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Here's the correct answer to the quiz:The solar panel will say: after the black hole moved closer I have been receiving more energy, the photons are more energetic and there are more photons per second.

Yes. when looked at as waves it will blue-shift from the view point of the solar panel, and as far as I understand it will increase its blue-shift the closer we get to the event-horizon. The interesting thing is why it can do it

A and B are identical robots with same mass, they are at floor 2.A is carried to floor 1. B uses the stairs to go to floor 1.A and B have different masses now. B has bigger mass.Because A has cool brakes, while B has hot brakes.

Oh here I come lolReplacing R in first formula with 2GM/c² and simplifying we get: ¼mc²So they say efficiency is 75%BUT efficiency is actually 100%. As we can see when we build a heat engine where a black hole serves as a heat sink. This engine has 99.9999999 efficiency, or 99.999999999999999999999 with bigger and colder black hole.Could someone explain this a little better to me. Where does this efficiency arise? The calculations?

Jartza, are you thinking of energy converted into mass?

Quote from: QuantumClue on 06/01/2011 00:39:20Oh here I come lolReplacing R in first formula with 2GM/c² and simplifying we get: ¼mc²So they say efficiency is 75%BUT efficiency is actually 100%. As we can see when we build a heat engine where a black hole serves as a heat sink. This engine has 99.9999999 efficiency, or 99.999999999999999999999 with bigger and colder black hole.Could someone explain this a little better to me. Where does this efficiency arise? The calculations?Expert's not so good efficiency calculation:Click this link: ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN

The Hawking Equation for Black Hole Entropy is a good start

Quote from: Foolosophy on 06/01/2011 12:12:57The Hawking Equation for Black Hole Entropy is a good startE=Rmc^4 /8GMThis is the swarzschild radius of a black hole with mass M:R=2GM/c²Replacing R in first formula with 2GM/c² and simplifying we get: ¼mc²So they say efficiency is 75%using the above, the OP simplifies 2GM/c² and simplifying we get: ¼mc²How is this simplification acheived? Am I missing something obvious? 1/4Mc^2 is quite different to the quantity 2GM/c^2. A bit lost here following the OP's calculations. And who says the black hole is 75% efficient?

I must be doing the calculation wrong somehow, because rereading, the OP is not simplyfing 2GM/c² exactly. The OP is asking me to replace that quantity with R in the first equation - it would be good to read it properly from my behalf. Right... the G's and M's cancel, 2 divides into 8 giving, 4... right fine. Yes, it leaves ¼mc².

I'll be honest, I'm not sure what it means. The OP says:''The experts say that when mass m is lowered into a black hole, that has mass M, then this is the energy of the mass m down at the event horizon''so the quantity here 1/4Mc^2 is referring to a particle with a mass yes? Or does the energy relate to the black hole? If its the particle, nothing spectacular has happened to the energy I would assume. Energies which are lowered or increased for a system with a mass usually have to do with the kinetic energy... so it's lost kinetic energy...I could be wrong.

Quote from: QuantumClue on 06/01/2011 14:04:55I'll be honest, I'm not sure what it means. The OP says:''The experts say that when mass m is lowered into a black hole, that has mass M, then this is the energy of the mass m down at the event horizon''so the quantity here 1/4Mc^2 is referring to a particle with a mass yes? Or does the energy relate to the black hole? If its the particle, nothing spectacular has happened to the energy I would assume. Energies which are lowered or increased for a system with a mass usually have to do with the kinetic energy... so it's lost kinetic energy...I could be wrong.Black Holes are quite different creaturesThey apparently seem to violate some fundamental laws of physicsthe 1/4mc^2 term relates to the rest mass ENERGY.The body of mass "m" accelerates towards the speed of light as it enters the black hole event horizonIs the mass converting to "non-kinematic" energy?Are you saying that the black hole absorbs 75% of the rest mass ENERGY and 25% is lost?What is this efficiency term you talk about?How does it relate to the Hawking radiation of balck holes?

Quote from: Foolosophy on 06/01/2011 14:17:19Quote from: QuantumClue on 06/01/2011 14:04:55I'll be honest, I'm not sure what it means. The OP says:''The experts say that when mass m is lowered into a black hole, that has mass M, then this is the energy of the mass m down at the event horizon''so the quantity here 1/4Mc^2 is referring to a particle with a mass yes? Or does the energy relate to the black hole? If its the particle, nothing spectacular has happened to the energy I would assume. Energies which are lowered or increased for a system with a mass usually have to do with the kinetic energy... so it's lost kinetic energy...I could be wrong.Black Holes are quite different creaturesThey apparently seem to violate some fundamental laws of physicsthe 1/4mc^2 term relates to the rest mass ENERGY.The body of mass "m" accelerates towards the speed of light as it enters the black hole event horizonIs the mass converting to "non-kinematic" energy?Are you saying that the black hole absorbs 75% of the rest mass ENERGY and 25% is lost?What is this efficiency term you talk about?How does it relate to the Hawking radiation of balck holes?Nothing is lost, especially once an object has passed the event horizon, as that would imply it destroys the information paradox. Kinetic energy is simply an energy of a system supplied to its momentum, so its an energy of a system which is in movement. A system can loose kinetic energy if its speed slows down, or gain it, if it gets faster.Again, I've never seen the term 1/4Mc^2 before, so I am unsure how to approach the question other than saying nothing is fundamentally lost.

Quote from: QuantumClue on 06/01/2011 14:21:00Quote from: Foolosophy on 06/01/2011 14:17:19Quote from: QuantumClue on 06/01/2011 14:04:55I'll be honest, I'm not sure what it means. The OP says:''The experts say that when mass m is lowered into a black hole, that has mass M, then this is the energy of the mass m down at the event horizon''so the quantity here 1/4Mc^2 is referring to a particle with a mass yes? Or does the energy relate to the black hole? If its the particle, nothing spectacular has happened to the energy I would assume. Energies which are lowered or increased for a system with a mass usually have to do with the kinetic energy... so it's lost kinetic energy...I could be wrong.Black Holes are quite different creaturesThey apparently seem to violate some fundamental laws of physicsthe 1/4mc^2 term relates to the rest mass ENERGY.The body of mass "m" accelerates towards the speed of light as it enters the black hole event horizonIs the mass converting to "non-kinematic" energy?Are you saying that the black hole absorbs 75% of the rest mass ENERGY and 25% is lost?What is this efficiency term you talk about?How does it relate to the Hawking radiation of balck holes?Nothing is lost, especially once an object has passed the event horizon, as that would imply it destroys the information paradox. Kinetic energy is simply an energy of a system supplied to its momentum, so its an energy of a system which is in movement. A system can loose kinetic energy if its speed slows down, or gain it, if it gets faster.Again, I've never seen the term 1/4Mc^2 before, so I am unsure how to approach the question other than saying nothing is fundamentally lost.One of the few things that Hawking contributed was to show how black holes can radiate energy at from the event horizon and would therefore eventually evaporate If you were to plot the velocity profile from just outside the event horizon and project it inwards towards the central singularity point, what do you end up with?Remember, according to relativity laws an infinite amount of energy is required to accelerate a body at rest towards the speed the lightSo what is happening at and past the event horizon?Our physical Laws break down

Here we have a ....

And now I'll have too look into that Because assuming that 'photons' have a mass will indeed change the relation.

And of course if the photon did indeed turn out to be NON-massless, then the speed of light cannot be a constant and even the innate beauty of the expression E=mc^2 will have to be re-written in another way.