Carrock

I don't understand how a vacuum can somehow be less than nothing. Please explain.

How was a photon observed to be moving slower without observing its behaviour? Saying it slows down because the photon can be treated as a continuous classical wave interacting with a not very classical continuous electron wave can give correct answers to a high degree of accuracy. No doubt this is one reason Newton's belief that light was composed of particles was rejected for some centuries. Zap your glass with gamma rays and as you increase the energy you can make each interaction occur in an arbitrarily small volume. (The gamma ray is the pre QM 'passive observer'). Has QM proven that photons travel at variable speed? You may be thinking of observing these photons using a short wavelength low energy electromagnetic field. Einstein's Nobel prizewinning paper on the photoelectric effect demonstrated you can't do this. The wavefunction of the field of the photoelectric photon could be 1/100th mm or a mile in diameter before the interaction. No way to tell and this experiment cannot be explained if light is not quantised. Using electron(s) in a double slit experiment you see an interference pattern provide you don't observe the interaction. Similarly you can calculate that eg a photon has a 10% chance of interacting with a field a ( or do you mean particle a?) and 3% with field b. IF you observe with a photon or particle you will affect it so much that you could say it has eg a 99.99% chance of interacting with a and a 3% (or so) chance of interacting with b. ie interactions do not localise particles until they are observed.

Some of the early A.M. transmitters used carbon microphones (as used in telephones) to modulate the carrier so it's not just theory!

The topic title is "A Steady State Universe". Unlike Steady state cosmology, my version has certain values set such that it is past and future complete. I presume you're referring to eternal inflation I could provide a similar quote from most papers on inflation. Is the value of such inflation theories a function of how many people have demonstrated that with certain assumptions, they predict eternal inflation? I didn't know, let alone understand any of the models you cited. There was one which I managed to work out by searching for "1090". Perhaps you will tell me if I got it right. Again in eternal inflation I presume you are stating that there are no particles ( and no space ) anywhere except in the visible part of the universe and no more will ever be created. This seems rather improbable but would certainly make inflation future complete. I wonder if you actually read my original post. I gave two important reasons that the Hoyle steady state universe was untenable; you state the ( Hoyle ) steady state universe has been proven wrong ( which I agree with ) as inflation has been observationally proved(!!!!) A brief (over?)simplified resume of my theory: Finite inflation is initiated in flat, past and future complete static Minkowski space. Most models of inflation are past incomplete and are consistent with this or a similar origin. Only finite inflation is permitted as no future incomplete processes are possible in a future complete universe. Therefor the inflation episode we're living in will end completely in less than a very long but finite time. Over long enough time and distance, this future complete static Minkowski space is unchanging, exactly as the BGH steady state universe was unchanging. A property of the static Minkowski space I use is that its temperature is asymptotically zero degrees so Olber's paradox is no a problem.

Mordred, michel123456, swansont et ( I hope ) al : Thank you for responding to my post. The "Steady State Universe" I referred to is and also asymptotically zero temperature. In my theory, our observable ( pocket) universe is a result of finite inflation from this steady state universe much as described in eg Eternal inflation and its implications: Except possibly for subtle CMBR variations my theory does not require any variation in the observable universe from predictions in other inflation theories (but is incompatible with theories requiring future-incomplete eternal expansion). Therefor the posts about the CMBR background are not really relevant to this theory. For brevity and laziness, there are a lot of implicit assumptions in my original post; some of them 99% of cosmologists would agree with, others not. I'd be happy to defend or abandon assumptions anyone on the forum finds dubious.

So many crackpots try and defend that idea, it is a bit cliched. We need someone to revive phlogiston. I can't revive every idea but if dephlogisticated air was good enough for Priestley it's good enough for me... Monday was rather optimistic.... A brief preemptive defense... This post Steady state cosmology, proposed by Sir James Jeans and later revised by Fred Hoyle, Thomas Gold, Hermann Bondi and others, postulated an eternal, exponentially expanding universe with matter creation such that the average matter density was always constant. This theory was effectively refuted observationally by the discovery of cosmic microwave background radiation (CMBR) in 1965. There was also a serious problem with this theory which did not affect its verifiable predictions but dealt a fatal blow to the 'steady state' description:- If it is assumed that at some past time the universe had a countably infinite ( ie aleph-null ) volume and number of discrete particles, and expansion continued for countably infinite time, the volume of space and the number of particles in it become uncountably infinite. That is, the volume and number of particles increases by the factor n^aleph-null, where n>1. Since n^aleph-null is equal to aleph-one, the volume of space and the number of particles in it would become equal to the uncountable ( or non-denumerable) infinity aleph-one, which is physically impossible. At least, I am not aware of any way it could be possible. A detailed and rigorous analysis of the problem is presented by Richard Schlegel in Philosophy of Science Vol. 32, No. 1 (Jan., 1965), pp. 21-31 Before observational refutation, Steady state cosmology could only be kept viable by assuming exponential inflation started at an indefinitely distant but finite time in the past and will end at an indefinitely distant but finite future time. ie, more formally, exponential inflation must be past-incomplete and future-incomplete. The same problem occurs with a newer theory of an eternal, exponentially expanding universe ie eternal inflation which also predicts exponentially increasing space and number of particles. Such future-incomplete expansion is often described by cosmologists as 'eternal to the future', a convention which I will adopt. Cosmology is a science where many competing theories can survive because confirming or refuting them is difficult or impossible. I have a subjective preference for theories which are past- and future- complete and do not require the universe to be finite. One possibility which has been somewhat neglected is an eternal steady state static universe with finite inflation and a concept originated by Dr. Schuetz: The specific aspect which I feel has been neglected is that in an eternal universe no eternal process ( not necessarily inflationary ) which requires the creation of space or discrete particles can ever be initiated. My steady state 'update' is not up to the old steady state theory in falsifiability, but it is incompatible with some respected theories and may soon make the trip to 'Speculations'. I assume an eternal ( ie past and future complete ), flat, static, spatially infinite universe which, on a large scale, has asymptotically zero energy and maximum entropy ie Minkowski space. I will follow precedent and call 'local' universes like ours 'pocket universes'. As eternal or finite inflation theories are the most consistent with the observed CMBR, I will use finite inflation in my theory. It is then necessary that there be a nonzero possibility of inflation and it is convenient and perhaps necessary to assume that the probability of producing Boltzmann Brains ( an awkward prediction of many theories ) is much lower than the probability of inflation. In Can the universe afford inflation? Andreas Albrecht and Lorenzo Sorbo propose that this is a viable assumption. There is a ( small ) possibility that ongoing observations of the CMBR will support this theory. Its main value, if any, is that some well regarded theories' predictions are incompatible with this theory. Therefor, in this post, rather than make predictions consistent with other theories I will only consider predictions of theories which are inconsistent with this theory. The most important constraint of this eternal universe theory, which does not apply to most theories, is that to avoid slow, exponential inflation of the universe it is necessary for everything created by an instance of inflation to disappear completely within finite time. That is:- Within finite time, each instance of inflation must end and all created space, particles and other entities eg singularities must disappear. This may take a very long time - eg the half-life of the proton is greater than 10^33 years. From this it follows that the pocket universe we live in ( and everything created by inflation ) cannot expand eternally to the future, but there need not be any presently detectable way for it to disappear. All models where quintessence, cosmological constant etc cause such expansion are not viable. As the expansion of space during inflation is finite, after sufficient time has elapsed, all created space must eventually be separated by time-like intervals. This should lead to the complete disappearance of everything created by the inflation episode. If, as is certainly plausible, new instances of inflation can start within an inflation field or pocket universe, finite inflation requires on average less than one in each new instance of inflation. ( Otherwise inflation would be eternal to the future.) An adaptation of reasoning regarded as dubious by Alan H. Guth: If finite inflation is assumed to have an exponential phase, it is likely our universe was created around the time of peak creation of universes when inflation was about to end; there may possibly be some trace of this in the microwave background. If it is possible for intelligent life to initiate inflation, this sets a further constraint on the probability of any single inflation episode producing intelligent life. If on average each instance of intelligent life creates x new inflation episodes, then all inflation episodes must on average produce less than 1/x instances of intelligent life. if this is the case, the total duration of inflation is further limited and there is a slightly better chance of observing transients dating back to the inception of inflation. I suggest one other constraint for finite inflation in an eternal universe, which is that its finiteness must not depend on carefully selected parameters. In an eternal universe the probability of eternal inflation must be 0. Finally there are so many extant theories I can only hope that I am not repeating one of the more obscure ones......

Good loft insulation.

I am certain you are not a skeptic

There is quite a lot of useful information here: https://www.physicsforums.com/threads/magnetic-force-inverse-cubed-law.587204/

Fred Hoyle's steady state universe is overdue for revival. I'll try to have something up for Monday.

No need to quote a poet...... Winners of the Ig® Nobel Prize 2000 PSYCHOLOGY: David Dunning of Cornell University and Justin Kruger of the University of Illinois, for their modest report, "Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments." [Published in the Journal of Personality and Social Psychology, vol. 77, no. 6, December 1999, pp. 1121-34.]

You mention a hypothesis that seems very like hormesis and clearly consider this to be a reasonable hypothesis and not pseudoscience. I'm not clear what you are arguing for. I suspect benign radiation induced DNA changes are swamped by the malign changes. The jury is still out on this. A couple of quotes from the original source of that quote indicative of its quality:

From the Wikipedia article ( http://en.wikipedia.org/wiki/Radiation_hormesis ) Strange cited: Strange: Do you have faith in totally error-free DNA repair or do you think damaged DNA is harmless or even benign? Perhaps you were referring to this study of the effects of a widespread accidental exposure to cobalt-60. I don't think you were referring to this later publication on the same incident, quoted in the Wiki. or this : As you seem to claim this Wiki has peer reviewed science supporting hormesis perhaps you would would specify where this can be found on the Wiki. I couldn't find anything that wouldn't be relegated to "Speculations" if it were presented as research on this forum. [edited for minor errors.]

I can't give any better answer than in my previous post.

'which way the conventional current flows through the capacitor' As (ideal) capacitors don't pass direct direct current the answer is ( at different times ) left to right, right to left and there is no current at all. 'ie which direction is the direction of conventional current around loopABCD' As current (and its direction and phase) varies around the loop (it may or may not change direction through CD) I can't answer this question or understand how it is the same as asking 'which way the conventional current flows through the capacitor' 'Now reverse the power supply to the resistor chain, as in fig2 and answer the same question.' After transients have become negligible the answer is as above. Was this a trick question?

from http://www.mi.mun.ca/users/cchaulk/eltk1100/ivse/ivse.htm etc Where the charge carriers are electrons, this is only true if the electrons are defined as having negative charge ie the conventions aren't independent.

from http://en.wikipedia.org/wiki/Landauer's_principle: Perhaps the EU is concerned more with improving efficiency rather than reducing computer speed. My current computer is only only able to consume twice as power as my first one but it runs about 1000 times faster....

This argument is often used by the nuclear industry. In any other context, body repair mechanisms are regarded as a means of minimizing and sometimes preventing long term damage. In other words, if low level radiation causes no harm, why do repair mechanisms try to minimize its effects?

Something wrong here. If ( as he can ) David can determine the pH then there are 3 answers to the question, not just B. (posted before I saw studiot's Response.)

All that's really needed for a counterargument is the title..... The End of Pascal's Wager: Only Nontheists Go to Heaven at http://infidels.org/library/modern/richard_carrier/heaven.html

I recall reading a long time ago that beekeepers rarely get arthritis. There are a lot of dubious claims but this seems pretty definitive: ( ref http://www.ncbi.nlm.nih.gov/pubmed/18807725 )

So failing to see something unexpected once somehow virtually guarantees that person will in future see any repetition?

First claim I've ever seen that a "a suite of scientific instruments powered by a warm battery containing 8.5lb of pure plutonium" in the LM descent stage helped the astronauts. Not up to the BBC's usual standard.

In jaydnul's post of 4 September 2014 - 10:29 PM he attempted to refute a double slit experiment referred to by IM Egdall on 04 Sept 2014 - 9:32 PM by referring to ( I presume ) Feynman's comments on a single slit experiment. As there was no reference in jaydnul's post to either single slit or double slit or Feynman, I assumed he was referring only to the double slit experiment. In this experiment, it's only possible to know the momentum and position if you know which slit the electron passed through etc and according to Feynman et al you can do that or have the two slit interference pattern. As he only referred to 'the experiment' in this post, I think it is unreasonable for jaydnul to criticise me for not having guessed 'the experiment' referred to two different experiments. It would be helpful in this topic if posters made clear which experiment(s) they're referring to.

You can't find the position and the momentum the electron needed to get there. ( eg you would break time symmetry ) An alternative rather simplistic view, without doing the maths.... If you want to find the position of the electron very accurately, detect it with a very short wavelength photon ( gamma ray ). The accuracy, and the energy of the photon, increases as you shorten the wavelength. As you've hit the electron very hard, you don't have much idea of the electron's momentum before the detection event. If you want to know the electron's momentum accurately, detect it with a very long wavelength low energy photon. You can't measure its position to much better than a wavelength. An example of a minimal observation:- in double slit diffraction set up minimally interacting detectors to see which slit each electron goes through without stopping them. Whether or not you look at the detectors' output, you will find the interference pattern has disappeared. There are lots of apparent getouts, many of them suggested by Einstein in thought experiments. They all failed. His nearest success was the EPR paradox; if QM is valid then eg a photon leaving the sun 'knows' what angle your polaroid sunglasses will be at when it hits them eight minutes later. Photons always get it right.