81–90 of 139 posts
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This: >when an object is dropped, it begins falling instantaneously. Is answering a different question than this: >the actual measurement confirms that the speed of gravity is equal to the speed of light to within 1%. It is true that things drop immediately when you let go of them. Because they're already in the gravitational field. It is not true that when I drop something, a gravity particle from the surface of the…
That's all true, but that's not what I quoted. RobotRollCall's comment said we can't measure the "speed" of gravity, but in the article linked, we do precisely that.
This is the winning comment from the reddit discussion from /u/RobotRollCall * This is a far more interesting question than it might seem at first glance, and it deserves some attention because it tells us something fundamental and wonderful and just bloody awesome about the universe. But I don't know how to tell the story succinctly. So I'm going to do that thing I do. I am very, very sorry. Please feel free to move…
> Yes, it's the Wile E. Coyote problem. Wile E. Coyote runs off a cliff, floats in mid-air long enough to hold up a sign that says "Help," then begins to fall. Clearly that's an exaggeration. But just how much time does elapse, in real life, between stepping off a cliff and beginning to fall? Meh, not so much. One is already in a gravitational field before one falls off a cliff. The time it takes you to start falling…
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Cellular automata violate continuity and isotropy, which means they're inconsistent with the continuous spatial formalism used in special relativity, general relativity, classical electrodynamics, and as far as I know, quantum electrodynamics. We have no experimental evidence inconsistent with continuous models of space. We also have evidence that Lorentz symmetry holds over scales smaller than the Planck length, whi…
Ah, here we go. Aaronson 2002 shows that Wolfram's model cannot be consistent with experimental evidence: In physics, we examine Wolfram's proposal for a deterministic model underlying quantum mechanics, with 'long-range threads' to connect entangled particles. We show that this proposal cannot be made compatible with both special relativity and Bell inequality violation. http://arxiv.org/abs/quant-ph/0206089
This is the winning comment from the reddit discussion from /u/RobotRollCall * This is a far more interesting question than it might seem at first glance, and it deserves some attention because it tells us something fundamental and wonderful and just bloody awesome about the universe. But I don't know how to tell the story succinctly. So I'm going to do that thing I do. I am very, very sorry. Please feel free to move…
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That's all true, but that's not what I quoted. RobotRollCall's comment said we can't measure the "speed" of gravity, but in the article linked, we do precisely that.
What? No - what you quoted is about measuring the delay between when I let go of something and when it starts to fall. That is what we've used lazers and rockets and microscopes to measure.
Or, as she puts it, "If you feel up to the challenging of following a lot of advanced mathematics, here's the best paper I know on the subject.".
What she writes is basically a long explanation of why the speed of light is not correct, right up until the end, where she hastily covers it up with what the actual science says.
What would be useful would be a dissection of the "best paper I know on the subject". The rest of it just says, "It's not the speed of light... actually yes it is. Don't look further unless you're smarter than I think you are."
This is the winning comment from the reddit discussion from /u/RobotRollCall * This is a far more interesting question than it might seem at first glance, and it deserves some attention because it tells us something fundamental and wonderful and just bloody awesome about the universe. But I don't know how to tell the story succinctly. So I'm going to do that thing I do. I am very, very sorry. Please feel free to move…
> To the absolute limit of our ability to measure it — and our ability to measure it is really good, since we used electromagnets and lasers and other expensive science things — when an object is dropped, it begins falling instantaneously. Not after a very small interval of time, but absolutely instantaneously. As in zero time elapses between dropping and falling. > This is fairly earthshaking, really. Because it imp…
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What? No - what you quoted is about measuring the delay between when I let go of something and when it starts to fall. That is what we've used lazers and rockets and microscopes to measure.
I get what is actually going on, what I'm saying is that RRC's comment does not go from A to B. It goes from A to A', then jumps ahead to B, without any reasoning why. Or, as she puts it, "If you feel up to the challenging of following a lot of advanced mathematics, here's the best paper I know on the subject.". What she writes is basically a long explanation of why the speed of light is not correct, right up until t…
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It takes a while for the test mass to notice that the big mass moved. So the test mass is pulled in a direction where the big mass no longer is, but rather where it was.
to say it's "pulled in a direction where the big mass no longer is" seems incorrect, because above we have "whenever a gravitating object moves inertially, the gravitational acceleration vector at a point removed actually points at where the object actually is at a given instant", due to the cancellaction and abberation effects. "Indeed, the vector (2.5) does not point toward the “instantaneous” position of the sourc…
The object is not moving inertially. Someone is forcing it to change direction, which is the exact opposite of inertially.
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I get what is actually going on, what I'm saying is that RRC's comment does not go from A to B. It goes from A to A', then jumps ahead to B, without any reasoning why. Or, as she puts it, "If you feel up to the challenging of following a lot of advanced mathematics, here's the best paper I know on the subject.". What she writes is basically a long explanation of why the speed of light is not correct, right up until t…
You said the article disagrees with RRC's post, which it does not. It seems now you're just taking issue with the progression RRC made to get to the point? Or that you think she should have gone into the paper she cited? OK. But it doesn't make claims contrary to the OP. And the thing you quoted does not disagree with the other thing you quoted.