MigL

Nothing is an abstract concept just like zero. One apple means you have an apple, but zero apples means no apples exist. Similarily 'nothing' does not exist, but as a concept,it facilitates reasoning such as logic and math. It also cannot exist physically, as there are things and processes which cannot be separated from any area of space-time.

And I thought I was getting old and cynical... Some of you guys need to do some drugs and be a little happier.

That is why I granted that you are right, and yes, that is usually the case. My interpretation of 'sustained' is actually self-sustaining. So, while a fusion bomb's reaction might last very briefly, It is self-sustaining ( at least till the fuel is used up ). A 'fusor', if I recall, needs a constant input of external energy to operate. I realise it's just semantics, but the energy of the reaction doesn't directly provide the necessary temp and press needed for the reaction as athe Sun or an H-bomb do. It has to be channeled to external equipment which provides the kinetic energy to the particles ( equivalent to temp and press ) in order to facilitate the reaction.

Is it really about order ? Western governments are evolving away from telling people what to do. You are allowed to overeat yourself to a heart attack. Drink and drug yourself into a stupor in all night bars and safe injection sites. Practice all sorts of risky behavior with communicable diseases. Etc. etc. We do however expect the government to take care of those people. And others who may not be as fortunate as we are, or who cannot take care of themselves. We ( hopefully ) have evolved past the wildebeest who sacrifice their weak and injured to the lions.

Re: post #60 iNow Exactly !

Electromagnetism is a gauge field. In simple terms that means HOW you measure it is more important than the actual measurement. What is important is not the absolute or actual potential ( voltage ), but the difference in potential. It is this difference which moves charges. A bird sitting on a 1500 V line is also at 1500 V. No charges move. It doesn't get fried. If you are standing on the ground and touch that same line, 1500 V of potential will move a lot of charges. You will be fried to a crisp.

I apologize profusely John. Technically you are right. Although in my previous post, I had granted that a collider can fuse light ions at low 'pressure', so arranging the equivalent of several together to fire at the same spot is essentially the same. And I still don't think that fits the definition of 'sustained'. The only sustained fusion reactions we know of are stars and thermonuclear bombs. And both use hi temps AND pressures.

Oh wow. Now we're arguing about the choice of variables. What's next, why x, y and z and not k, l and m ?

And while I can see two ions smacking together in a collider to acheive fusion at low 'pressure' ( stretching the meaning since both temp and press are a measure of particle energy ), I don't see how you can call that sustained fusion ( post #19 ). So I'm still going to need an example of an appropriate mechanism, John. Maybe I can patent it, solve the world's energy problems, and become incredibly wealthy. Or did you 'muddle' fusion with fission ( been waiting for that a long time, no, just kidding around ).

Very well Eise, then I suggest the OP is poorly worded ( since you like to use the OP to beat Studiot with ). One might as well ask about sources of conflict between the Hatfields and McCoys. There is only one source of conflict and it is ignorance ( willful or otherwise ). Science provides us with an undestanding of the workings of the universe. Religion provides us ( believers actually, as I don't care for it ) with our reason for being, a purpose if you will. To move past the ignorance you need to realise that science cannot provide our purpose for being, while religion cannot provide an understanding of the universe. Or would you like to try ? Incidentally iNow, I may find the colour yellow most pleasing today, but after some conditioning I may find the colour purple most pleasing next week. This can also be measured by the brain'sresponse. Does that mean a 'truth' can change from day to day ? Or is there some validity to the concept of subjective truths ( unverifiable beliefs ) and objective truths ( quantifiable, unalterable information ).

You did NOT see Thor yesterday making thunder and lightning ,Eise, but you may certainly believe that you saw him. A belief may be termed a subjective 'truth' as opposed to an objective truth An objective truth may be analised using the 'tools' of science, but a belief system cannot be analized scientifically ( and vice versa), They are based on different paradigms. That would be like saying 'I believe the colour yellow is the most pleasing', and trying to analise that scientifically

I'm getting more confused by the minute. Why is fusion being discussed along with Plutonium and Uranium ? I realise fusion and fission are easy to interchange but... Fusion occurrs in light element plasmas at extremely high temps and/or pressures, and becomes less and less likely as you rise towards atomic no. 26 ( iron ). An example is the Sun's core. All thermonuclear ( fusion ) bombs use an atomic ( fission ) 'bomb' in a specific arrangement to generate the required radiation pressure and temperature to initiate the fusion reaction Fission occurrs in heavy radioactive elements with no restrictions on temp./press.,and becomes less and less likely as elements become more stable coming down towards atomic no. 26. Examples are the atomic bombs dropped on Hiroshima/Nagasaki ( one Uranium, one Plutonium ). I'm going to needa reference for 'sustained fusion at fairly low pressures' John.

I'm not sure I understand you correctly, RobinPike. Are you applying Zeno's paradox to electron motion and radiation ?

Why are we comparing a belief system to an information system ? Are we gonna compare apples to oranges next ? Religion has its benefits. It makes believers feel good about themselves and gives their lives meaning and purpose. Sciense has its purpose. The understanding of reality and the world around us. It is only when you try to analize one with the 'tools' of the other that you run into conflicts.

Really ? You're comparing Einstein to a huckster like Jobs ?

Not exactly Sensei. Hawking radiation is a result of Heisenberg's principle. It is more along the lines that if I owe you $20, then I have negative $20. The $20 bill is still a positive quantity, but ownership makes a difference.

Easy enough to say " keep Africa agricultural ", while we enjoy the benefits of an industrial/information society. These benefits include, among others, the ability to feed our people to obesity levels., while Africans have to rely on our aid or starve. Who are we to deny them the choice of industrialization ? As for 'is economics a science ?'. Every valid science experiment has to be reproducible, The laws of science don't change depending on the day of the week, the location, emotions or seemingly random luck. Economics doesn't seem to currently pass this test. Economics is based on people and non-quantifiable emotions ( confidence in a certain stock ? ), but maybe, with further development oof chaos theory, we may eventually have a somewhat workable, scientific model.

OK, let me get ready for some personal attacks and name-calling... I only know of one demographic which carries out these types of suicide attacks ( although it is starting to spread ), and I will be first to name the 'elephant in the room' and ask the question. Would racial/religious profiling not eliminate at least 90% of the threats? Any response to this will be off topic, so please move appropriately,

I'm not sure either swansont, but since Hawking radiation is generated from particle-antiparticle virtual pairs, it could also be generated by massless particles which have an antiparticle, i.e. not photons. Also, the extreme temperature of an atomic scale black hole could and would generate massive particles which would quickly decay and produce gamma radiation. This is all external to the horizon, of course. I don't have much faith in baryon conservation either, since the universe is mostly matter. At some time, or under certain circumstances, baryons and anti-baryons were generated and destroyed asymmetrically.

There is a small but non-trivial difference between the three spatial dimensions and the time dimension. This leads to some confusion as to the existence of time. While we can measure separation directly in any of the three spatial dimensions simply by laying down a measuring tape between two co-ordinates, we cannot do the equivalent in the time dimension. The difference is that we only ever have access to the local present. The past is gone and the future hasn't happened yet, so direct measurement between two co-ordinates is impossible. Our only option is indirect measurement using properties that change over time. If we consider the property of position, then the resultant change over time, is motion. But other properties may be used. This does not mean that time is illusionary or equivalent to motion. Time is a certainly valid concept, and until there is proof otherwise, I, for one, will assume it is real.

Interesting read regarding HeLa cells. Thanks for the link, John. Is this a case of a cancer providing a useful ( not for Henrietta Laks unfortunately ) mutation at the cellular level ?

I don't think the bear attack was a case of revenge. If the authorities could be sure the bear wouldn't have mauled anyone else, they would not have shot it. It was a case of prevention of further attacks. I think the bear was just being a "bear'. It certainly couldn't form intent or be 'evil'. I think there is a vast difference between prevention ( deterrence ), justice and revenge.

Really ? I don't think the subject of the OP is grammar. It is our very nature (instinctual ) to survive and provide advantages for our off-spring to survive that makes us competitive and willing to exploit any advantage in our favour, that allows us to justify our cruelty to fellow human beings and other inhabitants of this world. It is in our nature ( and most other life on this planet ) and is what allowed us to reach our 'position' as the dominant life form of this world. So is it a bad thing, or a good thing ?

A white dwarf is sustained by electron degeneracy. I'm sure we all agree on this. As you try and constrain the electrons into a smaller and smaller volume, you are in effect fixing their position more and more accurately. The Heisenberg Uncertainty principle tells us that at a certain level of compression, the electron is 'fixed' into such a small box that the uncertainty in its momentum, I.e. electron mass times velocity, implies that its velocity could be larger than the speed of light. This is obviously non-sensical. This was the reasoning used by S. Chandashekar to arrive at the limit named after him. Nature gets around this by collapsing stars too massive to be white dwarfs into neutron stars, where the electrons have collapsed into nuclei, merged with protons, and formed a gravitationally bound mass of neutrons. Since the neutrons are approx. 2000 times heavier than electrons, their velocity can now be 2000 times less than it was for electrons, and still satisfy the HUP. But if the pressure keeps increasing still, we constrain the neutrons to a box small enough that the HUP demands that the uncertainty in their velocity ( momentum ) is larger than c . Now if the neutron could decay into a heavier particle, we could still avoid the black hole stage, but there is no such mechanism. gravitational collapse to a black hole is inevitable. I don't see how decay to the ant-matter counterpart of the original electron ( the positron ), be allowed under these conditions. It would only be possible if compression or constrainment of the neutrons or protons was eased, i.e. LESS pressure. A comment on the ( theoretical because they've been indirectly detected ) impossibility of black hole formation ( Mersini-Houghton )... A Black Hole by necessity, starts at the point of greatest density/compression of a collapsing star, i.e. the center, and it starts small and grows to engulf the collapsing star. The Hawking radiation of a BH increases exponentially as a BH gets smaller, until it vanishes in a powerful gamma ray burst. That means when it is first forming it is emitting massive amounts of radiation. Is this radiation pressure enough to keep the star from further collapse ? in effect you'd have the curious case of a BH starting to form, but immediately releasing all it energy in a gamma ray burst, then starting to form again and, again releasing all it energy, and so on, and so on. The star would ultimately radiate away without a BH ever fully forming. I haven't read this paper yet, but is this what it is alluding to ? This does not, however, agree with ( indirect ) observational evidence, and the mechanism is based on unverified assumptions.

Elfmotat's point remains, that the expansion is modeled on the Cosmological Constant, and is present everywhere. This constant is just one term in an equation, and only becomes the dominant term when 'gravity' is extremely weak, such as areas of nearly flat space-time, i.e. between galaxies/clusters. At shorter distances/densities the 'gravity' term is much larger than the Cosmological Constant, and dominates.