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Sorry. TFA is "this f... article". I agree about the "correlation does not imply causation" plague. It's especially problematic for purely observational scienc

Sorry. TFA is "this f... article". I agree about the "correlation does not imply causation" plague. It's especially problematic for purely observational sciences, where experiments are impossible or unethical. Prototypically for epidemiology, but also for astronomy and cosmology. And yes, it's a slippery slope, even for experimental sciences. I get what you say about the alignment of metal rods in magnetic fields. So yes, there could be some gravitational polarity over extremely large scales. I see that I was getting stuck on the idea that changes can't propagate faster than light, no matter what the mechanism. But now I get how arbitrarily separated stuff can be similarly affected by a given source. For example, there was a recent article about hot gas "sloshing" in a galaxy cluster.[0] And thanks for the YouTube links :) 0) https://phys.org/news/2020-01-sighting-hot-gas-sloshing-galaxy.html https://phys.org/news/2020-01-sighting-hot-gas-sloshing-gala...

K0SM0S 7y ago
Aha, TFA, right :p Yeah, the faster-than-light topic is actually a very, very tricky one, even for seasoned astro-peeps it seems. I didn't mention PBS Spacetime[1] but it's probably the best place to start for best-in-class high level mojo in astrophysics. Tons of back-catalog. Really great quality production. Less 'newsy', more 'substance' than the other two I mentioned (these are my trio on the topic). Case in point: they do a fantastic job at explaining, notably time shenanigans. They basically made it click for me, notably for FTL (Faster-Than-Light) space expansion, cosmic inflation, etc. Fantastic-everything about them, can't recommend enough. One thing, though: my best way of framing the FTL limit is in terms of a speed limit (c) to transfer "information". This is why entanglement is a valid principle, it does not violate c because entanglement cannot be used to transfer information faster than light[2]. So "structure" can change arbitrarily fast, from the perception of its objects, its contents; but "information", the contents, the objects, they are bound by c and all the rules actually defined by said structure. I really don't know if that's the correct view, but it seems to work to explain (actually rule out) most light-speed paradoxes, so... [1]: https://www.youtube.com/channel/UC7_gcs09iThXybpVgjHZ_7g https://www.youtube.com/channel/UC7_gcs09iThXybpVgjHZ_7g [2]: I think this vid does a good job at explaining why: https://youtu.be/2_4l5_G3dnM https://youtu.be/2_4l5_G3dnM

K0SM0S 7y ago

Aha, TFA, right :p Yeah, the faster-than-light topic is actually a very, very tricky one, even for seasoned astro-peeps it seems. I didn't mention PBS Spacetime[1] but it's probably the best place to start for best-in-class high level mojo in astrophysics. Tons of back-catalog. Really great quality production. Less 'newsy', more 'substance' than the other two I mentioned (these are my trio on the topic). Case in point: they do a fantastic job at explaining, notably time shenanigans. They basically made it click for me, notably for FTL (Faster-Than-Light) space expansion, cosmic inflation, etc. Fantastic-everything about them, can't recommend enough. One thing, though: my best way of framing the FTL limit is in terms of a speed limit (c) to transfer "information". This is why entanglement is a valid principle, it does not violate c because entanglement cannot be used to transfer information faster than light[2]. So "structure" can change arbitrarily fast, from the perception of its objects, its contents; but "information", the contents, the objects, they are bound by c and all the rules actually defined by said structure. I really don't know if that's the correct view, but it seems to work to explain (actually rule out) most light-speed paradoxes, so... [1]: https://www.youtube.com/channel/UC7_gcs09iThXybpVgjHZ_7g https://www.youtube.com/channel/UC7_gcs09iThXybpVgjHZ_7g [2]: I think this vid does a good job at explaining why: https://youtu.be/2_4l5_G3dnM https://youtu.be/2_4l5_G3dnM