## Entanglement

Entanglement is just a word we can use to describe a situation where knowledge of some property of one object gives us information about some (possibly different) property of another. The term is rarely used in the classical case, because we take it for granted. If we separate a pair of gloves for example and … Continue reading Entanglement

## Is special relativistic time dilation a real effect or just an illusion? Given two inertial frames each observer finds that the clock of the other runs slower than that observer’s own clock. So who is right?

This is a pretty good answer except that I wouldn’t say either of them is right if they think that their perception of relative slowness represents something that is objectively true for all observers. Time dilation is a real effect on the perceptions of observers (with regard to the rates at which one another’s clocks … Continue reading Is special relativistic time dilation a real effect or just an illusion? Given two inertial frames each observer finds that the clock of the other runs slower than that observer’s own clock. So who is right?

## (3) Alan Cooper’s answer to How can a moving/faster observer see a ‘stationary’ clock running slower, when it doesn’t, e/specially when his really does? All the YouTube videos about the Twin Paradox say so. In what sort of universe is that possible? – Quora

The relativity principle does NOT say that all frames are equivalent, just the inertial (unaccelerated) ones. In the twin “paradox” situation, the traveler and stay-at-home both figure that the other is ageing more slowly while their relative velocity is constant but when the traveler turns around he or she figures that the stay-at-home suddenly ages much more rapidly. … Continue reading (3) Alan Cooper’s answer to How can a moving/faster observer see a ‘stationary’ clock running slower, when it doesn’t, e/specially when his really does? All the YouTube videos about the Twin Paradox say so. In what sort of universe is that possible? – Quora

## (3) Alan Cooper’s answer to How does the twin (clock) paradox (in SR) really work? Please see the comment for the specific case. – Quora

According to the comment, what this question is really asking us to address is something completely different from “How does the twin (clock) paradox (in SR) really work?” What the comment asks us to explain is as follows: “A clock flies around the equator eastwards, it ages slightly less. A clock flies around the equator … Continue reading (3) Alan Cooper’s answer to How does the twin (clock) paradox (in SR) really work? Please see the comment for the specific case. – Quora

## (3) Alan Cooper’s answer to What is the Calabi-Yau manifold? Are we ‘inside’ it right now or is it just a mathematical concept? – Quora

Calabi-Yau manifolds (there’s not just one) are a type of mathematical concept, but they’re not “just” that as they do have applications in certain attempts to describe physics. The role they usually play in physics is to help us formalize the relationships that we postulate between the various internal variables that describe what particles are … Continue reading (3) Alan Cooper’s answer to What is the Calabi-Yau manifold? Are we ‘inside’ it right now or is it just a mathematical concept? – Quora

## (3) Alan Cooper’s answer to Why is the Raman effect’s classical interpretation not adequate? – Quora

The classical theory of the Raman effect is not adequate for determining the actual spectrum because it allows the molecule to have arbitrary amounts of vibrational (or rotational) energy and in fact the possible energy levels are quantized (just like everything else in physics). Source: (3) Alan Cooper’s answer to Why is the Raman effect’s … Continue reading (3) Alan Cooper’s answer to Why is the Raman effect’s classical interpretation not adequate? – Quora