PeterDonis's latest activity
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PeterDonis replied to the thread Undergrad Unexpected findings in need of an explanation (retrograde motion of Mars).To expand on this a bit: suppose we try to model the planetary motions in order to try to understand what determines the apparent size... -
PeterDonis replied to the thread Undergrad Unexpected findings in need of an explanation (retrograde motion of Mars).Wikipedia, referencing a dictionary, not a scientific textbook or paper. Note here that the term "ecliptic longitude" is used, not... -
PeterDonis replied to the thread Undergrad Unexpected findings in need of an explanation (retrograde motion of Mars).Please give a source for this definition. "East-west" does not properly capture the actual motion of the planet in the sky--the actual... -
PeterDonis replied to the thread Graduate Understanding Barandes' microscopic theory of causality.But he doesn't give any new "conception of causality" to replace the classical one. Perhaps he thinks that isn't required. But that... -
PeterDonis replied to the thread Undergrad Unexpected findings in need of an explanation (retrograde motion of Mars).@Sylvain9595 you mentioned JPL Horizons, and I was able to find that app here: https://ssd.jpl.nasa.gov/horizons/app.html#/ I pulled... -
PeterDonis replied to the thread Undergrad Unexpected findings in need of an explanation (retrograde motion of Mars).@Sylvain9595 where are you getting your figures for the retrograde arc covered? Your numbers seem too small by roughly an order of... -
PeterDonis replied to the thread High School Can gravitons be detected?.No. -
PeterDonis reacted to Ibix's post in the thread Undergrad Acceleration calculation in Special Relativity with
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Yes. In this case, the deceleration phase is just the time-reverse of the acceleration phase, and the return leg is the same as the... -
PeterDonis replied to the thread Graduate Understanding Barandes' microscopic theory of causality.In other words, violations of the Bell inequalities don't require "communication" between the systems according to his definition. Which... -
PeterDonis replied to the thread Undergrad Unexpected findings in need of an explanation (retrograde motion of Mars).They may be "geometrically distinct", but they are not independent. You seem to be assuming that they are, which is a wrong assumption... -
PeterDonis reacted to Nugatory's post in the thread High School True static equilibrium and effects on time with
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You are just cheating yourself out of essential background understanding (which is the really fun part) if you've skipped chapters 1-3... -
PeterDonis replied to the thread Alien life, probabilities, and interstellar propagation of human life."Science" as it relates to thread discussions here does not mean "something that I can plausibly argue is possible based on our current... -
PeterDonis replied to the thread Graduate Wavefunction in the context of quantum physics.Sure you have, just not under that name. The Hermite functions are Gaussians with polynomial prefactors--indeed, the zero-order Hermite... -
PeterDonis replied to the thread Alien life, probabilities, and interstellar propagation of human life.Um, sci-fi stories are about "the context of possible engineering" that doesn't currently exist. In our actual science forums like the... -
PeterDonis replied to the thread Alien life, probabilities, and interstellar propagation of human life.@DaveC426913 did not move this thread to the sci-fi forum. The moderators did, for the reason I gave in post #227 just now. That reason...