MigL

Let me see if I understand you correctly, Moontanman. Antimatter would exhibit antigravity only if it also had the property of antimass. Now since mass is more or less related to energy by Einstein's M=E/c^2 then antimass or negative mass implies antienergy or negative energy, since c^2 definitely cannot be negative. This opens up a whole new can of worms. Equal amounts of energy and antienergy ( contained in a proton and antiproton for example ), effectively equal to zero energy, would be able to produce a positive energy gamma emission. Oops there goes one conservation law. And as far as I know antimatter doesn't have the same properties nor is it equivalent to 'exotic' matter.

They may be both possibly singularities central to a black hole and at the beginning of space tme, but they have vastly different properties. If we draw a distance-time diagram ( y=time and x=distance ) we not that a black hole singularity is a timelike 'edge' to space-time. It is in effect a discontinuity on the left side of our diagram. The big bang singularity, on the other hand, is a spacelike edge to space-time. A discontinuity on the bottom side of our diagram and only in the past.

Well popcorn, you seem to be at least familiar with Newton's laws and gravity. So consider his gravitational equation where the force of attraction is directly proportional to the two masses involved and inversely proportional to the distance squared. Force= G(mass1*mass2)/radius^2 where G is the gravitational constant. If you were to squeeze the masses to incredibly tiny sizes so that you could bring them to very,very small separation, what do you think would happen to the attractive force? Would it not get incredibly large? I assume you can do multiplication and division, can you not see the ultimate fate when the separation approaches zero? I think ACG52 is right and ignorance is definitely more pertinent than incredulity in this case.

Why is it so strange that a voltage will pass through a capacitor to power an LED? The current doesn't have to, as the voltage will force charge carriers ( electrons or holes ) on the opposing side of the cap to become mobile. Ther would be little difference between a capacitor and a resistor, one would introduce a time delay while the other would require a minimum voltage. You display very little understanding of how electrical systems work.

The universe is bright in all directions with brightness differences of less than one part in a thousand, however it is not in the infrared but in the microwave region of the EM spectrum. Speciflcally 2.7 Deg.K above absolute zero. As swansont has pointed out this s because of the finite history of the universe and the infinite path ( the universe could be finite and unbounded ) and finite speed of lght. This microwave radiation is then, the faint 'echo' of the big bang. More exactly the period shortly after when all matter in the universe was ionized and not transparent.

Where exactly does GR predict that an extremely dense concentration of mass or energy behave as a white hole rather than a black hole ? Is it by the same mechanism that "simple time variances I describe are well within the scope of einstienian physics" ?

Thanks for the link MD65536. Interesting! I wasn't aware that an EH had no valid frame.

Your terminology is a little confusing MD65536. When the light cone tips over as it crosses the EH the only possible destination (not time ) in your future is the singularity. And I'm still not clear on the statement about the EH being lightlike, ie moving at c with respect to all observers. This would imply to me anyway, that anything which crosses the EH, whether massive or massless, does so at c, which is impossible.

Scott, simultaneity of events is not just a statement of GR ( Einstein said so ). Simultaneity cannot be proven, and so, predictions based on it are not valid.

Don't rotate space-time around the observer as he crosses the event horizon. Rotate the light cone of the observer towards the singularity or edge ( a single point in space ). The time to reach the singularity is still finite, but as he crosses the event horizon and the 'blackness' starts coming up to encompass him, he would see all future time go by in the outside universe. I'm not seeing the problems you mention.

Does any of this have anything to do with relativity being wrong???? Well someone mentioned FTL speeds when crossing an event horizon and we were making the opposing argument, so I guess it does! As for the idea that relativity is wrong, those who support said idea should give their heads a shake. It may not be complete as it fails at certain boundaries, but it has made predictions which have been found to be accurate to arbitrary precision. What predictions have the detractors of GR made ad how accurate are they ?????

If we assume the singularity is an 'edge' to space-time, ie an edge to a distance-time graph ( y=t and x=d ), then the big bang singularity would be the lower edge of the graph. Spacelike and only in the past. A black hole singularity may be the left edge of the graph, ie timelike and existing for a long time. Could this account for differences ?

Sorry MD65536, when I wrote in my previous post that vertical lines in the space-time diagram are lightlike, I meant timelike. You used the term lightlike and I mistakenly repeated it ( damn this middle age befuddlement ). I really have no idea what you meant by lightlike as its not a commonly used term like timelike and spacelike. And when we say light moves slower near an event horizon, as I said, because we are measuring elapsed time between events from a distant frame, light pulses or signals arrive at greater and greater intervals until the horizon is eached and the time between intervals becomes infinite. We would no longer see or receive these pulses or signals and so this is equivalent to the time base of the EM wave becoming infinite. Two different ways of looking at the same effect. Sorry for any confusion I may have caused.

First off, the comment 'thanks for the laughs' was meant for the poster who said light travels faster than c upon crossing the event horizon. If we were to draw a simplification of a black hole with one spatial and one time dimension, the singularity and the event horizon would both be vertical lines, ie light like. A horizontal line would be space like. Outside the event horizon, light cones are right side up, expanding foreward in time. A horizontal line would be impossible as it implies infinite distance travelled in zero time. Light speed would be the slope of the cone, 45 deg. with suitable units. Motionless for all time would be a vertical line ( NOT moving at c ). Upon crossing the event horizon, the future light cone is flipped over on its side opening towards the singularity. This implies that a position, not a time is in its future, and that position can only be the singularity. There are valid frames of reference all the way to the singularity, at which point GR ceases to be a valid descriptor of space-time, and in all those frames lightspeed is still measured as c. Even for a distant frame, where you would expect to see light slow down as it approaches the event horizon ( frozen star ), light would still travel at c in a local frame. What we are actually doing is measuring time intervals between events, and the time intervals are getting longer. Light, being a time varying transverse wave would have the time base of its frequency stretched to infinity, and effectively disappear ( no energy left ), but it would still be travelling at c in its local frame. All this means is that you can't measure c in one frame from another frame.

The simple explanation for why light does not move faster than c when falling through the event horizon of a black hole is because the event horizon is defined as the radial distance where the escape velocity is equal to c. If light were to move superluminally, it would be able to escape the event horizon, the event horizon would be luminous and there would be NO BLACK HOLE !! Thanks for the laughs !

It is not the density but the 'stiffness' of a material that determines the speed of propagation of a disturbance or or longitudinal wave such as sound. It is believed that the material which makes up neutron stars ( neutronium ? ) has an extremely high stiffness and the speed of propagation of disturbances through it is an appreciable fraction of the speed of light. Any increase in density at this point, would increase the stiffness and result in a propagation speed equal to or exceeding the speed of light. This is of course impossible , and is one of the many arguments against the existence of stable states of matter at densities exceeding neutron star density. The only possible outcome of a higher density is gravitational collapse to a possible singularity.

When a suitably large mass gravitationally collapses the space enclosed by the horizon is topologically 'closed' while the space preceding the collapse was topologically 'open'. This can be visualised two-dimensionally with a sphere ( topologically closed ) and a flat sheet ( topologically open ). The sphere CANNOT be mapped onto the sheet ( and vice versa ), just like maps of the spherical earth are distorted when on a flat paper. Therefore one cannot have arisen from the other. To be able to map every point on the spere with every point on the flat sheet, one has to introduce a 'hole', in effect an edge, to the sphere. The size is unimportant, even a single point will do. If we assume that at the centre of the event horizon there is a 'hole' or edge to space-time then the closed surface can follow from the open surface. This, if I recall correctly, is the gist of Roger Penrose's argument in 1965 to prove that the centre of a black hole must include a 'hole' in space-time, or an edge or a singularity if you will.

Isn't a red-ox reaction also a movement/transfer of electrons, John ?

Remember what the definition of the event horizon is; the radius where the escape velocity becomes equivalent to c. Do you think rotation would not affect the escape velocity ? What will really blow your mind is that a rotating Kerr black hole actually has two event horizons, an inner and an outer. At a specific rotation rate ( theoretically achievable but not practically ), you could have an inversion and a 'naked' singularity ( Also theoretically achievable with a charged Nordstrumm black hole once it reaches a certain charge, if I remember correctly ).

You actually do 'feel' gravity, Sam, as a result of tidal forces. These forces are actually more pronounced for smaller BHs than for larger ones. You could be at twice the event horizon's radius of a stellar sized BH and not feel any tidal forces, while you would feel tidal forces at ten times the radius of the event horizon for an earth sized BH. The energy ( Hawking ) density radiated by black holes increases as they get smaller because volume decreases as the cube of the radius of the event horizon but the surface area decreases less slowly, as the square of the radius. At a certain point ( size ) all the remaining mass is converted to radiation and emitted as a gamma ray burst. This would be a large amount of mass ( still ) undergoing 100% conversion to energy; I don't think you'd want to be close by when that happens.

Sam, swansont is being very patient with you, but i expect he has his limits. I really don't think you understand the "ultraviolet catastrophy" that well. Most textbooks introduce quantum mechanics with Max Planck's resolution of the catastrophy by introducing the quantum. There was no quantum jumps of electrons between energy levels at the time, as swansont has already explained. Don't mix the two. I suggest an elementary QM text to explain the process.

What does this even mean ... "what does it take to goad you into admitting vortex is the balance between inertia and differential pressure?" If there are two forces that are balanced, there is no acceleration, and even elementary physics teaches that circular motion is accelerated motion. Did you fall asleep during those classes ?

Its that darn common sense misleading us again zapatos. How can two events be 'simultaneous' when they happen at differing times in different locations or frames ? Common sense also tells us that even if we cannot know the position and momentum of an electron, it must be moving at a specific speed at an exact location. And that is also wrong. we have to unlearn common sense when dealing with uncommon situations like extreme energies, speeds and scales ( large and small ).

I would not presume to argue with D.H. about orbital dynamics, but multi-body problems can be solved to arbitrary accuracy ( not however, exactly ) by using approximate mathematical tools like perturbation methods. It all depends on the complexity of the math you are willing to tackle.

If I was going to seriously consider any constant as having changed over time, I wouldn't look at c but at G, the gravitational constant. It would have the most ( but still very little ) probable cause and the most 'convenient' results.