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Comment: Re:Which means (Score 1) 347

by Parlyne (#47312979) Attached to: Evidence of a Correction To the Speed of Light
It's not actually the neutrinos that produce the Cerenkov radiation in detectors. That only happens when a neutrino interacts in a way that either produces a high energy charged particle or gives a great deal of energy to a charged particle that is already present. In either case the need for an interaction with matter that's present in the detector means that such interactions will be very rare in vacuo; and, given how special the condition we need to actually see these events in detectors, it's unlikely that we would detect them in vacuo even if they happened. Further, since the Cerenkov radiation has to do with the speed of the charged particle, its presence or lack thereof wouldn't actually tell us about the mass of the neutrino.

Comment: Re:the force is weak with this one (Score 1) 347

by Parlyne (#47312969) Attached to: Evidence of a Correction To the Speed of Light
The need to interact with something to "turn into other shit" is a requirement for transitions into other "real" particles. For instance, to actually get out an electron/positron pair from a high energy gamma ray, the gamma needs to interact. But, what we're actually talking about here are what are often term "virtual particles," which are better thought of as excitations in those particles' quantum fields that show up with the wrong mass to be real physical particles. These sorts of excitations happen spontaneously even without interactions, but very quickly transition back to the original state.

Comment: Re:Which means (Score 1) 347

by Parlyne (#47312959) Attached to: Evidence of a Correction To the Speed of Light
The necessity of mass is not an assumption and it has nothing to do with the passage of time. In short, oscillation can only occur if the neutrinos are produced in states that are a mixture of multiple physical states. Generically, the physical states are the ones that have well-defined values of mass. But, if all of the neutrinos have the same mass (whether it's 0 or not), then any mixture of the states is equally physical; so, the flavor states in which neutrinos are produced are, themselves, physical states, meaning that there's no mixing. So, it's not that they need to have mass, per se, it's that their masses need to differ from each other, meaning that at least two of the three states have to have non-zero mass.

Also, neutrinos can turn into other things in flight. For instance, an electron neutrino can briefly turn into an electron and a W^+ (well, in the same sense that a photon can "turn into" and electron and a positron, which isn't really quite a correct description, anyway). The thing is, because the mass of the W is so high, this sort of fluctuation is much rarer and lasts for a much shorter time. (This is where the statement about the weak force making these oscillations less relevant comes in.)

But, the problem with evidence for deviation from the speed of light is that, to not be an effect too small to measure, we would need to be looking at extremely low energy neutrinos. But, we don't actually have any ways to detect neutrinos with such small energies.

All that said, I actually have some issues with the idea presented. I haven't gone through the paper in detail; but, it seems like it's probably generating a violation of relativity by not actually working in a fully relativistic framework in the first place. It looks like the treatment of gravity may be too classical; but, that's just from a cursory look.

Comment: Re:"Financial Sense" (Score 2) 668

by Parlyne (#45044343) Attached to: Are Shuttered Gov't Sites Actually Saving Money?
That's not why it's shut down. Government spending is split into two categories - mandatory and discretionary. Mandatory spending happens automatically; but, discretionary spending requires specific authorization from congress. If congress doesn't pass appropriation bills, discretionary spending stops. That's what happened here. It has nothing to do with revenue and everything to do with the Republicans in the House of Representatives refusing to pass appropriation bills that don't include language to end or delay the Affordable Care Act (which, it should be noted, mostly falls into the category of mandatory, not discretionary, spending).

Comment: Re:conservation (Score 1) 626

by Parlyne (#42775617) Attached to: Will Renewable Energy Ever Meet All Our Energy Needs?
To evaluate the merit of your argument it's necessary to consider the reasons for the decrease in fuel usage. Is it because (in the first example) people are actually traveling less total distance or is it because the conveyances being used waste less energy? If it's the later, improvements in efficiency will only have this effect for a finite time, as any useful process has a maximum possible efficiency determined (in essence) by the second law of thermodynamics. As technology gets closer to that limit, it will become increasingly difficult to achieve further advances in efficiency. At that point, we go back to increasing energy usage unless our behavior actually changes.

Comment: Re:Insufficient Data For A Meaningful Answer (Score 4, Insightful) 626

by Parlyne (#42757903) Attached to: Will Renewable Energy Ever Meet All Our Energy Needs?
1) If we wait for nature to turn our energy consumption into an S-curve, the process will be extremely unpleasant for the people involved (constraints due to resource scarcity have a habit of fueling some rather nasty conflicts). It seems to me that we're better served to point out the problem so that we can try to find a way to limit our own energy use intentionally so that we can do it in a less painful way.

2) Even if population growth stops, energy growth doesn't necessarily. Per capita energy use has been increasing for pretty much all of human history. And, there's no reason to think that we aren't going to keep inventing new technologies that need ever more energy. (And, I should note here that most improvements in energy efficiency work by reducing the amount of energy that goes to waste heat, not by reducing the amount of energy required for the purpose for which we're expending energy. CFLs and LED light bulbs put out the same amount of energy in light as do incandescents; but, they give off less heat, for example.) If this continues, we'll still have a problem.

3) Expanding into the galaxy still has a non-exponential limit on our growth. In that case, at best we increase the available space and energy resources quadratically, since our outward expansion is limited by the speed of light.

4) Human ingenuity does not trump physics. If there are no new energy resources to tap, no amount of cleverness will allow growth in energy use to continue. And, please note, zero point energy is not a magical reservoir of unlimited energy waiting to be tapped.

5) I don't have to believe that today's conception of physics is 100% correct (and, in fact, I can tell you with 100% certainty that our current understanding of physics is, at best, incomplete) to be extremely confident that there aren't major unknown sources of available energy that can supersede the output of the sun. I can conclude this because the only phenomena that are not fully explained by known physics are things that couple only extremely weakly to the ordinary matter we are able to exert direct control over. So, any major untapped sources of energy either don't exist or are not accessible in any practical way.

6) Even ignoring the point that cold fusion is total nonsense (fusion in general is not; but, cold fusion has been shown, time and again, to be totally unsupported by the evidence), any energy source reliant on materials present on Earth will be, at best, a temporary solution. Eventually, solar will be the only source practically available.

7) Finally, TFA doesn't need to consider "a lot more obvious possibilities" when they can all be dismissed as having far less total energy available than the sun. Maybe other technologies can allow us to use energy faster than the sun outputs for a time; but, ultimately, that's just putting off the inevitable limitations for a finite (and, frankly, surprisingly short) time, unless we learn to stem our energy use.

Comment: Re:Snowballs chance in Australia? 1 of many probs (Score 1) 626

by Parlyne (#42752461) Attached to: Will Renewable Energy Ever Meet All Our Energy Needs?
Congratulations. You've found a way to extend the possible horizon of energy use growth from 300 years to 1250 years. But, it doesn't solve the problem. At 2.3% annual growth, we'll need to be using 100% or the sun's output in about 1250 years. Then what? Your self-replicating space habitats don't give us any new sources of energy. At best, they just increase the surface area we can use to capture solar radiation. It simply doesn't change that fact that exponential growth in energy use is not physically sustainable in the long term.

Comment: Re:Supernovas (Score 1) 442

by Parlyne (#38101250) Attached to: OPERA Group Repeats Faster-Than-Light Neutrino Results
Model dependence isn't really relevant here. The point is that, even if the entire three hour delay were blamed on the neutrinos being superluminal rather than the light being delayed (which physics does say it has to be), the degree by which the SN1987a neutrinos would be faster than light is 4 orders of magnitude smaller than what the OPERA results claim.

Comment: Re:Years. (Score 1) 442

by Parlyne (#38101064) Attached to: OPERA Group Repeats Faster-Than-Light Neutrino Results
Quarks have the same sort of mixing as neutrinos. The only real difference is that the low mass and small couplings of neutrinos make it much easier for us to think about neutrinos in terms of flavor states (i.e. electron, muon, and tau neutrinos) rather than mass states, which is what we're pretty much forced to use for quarks. Anyway, neutrino mixing is totally consistent with relativity; and, in fact, almost required for massive neutrinos in quantum field theory. The only reason it was a surprising result in the first place is that there had been no previous evidence that neutrinos have mass. Superluminal neutrinos, on the other hand, are really not consistent with existing theories; so, they are, quite rightly, taken with a great deal of skepticism, at least until independently confirmed, or until all possible sources of systematic errors that could mimic the effect are ruled out.

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