KJW

No. JWs (apart from the 144000) are not looking forward to going to heaven. They are looking forward to an everlasting life on a paradise earth after Armageddon. The 144000 who go to heaven already know who they are. They are the ones who partake in the bread and wine at the Memorial of Jesus’ death while everyone else passes these items from person to person without partaking in them. They know they are of the 144000 because they have been anointed with holy spirit. That is a personal thing between them and their god, and the organisation is not involved with this (the bread and wine are made available for anyone to partake). In case you're wondering, I grew up in a JW household.

WTF

What is this? It looks like an answer to a homework question that was not provided. It is my understanding that benzyl bromide undergoes nucleophilic substitution via a predominately SN2 mechanism. Although the benzyl carbocation is stabilised by the benzene ring, it is a primary carbocation, and the transition state of the SN2 mechanism is also stabilised by the benzene ring. Thus, the benzene ring enhances both the SN1 and the SN2 mechanisms without necessarily favouring the SN1 mechanism over the SN2 mechanism. However, the use of a polar protic solvent does enhance the SN1 mechanism relative to the SN2 mechanism, while the use of a polar aprotic solvent enhances the SN2 mechanism relative to the SN1 mechanism, so the particular reaction conditions may be significant to the relative contributions of the two mechanisms.

I assume the post is hidden rather than deleted. The error message speaks of permission, not topic not found. On another forum I visit, one can do a search for something in a hidden post, have the search result display with a link to the hidden post, but the post itself be denied due to lack of permission.

Today I saw a meme that said: "Live your life in such a way that if the escalator stops, you don't assume it's because people hate you."

That topic is on the Home page and the Mathematics page, but not on the Analysis and Calculus page (where it is directed on the Mathematics page).

I sometimes see posts on the Home page, but when I click on them, I'm told I don't have permission to view them.

While I do consider the consistency of reality to be a reasonable argument against solipsism, I see solipsism as impossible to disprove. However, I think the biggest problem solipsism has is that, if the mind is all there is, what is it that is supporting the mind? Also, like the notion of a simulated reality, I don't see a usefulness in the notion of solipsism.

Spoiler Alert! 1/3 For two children, the possibilities are, along with their probabilities: GG = 1/4 GB + BG = 1/2 BB = 1/4 But with GG excluded, the possibilities now are, along with their probabilities: GG = 0 GB + BG = 2/3 BB = 1/3

test before Spoiler Alert! test box test after

It would've been interesting if MythBusters had carried out this modified version of the problem to see if people who think the outcomes are equally likely in the original 3-door problem still think the outcomes are equally likely in the 100-door version of the problem. I suspect that such people would still stay with their original choice because I don't think the obviousness of the 100-door problem would be apparent to those who do not understand the solution of the 3-door problem. On the other hand, if the host opened 98 doors, with your chosen door and say the 57th door left unopened, that might create a bit of suspicion, perhaps leading to the correct answer.

It's funny that you mention Deal or No Deal because I have often wondered if this has a Monty Hall problem aspect to it. I don't think it does actually. The Monty Hall problem is quite well known for its counterintuitive result. Even MythBusters had an episode that dealt with this problem.

What do you mean by this? When the contestant first chooses the door, there is a 1 in 3 chance that this door contains the prize, and a 2 in 3 chance that it doesn't contain the prize. When the host subsequently reveals what is behind one of the other doors, this does not in any way alter the probabilities of the contestant's original choice.

In relativity, everything has its own time. That is the main takeaway of the twin paradox. But whereas relativity seems to make use of already defined clocks, I think it is quantum mechanics that actually defines time (and space).

I'm currently watching a documentary series about how the universe works, and it says that it is crucially important to life for its planet to have a magnetic field. Without a magnetic field, the solar wind will strip away any atmosphere and volatile materials the planet may have. In the past, Mars was much more Earth-like, but when it lost its magnetic field, it became the desolate planet we see today.

A number of years ago, I simulated the second law of thermodynamics on an Excel spreadsheet. The system I simulated was very simple, intended to remove the complications associated with physics and chemistry. As a result of this simulation, it became clear to me that transition probabilities are not time symmetric. If one considers the reversible interconversion between two molecules, the rate constant of this reaction reverses sign under time reversal. This allows the description of the progress of the equilibration reaction to remain covariant with respect to time reversal, resolving an apparent incompatibility between the second law of thermodynamics and relativity. But transition probabilities are positive valued. Therefore, when the rate constant reverses sign under time reversal, it no longer corresponds to a transition probability. A process that obeys statistics in the forward time direction does not obey the same statistics or indeed any statistics in the reverse time direction.

What is the proportionality constant? And why is one extensive property (M) the exponential function of another extensive property (S)? It is my understanding that entropic theories of gravity have already been tested and failed.

White holes don't exist because black holes are formed from collapsing matter. The past singularity doesn't exist because that region is occupied by the collapsing matter. Only the future singularity exists.

If you have a recording of the episode, you could try Shazam.

IF you have a test for semiprime that is simpler than a test for prime, then multiplying the number by a prime would simplify the test for prime. But that's a big hypothetical IF. I don't think it's likely that such a test exists, and even if such a test does exist, I think it would be above the pay grade of both you and I to find it. Nevertheless, the idea that there might be a test of semiprimes that is simpler than a test of primes is actually not a bad idea.

What the text is saying is that the equilibrium constant for the reverse reaction is the inverse of the equilibrium constant for the forward reaction. So, it should not be: Kc = 1/Kc but: Kcreverse = 1/Kc In the text, I can't see whether they distinguished between the equilibrium constants of the forward and reverse reactions, but it would be wrong if they did not.

Because that is the stoichiometry of the chemical reaction.

No. Multiplying a number by a prime number only increases the number of factors by one, the prime number you multiplied the number with. You do know that the factorisation of a number into primes is unique up to order, don't you?

One thing I'd like to point out to @HbWhi5F is that everything in thermodynamics is about the system and everything that happens to the system. For example, suppose one has some gas in a cylinder with a piston, and one presses on the piston to compress the gas. The work done on the gas depends on the pressure of the gas inside the cylinder and the decrease in volume of the gas inside the cylinder. All well and good. But now release the piston and allow the gas to expand. The work done by the gas now depends on the pressure of the environment. That's no good because the environment is outside of the system which everything is about. So what one has to do is make the pressure of the environment equal to the pressure inside the cylinder at all times. But if the two pressures are exactly equal, there will be no compression or expansion of the gas. So to make the gas compress, one makes the pressure outside the cylinder infinitesimally greater than the pressure inside the cylinder; and to make the gas expand, one makes the pressure outside the cylinder infinitesimally less than the pressure inside the cylinder. Because the two pressures differ by only an infinitesimal amount, they can be regarded as equal. Now the work done by the expanding gas depends on the pressure inside the cylinder (because it is equal to the pressure outside the cylinder) and the increase in volume of the gas inside the cylinder. Now everything is about the system. Also, note that expansion and compression of the gas inside the cylinder are the reverse of each other. Also note that to go from compression to expansion (or from expansion to compression), one only needs to change the pressure outside the cylinder from infinitesimally greater than to infinitesimally less than the pressure inside the cylinder (or from infinitesimally less than to infinitesimally greater than the pressure inside the cylinder). In either case, only an infinitesimal change in pressure is required to reverse the process. Processes that are reversed by applying an infinitesimal change are called reversible processes. Reversible processes are very important in thermodynamics because thermodynamic quantities such as enthalpy and entropy are defined in terms of them. You may have noticed that only in the case of the reversible compression and expansion of the gas inside the cylinder that you get back all of the work that you put into it. In the case of the irreversible expansion, because the pressure outside the cylinder must be less than the pressure inside the cylinder (in order for the gas to expand), the work done by the expanding gas must be less than the work done on the gas when it was compressed. So, what happens to the compression work not done by the gas during its irreversible expansion? It gets converted to heat. The heat increases the temperature of the gas inside the cylinder. Now let the temperature inside the cylinder cool to the temperature it was before it was compressed. The state of the system (its pressure, volume, and temperature) is now the same as it was before the compression. But the total work of the system is not the same. Neither is the total heat of the system. That is, by performing some process of changing the state of the system and eventually returning the system to the original state, neither the work nor the heat of the system return to the same value. It is said that neither work nor heat are functions of state. A function of state is a function that returns to the same value when the state variables return to the same values after traversing any path in the space of states. However, reversible processes do ensure that quantities do return to the same value after the system returns to the same state. Thus, thermodynamic quantities such as enthalpy and entropy are functions of state.

For me, it's the Many Worlds Interpretation. I'm not nearly as comfortable with quantum mechanics as I am with general relativity. I'm not sure that a "correct" quantum theory is even tractable. I like MWI because it provides a natural explanation of intrinic randomness. The mathematics of the Born rule points naturally to the MWI by removing wavefunction collapse and allowing all the eigenstates to prevail. Also, in the high-dimensional Hilbert space of classical-scale quantum physics, arbitrarily chosen vectors are almost certainly orthogonal, which not only provides an explanation of one aspect of the Born rule, but also why classical states don't exhibit interference, including why only a single eigenstate outcome is observed. A difficulty of MWI is explaining the nature of wavefunctions because all the "worlds" seem naturally to be weighted classically. Could it be that you are trying to visualise this as if from outside of spacetime? No, spacetime curvature is intrinsic and doesn't need any higher-dimensional space in which it is embedded. I tend to visualise spacetime as a rectangular grid overlay in which the distances between the nodes do not necessarily obey Pythagoras' theorem. I first became convinced of spacetime curvature when I saw the metrics of seemingly random coordinate systems over a flat space, and noted that these ostensibly didn't look any different from random metrics. But the random metrics will almost certainly not be flat. Inspecting the metrics themselves, unless they are especially simple or familiar, one can't tell if they are describing a flat spacetime, one has to obtain the Riemann tensor to determine this. In other words, given the infinitude of flat spacetime metrics, why not go all the way and consider the infinitude of all spacetime metrics. Anyway, I tend to regard spacetime curvature like the Mercator projection map of the world. I am somewhat ambivalent about spacetimes with non-trivial topologies. I have considered removing the entire interior of the Schwarzschild blackhole using a wormhole metric obtained from the Schwarzschild metric by a coordinate transformation. This raised an interesting question concerning the role of complex coordinates in physics.