Earlier quoted context omitted.
Out of curiosity, why do you think this is not possible?
You can't transmit data faster than the speed of light.
What is the Speed of Gravity?
91–100 of 122 posts
Re: What is the Speed of Gravity?
#92Earlier quoted context omitted.
I was under the impression that tachyons (should they exist) would be expected to give off Cherenkov radiation in vacuum, but I'm not sure where I got that impression. I hadn't actually heard anything about Mallett for a few years, and I guess this is why. :)
That would imply that tachyons interact with the electromagnetic force. But if they do we would have detected them long ago. But it's wrong anyway, it's not the moving particle that gives off the Cherenkov radiation, it's the matter that they move near. And there is no matter in a vacuum.
Only virtual matter.
Re: What is the Speed of Gravity?
#93Earlier quoted context omitted.
Maybe not "taking shots", but I also feel a general "ha, he missed that big one" attitude. Newton was such a great scientist that he made his famous "I don't make hypotheses" statement in regards to the nature of gravity. Knowing the limits of your (current) knowledge is a fundamental trait of being a scientist (and a philosopher, e.g. see Wittgenstein's motto "Whereof one cannot speak, thereof one must be silent." a…
I don't. Technology had not yet progressed to the point that one could design experiments to test relativity. And such technology depends on insights from other areas of physics. Quoting Cecil Adams ( http://www.straightdope.com/columns/read/957/was-isaac-newto... ), [He] took six thousand years of disjointed fumbling and made it into a science. Two sciences, actually, physics and to a large extent mathematics. Feeli…
Yes. Although Newton did lose out on notation. Leibniz had the better notation for integrals and differentiation at around the same time.
Re: What is the Speed of Gravity?
#94Personally I think it's easier to tell people to stop thinking of gravity as a particle or wave - it's not like a beam of light or radio wave. Think of the space/time as the blanket the universe is wrapped in. If that blanket is stretched out like a trampoline, every object on it or moving around on it is causing flexing and ripples. That's gravity. When a girl bounces off a trampoline, the specific instance of her g…
Our reality was build on a 299 792 458 m / s processor. Newer realities are much faster.
Ha! But what if it was the opposite and we are simply a cycle down the road of big bang/big crunch/big bang/big crunch/big bang where the speed of light used to be faster but is slowing each cycle because of lost mass/energy.
What if the speed of light was slightly faster or slightly slower, how would it affect the development/entropy of the universe?
Re: What is the Speed of Gravity?
#95Earlier quoted context omitted.
What is the technical definition of "information"? I know what information is in a colloquial sense, and I know something about it's technical definition in the field of computer science, but I don't know what physicists mean when they use the word. Is information the same thing as light? Is it analagous to light? Is it a property of light? Matter?
I guess that information is change of state that is clearly distinguishable from some "random" change of state and caries a "meaning". Eg. If you had an entangled pair of particles on this side of galaxy and another on other side of galaxy. Now you "wiggle" (change its state) one then the other one "wiggles" too - but you didn't send any information - since the other observer cannot know if the particle changed state…
Meaning isn't necessary, and randomness is still information. The computer science definition works well for physics, too.
Re: What is the Speed of Gravity?
#96Earlier quoted context omitted.
You don't have to go 'faster than the speed of light' to escape a black hole if you're not affected in the usual manner by gravity. And I'm not aware of any suggestion that gravity itself is affected by gravity.
Gravity absolutely is affected by gravity. The Einstein field equations are non-linear, so gravitational energy is itself a source of gravity. All forms of energy, and momentum, and even stress and pressure are combined into the "stress energy tensor" which determines the local curvature of space-time.
> The Einstein field equations are non-linear, so gravitational energy is itself a source of gravity.
Non sequitur? I mean, non-linearity is not the same as feedback. Linear system can exhibit feedback (and still stay linear), and non-linear systems do not have to exhibit feedback.
Re: What is the Speed of Gravity?
#97Earlier quoted context omitted.
What is the technical definition of "information"? I know what information is in a colloquial sense, and I know something about it's technical definition in the field of computer science, but I don't know what physicists mean when they use the word. Is information the same thing as light? Is it analagous to light? Is it a property of light? Matter?
I just define it for myself as "If it can transmit information, it could also be used given enough technology to send any kind of data, such as a Microsoft word document."
That definition would probably work. Have a look at Feynman's lectures on computer science. He also investigates how much energy has to be used for computing. (Or to be more precise, how much entropy has to be created.)
Re: What is the Speed of Gravity?
#98Re: What is the Speed of Gravity?
#99Re: What is the Speed of Gravity?
#100I am not a physicist nor an astronomer. I wanted to ask however, when they explain gravity by the analogy of holding a blanket, first the blanket is on earth thus any object that is put on it is being pulled down by earth and the blanket is being held by two people, thus what is pulling the earth and sun down and who is holding the space blanket? Also, seeing some of the images on the site, it is clear that space is something and it is not nothing. Thus, what is space?
The second thing is that if you carry out the above experiment, the ball would eventually stop. That is because of friction. Why does the earth never stop? What makes it overcome friction?
Someone is probably going to shoot me down for being a complete idiot and knowing nothing, but I am genuinely interested to know the answer or to know if there is no answer.