MigL

Only old people in their 70s would have known more than one Shah.

And do you think a centrifugal pump that si pumping a liquid or flowable solid actually works by compressing it ? (as opposed to a centrifugal compressor on turbomachinery )

Why ? How does the pressure change from the pail at rest and the spinning pail ? It doesn't . What does change is the angular momentum, and as a consequence, the net force, or weight.

He's not the only one involved in this discussion. Do the rest of us have to confirm we're not trolling for you to share those options ? Be careful though, some members will jump all over your proposals, while providing none of their own ( its happened to my proposals in other threads ). It seems they don't want to fix problems, just want us to all wallow in collective guilt.

It would be interesting to know wether the Iranian population misses life under the Shah, or if he's still detested by the populace.

OK, this is my last attempt. And only because studiot said I was wrong ( wouldn't want him to think less of me ). Take a pail with outward sloping sides and fill it with water, or if you prefer sand or mud to more closely resmble the Earth's crust. Now spin it about its vertical axis and see what happens to the contents of the pail. We note that the liquid ( or flowable solid ) goes from a flat surface to one that is concave. The edges close to the pail sides rise wwhile the center sinks. It is still at its lowest energy state, but that has now been modified by the angular momentum ( and the angle of the pail's sides ). The force of gravity acting on the contents of the pail has been modified also by the angular momentum ( as Pavel has also agreed ) such that the NET force is lessened close to the edges, and this leads to the deformation of the pail's contents. Now weight is nothing more than the measure of the force of gravity. It has been conveniently been given units which are equal to inertial mass on earth, but while mass is invariant, weight will change on the moon, or any othe place where gravity has changed. So when we say that the deformation of the pail's contents is due to a modification to the force of gravity ( by angular momentum ), it is equivalent to saying the deformation is due to a change ( lessening ) of its weight. Not mass mind you, the contents have the same mass throughout, but its weight has changed, and it 'floats' higher along the sides of the pail. This is the exact same effect as the Earth spinning about its axis. And the deformation to the lowest energy state is caused by the angular momentum changing the NET force acting on the Earth's composition. This NET force is also known as weight ( sometimes given in Newtons, go figure, a unit of force, not mass ). In effect, the, the deformation is caused by the change in weight of the composition of the Earth. So, again, saying that the deformation causes a change in weight is redundant.

I have a feeling this thread is going to be split off again. Now wiith regards to Earth's composition and fluidity. I'm no expert in this field, I'm just going by memory of things I've read or been told. But back to the original point... You cannot just eliminate Earth's angular momentum by snapping your fingers. If you could dissipate it and 'brake' the Earth, it would take time, and in the end, you'd find that the Earth would be close, if not spherical. Just like, as it was coming together 4.5 Bi yrs ago, it was probably extremely flattened ( accretion disc ), and slowly rotating. It then speeded up ( conservation of ang. momentum ) and reached an equilibrium of forces in the somewhat flattened spherical shape it has today. The very fact that the surface of the Earth sits appreciably higher in the gravity well, at the equator, is because it feels less net force. In effect, it weighs less. Even rock feels the effects of buoyancy, given several billion years to react, and so the surface has 'floated' up higher at the equator than the poles. I stand by my original assertion... The earth's shape ( flattened sphere ) is due to the fact that things weigh less at the equator. And while not wrong, saying that things weigh less at the equator because of Earth's shape, is redundant. We could argue about it till the cows come home, but its probably just semantics anyway.

While I agree that the gap between theoretical physics and experimental physics is widening ( our technology hasn't kept up with the energies needed to explore closer and closer to Planck scale ), string theory is a viable area of research. And even if ultimately proved to be a dead end, it will provide insight into other areas where the math may be applied. Maybe 'theory' is the wrong word for it, as that implies testability, but does it really matter ? Anyway, my gut still prefers LQG.

Thank you xyzt ( I'm re-enforcing positive behavior ). Rolando's consideration of the cause of the red shift presented two options... 1- The radiation is red-shifted because the atom emitting the light is time dilated, deeper in the gravity well. 2-The radiation is red-shifted as it loses energy climbing up the gravity well. They are not mutually exclusive as he believes, nor are they additive. Even without consideration of the math you presented, the atom emitting the radiation does not experience time dilation IN ITS OWN FRAME. The time dilation is only measured from the observer's frame, after the signal ( the radiation ) has climbed up the gravitational well. In other words, it is the exact same effect. The geometric explanation ( GR ) is the time dilation, but it can only ever be measured as the energy loss on the climb out ( as shown by the radial or potential dependence in xyzt's math )

Motorcycle analogies always seem to work best.

If I remember correctly Pavel, the Earths two largest layers are the low viscosity outer core, and the high viscosity mantle, accounting for approx. 5000 km of the radius almost evenly split. Now a high viscosity liquid like toffee, may not seem to flow very fast, but you'd be surprised how fast it flows when it has billions of pounds pressing on it. Do you call lava from a volcano a solid or a liquid; it certainly seems to flow very readily. And no, you can't consider what would happen if you suddenly stopped the Earth as then you'd have to ignore angular momentum, which is the cause of the effect in the first place. Look, I'm not saying DrP is wrong, what he said is certainly valid. But as an explanation he has put 'the cart before the horse'.

Take one of those little self-propelled toy cars, Mike. The kind that only go in a straight line. Now wind it up ( or whatever ) and set it down about a foot away, and offset, from a pole in the ground. The car will travel in a straight line, past the pole. Now introduce some form of attraction between the pole and the toy car, like gravity, or any other centripetal force. For our case we will use a string tied between the car and the post. What happens when we repeat the previous experiment ? We now see the string go taut and the toy car is constrained to travel a circular path around the post. From your mistaken point-of-view ( and any occupant of the toy car ) there is a force which is making the string go taut. Everyone else on this forum is telling you that this centrifugal force, which seems so real to you, is fictitious and only apparent in that accelerated ( spinning ) frame of reference. In the inertial frame of the person who sets the tied off car in motion, there is only the toy car's inertia and the string's centripetal force.

I made no mention of 'centrifugal' force Mike, as that would only be 'apparent' from the Earth's surface accelerated ( spinning ) frame. An inertial observer at rest, high above one of the poles, would note the angular momentum at the rotating equator, and attribute the centripetal ( gravitational ) force modification to inertial effects. And as Earth is mostly in a liquid form, surrounded by solid plates, I think it would take a spherical form very quickly, Strange; although with world-wide, extreme earthquakes. Again I make no mention of centrifugal or other frame dependent forces.

No. If it wasn't spinning the earth would be spherical and there would be no difference in radius between equator and poles. It is the spin, which alters the force ( also called weight ), which then alters the shape. Saying that the shape then alters the force, is redundant..

Don't know much about her opponents, but this is her election to lose. There are no Democrats who can beat her for the nomination ( but didn't they say that when she went up against B. Obama ). And there are no Republicans who can beat her on election day ( Jeb who ? Although if he plays his cards right, he may have a shot at her second term ). I like her, more so than Bill. Let's hope she ( is allowed to ) gets things done. I guess it'll be all male interns in the white house after 2016.

Used gel in my hair for about 15-20 yrs whenever I'd go 'clubbing'. Only problem I experienced was a build up after many uses as shampoo is very mild. Solved the problem by shampooing with dishwashing liquid occasionally to remove the build up. It may have some gray in it now but I still have all my hair. Hasn't thinned or receded.

I really don't think this is that important an issue to warrant splitting and continued discussion, but I'll explain my reasoning... The distribution of mass/matter, due to gravity, for a non spinning object, tends to a perfect sphere, as gravity is radially symmetric. The force felt by the mass/matter is the only arbiter of the shape, so if we modify the force by imparting an axial spin, the equatorial region will feel a modified ( lessened )force. This is because, at the equator, the inertia of the mass/matter resists the gravitational or centripetal force to a greater extent than at the poles where angular momentum is trivial. We can measure gravitational or modified gravitational ( due to spin, not MOND ) force directly by weighing things. What we find is that things weigh less at the equator because they feel less net centripetal force compared to the poles. Since they feel less net force there is a deviation from the spherical distribution of the mass/matter such that the radius at the poles is smaller than the equatorial radius. So, using weight as a measure of force, the radius of the Earth is larger than the polar radius, because mass/matter, or anything else, weighs less in that radial direction. So having established that the surface of the Earth is farther away from the center because the constituent mass/matter weighs less. it makes no sense to say ( as DrP did ) that things weigh less because they are farther away from the center. While not technically wrong, it is circular reasoning at best.

Time dilation IS the reason for the frequency change between source and observer. And xyzt, you made a valiant attempt at being civil but quickly regressed. Still it was appreciated by all of us who wish to learn. Thank you.

Sorry Strange, I thought I made myself clearer, but I guess not. Things farther away actually weigh less because weight is a force due to gravity and changes with the inverse of the radius squared. In effect, the equatorial surface is feeling less gravitational force Mass does not change, and the two are not the same.

So Hillary has thrown her hat in the ring for the head honcho position in 2016. No big surprise there. But this second time around, she's not going to be Margaret Thatcher Lite. She's made tackling wealth inequality her platform, and is running as a woman, not trying to prove she's got bigger b*lls than her opponents. I like it. What do you guys think ?

Most of us are here to learn and teach. Your math skills are way above mine, but no-one is an expert in everything. You could certainly be a teacher to a lot of us with regards to math, but you, yourself, realize that you're no 'Mr. Congeniality", as you describe yourself as a 'curmudgeon'. A little more teaching and less put-downs would be appreciated. Not a request or order by any means, just a suggestion.

Ah, but the rebate ( at least in Canada ) is dependent on battery power. A more powerful battery, as installed in a larger, sportier or more luxurious vehicle, will get you a larger rebate. If the point of the rebate was to encourage adoption of more economical, less wasteful Evehicles, should it not be the other way around ? And you're right, Phi, I should have been more clear in my wording and not used 'spending' to mean 'wasteful spending'.

No offence taken DrP. And I hope you don't take my referring to your answer as a 'non-answer' as an implication that it is wrong. It is accurate, it just doesn't add new information. A mass weighs less at the equatorial surface because it is further from the center of the earth. But the surface at the equator is further from the center than at the poles, because it weighs less ( weight being a force due to Earth gravity ). A proper explanation for this would include that the centripetal force ( gravity ) at the equatorial surface has a greater inertia to overcome ( higher angular momentum due to greater distance from axis of rotation ) than at the poles. This is what leads to the flattened spheroid shape > greater radius > lower weight. Or is this just semantics ? In which case you could call this a non-argument.

Don't have a problem with the smart appropriations. You want to tax me for building a free, working, useful mass transit system ? I'm in. Taking that tax money and giving a rebate on a luxury Evehicle to a millionaire, would be one example of a stupid appropriation ( and of not being able to control spending ).

DrP your non answer was... An object weighs less at the equator because it is farther from the center of the Earth. I replied that... For the surface (rocks, dirt, etc. ) of the Earth to be farther from the center, it must also weigh less ( not mass, mind you, but weight ) otherwise it would form a perfect sphere. So why does the surface weigh less ( and everything below it ) ? I.E. your answer doesn't answer anything. And I only wish I was back in school ( No responsibilities, spending 6 out of 7 nights in clubs, etc.; I'm getting depressed just thinking about it. Damn this middle/old age sucks. )