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Messages - fozington

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Flat Earth Theory / Re: Question from a physicist
« on: May 17, 2017, 03:50:38 PM »
Dear all,

Thank you for the replies that have come in so far, they have been interesting to read.  As a scientist, one universal truth I've come to understand is that answering one question creates innumerable additional questions.  So, I hope you'll permit me to keep this conversation going.  Please try to keep it civil and respectful though, it's important (and extremely interesting) that everyone has a chance to express their opinion. 

I'd like to address some specific points:

Searching "the Wiki" for "gravity" leads to: Universal Acceleration where this is particularly relevant to your query
Quote
Tidal Effects
In the FE universe, gravitation (not gravity) exists in other celestial bodies. The gravitational pull of the stars, for example, causes observable tidal effects on Earth.
Q: Why does gravity vary with altitude?
A: The moon and stars have a slight gravitational pull.

Thanks, Rabinoz, for finding that for me.  Looks like I must have missed it when I was reading the FAQ.

This point has lead me down a whole path of questions; far too many for this conversation.  I guess the thing that really sticks out to me though is this:  surely that would mean any two locations which have the same altitude would have an identical gravitational force, but this is demonstrably untrue.  Perhaps I'm missing something.

Rabinoz also said:

I still query:
  • How the "gravitation" can exist between "other celestial bodies" and objects on earth
    and not between the massive earth and objects on earth.
  • What explains the variation of gravity with latitude, north and south of the equator.
  • How Einstein's Special Relativity can be accepted,
    but not General Relativity, which reduces to Newton's Laws of Motion and Gravitation.

These are all interesting questions, and I'd like to play devil's advocate here (if you'll pardon the expression) with your first point.  I suppose that, if we assume the flat Earth is an infinite plane of limited depth, then (in classical physics) the main pull of gravity will be in all directions horizontally.  The net effect would be a very slight downward acceleration (caused by the depth of the plane), but nothing like the 9.8m/s^2 we experience.  Hmmm... I'm far from convinced about this, but it's going to be a fun thing to think about later!  Thanks again, Rabinoz, your questions are very interesting and I'd love to hear what others have to say about them.

Most part believers accept the "gravity effect" as caused by atmospheric stringency.

Thanks, İntikam.  Your explanation leads me to two questions/observations:
  • What is a "part believer"?  Do you accept some parts of the flat Earth theory but not others?
  • If what we feel as gravity is actually the pressure of the air above us pressing us down, and we can accurately measure the mass of air, we can calculate how much air is above us, pressing us down.  In your model, do you think that the air pressure is constant between the ground and the dome above us (or whatever it is)?  Or does air pressure reduce as our elevation increases?

An object of constant density and volume will weigh more when the air pressure decreases.  The phenomenon is known as air buoyancy.  There are correction formulas established to accommodate for this effect when doing mass calibrations.  The less dense the object is the more pronounced the weight increase will be as elevation increases.

Thanks, Flatout.  The videos you attached were a good example of this phenomenon and I enjoyed watching them.  Now, I'm being a bit pedantic here, but I think I see a problem with this explanation.  Imagine we've got a buoyant object (for example a boat) floating in a fluid medium (like water).  If the density of the fluid increases (maybe you change it for liquid mercury) then the boat will be raised higher, making it appear to have a lower weight.  In fact the weight of the boat remains constant (please note, I'm using the word "weight" as being synonymous with "mass" here.  I understand this is inaccurate, but it keeps things simple.) The apparent mass is what changes here.

So, after saying that, the question I have is this:  In flat Earth theory, what is the difference between weight and mass?  In classical physics weight is the force of an object due to its mass and the acceleration of gravity.  How would it be described in the absence of gravity?

You are already an anti flat earth fascist. You have none of reliablity.

İntikam, please don't say things like that.  It is disrespectful and upsetting.

Thank you all very much for your replies.  As a research physicist I often encounter people with views that are different from my own, and I very much enjoy trying to understand them.  If you have any questions for me, I'll be happy to try to answer them.

F

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Flat Earth Theory / Question from a physicist
« on: May 16, 2017, 12:57:56 PM »
Hello everyone. 

I have a question for you all.  I've been through the FAQ and, although the concept of gravity is discussed, I couldn't see any reference to this particular point.

Imagine that you're travelling around with an accurate accelerometer (a device which measures acceleration).  At various places you stop and take a measurement, and after a while start to notice that these measurements differ from each other by a small amount.  This shows that the strength of gravity is different at different places on the planet. 

In classical physics this is well documented and can be explained by a number of different phenomena.  For example, according to Newton's law of gravitation [F=G(Mm)/r^2] if you are at the top of a mountain, gravity should be slightly weaker than if you were at sea level.  Also, the non-uniform mass density of the planet can account for some considerable variation, even if measurements are taken at the same altitude.  In fact, the measurement you take can vary by as much as 0.7% from place to place.

Now, as I understand it (and do please correct me if I've got the wrong idea) you suggest that the flat Earth is being accelerated upwards at a constant 9.8m/s^2.  Surely, if that were the case, the acceleration measured at any point on the planet would be exactly the same.

Thanks for taking the time to read this, and I look forward to hearing what you have to say.  Please note, I'm not here as a troll, I just find the whole topic fascinating.

Thanks!

F

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