Measuring the curvature of spacetime

Or better yet ; looking for an answer.

 

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Well, you won't find any valid answers by begging the question. It is the polar opposite of looking for a answer. You might find the correct answer if your begging assumes a fact, but in general its not useful.

I am not sure a zen koan is even meant to have any answer.

 

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I know this only too well. The physicsstackexchange is full of conversations about entanglement communication that run pretty much like this thread.

The D-wave is just the beginning of our exploration of what quantum entanglement can do. Ftl data processing will get better also. But it isn't likely to do so with a mindset like I saw there. Or here. These devices will need to be linked with each other. If that communication is limited by the speed of light, the technology isn't going to get very far.

Decoherence is what you get when trying to combine states of entanglement at speeds >> c (photons) with entanglement in bulk equipment (electrons or qubits) that is at rest (+c vector added to -c). The fact that we are able to do that sort of processing at all is an awesome achievement.

And some of these folks still haven't figured out that gyroscopes have exactly nothing to do with spacetime curvature either. They react to gravitating masses and conserve angular momentum. That's all. Fewer spooks and demons invoked to explain spooky action at a distance would be nice also.

Happy 2016, Ancient Greece.

 

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danshawen, I think I have a pretty open mind. But you keep talking about things like superluminal communication using quantum entanglement, but you never actually quote anyone or any paper that actually says such a phenomenon exists. The papers you mentioned above did not say there was any information transferred, only that the entanglement seemed to work at speeds of 10kX the speed of light. You mentioned quantum cryptography, but as I understand it, that does not involve superluminal transfer of information either. If you want to "win" this argument then simply quote a reputable experiment that explicitly mentions faster than light information transfer. All of your posts seem to read between the lines and make assumptions that are not clearly mentioned in the literature. Surely you understand how to provide some evidence. I am pretty sure that if someone found that information could be transferred faster than light, there would be some Nobel prizes awarded and a media blitz that would be as obvious as Einstein's theories were.

 

https://www.quora.com/Is-spacetime-a-real-thing-or-just-a-mere-concept
"Thing" is not a well-defined word, and concepts are not classified into "things" and non-things beyond elementary school. Usually, everyone agrees that matter is a thing. I think they are less sure about light.

Would you consider the electromagnetic field to be a real "thing"? If yes, you should consider spacetime to be a real "thing" as well.

Spacetime is not just a passive arena for light and matter. It has its own dynamics; it interacts with (i.e influences and is influenced by - there are no one-way interactions) energy/momentum (and also with itself), so it should be thought of as an independent physical entity.
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http://www.sciforums.com/threads/measuring-the-curvature-of-spacetime.154259/page-2

What is a space time continuum?
In 1906, soon after Albert Einstein announced his special theory of relativity, his former college teacher in mathematics, Hermann Minkowski, developed a new scheme for thinking about space and time that emphasized its geometric qualities. In his famous quotation delivered at a public lecture on relativity, he announced that,

"The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. henceforth, space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality."

This new reality was that space and time, as physical constructs, have to be combined into a new mathematical/physical entity called 'space-time', because the equations of relativity show that both the space and time coordinates of any event must get mixed together by the mathematics, in order to accurately describe what we see. Because space consists of 3 dimensions, and time is 1-dimensional, space-time must, therefore, be a 4-dimensional object. It is believed to be a 'continuum' because so far as we know, there are no missing points in space or instants in time, and both can be subdivided without any apparent limit in size or duration. So, physicists now routinely consider our world to be embedded in this 4-dimensional Space-Time continuum, and all events, places, moments in history, actions and so on are described in terms of their location in Space-Time.

Space-time does not evolve, it simply exists. When we examine a particular object from the stand point of its space-time representation, every particle is located along its world-line. This is a spaghetti-like line that stretches from the past to the future showing the spatial location of the particle at every instant in time. This world-line exists as a complete object which may be sliced here and there so that you can see where the particle is located in space at a particular instant. Once you determine the complete world line of a particle from the forces acting upon it, you have 'solved' for its complete history. This world-line does not change with time, but simply exists as a timeless object. Similarly, in general relativity, when you solve equations for the shape of space-time, this shape does not change in time, but exists as a complete timeless object. You can slice it here and there to examine what the geometry of space looks like at a particular instant. Examining consecutive slices in time will let you see whether, for example, the universe is expanding or not.

I truly suggest that it is you who is totally brainwashed by your religious beliefs and what cosmology and Einstein have done for the reality [or lack of] of any deity. It has been pushed back into oblivion and that sticks in your craw, as it does with many religious zealots.

The only non science presented so far in this thread and other threads that you start or take part in is that presented by yourself, and that has been rienforced a few times by professionals that tashja has taken the effort to get an opinion from.
Also any lacking in formal education begins with yourself.

 

Whenever I do post them, people here seem to just glaze over and pretend I didn't. Or complain that it doesn't come from a peer reviewed jprofessional journal I don't subscribe to. Why would I reference something everyone else already seems to know anyway? If everything I knew came from there, would I know much? Peer review means, some stuff gets rejected, doesn't it? It isn't always the best stuff that gets crammed into those journals. Over 90% is 'boilerplate'. It makes it look pretty. It isn't functional. There isn't any reason to plate a boiler, other than that.

It's already there. If you can't find it, it isn't my fault. I have no idea. Maybe someone else filters it out before it gets to you. I wouldn't know that either. I'm no conspiracy theorist, but stranger things have happened. I can see things on my iPad I can't see with my computer, too. Life is too short for either of us to track down the reason.

 

Now please someone explain, how do you create curvature (Local curvature) in spacetime when there is no missing points.....don't anyone realise that any warp or bending or bumping will be immediately filled up, as there is no missing point....

 

Are you saying gravity isn't real?

 

Deleted

 

Not at all, otherwise how could we eat apples...

 

What is my religious belief ? May be you can help me find one ? So far I have none.

 

We achieved great stuff with GP-B

1. We could design a real highly accurate gyro.
2. We could place it so delicately, free of other man made vibration.
3. We could even shield it with EM momentum.
4. We could really understand the real noise level noise analysis (whatever that means).
5. Our ability to justify huge expenses to taxpayer got strengthened. It also got confirmed that in general taxpayers don't bother where the tax money actually goes.

I can't think of any other achievement of GP-B.

 

It mapped the Earth's mass concentrations.

 

Curvature of space is only a useful concept if space or spacetime has curvature independent of gravitating masses. It does not.

Time dilates, mostly because of relative (orbital velocity) motion for a satellite but a smaller contribution is from gravity. The two effects are easily separated, and the pictures obtained were impressive. Why didn't this thread display them?

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From: http://www.gizmag.com/gravity-probe-drought-groundwater-reserves/24271/
See any "spacetime curvature?" I don't. I see mass concentrations that are separable from time dilation effects because GPS (and General Relativity's corrections to GPS time) existed before the sophisticated gravity probes were launched. Only time dilation and satellite position/velocity needed to be taken into account to produce this map. This is exactly what I've been trying to say. Objections?

BTW, I don't know if the effects of tides produced by the Earth-moon system were nulled out of this map, but that obviously would be the largest contribution to any mass concentrations that were due to gravitational influences outside of the Earth's atmosphere, and the atmosphere itself has tides of significant mass.

 

OK, so let's see how you are wrong here...

We could say that the first problem is phys.org, but let's skip this crank favorite for now.

So, your support for your claim is a description of a procedure that transmits data at less than the speed of light.

So, that's a fail.

Oh, maybe because they were bad reporting? And you simply latch on to the first stupid pop science article that you see that you think you can use to attack a mainstream position that you do not understand?

Sure, but the speed-of-light limit on using quantum entanglement to make a signal has been known for decades. There is no excuse for you not knowing this.

Predictable crank behavior to retreat to conspiracy theory.

 

No, actually, not everyone will say this.

GR makes the argument that spacetime curvature is dramatically real because in order to describe certain physical scenarios, you have to include a certain amount of curvature in some combination of space, time or a pervasive acceleration field throughout space with no physical source. Only curvature allows us to relate all physical behavior to a physical source.

 

Yes, because someone is always willing to ignore decades of very public reasoning and teaching about quantum mechanics and state that entanglement can be used to communicate at superluminal speeds despite the evidence and the actual design of every attempt to use entanglement for secure communications. Or when they do not understand terms like "decoherence" or understand the nature of supposed speed increases in quantum algorithms.

 

https://en.wikipedia.org/wiki/Phys.org

"Phys.org is a science, research and technology news website specializing in the hard science subjects of physics, …"

Yeah, let's skip that.

It was on the physicsstackexchange that I had an extended exchange with who I found out later was a 14 year old individual from India "Dimension" who swore he was a misunderstood and very cranky physics guru. That's obviously a better source for good answers. I was convinced.

 

Good work trying to avoid the actual criticisms and focus on something that I wasn't going to go into. I'm still going to skip it, and you can wallow in that site all you want to. I suggest you read a simple textbook on quantum mechanics before you use words like "decoherence" and "entanglement" again.

Let's be clear about the design of every attempt to send communication using entangled states. Here is how it goes: 1) prepare two subsystems that are entangled; 2) send one subsystem to one place, the other to another; 3) prepare one subsystem so that it ensures that the properties of the other, distant, subsystem are set; 4) send to the location of the other subsystem the details of the preparation that has been done along with a message encoded using the results; 5) use the preparation details and the results to decipher the message.

Because 4 has to be done at the speed of light or lower, the whole process of communication takes place at the speed of light or lower. Because the results of 3 are random, it doesn't communicate, but it can be the basis of a template of a cypher that encodes and decodes communication.

 

Fine. Go collapse your wavefunction or something.