A frame of reference is relative. Just a comparison to another system. It is not a physical thing. It is a physical system, be it thermodynamic, relativistic, quantum, non/inertial, whatever. A lot of folks just assume that when frames of reference are talked about, that it must be inertial.
.../... Thankfully because acceleration is relative, an observer outside of your frame of reference will see your virtual particles become real. That doesn't help us either, but the methodology is key. As you know, frames of reference are relative.
So I flipped it. How about this: We live in an accelerating universe. Our universe is accelerating at rates which we cannot ever hope to achieve. Furthermore, the rate of expansion is a curve, meaning galaxies further away are flying apart faster than the ones flying apart closer to us. Neat. So from the point of view of the universe, which is the accelerating frame of reference, our emdrive is accelerating slowly, compared to say the CMB frame of reference.
So lets imagine ourselves on a spaceship in Earth orbit and you are equipped with our brand new emdrive technology. From your frame of reference you are barely moving compared to the accelerating speed of universal expansion happening around you.
So imagine yourself inside your space ship and you're looking intently at your prototype emdrive looking for real particles to appear out of the qv fluctuations, you don't see them. Now imagine the universe is the observer. The universe observing your emdrive would see some virtual particles from the qv becoming real. This only works if the universe is expanding.
So with this mechanism, you get some arbitrary flux of real particles from the qv frame of reference (I'm assuming the qv and its randomly produced particle pairs are not inertially related to our inertial frame of reference) popping into your local frame of reference (as observed from the point of view of the universe). So I'm picturing the pair production happening randomly, becoming real, and immediately flying away at a rate matching the speed and direction of the expansion of the universe minus the influence of gravity, isotropically. My head hurts.
.../... Is gravity keeping the expansion of the universe in check at small scales? .../...
I think the logic above would have us all awash in real particles all the time. Maybe that's where matter comes from, lol.
We also under QM fully, too
I think I can safely say that nobody understands quantum mechanics.
Quote from: Raj2014 on 08/19/2014 12:31 amHas there been any new news on the EM/Cannae drive? http://xkcd.com/1404/
Has there been any new news on the EM/Cannae drive?
Jeff Foust has half an article on this in Space Review: http://www.thespacereview.com/article/2580/1, including a brief interview with White after his talk in Mars Society conference
It's not clear what time derivative you are talking about : the rate of expansion (Hubble "constant") that goes as ~2.3e-12(m/s)/m (hey, it has dimension of a frequency !), or the change of this rate, which right now seems to be decelerating ( for a given distance you will see slower receding objects crossing this distance in the near future ) in spite of the mysterious acceleration of expansion (expansion not slowing as fast as it should, but still slowing from usual mass content gravity) ?More confusing : the universe isn't locally accelerating, makes no sense, its local content has a local average speed that can be used as a local inertial frame of reference, but it is not accelerating in any absolute sense, there is nowhere special toward where it could accelerate ! The CMB is part of the content, take or give a few 100s km/s it's the same local inertial frame as the stars and gas averaged on a decently sized local patch, it goes with the flow, and this flow is 0 relative to receding neighbouring patches all around. Local universe is not accelerating if seen at coarse graining bigger than anisotropies. What particular direction of the sky the CMB is supposed to be accelerating (I'm not speaking of our galaxy relative velocity with CMB) ? And even if it were, it would just be free falling with us (say, with the local cluster) at the same acceleration toward a big lump in the neighborhood. Anyway it's not accelerating relative to us and relativity makes no difference between free-falling and inertial velocity in nothingness.
Hubble's Constant: H0 = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second.The further away from the observer, you'll observe the velocity of galaxies increasing.
Quote from: JohnFornaro on 08/18/2014 05:46 pmJust wanna add that we understand quantum mechanics "quite well" too. Nobody claims complete knowledge of QM or magnetism.No, we understand exactly what's going on in magnetism. We also under QM fully, too, it's just very counter-intuitive. Just because you don't understand it and just because it takes a lot of effort to understand it doesn't mean it isn't understood.
Just wanna add that we understand quantum mechanics "quite well" too. Nobody claims complete knowledge of QM or magnetism.
Quote from: JohnFornaro on 08/18/2014 01:42 pmMy objection continues to be the careless, unsubstantiated use of the word "likely"....Some fusion propulsion is likely near term both because there are a couple of fusion projects that lend themselves to propulsion ...EDIT I need to fix it again XD. There is one fusion project blatantly stating they are working with NASA on a fusion engine. ...
My objection continues to be the careless, unsubstantiated use of the word "likely".
What we do know from innumerable experiments is that in a broad range of contexts QM is phenomenally accurate. ...
So while we don't understand all QM at the frontiers of its validity and beyond, we do know quite well experimentally where the frontiers are...
...indulging themselves in "what if" scenarios of missions at the end of the paper does not serve them in terms of credibility...
I also want to point out that inanimate interpretations of the universe and evolution are as faith based as any other interpretations.
Quote from: JohnFornaro on 08/18/2014 01:42 pmI also want to point out that inanimate interpretations of the beginnings of the universe and evolution are as faith based as any other interpretations.[Edit: Inadvertently forgot to include the important word "beginnings" of the universe, as was pointed out below.]You obviously don't understand the difference between "faith based" and "evidence based".
I also want to point out that inanimate interpretations of the beginnings of the universe and evolution are as faith based as any other interpretations.[Edit: Inadvertently forgot to include the important word "beginnings" of the universe, as was pointed out below.]
I think one has to be careful when calling found physical principles 'laws'. They are not laws in the absolute sense, as in given by 'God', or being the final answer. The only thing we can say about the principles that we found and verified by peer-reviewed experiments up to any given point in time is: To the best of our current knowledge, this is what happens. A very important point to make.
Just want to add the observations of C.S. Peirce, who has suggested quite some time ago, that the "laws" of physics might be "habits", and that they change over time.The gravitational constant, it turns out, is not exactly constant, but appears to vary.
A new point of view towards the problem of the relationship between gravitational and quantum phenomena is proposed which is inspired by the fact that the distinction between quantum fluctuations and real statistical fluctuations in the state of a system seems not to be maintained in a variety of phenomena in which quantum and gravitational effects are both important. One solution to this dilemma is that quantum fluctuations are in fact real statistical fluctuations, due to some unknown, but universal, phenomena. At the same time quantum fluctuations have certain special properties which distinguish them from other types of fluctuation phenomena. The two most important of these are that the action of quantum fluctuations is non-dissipative for the special case of systems undergoing inertial motion in the absence of gravitational fields, and that the dispersion constant for quantum fluctuations for a particle is inversely proportional to the inertial mass of the particle. These properties are summarised in a set of principles which, it is proposed, govern the relationship between quantum phenomena, gravitation and inertia.
Smolin is among those theorists who have proposed that the effects of quantum gravity can be experimentally probed by searching for modifications in special relativity detected in observations of high energy astrophysical phenomena. These include very high energy cosmic rays and photons and neutrinos from gamma ray bursts. Among Smolins contributions are the coinvention of doubly special relativity (with Joćo Magueijo, independently of work by Giovanni Amelino-Camelia) and of relative locality (with Amelino-Camelia, Laurent Freidel and Jerzy Kowalski-Glikman).
Smolin has worked since the early 1980s on a series of proposals for hidden variables theories, which would be non-local deterministic theories which would give a precise description of individual quantum phenomena. In recent years, he has pioneered two new approaches to the interpretation of quantum mechanics suggested by his work on the reality of time, called the real ensemble formulation and the principle of precedence.
Since 2006, he has collaborated with the Brazilian philosopher and Harvard Law School professor Roberto Mangabeira Unger on the issues of the reality of time and the evolution of laws. ...A book length exposition of Smolin's philosophical views appeared in April 2013...
I'm seeing a lot about knowing qm quite well vs fully. This really is moot. It is a distraction from the subject at hand which is the emdrive or derivatives. It is the height of hubris to state you fully understand anything. If we fully understood qm or its offshoots, the subject would be closed, further study wouldn't be warranted and, we'd all be Doc Brown.
I like the notion, also expounded by Smolin I beleive, that physics is good at describing what happens, but not good at explaining what happens. The great precision with which QM describes events can be mistaken for accuracy in explaining what is going on. Agreed this is getting away from Emdrive.
Quote from: Mulletron on 08/19/2014 03:03 pmHubble's Constant: H0 = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second.The further away from the observer, you'll observe the velocity of galaxies increasing.a parsec = 3.2 lyobservable universe 12-13 billion light years... let“s consider it 13... 13 billion / 3.2 = 4 billion parsecs.4 billion / 1 million = 4000 4000 * 67 = 268 thousand kilometers per second. So at the edge of the universe, it is expanding almost at light speed away from us, right?