thats exactly what you do to me... You have been unreasonably patient. You can lead a man to a book but you can't make him think. Unreasonably patient? well...ive been arguing the same realities to different people over and over...so perhaps my patience is growing thin compared to someone who just joined in...and I apoogize Now accusing me of not thinking? Im not the one running to other peoples words...i never have... Link to comment Share on other sites More sharing options...
Phi for All Posted January 10, 2015 Share Posted January 10, 2015 Being able to express these concepts in my own words seems to be a strength of mine. This seems to be saying, "I really make sense to me!" Am I missing the importance? 1 Link to comment Share on other sites More sharing options...
JohnSSM Posted January 11, 2015 Author Share Posted January 11, 2015 If someone is using and researching this subject on wijkipedia, as we go, what type of thinking is that? substitutive? This seems to be saying, "I really make sense to me!" Naw...logic can and is used to dictate facts...If I had math to back it all up, then it could finally also make sense to you...and i agree...im speculating...some guys do the stock market really well, others do not...I did i didnt use math for that either...just observation...lucky again! I am certainly taking back my statement about "all energy has a vector"...i was blindly locked into ONLY considering the energy that would effect the geometry of gravity...im now looking for "do those energies without a vector (such as kinetic) effect the geometry of gravity...and if they do, I will learn how they do...as best I can... Link to comment Share on other sites More sharing options...
Phi for All Posted January 11, 2015 Share Posted January 11, 2015 Naw...logic can and is used to dictate facts... If I had math to back it all up, then it could finally also make sense to you...and i agree...im speculating...some guys do the stock market really well, others do not...I did i didnt use math for that either...just observation...lucky again! It sounds like you're starting to really take this personally. Nobody is attacking you, but your behavior is deteriorating, so they're saying you're acting (not are) less than your normal civil self. For what it's worth, deep breaths can be refreshing. Link to comment Share on other sites More sharing options...
JohnSSM Posted January 11, 2015 Author Share Posted January 11, 2015 It sounds like you're starting to really take this personally. Nobody is attacking you, but your behavior is deteriorating, so they're saying you're acting (not are) less than your normal civil self. For what it's worth, deep breaths can be refreshing. Naw...it seems that calling someone ignorant, or a dick, does create offense in most cases...which is why they chose to use those words...which is why the forums rules suggest very deeply that people not refer to each other in derogatory ways...i think...wheres the math? dont got any The rest of the world seems to know that calling people names does create negative feelings...which are usually reflected right back...and there we were... even if ignorant is accurate, it doesnt add anything to the convo... Do you need an equation to figure that name calling is childish and not well received by others? Link to comment Share on other sites More sharing options...
Phi for All Posted January 11, 2015 Share Posted January 11, 2015 Naw...it seems that calling someone ignorant, or a dick, does create offense in most cases...which is why they chose to use those words...which is why the forums rules suggest very deeply that people not refer to each other in derogatory ways...i think...wheres the math? dont got any The rest of the world seems to know that calling people names does create negative feelings...which are usually reflected right back...and there we were... Calling out ignorance of a specific subject is honest, at least. Nobody called you ignorant of everything. I'm ignorant on many subjects, myself. And there is a difference between calling you a dick, and Strange saying, "You are now behaving like a total dick. I don't know why." You can see that, yes? If not, you're taking it too personally, too emotionally. You are much greater than this idea, whether it's wrong or right, and most ideas in science are wrong. 1 Link to comment Share on other sites More sharing options...
JohnSSM Posted January 11, 2015 Author Share Posted January 11, 2015 (edited) Once again, I feel that the GR/QM conflict is coming up...IN terms of GR, i was only trying to consider the properties of mass-energy and its effect of changing the geomterical vectors that are "created" or "figured for" by general relativity, which, as I understand it, is purely a theory of geometry...not particles...its math in action that creates the curves in space time...but it is the mass-energy within the spacetime that causes the effect itself...not an outside force...it is the properties of mass-energy that effect the geometry of spacetime curves...Can some address that and let me know where im short? I really thought i grasped this...if all that isnt right, then nothing i said would be right... Calling out ignorance of a specific subject is honest, at least. Nobody called you ignorant of everything. I'm ignorant on many subjects, myself. And there is a difference between calling you a dick, and Strange saying, "You are now behaving like a total dick. I don't know why." You can see that, yes? If not, you're taking it too personally, too emotionally. You are much greater than this idea, whether it's wrong or right, and most ideas in science are wrong. cmon...its giving offence and you know it...Im just sticking by the rules of the forum as best I can and i include not calling people names in mine...Calling out fatness when someone is complaining about their clothes is also honest...but the word implies hurt feelings...and we all know that....i think...i do...differing realities once again I was right...I was considering black holes purely from a GR point of view and supernova use lots of QM...This conversation could ONLY be speculative in nature...Supernova in a world where QM and GR come together does not have a proof...If they have been successfully unified then im wrong...or maybe its ok to consider them unified for certain models...like that of supernova formation and BHs? I see that the word dick has one purpose and it is to offend...another word could have been chosen that would have fit the rules of the forum much better...like "you are being impatient"...that was not offensive as it desribes more then someone being akin to a penis...impatient was a non-offensive label to give me...dick was not... Let me guess, you all have already reasoned that its ok to say "you are acting like a dick"...and not allow..."Youre a dick"...does "youre acting like" wash away the accusation somehow? I dont wanna argue with a moderator...i think that breaks the forum rules... I dont want this to get lost in the fray...it speaks to the friction between ELFMOTAT and my discussion about black holes...""Once again, I feel that the GR/QM conflict is coming up...IN terms of GR, i was only trying to consider the properties of mass-energy and its effect of changing the geomterical vectors that are "created" or "figured for" by general relativity, which, as I understand it, is purely a theory of geometry...not particles...its math in action that creates the curves in space time...but it is the mass-energy within the spacetime that causes the effect itself...not an outside force...it is the properties of mass-energy that effect the geometry of spacetime curves...Can some address that and let me know where im short? I really thought i grasped this...if all that isnt right, then nothing i said would be right..."" I think it could be appropriate for me to look for forums in GR that discuss black holes...I just hit a wall on confusion and was interested in some input...In "Relativity" as a whole, we have general relativity and special relativity...and it seems that special relativity describes the particles as energy and begins the QM equations which sprout all over the place..With special relativity being particle physics and general relativity not being unified with particle physics, does that mean special and general relativity dont unify? no harsh feelings fellas...This topic could spur on many more topics and i think it did. Im going to try to keep my thoughts on the straight and narrow when sticking to the rules im learning and realizing...and I started a new topic that addresses my very first bit of observation about GR and SR... I EFOMAT "I don't understand how you're getting from "some of the BH's energy is stored in its angular momentum" to "therefore its event horizon is smaller." The two seem utterly disconnected."Thats a question I was hoping to answer...Here it isIn schwartzchild, You can keep saying "event horizon", but I think radius keeps terms better with volume and mass...The event horizon would exist at this theoretical radius ( this is not true, but i wanted to keep it in the thread), if the object had no spin. If the object weren't perfectly symmetrical, it WOULD spin...its has no choice, GR would make it spin, or maybe SR...all I know is that it will spin...thats why those two are grouped together like that, ie "in a symetrical, non spinning object" being a preface to the theory...So, if it isnt spinning,because it is perfectly symmetrical and has no other forces effecting it which means this object is alone in spacetime...there is no reason to deduct the total amount of energy that spin takes, or reduce radius of schwarztrman...it takes energy to spin something though...Now...if the total energies of that object, are creating a spin, that means some of the vectors from some of the energies are not working to create more gravity...spin does not create gravity...but those vectors have to work to create spin...the energy it takes to spin cannot be used to create its total gravity anymore...So...the Radius distance which dictates how much energy is applied to a mass as you decrease its volume (or in whatever terms you want to view it), now has to account for the energy of spinning and demands more compression before it has the energy to create the properties of a BH...In shcwartzman, i dont know how to not use the word compression, because adding more mass to volume is compressing more mass into a volume, and reducing the volume is still compressing that mass...by the way, both of which would take lots of energy, and in schwartzman theories, we move it around with no such demands....you kinda should be asking, "what makes the volume of the mass decrease?" or, "you just cant stuff more mass into that volume without energy"...and then, where is that energy coming from?Try this...we are going to test the schwartzman radius by slowly reducing the volume of the earth...we need a mechanism to smash earth down to 6000 km from 6300, not losing a drip of mass...anything you might envision is going to require energy that you cannot imagine...but lets say you did and you could just rob a pit of unlimited energy to run your mechanism...by the way, the device not only needs to smash it down, itll need energy at every moment to keep it smashed down...and we run this device, adding more and more compression to the volume of earth, using more and more energy...we will eventually spawn fusion...itll be hydrogen or some assimiliation of gases that will begin that process...now...if we can keep the pressure on with our device and we can keep it compressed that entire time as fusion does its destructive thing, well, eventually, with the right conditions, its seems you would form a black hole...thats how i see schawatrsman...interesting to note...if you could imagine all of the energy your device would have needed to smash earth down to create a black hole, now you would need a rocket with that much energy to escape it...and that is more energy than the velocity of light...there is another way to smash more space into into a volume...its acceleration...acceleration gives you the ability to cram more kilometers into the same time...spacetime, it is a continuum...this effect could also cause a black hole if it were possible to have the energy to move that fast...and the event horizon seems to be a speed for every mass, and not a radius for every mass...there should be a schwartxman acceleration limit for any given mass, just as there is a scwartman radius for any given mass...at that acceleration limit, the forces of spacetime are changed, just like it was a massively compressed object...Lets say you had an object at the schwartzman radius...or the event horizon...and that object is not using the energies from its own resulting vectors, or outside vectors to spin....which will be impossible unless it is perfectly syymetrically spherical...if we now wanted to make the black hole spin, we would have to deduct the amount of energy from its gravitational force to get the energy to make it spin...and you need less volume, more compression, more energy..so you make the radius to acomodate for that...and it finds its new shcqwartzman radius, with spin...not the same distance of the scjhwartsman radius with no spin... You apparently would not be able to increase the radius for a BH without slowing its spin...and the radius does have a limit on the big side...no amount of spin or no spin can make the radius larger once it is calculated for a given mass...only smaller... Heres a good linkhttp://www.quora.com/Why-does-the-centrifugal-force-reduce-the-effect-of-gravity Here is another really interesting perspective...The volume that we discuss getting smaller with r, to me, is the volume of space-time that a mass fills...so the earth right now fills a volume of space-time roughly 6300km in radius...that does not define the point at which gravity interupts space time or, the point which requires an escape velocity that exceeds the velocity of light...that would assume when you hit the event horizon you are hitting the mass of a BH...thats a big assumption...I assumed the point at which gravity creates the event horizon is NOT the schwartzman radius...the smawrtsman is the radius of the mass that you fit into a specfic volume... The event horizon of a black hole could not be inside the volume of its mass...im pretty sure the event horizon could exist relativley far away as a diferent radius...10 feet from the surface of mass? 10 miles? 10,000? i have no idea...the theory suggests the event horizon would be larger in r than the schwartsman r Calling out ignorance of a specific subject is honest, at least. Nobody called you ignorant of everything. I'm ignorant on many subjects, myself. And there is a difference between calling you a dick, and Strange saying, "You are now behaving like a total dick. I don't know why." You can see that, yes? If not, you're taking it too personally, too emotionally. You are much greater than this idea, whether it's wrong or right, and most ideas in science are wrong. The last line is very cool...thanks... This seems to be saying, "I really make sense to me!" Am I missing the importance? No...you missed the point The point is, if you cant describe the ball, you must not be able to see it...When i make a description, none of you can keep up with it, and out of frustration, you turn to math that you dont even "SEE" and call it your explanation...I havent heard any of you describe the geometery of space-time...I wonder why not when you understand it so well...hmmm Edited January 11, 2015 by JohnSSM Link to comment Share on other sites More sharing options...
Mordred Posted January 11, 2015 Share Posted January 11, 2015 (edited) The point is, if you cant describe the ball, you must not be able to see it...When i make a description, none of you can keep up with it, and out of frustration, you turn to math that you dont even "SEE" and call it your explanation...I havent heard any of you describe the geometery of space-time...I wonder why not when you understand it so well...hmmmWow I take the day of to spend some quality time with my wife. Then read all that has transpired. I have one question to ask. Did anyone teach you the meaning of humility?. From your opening post how much did your understanding change? Yet you sit there insulting those that spent the time correcting your understanding. How much discussion did it take to get you to see the geometry relations or that space time is a mathematical descriptive? Your last posts were in regards to vectors . However your opening posts was gluons. We corrected a large amount in this thread. Albeit some mistakes were made, however this shouldn't distract you from the fact that every took the time and effort to assist you. I really don't know what to say at this point. I've helped a lot of people online over the years. Yes sometimes I make mistakes however I admit to them. I can't recall any that change the way they discuss a problem, get corrected then claim they were always right. Just my take, I know you won't agree but quite frankly its no sweat off my back as they say. You have the material I provided I truly hope you learn from that material. As for me I have my own studies which involves the Higgs field and the cosmological constant. I fully expect this to take a few years. Ps you can't have energy momentum without something to measure. Neither can you measure spactime without something to measure. You already know I will state you measure particles Might think about that in terms of the test particle YdoaPs used. Remember energy and momentum are both properties. They do not exist on their own. For that you need ? One last question "Why do you choose to self limit yourself, not taking the time to understand the math is self limitation". Imagine what you can do with your ability to visualize coupled with the mathematics.... For example a good mathematician can look at a random sinusoidal wave form and perform a laplace transformation. Aka electromagnetic waveforms. Visualization is only a beginning, mathematics is the tool to describe that visualization Ajb for example is a mathematician. He can probably pick up ANY physics article and see the relations of influence involved. As one that tried to ignore the math then took the time to learn it. I can honestly say I can decipher far more in random physics articles. Even to the point of recognizing math to invalid premise errors. ( in the fields I study,) Makes it easier to recognize pop media or crank articles Edited January 11, 2015 by Mordred 1 Link to comment Share on other sites More sharing options...
Strange Posted January 11, 2015 Share Posted January 11, 2015 (edited) IN terms of GR, i was only trying to consider the properties of mass-energy and its effect of changing the geomterical vectors that are "created" or "figured for" by general relativity, which, as I understand it, is purely a theory of geometry...not particles...its math in action that creates the curves in space time...but it is the mass-energy within the spacetime that causes the effect itself...not an outside force...it is the properties of mass-energy that effect the geometry of spacetime curves... That is pretty much it. Did you read the John Baez article that Mordred referenced. It explained that (but in quantitative terms, so it is useful, rather than just a vague concept which is not useful). The only bit I would question is "not particles". You will note that the Baez article uses particles to describe what will happen in particular cases. The idea of a "test particle" is an important concept. Admittedly, this is not the same as a "particle" in QM, which may be what you are thinking of. I was right...I was considering black holes purely from a GR point of view and supernova use lots of QM...This conversation could ONLY be speculative in nature...Supernova in a world where QM and GR come together does not have a proof...If they have been successfully unified then im wrong...or maybe its ok to consider them unified for certain models...like that of supernova formation and BHs? The behaviour of supernovae and the creation of black holes is, as far as I know pretty well understood and modelled. (It is not something I know much about as it is very complex.) No doubt there are some open questions (this is science, after all). But it is certainly not speculation. In "Relativity" as a whole, we have general relativity and special relativity...and it seems that special relativity describes the particles as energy and begins the QM equations which sprout all over the place.. No. They both describe exactly the same thing. SR is just a subset that only consider inertial motion. GR is the full version that includes gravity. With special relativity being particle physics and general relativity not being unified with particle physics, does that mean special and general relativity dont unify? Definitely not. GR is an extension of SR. GR can be simplified to SR in the absence of gravity (this is effectively the definition of "local" in GR). If the object weren't perfectly symmetrical, it WOULD spin...its has no choice, GR would make it spin, or maybe SR Neither of these will make it spin. It is very likely that all black holes spin because the stars they formed from were spinning. I suppose there might be a star somewhere that is not spinning - that would create a black hole with no spin. Or two black holes with exactly opposite spin could merge. It is just very unlikely for a black hole to have no spin. or reduce radius of schwarztrman...it takes energy to spin something though...Now...if the total energies of that object, are creating a spin, that means some of the vectors from some of the energies are not working to create more gravity...spin does not create gravity...but those vectors have to work to create spin...the energy it takes to spin cannot be used to create its total gravity anymore... And this is why you get some negative reactions. "schwarztrman" ? "it takes energy to spin something though" - it might take energy to start something spinning. But we are talking about something which is already spinning (or, strictly speaking, in the case of a black hole has angular momentum). No energy is required to keep it spinning. "vectors from some of the energies" - energy is not a vector "vectors have to work to create spin" - see above. you kinda should be asking, "what makes the volume of the mass decrease?" Gravity. the theory suggests the event horizon would be larger in r than the schwartsman r The Schwarzschild radius is the radius of the event horizon (for a non-rotating) black hole. For a rotating black hole, the event horizon is smaller, as has been shown. When i make a description, none of you can keep up with it, and out of frustration, you turn to math that you dont even "SEE" and call it your explanation.. The problem is, your descriptions are vague and based on the misuse of well-defined terms. What you think is a failure to "keep up" or "see" is people attempting to give you better explanations (i.e. ones based on what science actually knows) and to correct nonsense like "energy vectors". Sometimes giving a better explanation can only be done by reference to the maths. Sometimes the maths is provided to demonstrate that it is not just someone's opinion or belief. You may have figured out the inverse square relationship based on the areas of spheres (well done) and had a lucky guess (*) about the radius of spinning black holes but that does not mean that your imagination will always get you the right answers. (*) And it was a guess because your attempt to justify it is just unmitigated nonsense. Edited January 11, 2015 by Strange Link to comment Share on other sites More sharing options...
ajb Posted January 11, 2015 Share Posted January 11, 2015 If schwartzchild is right, or there is ANY radius, that a certain mass, when reduced to it, will create a black hole... The most general conditions for the formation of a horizon are not known. (As far as I know) If energy exists, can it exist without a vector? I dont think so...look to the definition of vectors...every energy has a directional component called a vector Energy is a scaler. Link to comment Share on other sites More sharing options...
Mordred Posted January 11, 2015 Share Posted January 11, 2015 To add to Strange's comments on spinning think of conservation of angular momentum. If a slow spinning object compresses, it's spin rate increases. Take a spinning skater with arms open,now close the arms rate of spin increases . Open up the arms it decreases Same principle applies to all rotating bodies. Including BH's 1 Link to comment Share on other sites More sharing options...
ajb Posted January 11, 2015 Share Posted January 11, 2015 Can some address that and let me know where im short? I really thought i grasped this...if all that isnt right, then nothing i said would be right... This is more or less okay. The matter or non-gravitational field content is described by an energy-momentum tensor. This contains all the necessary information about the 'stuff'. This then determines the local geometry of space-time through the Einstein field equations. With special relativity being particle physics and general relativity not being unified with particle physics, does that mean special and general relativity dont unify? Special relativity 'sits inside' general relativity. You can see this in two ways. First the Minkowski metric is a solution to the vacuum field equations, and this is what one could expect. The physics without gravity should be the physics on a flat space-time. Secondly, locally in a small enough region space-time looks flat. Thus, locally all non-gravitational physics reduces to that on flat space-time; this is one form of the equivalence principle. Both special and general 'unite' in these two senses. 1 Link to comment Share on other sites More sharing options...
StringJunky Posted January 11, 2015 Share Posted January 11, 2015 .Neither of these will make it spin. It is very likely that all black holes spin because the stars they formed from were spinning. I suppose there might be a star somewhere that is not spinning - that would create a black hole with no spin. Or two black holes with exactly opposite spin could merge. It is just very unlikely for a black hole to have no spin. Couldn't the origin of the spin of a black hole come from a vortical/spiral collapse of the star rather than a radial one; the gas molecules following the spacetime curve inwards, creating increasing angular momentum as the centre gets denser? I was thinking along the lines similar to a black hole accreting material from a nearby star and how it spirals inwards rather than radially. Link to comment Share on other sites More sharing options...
Mordred Posted January 11, 2015 Share Posted January 11, 2015 Not really a rotating BH can lose its rate of rotation via the Hawking Berkenstien radiation. In rotation you must consider all interactions with particles. A feeding BH will most likely increase its angular momentum, however this rate can be reduced by the process I mentioned. A good analysis is done in this article. http://arxiv.org/abs/1104.5499:''Black hole Accretion Disk'' -Handy article on accretion disk measurements provides a technical compilation of measurements involving the disk itself. what a lot of people ignore is the influence the accretion disk can have via gravity A Kerr rotating BH can theoretically become non rotating and vice versa 2 Link to comment Share on other sites More sharing options...
Strange Posted January 11, 2015 Share Posted January 11, 2015 A Kerr rotating BH can theoretically become non rotating and vice versa Which again reinforces the idea that one can't rely on intuition when thinking about these things! I have been using my imagination... I would be interested to know how your imagination answers the following questions (this is not an attempt to trick you, I'm just curious what your intuition tells you). Imagine you are in a spaceship (like one of those one-man submarines) exploring black holes. You decide to go into one by letting your craft just fall towards it. 1. Is it better to do this with a supermassive black hole (with the mass of millions of stars) or a smaller one (about 10 stellar masses)? (And why?) 2. What will you experience as you fall past the event horizon? (And why?) 3. Will it take longer to fall to the center if you carry on in free-fall, or if you use you engines to try and orbit? (And why?) 2 Link to comment Share on other sites More sharing options...
JohnSSM Posted January 11, 2015 Author Share Posted January 11, 2015 That is pretty much it. Did you read the John Baez article that Mordred referenced. It explained that (but in quantitative terms, so it is useful, rather than just a vague concept which is not useful). The only bit I would question is "not particles". You will note that the Baez article uses particles to describe what will happen in particular cases. The idea of a "test particle" is an important concept. Admittedly, this is not the same as a "particle" in QM, which may be what you are thinking of. The behaviour of supernovae and the creation of black holes is, as far as I know pretty well understood and modelled. (It is not something I know much about as it is very complex.) No doubt there are some open questions (this is science, after all). But it is certainly not speculation. No. They both describe exactly the same thing. SR is just a subset that only consider inertial motion. GR is the full version that includes gravity. Definitely not. GR is an extension of SR. GR can be simplified to SR in the absence of gravity (this is effectively the definition of "local" in GR). Neither of these will make it spin. It is very likely that all black holes spin because the stars they formed from were spinning. I suppose there might be a star somewhere that is not spinning - that would create a black hole with no spin. Or two black holes with exactly opposite spin could merge. It is just very unlikely for a black hole to have no spin. And this is why you get some negative reactions. "schwarztrman" ? "it takes energy to spin something though" - it might take energy to start something spinning. But we are talking about something which is already spinning (or, strictly speaking, in the case of a black hole has angular momentum). No energy is required to keep it spinning. "vectors from some of the energies" - energy is not a vector "vectors have to work to create spin" - see above. Gravity. The Schwarzschild radius is the radius of the event horizon (for a non-rotating) black hole. For a rotating black hole, the event horizon is smaller, as has been shown. The problem is, your descriptions are vague and based on the misuse of well-defined terms. What you think is a failure to "keep up" or "see" is people attempting to give you better explanations (i.e. ones based on what science actually knows) and to correct nonsense like "energy vectors". Sometimes giving a better explanation can only be done by reference to the maths. Sometimes the maths is provided to demonstrate that it is not just someone's opinion or belief. You may have figured out the inverse square relationship based on the areas of spheres (well done) and had a lucky guess (*) about the radius of spinning black holes but that does not mean that your imagination will always get you the right answers. (*) And it was a guess because your attempt to justify it is just unmitigated nonsense. I Must say, it seems you have made a mistake..I finally went and read the swartzchild radius on wiki...before this point in time i didnt...I only took from the scwartchild descrip in this topic...In the third sentence it says... "An example of an object smaller than its Schwarzschild radius is a black hole." This means that the radius of the mass of a black hole is NOT the point of the event horizon...and also says that the event horizon for a black hole happens at a larger radius than the volume radius....The scwartzchild radius detemines when the volume of a mass can create the energies needed... the geometry it changes to create the event horizon DOES NOT correspond to its radial volume. This is what i envisioned and described... Explaining "energy vectors" as I see them may be a waste of time, but maybe you can help me sort it if i decribe what Im talking about... IF someone pushes me, all I really know is they are transferring energy to my mass in a direction...so, you have energy and a vector...im trying to understand how one can have energy appiled to a mass without a vector...I know now that kinetic energy has no vector but i dont understand why it doesnt...and i dont understand how you could have a vector without energy...if the guy never pushed me, then there would be no vector created...but when he does push me, a vector is created...or is it transferred like the energy? IN terms of gravity, I see vectors as the directions of the momentum being carried...or the direction of that energy...those energies (of momentum) and their vectors seem to be what those GR equations would need to calculate the curves in spacetime... Everytime i mentioned energies and vectors, I was really referring to the energy of momentum... What is the 9/8ths that someone mentioned? IS that where the event horizon is created for a BH in regards to it's volume of mass? that makes sense...at least its bigger and thats all I claimed to know...i can envission "bigger" just have no way to calculate the actual size... I can envision that spin would require a smaller shwartzchild radius, but i dont know how much... If we take a golf ball being hit by a club, the club can hit it "straight" on and result in very little spin and the majority of its energy is applied to force in a vector with the contact...If the golf club swipes the ball and does not make contact "straight" on, it creates spin and reduces the amount of energy transferred in the vector...if it werent for the influence of spin on air, the furthest hit golf ball would have the most energy and the least spin... Thats why I figure BH, or masses that become black holes, must have a smaller schwartchild radius the more they spin...a smaller radius implies more energy... If i had a spinning golf ball and a non spinning golf ball, the spinning golf ball would need more energy at impact to go the exact same distance as a non spinning ball.... Link to comment Share on other sites More sharing options...
elfmotat Posted January 11, 2015 Share Posted January 11, 2015 (edited) A vector is a mathematical object. It is not a "thing" that exists. I recommend picking up an introductory Newtonian physics textbook. For a black hole with zero angular momentum (called a "Schwarzschild black hole") the event horizon is at [math]R_{EH}=R_S=2GM/c^2[/math]. This radius is called the "Schwarzschild radius." For a black hole with angular momentum (called a "Kerr black hole") the event horizon is not at its Schwarzschild radius. Instead, it is found at: [math]R_{EH} = \frac{GM}{c^2}+ \sqrt{\left ( \frac{GM}{c^2} \right )^2 - \left (\frac{J}{Mc} \right )^2} = \frac{R_S}{2}+ \sqrt{\left ( \frac{R_S}{2} \right )^2 - \left ( \frac{J}{Mc} \right )^2}[/math] If you take a ball of mass M and compress it down to a radius of less than [math]R=9GM/4c^2 = 9 R_S / 8[/math], the internal pressure required to counteract gravity and prevent collapse into a black hole becomes infinite. In other words, if you compress a mass down to less than 9/8 its Schwarzschild radius, it has no choice but to become a black hole. I believe that probably answers most of your questions. Edited January 11, 2015 by elfmotat Link to comment Share on other sites More sharing options...
JohnSSM Posted January 11, 2015 Author Share Posted January 11, 2015 I would be interested to know how your imagination answers the following questions (this is not an attempt to trick you, I'm just curious what your intuition tells you). Imagine you are in a spaceship (like one of those one-man submarines) exploring black holes. You decide to go into one by letting your craft just fall towards it. 1. Is it better to do this with a supermassive black hole (with the mass of millions of stars) or a smaller one (about 10 stellar masses)? (And why?) 2. What will you experience as you fall past the event horizon? (And why?) 3. Will it take longer to fall to the center if you carry on in free-fall, or if you use you engines to try and orbit? (And why?) I have no intuitive knowledge of what may happen inside a black hole... My intuitive knowledge says that I could never get close enough to an event horizon without being physically destroyed by forces created by the black hole...I myself have never imagined the inside of a black hole...i figured that the forces of the universe change inside it...it my thoery and how i have envisioned it before, spacetime itself is totally interupted at the event horizon which makes passing through it impossible from either direction...i suppose i always envissioned everything which makes contact with the event horizon is suspended in animation, physicaly smashed on the surface of it... as far as I know the only way to increase my fall into the center would be to add energies in the direction to the center...and to slow it would be adding energies away from center...Adding orbital energies would have little effect on free fall towards the center... Link to comment Share on other sites More sharing options...
Strange Posted January 11, 2015 Share Posted January 11, 2015 This means that the radius of the mass of a black hole is NOT the point of the event horizon... The radius of a (non-rotating) black hole is the Schwarzschild radius. The scwartzchild radius detemines when the volume of a mass can create the energies needed... It doesn't create energy. Explaining "energy vectors" as I see them may be a waste of time Yes, because there is no such thing. IF someone pushes me, all I really know is they are transferring energy to my mass in a direction... You may be thinking of momentum. Or force. Or acceleration. Or.... who knows. Link to comment Share on other sites More sharing options...
JohnSSM Posted January 11, 2015 Author Share Posted January 11, 2015 A vector is a mathematical object. It is not a "thing" that exists. I recommend picking up an introductory Newtonian physics textbook. For a black hole with zero angular momentum (called a "Schwarzschild black hole") the event horizon is at [math]R_{EH}=R_S=2GM/c^2[/math]. This radius is called the "Schwarzschild radius." For a black hole with angular momentum (called a "Kerr black hole") the event horizon is not at its Schwarzschild radius. Instead, it is found at: [math]R_{EH} = \frac{GM}{c^2}+ \sqrt{\left ( \frac{GM}{c^2} \right )^2 - \left (\frac{J}{Mc} \right )^2} = \frac{R_S}{2}+ \sqrt{\left ( \frac{R_S}{2} \right )^2 - \left ( \frac{J}{Mc} \right )^2}[/math] If you take a ball of mass M and compress it down to a radius of less than [math]R=9GM/4c^2 = 9 R_S / 8[/math], the internal pressure required to counteract gravity and prevent collapse into a black hole becomes infinite. In other words, if you compress a mass down to less than 9/8 its Schwarzschild radius, it has no choice but to become a black hole. I believe that probably answers most of your questions. IS anything in math a "thing" anymore? mass, volume, energy? isnt it all just existance of values in math? Angular momentum...like my golf ball example...im with you... Why is the schwartzchikd radius a defined as the radius at which a BH occurs if its actually 9/8ths? I dont get that at all...was schwarctzcgild wrong is his original math? I have not seen 9/8ths anywhere in reference to schwartzchild, now that im reading about it..so, the only source of this info is you and im wondering if youre still confused about it.. Do you still think the schwartzchild radius defines the beginning of an EH? cuz it does not... The radius of a (non-rotating) black hole is the Schwarzschild radius. It doesn't create energy. Yes, because there is no such thing. You may be thinking of momentum. Or force. Or acceleration. Or.... who knows. http://en.wikipedia.org/wiki/Schwarzschild_radius "The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is the radius of a sphere such that, if all the mass of an object were to be compressed within that sphere, the escape speed from the surface of the sphere would equal the speed of light. An example of an object smaller than its Schwarzschild radius is a black hole." Strange, according to wiki, you are incorrect...wiki agrees with my logic "An example of an object smaller than its Schwarzschild radius is a black hole." Link to comment Share on other sites More sharing options...
Strange Posted January 11, 2015 Share Posted January 11, 2015 My intuitive knowledge says that I could never get close enough to an event horizon without being physically destroyed by forces created by the black hole...I myself have never imagined the inside of a black hole...i figured that the forces of the universe change inside it...it my thoery and how i have envisioned it before, spacetime itself is totally interupted at the event horizon which makes passing through it impossible from either direction... So you would actually be safer falling into a very large black hole as the tidal forces would be less and so you wouldn't be torn apart (well, not immediately). You wouldn't notice anything at all as you pass through the event horizon. And finally, if you try and use your rockets to slow your approch to the center, you will actually get there faster. Apparently. So your imagination isn't always helpful. Link to comment Share on other sites More sharing options...
JohnSSM Posted January 11, 2015 Author Share Posted January 11, 2015 Did you ration that all yourself of take info from somewhere else? Is there any evidence to support your claims? Link to comment Share on other sites More sharing options...
Strange Posted January 11, 2015 Share Posted January 11, 2015 Strange, according to wiki, you are incorrect...wiki agrees with my logic "An example of an object smaller than its Schwarzschild radius is a black hole." That is just an example of the poor wording you find on Wikipedia occasionally. Even on the pages that are accurate. All it means is that if the mass is within a radius less than (or equal to) the Schwarzschild radius then it will become a black hole. There could be two ways of defining the size of black hole: the event horizon (Schwarzschild radius) or zero (which is the radius of the mass inside the black hole). Did you ration that all yourself of take info from somewhere else? I know you think that making stuff up is better than using well established and tested science, but I tend not to agree. Is there any evidence to support your claims? Of course. You have been given any number of references to books, websites and other sources of information. (But then you complain because we are not just making it up. Can't win with some people.) Link to comment Share on other sites More sharing options...
elfmotat Posted January 11, 2015 Share Posted January 11, 2015 I have no intuitive knowledge of what may happen inside a black hole... My intuitive knowledge says that I could never get close enough to an event horizon without being physically destroyed by forces created by the black hole...I myself have never imagined the inside of a black hole...i figured that the forces of the universe change inside it...it my thoery and how i have envisioned it before, spacetime itself is totally interupted at the event horizon which makes passing through it impossible from either direction...i suppose i always envissioned everything which makes contact with the event horizon is suspended in animation, physicaly smashed on the surface of it... as far as I know the only way to increase my fall into the center would be to add energies in the direction to the center...and to slow it would be adding energies away from center...Adding orbital energies would have little effect on free fall towards the center... This is why it's important to learn the math. Intuition is not a good guide for physical matters. Falling into a supermassive black hole would be better. The tidal forces at the horizon would be negligible, and you would pass right through without noticing a thing. Nothing special happens there, it's just a point of no return. As for how to maximize your time of survival: do precisely nothing. Geodesics are paths of maximal proper time. Trying to fight your way out will only make you die faster. IS anything in math a "thing" anymore? mass, volume, energy? isnt it all just existance of values in math? Angular momentum...like my golf ball example...im with you... Mass, volume, and energy are all observables. I.e. you can measure them. You can't measure a vector. There are different types of vectors, and some of them have absolutely nothing whatsoever to do with physics. Why is the schwartzchikd radius a defined as the radius at which a BH occurs if its actually 9/8ths? I dont get that at all...was schwarctzcgild wrong is his original math? I have not seen 9/8ths anywhere in reference to schwartzchild, now that im reading about it..so, the only source of this info is you and im wondering if youre still confused about it.. Do you still think the schwartzchild radius defines the beginning of an EH? cuz it does not... The point at which gravitational collapse becomes inevitable is at 9/8 the Schwarzschild radius. This is known as Buchdahl's Theorem -- Schutz's textbook has a section on it. After the mass has collapsed into a black hole, its event horizon will be located at its Schwarzschild radius (assuming it has no angular momentum). Link to comment Share on other sites More sharing options...
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