Everything posted by Genady
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The Physicist and the Philsopher:
What are the examples of them not getting on?
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The Physicist and the Philsopher:
Yes, but what are the causes of this phenomenon? Is it historical? I understand frictions between physics / biology and religion, they do overlap in some areas. But physics and philosophy don't overlap, or do they?
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The Physicist and the Philsopher:
What is so special about comparing and contrasting physics and philosophy? Why not e.g. physics and music? Physics and sport? Or, music and sport? Aren't they all different human activities, and different humans like, dislike, or are indifferent about some or others?
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Gyroscope in a curved space
AFAIK, the orbital precession doesn't depend on the planet's own spin.
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How to determine up and down far away?
I'll try to describe my question in a more concrete setting. Let's say we have two Stern–Gerlach apparatuses, side by side, and two entangled electrons as before. The apparatuses are parallel to each other. We measure one electron in one apparatus and find out that it moves toward the magnetic N of the apparatus. If we measure the second electron in the second apparatus, it will move to its magnetic S. If the second apparatus were set e.g. perpendicularly to the first, then the second electron could move there to the N or to the S with equal probabilities. Now, the second apparatus is in M87 and we want it to be set parallel to the first for the purpose of the measurement of the second electron spin. How do we determine the correct setting for the second apparatus? Wouldn't it depend on the path of the electron from Earth to M87 through the curved space?
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Gyroscope in a curved space
Thank you. But at least if the second half of the path traces back the first half exactly, there will be no drift?
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Gyroscope in a curved space
Is it correct that if a gyroscope is moved around in a curved space then after returning to the original location it may or may not return in the original orientation, depending on the trajectory?
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Can Someone Explain Quark Binding Energy?
I think, my example above needs correction, because it doesn't work energetically. For a new hadron to be created at the end, its binding energy needs to be supplied as well, not only the mass of new quarks and antiquarks. It still works, but the required energy to be added to the original baryon is not 9 MeV but rather at least 135 MeV, the lightest pion.
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A new discrepancy in the Hubble parameter, from the Hubble telescope
"The expansion rate of the universe was predicted to be slower than what Hubble actually sees. By combining the Standard Cosmological Model of the Universe and measurements by the European Space Agency's Planck mission (which observed the relic cosmic microwave background from 13.8 billion years ago), astronomers predict a lower value for the Hubble constant: 67.5 plus or minus 0.5 kilometers per second per megaparsec, compared to the SH0ES team's estimate of 73. Given the large Hubble sample size, there is only a one-in-a-million chance astronomers are wrong due to an unlucky draw, said Riess, a common threshold for taking a problem seriously in physics. This finding is untangling what was becoming a nice and tidy picture of the universe's dynamical evolution. Astronomers are at a loss for an explanation of the disconnect between the expansion rate of the local universe versus the primeval universe, but the answer might involve additional physics of the universe." Hubble Reaches New Milestone in Mystery of Universe's Expansion Rate | NASA
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Cool videos of weird creatures from the depth of 2+ km
Alien shopping-bag ocean weirdo has glowing Cheetos for guts | Live Science
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Can Someone Explain Quark Binding Energy?
Energetically so, except you cannot create three quarks, but only quark-antiquark pairs. These pairs will combine between themselves and with the original quarks in different ways. Actually, even 9 MeV could be enough. It could create one quark-antiquark pair, then an original quark with a new antiquark would make a meson, and a new quark would replace an original quark in the baryon.
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How to determine up and down far away?
Thank you, I understand this. My question is, what determines relative orientation between two localities in two different places in the universe? What determines that two directions in these two localities are parallel? Is it determined according to some kind of parallel transport? If the space were flat the answer would be obvious, but it is not. I would guess, that in the curved and dynamic spacetime, we would need to establish parallel spatial directions between locality 1 at time t1 of one measurement and locality 2 at time t2 of the other measurement. In these two directions, the results of the measurement will be opposite. OK, 40 minutes later, I've solved it. The relative orientation could be determined by a gyroscope. We can send the entangled electron to M87 together with a gyroscope, which is prepared in parallel to a gyroscope that stays on Earth. Then we measure each spin in the direction of the respective local gyroscope's axis.
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How to determine up and down far away?
Let's take a pair of entangled electrons in the state |ud>-|du>. If the first electron measures up, the second is down, and vice versa. Let's keep one electron on Earth and let's send another one, very carefully, to a planet far away, say in the M87 galaxy. They are still entangled, so if the first electron is up the second is down... But what are the directions 'up' and 'down' on that planet? How do they relate to the direction of the measurement here on Earth?
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Can Someone Explain Quark Binding Energy?
But quarks cannot be free from what binds them. If we try to separate them, the energy of what binds them will increase. Thus, it would be a higher energy state.
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Projected Timeframe for Human-Crewed Deep Space Exploration
Yes, I hope they are wrong and the NASA budget will be used more wisely.
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Can Someone Explain Quark Binding Energy?
You mean, it is a binding energy because it is the energy of gluons which bind the nucleon? OK.
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Does somebody study complex energy particle ?
Of course, you're right. The "fuss" here is about the rest mass of fundamental particles, specifically.
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Can Someone Explain Quark Binding Energy?
I have an issue with this energy being called binding energy, too, and would like to know a justification for that.
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Does somebody study complex energy particle ?
This issue can be solved by replacing the m with its norm in that factor. (But I was not serious to start with.)
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Are we evolving towards a pan-language? (Linguistics)
Did you know that the total number of world languages went up in recent years? Some languages went extinct, but more languages were added, some that were declared extinct prematurely, and some previously unknown, spoken as well as sign languages.
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Does somebody study complex energy particle ?
This question is inspired by another thread in this forum, but it would be OT there. So: Does anybody have a valid reason to believe complex rest energy/mass particle can't exist ?
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Are we evolving towards a pan-language? (Linguistics)
In old times and also the older generation spoke mostly one language, the language of their community. Today most of younger people seem to speak several languages as appropriate, e.g. in the family, at school, at work, for entertainment, for travel, etc. When you live in a multilingual society it is easy to be a multilingual.
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Are we evolving towards a pan-language? (Linguistics)
It seems to me that we're moving rather toward a society of multilinguals.
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Can Someone Explain Quark Binding Energy?
As I understand, there is no "free state" of a quark, and quark mass cannot be interpreted consistently as mass of a "free quark." The quark mass is a coefficient of the quadratic term in the quark's Lagrangian. It is a mass term in the corresponding equation of motion, Dirac equation.
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The Futility of Exoplanet Biosignatures
The authors compare "theory of life" to theory of gravity; a theory that would allow to make predictions and to direct research regarding life in general, unlike biology which is a "theory of life on Earth." They mention a path to develop such theory by creating forms of life in a lab. I think it is possible to get samples from exoplanets via interstellar asteroids. Not within our lifetime, though.