41

Philosophy, Religion & Society / Re: Trump

« on: May 10, 2020, 02:33:14 PM »

Reade has said she was struggling to find a lawyer to represent her.

Wigdor suggested Reade’s struggles to find representation were because of “politics,” according to the news source. 

“I think highly of a lot of these people,” he told AP. “These are my friends and colleagues, people who I respect, but they tend to be Democrats or liberals, and they were not interested, because of that, in representing Tara Reade.”

Sounds pretty clear to me. Liberals 'protect their own'.

Guy gives opinion on something

Tom: I now know The Truth^TM!

As with almost ever story, the real reason is somewhere in between.  Some probably don't want to risk the political backlash, some are motivated by dollars, some don't think the case holds water, some don't want to ruin Biden's chance of getting elected, etc...

I agree that in complicated multi-faceted situations, there can be several competing interests and interpretations.

But I respectfully disagree that the truth is always “in the middle” with both true and false opinions from both sides.

To take a silly example, suppose I say that I am a banana. And suppose you say that I am not a banana. Is the truth somewhere in between?

Am I a half-banana?

Sometimes people are just incorrect in their statements, and to seek compromise on each opinion (not saying this was what you were implying however) dilutes facts and truth according to whomever offers the most outrageous claim.

Rather, I propose seeking compromise with the debate process itself, and be willing to acknowledge claims the other side makes that are factual, in order to find common ground and preserve civility.

Just my two cents.

42

Flat Earth Theory / Re: 3 Body Solution Simulations

« on: May 10, 2020, 04:10:51 AM »

The author does not call it a proof of the stability for the n-body problems and I see no reason to assume that it is. There is a body of science for the n-body problems and this isn't it. I would suggest citing that science in the future.

I still haven't seen any quotes of published papers that state that we can't use n-body calculations to predict comets and land spacecraft on other worlds

There are dozens of physcists who say that the three body problems are insoluable. They cite Poincare's paper as proving that it is insoluble and inherently chaotic. We post those quotes all the time.

This is the response to that, to post random found simulations which do not state that they are solving the stability issues of the n-body problems. We must "infer" that this is the purpose or feature of the simulation.

I agree that the author does not claim to address chaotic systems. It looks like precise initial conditions are inputted - so there would be no chaotic dynamics to analyze.

I agree and have also read about the inability to find analytical solutions to the differential equations. But I’m confused why this is being raised - this isn’t the topic of the post.

The topic is numerical solutions using a known mathematical process. They show the orbits that follow from the equations when solved using this method. Do you dispute any of the mathematics on the webpage?

It is convincing to me that the numerical method used is accurately applied. So I take this as computational evidence that Newton’s gravity can depict orbits.

However, this doesn’t mean I think you are wrong in your replies. The chaotic dynamics and variations using initial conditions are interesting, and arise when perturbation analytical methods are used to try to find closed form solutions for the differential equations.

I would enjoy discussing that in a new thread, but that is not what THIS thread is about.

Lastly, I respectfully object to statement that this post was a response to Poincare’s work and the chaotic dynamics. It was not, and I never said this. I fear it would “poison the well” to hold this numerical solution to an analytical standard. They are different things.

43

Flat Earth Theory / Re: 3 Body Solution Simulations

« on: May 10, 2020, 02:45:06 AM »

Well, I cannot speak to the phet sim thing, but the java script I posted is from a graduate student in one of the top astrophysics programs. Of course, it isn’t published work - and I never meant for it to be interpreted that way. But why does that mean it’s for children?

On that website it says right ton that page: "This work is based on Rosmary’s ideas and code."

It's not even that person's ideas or code. They copied code from another author, who may be using it for a different purpose than a true simulation of the n-body problems.

You know that we have an established body of science for the n-body problems and the study of gravity isn't taking place on blogs with plagiarized code, right?

Oh yeah, I saw that. It doesn’t bother me though - proper credit was given to the original author, so it isn’t plagiarized.

This doesn’t strike me as a “study of gravity.” The published works on n body simulations I’ve read are on a different level of difficulty and sophistication.

This student took Newton’s second law for each body, solved the differential equations using the Runga-Kutta method, and plotted the resulting orbits.

I think it’s cute, but it’s okay to disagree.

I still don’t see how the basic mathematics required could ever be found in a published article though...it seems more like a homework problem given to students, or something.

44

Flat Earth Investigations / Re: Short note on perspective : moon-sun

« on: May 10, 2020, 02:39:04 AM »

Looking at the moon from earth three different phenomena can be observed :

1) The actual path of light from the sun to the moon is of course a straight line but visual observation of the orientation of the phases of the moon seem to contradict this when one draws a straight line between sun and moon when both happen to be visible at the same time.

2) At exactly the same time all observers of the moon see the same side - the near side - of the moon irrespective of their location on earth at least by observing with the naked eye.

3) The apparent rotation of the moon's "face" and the day-night terminator during the course of a night.

All three phenomena are distinct from each other in the sense that the underlying reasons are different. Let me give the explanation for point 1) here by bringing it down to earth - literally.

Let me start off with a statement : If we were able to see light travel from the sun to the moon the light would follow a curved path as seen from an observer on earth. This phenomena is not restricted to the sun-moon problem but very general in nature. Why is that ?

The underlying reason is that we don't have any perception of depth of an object in the sky but describe its location only in terms of two angles : the angle of elevation ( 0 when the object is at the horizon, 90 degrees when straight overhead) and azimuth angle ( 10 deg east of south or something like that ). So let's bring it down to earth.

Imagine you are standing on a big level field - it is pitch dark and all you can see is five very small lights which are NOT moving. Because of the total darkness you don't have any depth perception. You also have no knowledge about how the actual brightness of each light; one might be actually very bright but far away, the next one very dim but close by. So, you do what astronomers do when measuring the positions of objects in space, you measure azimuth and elevation angle. Here are the numbers you measured, assigning 0 deg azimuth to the left most post and 90 deg azimuth for the right most post (you will be able to verify these numbers yourself shortly) :

Post  azimuth [deg]  elevation [deg]
 1       0.00              15.00
 2      18.43             18.72
 3      45.00             20.75
 4      71.57             18.72
 5      90.00             15.00


Now, before you leave the field you mark the spot you were standing to come back to it during day light.

You go home, take a piece of paper to create a nice x-y drawing, azimuth angle along your x-axis and elevation angle in the y-direction. Connect the five points by a nice arc.

Next morning you come back to the field to the spot you marked the night before and you make the following discoveries : from where you were standing you had looked at five poles with little tiny lights on top. The center post (# 3) being exactly 100 meters away. The posts are located along a line perpendicular to the line from you to the center post. The posts are equally spaced, 25 m apart. They also turned out to be exactly the same height as verified with a laser beam going from the right most to the left most post just grazing all five light bulbs. Of course, if you could have seen the laser light at night it would have followed the nice arc you drew.

With this new information, your calculator and knowledge of trigonometry you can now not only calculate the height of the posts (quite high I might add) and verify the numbers in the above table.


Finally, some food for thought : I presented all the distance in terms of meters. Would you have to make a new azimuth-elevation drawing if they ALL were in feet or all in miles ?

I’m going to guess “no,” that you would not need to make new drawings. If you’re computing angles using trig, then it is the ratios of distances that matter.

Am I right?

45

Flat Earth Theory / Re: 3 Body Solution Simulations

« on: May 10, 2020, 02:12:28 AM »

You guys are citing gravity learning resources for children.  PHet made a 'gravity simulation' for elementary school teachers to show how gravity makes the Earth go around the Sun. I would recommend finding better evidence for this.

Well, I cannot speak to the phet sim thing, but the java script I posted is from a graduate student in one of the top astrophysics programs. Of course, it isn’t published work - and I never meant for it to be interpreted that way. But why does that mean it’s for children?

You’ll probably be hard pressed to find this stuff that’s published, because it doesn’t seem to be a topic that is of publishable difficulty - as you see, this graduate student did it for their webpage.

What I like about it is if you scroll down, the author details the calculations that go into the code, and even gives the code.

I think that’s pretty neat! And it shows mathematically how you can start from Newton’s gravity and plot actual orbits.

I dunno what top math minds say it isn’t possible, but it seems pretty possible to me. I mean, it’s staring me in the face

46

Flat Earth Theory / Re: The Math for universal Acceleration IS INCORRECT

« on: May 10, 2020, 12:22:39 AM »

I don’t see any use in talking about relative muon velocity either.

From what I gather, it seems like entire RE argument boils down to this:

1. Muons are made by cosmic ray interactions in the atmosphere. The reaction that makes them results in a tight muon energy distribution and so predictable muon speed.

2. In standard (non circular) UA, our speed on the surface increases as Earth undergoes constant acceleration.

3. Muon #1 has some proper speed, add that to ours and that is the relative speed we measure in our rest frame.

4. Muon #2 (a week later) has some similar proper speed, and that to our much faster speed than last week: change of speed would be 9.8*(86400*7) m/s.

So we would measure an increasing speed of incoming muons by about 864000 m/s each consecutive day.

5. We don’t measure that - muons have similar speeds.

47

Flat Earth Theory / 3 Body Solution Simulations

« on: May 09, 2020, 09:49:38 PM »

I ran across a cute Java script from a student at Monash Center for Astrophysics, that plots the numerical solutions of the differential equations that describe central force from gravity on three bodies. Enjoy!

https://evgenii.com/blog/three-body-problem-simulator/

The solutions are found using the well-established Runge-Kutta method in mathematics. For details, see:

http://calculuslab.deltacollege.edu/ODE/7-C-3/7-C-3-h.html

48

Flat Earth Community / Re: More fake moon landing proof.

« on: May 09, 2020, 07:41:17 PM »

Hi Somerled. Just saw your reply (the posts after came fast) and so wanted to respond.

Isn’t the fuel in the rockets under pressure though? That’s my understanding. But it sounds like you disagree that deflagration could happen in a vacuum?

So when you say the principle of Momentum cannot produce a force, do you mean in general or just in a rocket-vacuum situation?

Because I see two topics here for discussion:

1) deflagration cannot proceed in a vacuum.

2) momentum cannot produce forces.

Both are required to happen for a rocket to work, and so maybe it would be useful to address these separately?

That is, of course, if I understand you right. Do let me know!

Hello BRollin,
1 . Don't know if they still teach this stuff in school but chemical reaction rate increases and decreases according to corresponding  temperature/pressure increase or decrease - particularly in gases. Nicely explained here

 https://www.chemguide.co.uk/physical/basicrates/pressure.html

The rocket fuel may be under pressure in the tanks but as soon as the tanks are open to vacuum then the pressure is gone .

I've already posted a video by this budding scientist , not a FE'r, but watch him trying to ignite various things including rocket fuel with it's own oxidizer in a vacuum chamber .



It's not a long video - 15mins - but it shows the principle . Listen carefully to what he says.
 
2. Well that's not what I said . The only way to accelerate an object / change its momentum is to apply a force . The principle of conservation of momentum is nothing to do with accelerating a rocket .
[/quote]

Okay, I think I’m getting a better understanding of your position.

1. I think I agree with you here. If fuel was exposed to a vacuum then it wouldn’t ignite. So if fuel was ignited before it was exposed the vacuum, then it would still be under pressure, and the chemical reactions could take place?

2. I think in this hypothetical situation, there are forces involved. If I am in outer space, and I throw a heavy object, then the recoil from my throw should push me in the opposite direction. Do you agree with this?

I push on the object with a force, there is an equal and opposite force on my by Newton’s third law. The effect is that both the object and myself now has a momentum. Do you agree?

49

Flat Earth Theory / Re: Aristotle's most famous proof for the rotundity of the Earth

« on: May 09, 2020, 01:57:29 PM »

So you verify that if the shadow is coming from a slightly different angle than the observer, the curvature would occur. If the shadow were exactly  coming from the observer's location, the curvature would not occur.

Is there any reason to assume that the shadow is coming directly from the observer other than because that's what RE says? Under the EA explanation for the Lunar Eclipse I could see the Moon being exactly full, in the vertical rays of the Sun, with the angle of the incoming shadow offset from exactly vertical.

Your model with a curving shadow seems to disprove Aristotle's claim that only a round object can cause a round shadow. We see a round shadow. It seems appropriate to say that Aristotle was wrong, and that a flat-sided shadow can project as round on a round moon.

Was that Aristotle’s claim though? He said:

As it is, the shapes which the moon itself each month shows are of every kind straight, gibbous, and concave but in eclipses the outline is always curved: and, since it is the interposition of the earth that makes the eclipse, the form of this line will be caused by the form of the earth's surface, which is therefore spherical.

So from my reading of it, it sounds like to me that he didn’t claim that only curved shapes produce curved shadows. It sounds like to me that he claimed the surface of the Earth must be curved under the assumption that the shadow comes from the same angle as the observer: “since it is the interposition of the earth that makes the eclipse.”

So if the shadow on the moon comes not from the earth where we are but some other object, it seems like that object can be flat, according to the demonstration, yet not contradict Aristotle’s claim, since it departs from his assumption.

50

Flat Earth Investigations / Re: Asteroid and planetoid collisions and ther orbit?

« on: May 09, 2020, 12:11:10 PM »

I believe Scripture to be fallible, and I think this testifies to the power of God rather than detract from it.

God used imperfect beings to spread his glory, often making concessions to meet them on their terms.

51

Flat Earth Theory / Re: The Math for universal Acceleration IS INCORRECT

« on: May 09, 2020, 12:12:03 AM »

If an apple with mass 0.1 kg falls from a tree, what is the acceleration of the Earth towards the apple?

Assuming the only force on the earth is from the apple:

a = Gm/r^2

Where a is the acceleration of the earth, G is Newton’s gravitational constant, m is the apple mass, and r is the distance between the center of the earth and the apple.

Easier way:

AM=am

A is acceleration of earth, M is earth mass, a is apple acceleration (9., m is apple mass.

First way uses Newton’s gravitational force directly. Second uses Newton’s third law pair forces.

52

Flat Earth Community / Re: More fake moon landing proof.

« on: May 08, 2020, 08:57:15 PM »

So sorry. I didn’t mean to duplicate a post. I guess after 15 pages it gets hard to keep track of everything that’s been said.

No need to be sorry. I didn't want to criticize  your effort (I hope you didn't take it that way), just make you aware that it has come up before.
Here it says page 30, so believe me, I know the feeling.

Yeah I just wanted to find some common ground between everyone, since it has become so contentious (I was part of that, of course).

A commendable effort; it usually makes sense to get the things we agree on out of the way and focus on the aspects we disagree about.
At this point the "uncommon ground" has already been pretty much established as "does free expansion prevent rockets from working or not"? (It does not.)
There was some side discussion, if fuel would burn in a vacuum. (Rocket fuel will burn in a rocket in a vacuum.)

From how I understand it, a gas freely expanding in a vacuum has a velocity, no matter what. If it is a stable state, then the velocity distribution is maxwellian, but obviously for a rocket it wouldn’t be.

If gas is expanding, it is obviously moving, so it would have to have a velocity.
With maxwell you're not looking a "the gas" as such, but the molecules it is composed of.

In the case of a rocket those molecules will share a common velocity vector by having been expelled together (it will, of course, not be exactly identical for each molecule).
This is significant for propulsion and has recently become known as "oomph" in this thread.

They will also have individual (comparatively small) velocity vectors due to the way gas molecules constantly move.
This part will make the gas expand (freely) and is not significant for propulsion.

So in the compartment example, it expands with a maxwell distribution. And if it hits an object, then work would be done I suppose. But then it really wasn’t a vacuum, right?

It wouldn't be a total vacuum and as the object would be "hit" in an non-stable state, I guess work may be done depending on the circumstances of the experiment. 

I see the rocket gas as the same thing - just a velocity determined by the deflagration.
I don’t think the distribution affects the thermodynamic behavior of free expansion, but I could be wrong.

What kind of distribution and behavior are you referring to exactly?

iC

Let’s see, I think I agree with all of your comments - any differences are probably just semantical.

By different velocity distribution, I just meant not maxwellian - because it is not a thermally averaged state. I don’t know what the distribution would actually be for a rocket, so I can’t help there.

But I was thinking that once the gas leaves the rocket then it would freely expand just like the compartment gas. Hence, the relevant topic is what happens before then.

Of course, the density distribution wouldn’t look that same, since there rocket gas is sent isotropically. I just mean from a thermodynamics expansion point of view.

Hope that makes sense...

53

Flat Earth Theory / Re: Question about the moon according to FES

« on: May 08, 2020, 07:04:29 PM »

How does the flat earth theory describe the same face of the moon being visible from all places on earth at any given time? The globe theory has a simple explanation, tidal locking, but how can it be explained if the earth is flat?

To share some of my own experiences, I’ve been to both the northern and Southern Hemispheres. And I saw a “different moon” in Australia than I see on the west coast US.

So I’m not sure that seeing the same face of the moon is accurate.

Just my experience, and I didn’t take any pictures, so I don’t have any visual evidence to support this claim. So I understand if you choose not to believe me

You see a rotated moon due to "up" being a different direction when looking at the moon, but should still see the same features.  Same moon, same face, but upside down.

That could be!

I admittedly didn’t consider that and didn’t have it in mind when I was looking. I just remember that it looked different.

An opportunity wasted!

54

Flat Earth Community / Re: More fake moon landing proof.

« on: May 08, 2020, 06:23:18 PM »

Let's repost the claptrap source and see what it defines as being isentropic at the nozzle:

""Isentropic flows occur when the change in flow variables is small and gradual, such as the ideal flow through the nozzle shown above. The generation of sound waves is an isentropic process. A supersonic flow that is turned while the flow area increases is also isentropic. We call this an isentropic expansion because of the area increase."

The paragraph you quote is not a "definition of what is isentropic at the nozzle"; it is only elaborating on what (some) isentropic flows are.
If you follow the embedded link in "the generation of sound waves is an isentropic process.", it explains the isentropic nature of sound waves in more detail.

Yeah, which is what is isentropic at the nozzle.

Period.

Now, knowing that gas released to the confines of a vacuum does 0 work, and knowing the entirety of the nozzle (both the outside of the bell and the inside of the bell) are exposed to vacuum, neither of the conditions for "isentropic process, " are met.

The gas is not released, it is expelled. => "does 0 work" does not apply.

All gas, when released from its container, is expelled.

Take a CO₂cartridge and pop a hole in it.

When you do that, the gas is expelled under great force.

The gas goes one way, the cartridge goes the other...INSTANTLY!!!

Now do the same thing when the CO₂cartridge is in a vacuum...nothing, nada, zilch, bupkus...

You are wrong, as usual...

Gas released or expelled to a vacuum does 0 work.

Once the rocket is operating, the inside of the "bell" will be filled with gas. => no vacuum.

Wrong...the bell has an opening and when, as claimed by mystical outer space rocket engineers, it is in outer space...that opening is in a vacuum...and gas, when coming from one container through an opening to the presence of a vacuum, freely disperses...and does 0 work...

Even after leaving the bell there will not (immediately) be exposed to vacuum as the dispersing exhaust is still there.

You're really trying, but sorry...you got this all wrong...

The video evidence is clear and the science is clear.

You're wrong.

Give it up.

Imagine a container with a barrier cutting it in half. In one half is a gas, and the other is a vacuum. If we suddenly remove the barrier, the. The gas expands into the vacuum, and zero work is involved.

I think this is the idea that you are talking about. And I absolutely agree with you.

The difference between this thought experiment and a rocket is that the gas is propelled from the rocket with a velocity. Since the rocket fuel is burned (a deflagration) which converts stored chemical potential energy into kinetic energy.

Since the rocket + fuel starts off with no initial momentum, as the fuel leaves in one direction with a velocity, there must be a corresponding momentum of the rocket in the other direction to cancel it.

Once the fuel leaves, it freely expands into the vacuum and does no work.

So in my opinion, you are both correct - you’re just looking at different parts of the process.

This "thought experiment" was carried out ,in reality , by James Joule . It's how science knows that a rocket engine won't produce thrust in a vacuum. It's a physical law , Joules law , amply demonstrated in all videos attempting to show rocket engines working in a vacuum.

In these videos the rocket fuel will not sustain a chemical reaction in a vacuum - even with it's own oxidizer . Pressure is required for combustion which is why we see these  rocket engines being sealed under pressure of air -turned into bombs - in order for the fuel burn to occur , or explode.

The principle of conservation of momentum will never produce a force and will never accelerate a rocket in a vacuum .

Hi Somerled. Just saw your reply (the posts after came fast) and so wanted to respond.

Isn’t the fuel in the rockets under pressure though? That’s my understanding. But it sounds like you disagree that deflagration could happen in a vacuum?

So when you say the principle of Momentum cannot produce a force, do you mean in general or just in a rocket-vacuum situation?

Because I see two topics here for discussion:

1) deflagration cannot proceed in a vacuum.

2) momentum cannot produce forces.

Both are required to happen for a rocket to work, and so maybe it would be useful to address these separately?

That is, of course, if I understand you right. Do let me know!

55

Flat Earth Theory / Re: Question about the moon according to FES

« on: May 08, 2020, 06:08:14 PM »

How does the flat earth theory describe the same face of the moon being visible from all places on earth at any given time? The globe theory has a simple explanation, tidal locking, but how can it be explained if the earth is flat?

To share some of my own experiences, I’ve been to both the northern and Southern Hemispheres. And I saw a “different moon” in Australia than I see on the west coast US.

So I’m not sure that seeing the same face of the moon is accurate.

Just my experience, and I didn’t take any pictures, so I don’t have any visual evidence to support this claim. So I understand if you choose not to believe me

56

Flat Earth Community / Re: More fake moon landing proof.

« on: May 08, 2020, 05:01:03 PM »

Imagine a container with a barrier cutting it in half. In one half is a gas, and the other is a vacuum. If we suddenly remove the barrier, the. The gas expands into the vacuum, and zero work is involved.
I think this is the idea that you are talking about. And I absolutely agree with you.

I'm not sure how long you have been reading along or how far you backtraced this discussion - that specific "image" came up around page 14.
And it has been pointed out at the time, that there is an obvious difference between free expansion (top half) and a rocket engine (bottom half).

As far as I remember nobody has doubted Joule's Law, i.e. no work being done if gas expands freely.
Gas may expand freely, but it can also expand otherwise.

The difference between this thought experiment and a rocket is that the gas is propelled from the rocket with a velocity. Since the rocket fuel is burned (a deflagration) which converts stored chemical potential energy into kinetic energy.
Since the rocket + fuel starts off with no initial momentum, as the fuel leaves in one direction with a velocity, there must be a corresponding momentum of the rocket in the other direction to cancel it.

Agreed, that would be a direct result of Newton's Third Law.

Once the fuel leaves, it freely expands into the vacuum and does no work.

Now, that requires some pondering ...
It is not relevant for rocket propulsion, as this part of the process takes place "after the fact", but is it really fully covered by free expansion?
The exhausted gas will disperse, pretty much in accordance with free expansion, but it also still carries momentum from being expelled - if it was to hit some random object in space, wouldn't it transfer that momentum and do work?
Also "no work" is requires an stable end state, which will never be reached in endless space. (We went back and forth about this at about the same time we were discussing the referenced image.)
Admittedly, rather philosophical questions with little bearing on the question at hand (if rockets in a vacuum). 

So in my opinion, you are both correct - you’re just looking at different parts of the process.

I agree with your explanation of the process (except, maybe for the philosophical part) and I'll leave it to totallackey to disagree with you, if he so chooses.
However, his conclusion is "rockets do not work in a vacuum" and my conclusion is "rockets do work in a vacuum" we cannot both be correct.

iC

So sorry. I didn’t mean to duplicate a post. I guess after 15 pages it gets hard to keep track of everything that’s been said.

Yeah I just wanted to find some common ground between everyone, since it has become so contentious (I was part of that, of course).

I agree with your added comments, and although they are about what happens after the propulsion event, the physics still seems relevant.

From how I understand it, a gas freely expanding in a vacuum has a velocity, no matter what. If it is a stable state, then the velocity distribution is maxwellian, but obviously for a rocket it wouldn’t be.

So in the compartment example, it expands with a maxwell distribution. And if it hits an object, then work would be done I suppose. But then it really wasn’t a vacuum, right?

I see the rocket gas as the same thing - just a velocity determined by the deflagration.

I don’t think the distribution affects the thermodynamic behavior of free expansion, but I could be wrong.

57

Flat Earth Theory / Re: The Math for universal Acceleration IS INCORRECT

« on: May 08, 2020, 04:53:01 PM »

There is an equal and opposite force from the Earth, but the acceleration would be %5Cfrac%7BF%7D%7Bm%7D  where m is the mass of the Earth, so the acceleration very, very small.

Can't believe I've just said the Earth is accelerating upwards 

The "earth" isn't accelerating.  The ground directly beneath you is accelerating you.  That's an important distinction. The acceleration is caused by the normal force, so if there is nothing in contact with the ground...there is no acceleration.

A point of clarification on behalf of UA: from my (imperfect) readings, it could be that the air above the earth’s surface accelerated too - like everything contained in the dome undergoes UA. If true, then contact with the ground is not needed.

I guess in that case the acceleration on us is not caused by a normal force but by whatever drives UA.

I could be mistaken - I am not a UA expert, just wanted to point out a way UA could be interpreted to match observations.

58

Flat Earth Community / Re: More fake moon landing proof.

« on: May 08, 2020, 03:25:15 PM »

Let's repost the claptrap source and see what it defines as being isentropic at the nozzle:

""Isentropic flows occur when the change in flow variables is small and gradual, such as the ideal flow through the nozzle shown above. The generation of sound waves is an isentropic process. A supersonic flow that is turned while the flow area increases is also isentropic. We call this an isentropic expansion because of the area increase."

The paragraph you quote is not a "definition of what is isentropic at the nozzle"; it is only elaborating on what (some) isentropic flows are.
If you follow the embedded link in "the generation of sound waves is an isentropic process.", it explains the isentropic nature of sound waves in more detail.

Yeah, which is what is isentropic at the nozzle.

Period.

Now, knowing that gas released to the confines of a vacuum does 0 work, and knowing the entirety of the nozzle (both the outside of the bell and the inside of the bell) are exposed to vacuum, neither of the conditions for "isentropic process, " are met.

The gas is not released, it is expelled. => "does 0 work" does not apply.

All gas, when released from its container, is expelled.

Take a CO₂cartridge and pop a hole in it.

When you do that, the gas is expelled under great force.

The gas goes one way, the cartridge goes the other...INSTANTLY!!!

Now do the same thing when the CO₂cartridge is in a vacuum...nothing, nada, zilch, bupkus...

You are wrong, as usual...

Gas released or expelled to a vacuum does 0 work.

Once the rocket is operating, the inside of the "bell" will be filled with gas. => no vacuum.

Wrong...the bell has an opening and when, as claimed by mystical outer space rocket engineers, it is in outer space...that opening is in a vacuum...and gas, when coming from one container through an opening to the presence of a vacuum, freely disperses...and does 0 work...

Even after leaving the bell there will not (immediately) be exposed to vacuum as the dispersing exhaust is still there.

You're really trying, but sorry...you got this all wrong...

The video evidence is clear and the science is clear.

You're wrong.

Give it up.

Imagine a container with a barrier cutting it in half. In one half is a gas, and the other is a vacuum. If we suddenly remove the barrier, the. The gas expands into the vacuum, and zero work is involved.

I think this is the idea that you are talking about. And I absolutely agree with you.

The difference between this thought experiment and a rocket is that the gas is propelled from the rocket with a velocity. Since the rocket fuel is burned (a deflagration) which converts stored chemical potential energy into kinetic energy.

Since the rocket + fuel starts off with no initial momentum, as the fuel leaves in one direction with a velocity, there must be a corresponding momentum of the rocket in the other direction to cancel it.

Once the fuel leaves, it freely expands into the vacuum and does no work.

So in my opinion, you are both correct - you’re just looking at different parts of the process.

59

Flat Earth Investigations / Re: Asteroid and planetoid collisions and ther orbit?

« on: May 08, 2020, 12:14:01 AM »

Galileo: The Bible supports heliocentrism!

Also Galileo: The Bible doesn't tell us how astronomy works.

I see. Not really the best source there. Galileo seems to only accept the Bible's support of astronomy when it supports his view.

Yeah I’d doubt anything Galileo said about Christianity as genuine, given the religious zealotry of the time and the pressures involved. He seemed like a smart enough guy to say what folks wanted to hear, at least part of the time.

60

Flat Earth Projects / Re: UA Circular Motion Theory

« on: May 07, 2020, 03:53:03 PM »

Yes, the acceleration speeds would build up in the circle, but to the rest of the universe there is no drastic (relational) speed changes. Look at this diagram:



In relation to Points A and B the xy coordinates are the same after a complete circuit.

It would be like spiraling into a black hole. The speeds increase locally to extreme rates, but that would be unrelated to the outside universe.

I guess this would have to include all of what we call the visible universe?

I’m not following. Why would it need to include all that?

Becuase if we were zooming around a circle our view of the universe would constantly change right?   Stars would be useless for navigation etc

I see. But if the circle was large enough then maybe our view wouldn’t change noticeably even over long periods of time. I think that is kind of the point of the model.