Timocrates wrote:

Quora wrote:

Let's pretend we have Superman's microscopic vision and can see every molecule in the atmosphere.  We'd see something like this:
...
We would see a chaotic scene...

But nature abhors chaos. Things tend to a state of rest or equilibrium/balance. Right off the bat I am having issues with this authority, that they could seriously entertain the idea that the atmosphere is really chaotic. That speaks to me of ignorance: few specialists ever see chaos in whatever aspect of nature they study. I mean a decent meteorologist should take issue with his statement that the atmosphere is chaotic. We can generally gauge and predict, e.g., the weather for a reason. It is not in a state of chaos at all. We can predict how things will behave for a reason.

Quora wrote:

Most of our atmosphere (about 78%) is nitrogen.  At 25 degrees Celsius (77 F), nitrogen molecules have an average velocity of about 511 m/s (1676 ft/s).

What? Okay anyone can play this game, but let's expose how the author of this article is setting us up. Notice that he had to say "average" there. What is the velocity of nitrogen at 25 C on, say, Mars or the Moon? Different than the average here, of course. And in "outer space"? Different again. But why? Largely owing to the relevant pressures being generated or exerted, which absolutely cannot be ignored when determining how a thing might move in any given situation. Again, the less resistance available to a thing will alter its speed. Ceteris paribus, a bowling ball with velocity X upon entering air from a thicker medium will retain or gain velocity; upon entering a thicker medium, lose velocity. The author knows this full well. This is just a magician's sleight of hand and he is just setting up the necessary (false) assumptions to make his subsequent model "work." Heat, furthermore, needs a physical medium through which to be transferred; but because space is supposed to be an almost complete void, the theory holds that heat is somehow transformed into pure electromagnetic energy waves: hence in that form it travels through the void of space until entering into contact with a mass, which will transform it into heat. Now of course electromagnetic waves are perfectly real but the only point here is that heat will affect things differently in different circumstances because hot moves to cold. That is actually another problem with the theory of the vacuum void of space: anything heated will want to fill it with a fury and dissipate its heat into it.

Indeed, one of the strongest points raised against Einstein's removal of the aether just was the fact that electromagnetic waves and fields propagate in and through a vacuum, thus affecting the space. Now obviously for this to be there has to be something there being affected by these forces and fields otherwise they couldn't be said to be in that space/place.

Again, he's also ignoring the fact that molecules in the upper atmosphere are radically heated, which as he admits inclines them to move at a faster velocity. So gravity is getting weaker and things are getting hotter. This is not helpful. Even assuming gravity is actively resisting the thing's movement, exerting an external positive force upon it, the heat will incline the object to move more while gravity is only getting weaker. Once again the very fact that the molecule headed upward demonstrates that gravity cannot negate the forces in question.

I also dislike how the author just picks and chooses what physical forces will be at play. Notice he talks only about gravity and kinetic (heat) energy, as if even a cool, pressurized gas wouldn't rapidly expand inside a vacuum chamber, regardless of the fact its actually cool.

Ordinarily I would probably have made a much more charitable interpretation, except for the fact that the author definitely knows these things; hence, he knows there are real problems and is suppressing those facts. The man makes his living, apparently, at least teaching this stuff. I don't believe it is in his interest to point out seriously fundamental problems. The fact that he's an engineer tells me he can't not know that kinetic energy and gravity aren't the only relevant factors here:

"Robert Frost, Engineer with specialization in spacecraft operations, orbital mechanics, and..."

I try to answer some issues that I know the answer to.

1. Chaotic: Just like in philosophy where you define your terms, here you must also realize what is implied by chaos. Simply, it means that the particles are moving in many different directions. They do follow the newton's law but since their intial speed and position is unknown and we have tons of particles, we use statistical mechanics to describe the system. e.g you have a distribution of velocity for gas molecules

I also dislike how the author just picks and chooses what physical forces will be at play. Notice he talks only about gravity and kinetic (heat) energy, as if even a cool, pressurized gas wouldn't rapidly expand inside a vacuum chamber, regardless of the fact its actually cool.

Well, actually the author is right. There is only kinetic energy and gravity. Nothing else!

If you remember my previous post, I did mention that there is no force involved. Simply the gas molecules have velocity and move in random directions (by random it means, you have many gas molecules which move in many different directions). So there is no force requried for the gas molecules to fill void and actually there is not.

Now what you feel as the force due to pressure difference is because:

Suppose there are two vessels and there is movable wall betweetn these two. now if in the intial condition we have different pressures for the two vessels the wall starts to move. A gradient of pressure has resulted in a force. But look closer, the force comes from the fact that on each side of the piston, the gas molecules have different velocities which result in different pressures. When these gas molecules collide with the wall and bounce back they exert force on the wall. So the force is made by a bouncing of a collection of gas molecules on a wall. In the case of atmosphere we only consider one gas molecule and investigate its movement (there is no wall and therefore no force in the way that your common sense tells you). yes it does collide with other molecules, but the collision can help to move up or down. if you want add the collision into picture it would just complicate it.

So in this case, its actually only the gravity as the force! 
I used  simplified language. In physics you make a simplified model and take into account that which matters. It is not philosophy. So yes what I said is approximation, but the other effects are marginal and these are empirical fact and you need to make calculations (to have numbers) to judge what happens


Just one small note as I said earlier please avoid the qualitative language. Yes the gravity force decrease with force. But believe me the g on the sea 9.8 m/s^2! at toposphere (90km away) it is also very near to 9.8 m/s^2 . 

Last edited by nojoum (7/20/2016 3:48 pm)

Timocrates wrote:

nojoum wrote:

Timocrates wrote:

But you are still moving circularly at 1,030mph or 500+m/s. If we constructed a centrifuge with a radius the same as the earth's, and spun it at 1,030mph, the forces generated would be enormous, because it is not RPMs that matter here: if they did, then there would be no difference between the mid-point of the radius of a centrifuge and its outer edge.

This brings to mind other problems in modern mechanics. The actual velocities of things are treated effectively as irrelevant. Hence, though everything on earth is moving at something like 66,000+ mph, we can still bump into each other and not expect a violent catastrophe. Two cars colliding at 1 and 2 mph respectively will produce minimal force and damage (on each other); two cars moving at 100 and 101mph, much more. But these forces all just manage to disappear, just as the centrifugal force of the earth's spin does.

Dear Timocrates, with all the respect, I must say that it is better to study physics more deeply and also to avoid qualitative language. You can calculate the force, it will be small compared to the weight of the body( mg)
I understant that it is not nice to say this. But please, do study the fundamentals of physics by David Halliday.
I cannot simply start teaching here because I am not in the position to be a teacher and you to be a student of mine. But these things are like saying earth is flat. Or that if God does not need a cause why does the universe needs a cause? Or what caused God?

Well, nojoum, I don't expect a full physics lesson. But can you please let me know how these equations could fail to cause gravity to be a sufficiently effective negating force on earth? Wouldn't this equation work out such that even a very light object would only suffer a percentage loss of its weight; whereas, we know we are dealing with absolute forces in this situation? I mean, is it even credible to believe the centrifugal force generated by earth's rotation about its axis would have the effect of making a man and a feather both only 0.3% lighter in weight?

What I think is happening in these maths is that certain factors are being made purely relative, thus negating any actual absolute consequence from their acceleration.

What happens, too, when we add in the fact that the man is already being accelerated by 66,000 mph? Shouldn't the earth's rotation around the Sun likewise generate another centrifugal force? But something tells me the math will yet again work out just fine and we will not get a meaningful consequent, which is rather convenient: a man with a mass of 80kg will still weigh 176lbs at the polar regions and perhaps 0.3% less at the equator. This is indeed counter to commonsense because centrifugal forces are experienced as absolute forces, not relative forces. Centrifugal forces and pressures will simply overwhelm certain systems, actually causing things to be thrown off of them or causing the spinning object to break/fly apart.

Moreover, as we increase in altitude the air around us would have to be moving faster than the air below us, which means more centrifugal force, and greater weightlessness for that air, even if we hold gravity as constant (though in fact it is actually supposed to be getting weaker). This again seems to add problems about how the earth's atmosphere isn't filling the vacuum of space.

As a follow up, and for the sake of simplicity, I ran what an object with 1/10th the mass of the 80kg man (8kg) used in the paper would experience in terms of weightlessness and in fact (as expected) that its weight, too, would be reduced also only by 0.3% or 1/10th of what the 80kg man's weight would be reduced by (0.269 Newtons; whereas, the 80kg mass had his weight reduced by 2.69 Newtons).

That just does not seem right to me.

Last edited by Timocrates (7/20/2016 5:17 pm)

Just one small note. The inward force, the weight and all of these are not easy concepts to grasp. I studied these in high school. It took me great efforts to understand these. I think for this weight loss problem, I thought for about 1 hour or something when I was given this problem in high school. Consider that I was familiar with the physics, formulas and so on and I had seen similar problems but still it was hard to get my head around these subjects.

So it is not wrong to ask even the simplest question. The thing that I did not find justifiable is to claim that physics is wrong and scientist are wrong about it and so on. I'm not saying to trust completely in authority. All I want to say is that, study enough and then question what is being taught in universities and books.

And I would say physics is much better than philosophy. You have Feser on one hand who is catholic, you have Craig who is protestant. They are both major figures of defending Christian faith but you can see that you cannot simply trust them.

Last edited by nojoum (7/20/2016 5:51 pm)

nojoum wrote:

Just one small note. The inward force, the weight and all of these are not easy concepts to grasp. I studied these in high school. It took me great efforts to understand these. I think for this weight loss problem, I thought for about 1 hour or something when I was given this problem in high school. Consider that I was familiar with the physics, formulas and so on and I had seen similar problems but still it was hard to get my head around these subjects.

So it is not wrong to ask even the simplest question. The thing that I did not find justifiable is to claim that physics is wrong and scientist are wrong about it and so on. I'm not saying to trust completely in authority. All I want to say is that, study enough and then question what is being taught in universities and books.

And I would say physics is much better than philosophy. You have Feser on one hand who is catholic, you have Craig who is protestant. They are both major figures of defending Christian faith but you can see that you cannot simply trust them.

Nojoum,

I don't think physics or even the basics of Newtonian mechanics is or are wrong, certainly not in ordinary day-to-day application of their basic principles and assumptions. What I do think is that the astrophysical or cosmological component of it is problematic and not consistent with its actual, more practical virtues.

And thank you for the physics course recommendation, Armando. But the fact that I expect an absolute force to be produced by a rotating object is based on empirical observation without fail. How or why it suddenly becomes a merely relative force is beyond me. The centrifugal force generated by a spinning object isn't typically measured by how much weightlessness an object on the edge of the rotating object will experience. It will simply exert a determinate force that will cause some things to be flung off of it or for the object itself to fly or break apart or some things to remain on/fixed if the object is itself sufficiently strong and any objects on it are firmly fixed enough.

That a feather no less than a man only becomes 0.3% lighter owing to this force is, to me, just plain suspect. In my experience centrifugal forces just don't work like that. Given this logic, it's not even clear how any centrifugal force could even succeed in throwing an object away from itself: worse, it would if this logic were true only throw off a 1kg object at the same time it had sufficient force to throw off a 100kg object.

That is, again, just wrong in my mind.

Now classic mechanics has made use of relative inertial frames since Galileo(1), who used the example of someone being below deck in a ship being unable to know whether or not he was actually moving. This thought experiment was of course revived to great effect by Einstein. That is perhaps the core issue in these systems: whether or not physical motions have necessary effects or consequences. Notice also that Galileo effectively compared the Earth to a ship: yet another closed, sealed physical system.

Last edited by Timocrates (7/20/2016 7:12 pm)