PeterDonis's latest activity
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PeterDonis reacted to Dale's post in the thread Undergrad Check for geodesically-followed path in a coordinate-free way with
Like.
But to do that you would have to turn the direction you are facing relative to a gyroscope or to a great circle path. -
PeterDonis replied to the thread Undergrad Getting to the Heart of Entanglement and Locality in Plain English.It is, but the hidden variables are unobservable particle positions. They are not anything like "the direction of spin". When you...
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PeterDonis reacted to .Scott's post in the thread High School Could instrumental error be the cause of interference in radio telescopes? with Like.
I am not familiar with FAST telescope, but I can answer more generally. In general, those supercomputers will not be tasked with...
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PeterDonis reacted to Baluncore's post in the thread High School Could instrumental error be the cause of interference in radio telescopes? with Like.
There are several thousand satellites, any of which could have transmitted, or scattered a signal. There are too many sources of...
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PeterDonis replied to the thread High School How can a local interaction affect different parts of an atom?.@Demystifier answered this in post #4.
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PeterDonis reacted to Demystifier's post in the thread High School How can a local interaction affect different parts of an atom? with Like.
The interactions are described by local field theory. The change at one place creates a local change in the field, after which this...
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PeterDonis replied to the thread Undergrad Spatial separation of entangled particles implies physical separability?.Moderator's note: Based on the subject matter, this thread has been moved to the QM interpretations subforum.
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PeterDonis replied to the thread Undergrad Spatial separation of entangled particles implies physical separability?.It doesn't seem like it to me. See below. This looks like a classic interpretation question. "Exhaustive ontological independence" is...
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PeterDonis replied to the thread Graduate I have a couple of questions about general relativity.Yes. And then when we learn General Relativity, we learn that "no matter or energy" means that the stress-energy tensor is zero, but...
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PeterDonis replied to the thread Undergrad Does time stop for objects traveling at light speed?.Your "explanation" in the other thread was wrong. See my responses there. Please do not clutter multiple threads with wrong information.
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PeterDonis replied to the thread High School Do photons experience zero time between emission and absorption?.None of these limits are relevant to lght. They are limits as you apply Lorentz transformations to timelike vectors, but light is not...
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PeterDonis reacted to Dale's post in the thread High School Do photons experience zero time between emission and absorption? with Like.
Whether or not something is defined is a matter of definition. We choose the definitions for our convenience. There are two reasons that...
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PeterDonis reacted to Herman Trivilino's post in the thread Undergrad Mass, inertia and momentum in reativity with Like.
The speed of an object depends on how fast the observer is moving. It's not absolute. If an object is moving at nearly the speed of...
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PeterDonis replied to the thread Undergrad Mass, inertia and momentum in reativity.Where? Please give a specific reference. This depends on what you mean by "mass". The invariant mass of the object doesn't change, but...
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PeterDonis replied to the thread Graduate How and when to know if eigenvalue of H is energy?.It's the generator of time translations, but that is the energy operator, by Noether's theorem. Please be more specific. A reference...