Debunking Flat Earth and the Hollow Earth

a reply to: Hyperboles

Thanks for the clarification.

originally posted by: Rollie83
a reply to: Hyperboles

Thanks for the clarification.

You are welcome dear.

originally posted by: Rollie83

turbonium1, you’re incorrect.

The VSI directly reads only atmospheric pressure changes, and therefore it indicates ascent/descent only indirectly. Furthermore, the instrument neither knows nor cares about the shape of the Earth below, or even the Earth's relative position. (The VSI works fine when an aircraft is inverted.)

I've been saying the ground is not relevant over and over..

Thanks for agreeing with me on that.

originally posted by: Rollie83
In aeronautical terminology, the “descent” that you describe—flying “around the curvature” at a constant altitude—is actually LEVEL flight, and if the atmospheric pressure remains constant throughout such a flight path, the VSI will not indicate a descent.

You have not read my posts, that's the problem here....

'Curvature' has to be followed, in the round Earth argument.

This requires a constant descent, to maintain altitude. I didn't say they DID descend, I said they'd HAVE to descend, in such a scenario..Do you get my point, now?

We know the ground is not relevant to level flight.

We know level flight is achieved within air, or atmosphere.


What is level flight? Not level to the ground. A 'curving' ground, or 'flat' ground, or 'mountain range', is not a bit relevant to level flight.

It means a plane is flying level within the atmosphere.


Let's consider the atmosphere, now...

Ever-changing atmosphere, yes.

Whether the change is during an ascent, or a descent, or during level flight, we adjust to the changing conditions, and ascend, or descend, or fly level, in revised conditions.

Adjusting to the environment.

And what's your point?....

So, instruments measure level flight within air, not the surface below.

And it stays level, in air.

Same altitude, means it's a flat surface.

The VSI measures descent, or ascent, by the pressure around the plane.

A plane cannot ascend or descend if the pressure is equalized around it.

Equalizing the pressure around a plane is leveling it. Equal force is applied around the plane, to become level within the atmosphere.

originally posted by: mytquin
I'm not convinced one was or the other. Both sides have very good points. Here's one on the Flat Earth side that I can't explain...
Why doesn't a pilot ever have to tip the nose of the plane down to keep from gaining altitude...if said pilot never dipped the nose of the plane down while flying over a globe, logic dictates that as the plane kept flying level he would fly right out into space... wouldn't it

By the way, pilots have been asked if they occasionally have to dip the nose down to account for flying over a curved earth and they are on record as stating that they in fact don't ever have to do this.

By gravity. If you go up in the air and then sideways and then straight you never have to tip the nose down unless you want to go down. No reason you should be going up if you're not going in that trajectory. Gravity bounds you unless you meet it with an even stronger force, aka propulsion for instance. You can use energy to work on gravity but only to a certain extent. So thats how things go up and down and can revolve around a large mass planet like ours.

originally posted by: AngryCymraeg
a reply to: turbonium1

And there you go, cherry-picking responses yet again. A plane is not flying over curvature. It's always flying over level ground, as it measures it. Cumulatively there's a curve, but it's always seeking to maintain a constant altitude.
You either cannot grasp this or you are trolling us all.
I now know which one.

We're past the lame 'ground' excuses.

Planes seek LEVEL flight within air, no matter what the altitude. No matter what the ground is - far, far below it.

originally posted by: turbonium1

originally posted by: AngryCymraeg
a reply to: turbonium1

And there you go, cherry-picking responses yet again. A plane is not flying over curvature. It's always flying over level ground, as it measures it. Cumulatively there's a curve, but it's always seeking to maintain a constant altitude.
You either cannot grasp this or you are trolling us all.
I now know which one.

We're past the lame 'ground' excuses.

Planes seek LEVEL flight within air, no matter what the altitude. No matter what the ground is - far, far below it.

Yeah, but to fly at a level horizon reading and a constant altimeter reading relative to the curved surface, a pilot (or autopilot) constantly and actively makes micro-adjustments to the controls in order to keep the horizon reading level and the altimeter reading constant.

Adjustments must also constantly be made for air currents, changes in pressure, ect and these are also all part of the tiny pilot (or autopilot) are making at all times in order to fly at a constant altitude.

Most of these micro-adjustments would be so small because they are being done continuously, and not one could be called a "noticeable correction".

originally posted by: turbonium1

originally posted by: AngryCymraeg
a reply to: turbonium1

And there you go, cherry-picking responses yet again. A plane is not flying over curvature. It's always flying over level ground, as it measures it. Cumulatively there's a curve, but it's always seeking to maintain a constant altitude.
You either cannot grasp this or you are trolling us all.
I now know which one.

We're past the lame 'ground' excuses.

Planes seek LEVEL flight within air, no matter what the altitude. No matter what the ground is - far, far below it.

It's impossible to debate you, you twist everything around and misrepresent evidence, even in this case from a pilot who understands flying more than you ever will.
You're a troll.

a reply to: AngryCymraeg

haha... There was even a pilot that explained everything that he just brought up again...

he completely ignored it... as IF THE POST didn't exist

Hes a Mastermind!!

The Supertroll

Or just a typical Flat earther... (Moron)

originally posted by: Soylent Green Is People

Yeah, but to fly at a level horizon reading and a constant altimeter reading relative to the curved surface, a pilot (or autopilot) constantly and actively makes micro-adjustments to the controls in order to keep the horizon reading level and the altimeter reading constant.

Adjustments must also constantly be made for air currents, changes in pressure, ect and these are also all part of the tiny pilot (or autopilot) are making at all times in order to fly at a constant altitude.

Most of these micro-adjustments would be so small because they are being done continuously, and not one could be called a "noticeable correction".

You forgot to mention the VSI, for some reason....


I've explained the VSI to you, ad infinitum, yet you just go on and on, acting like it doesn't even exist.


The VSI measures pressure around the plane. Ascent or descent have nothing to do with the ground. Whether the ground is completely flat, or curved, or mountain laden, or cavernous, or anything else - IT HAS NOTHING TO DO WITH FLYING LEVEL.

originally posted by: AngryCymraeg

originally posted by: turbonium1

originally posted by: AngryCymraeg
a reply to: turbonium1

And there you go, cherry-picking responses yet again. A plane is not flying over curvature. It's always flying over level ground, as it measures it. Cumulatively there's a curve, but it's always seeking to maintain a constant altitude.
You either cannot grasp this or you are trolling us all.
I now know which one.

We're past the lame 'ground' excuses.

Planes seek LEVEL flight within air, no matter what the altitude. No matter what the ground is - far, far below it.

It's impossible to debate you, you twist everything around and misrepresent evidence, even in this case from a pilot who understands flying more than you ever will.
You're a troll.

I don't care how many insults you spew at me, it's all about your own problems, which you refuse to deal with, calmly, intelligently, and maturely.

That pilot also forgot to mention the VSI.

If he understands flying more than I ever will, he should also know there's an instrument on every plane he's flown, called the VSI. Being a pilot, he would know what it measures, and how it is relevant to this issue.

Maybe that's the reason he didn't mention it....

Maybe that's the reason he didn't mention it

But he did mention it. Weren't you listening?

originally posted by: turbonium1

originally posted by: Soylent Green Is People

Yeah, but to fly at a level horizon reading and a constant altimeter reading relative to the curved surface, a pilot (or autopilot) constantly and actively makes micro-adjustments to the controls in order to keep the horizon reading level and the altimeter reading constant.

Adjustments must also constantly be made for air currents, changes in pressure, ect and these are also all part of the tiny pilot (or autopilot) are making at all times in order to fly at a constant altitude.

Most of these micro-adjustments would be so small because they are being done continuously, and not one could be called a "noticeable correction".

You forgot to mention the VSI, for some reason....


I've explained the VSI to you, ad infinitum, yet you just go on and on, acting like it doesn't even exist.


The VSI measures pressure around the plane. Ascent or descent have nothing to do with the ground. Whether the ground is completely flat, or curved, or mountain laden, or cavernous, or anything else - IT HAS NOTHING TO DO WITH FLYING LEVEL.

The air pressure is what the altimeter uses to ascertain atitude above sea level. If you know the elevation of the ground beneath you, you can then know how high you are off the ground.

Similarly, the VSI can use air pressure to determine climb or descent rate. This all goes hand-in-hand with the altimeter -- i.e., if the VSI is zero, then the altemieter would not change. If VSI is showning that you are climbing, then the altimeter would increase at the rate the VSI says you are climbing. Similarly, if the VSI indicates that you are descending, the atimeter reading would decrease.

So when I wrote "constant altimeter reading", that would indicate a VSI reading of zero.


However, just like I mentioned above, if a pilot or autopitot wants to keep the VSI at 0 or other constant number, micro-corrections to the controls must contstantly be made. That's because (1) in the short term (locally), atmospheric pressure varies slightly due to weather factors, and (2) In the long term (over greater distances), the atmosphere is a spherical bubble, so even in a hypothetical world where local atmospheric pressures don't vary due to weather conditions, the amount of atmosphere above you could constantly vary along that spherical shape.

None of those microcorrections on their own would be something that is a noticeable flight correction, but it adds up over the long run.

a reply to: Hyperboles

If the earth were flat and capable of sustaining an atmosphere on one side, then by extension, it would have an atmosphere on the other side. If we follow that logic, the "underside" would receive the same amount of sunlight and therefore it would be a viable environment. Why haven't we been to the underside? LOL. There is also a problem with the poles and seasons, how do you fit two poles onto a flat disk and have them receive lesser amounts of sunlight and how do you regulate seasons. This FE crap is easily debunked, but anything is possible, just not likely probable.

The hollow earth scenario is a little trickier. On the inside of a spinning sphere, centrifugal forces mimmick gravity and would have to if anything were to "stick" to the ground. Inside a sphere with a reasonable shell mass, all gravity points inside the sphere would be nullified (all gravity shell points pulling on all other gravity shell points). This occurs with magnetics as well, eg, all magnetic points inside say a highly magnetic hollow cobalt sphere become zero (we've done the physical experiments). Now about that 300lbs per sq foot of atmospheric pressure ;-) Allegedly, there is a light source inside the hollow earth! Well, the light source would have to be huge or be small economy size and have high mass. Possibly, enough mass to offset the 300lbs/sq atmospheric pressure and reduce it to something more livable. It would have to be non-nuclear or non-chemical however, otherwise it would get pretty polluted or radioactive in there in a couple of days. So, what are the chances of having a highly advanced most likely alien (to us) technology floating around at the virtual center of the earth's mass with a complete civilization inside the hollowed out part? Not likely, but there is a non-zero probability ;-)

Funny stuff to think about lol.

Cheers - Dave

originally posted by: bobs_uruncle
a reply to: Hyperboles

If the earth were flat and capable of sustaining an atmosphere on one side, then by extension, it would have an atmosphere on the other side. If we follow that logic, the "underside" would receive the same amount of sunlight and therefore it would be a viable environment. Why haven't we been to the underside? LOL.

So in this scenario (and I realize you are not advocating it) would gravity -- or whatever it is that keeps us on the surface -- work the same to hold people to the underside as it does on the topside?

originally posted by: Soylent Green Is People

originally posted by: bobs_uruncle
a reply to: Hyperboles

If the earth were flat and capable of sustaining an atmosphere on one side, then by extension, it would have an atmosphere on the other side. If we follow that logic, the "underside" would receive the same amount of sunlight and therefore it would be a viable environment. Why haven't we been to the underside? LOL.

So in this scenario (and I realize you are not advocating it) would gravity -- or whatever it is that keeps us on the surface -- work the same to hold people to the underside as it does on the topside?

In this speculative situation of fairy dust and unicorns (lol), it would not be gravity alone but rather centrifugal force. The planet is spinning at about 1000 mph, I haven't done the math, but it might be sufficient to create gravity-like conditions on the inside of the sphere, if it were hollow. It would be something like the spinning of a space station to create artificial gravity. It would be a very odd horizon to be sure.

Cheers - Dave

a reply to: turbonium1

turbonium1, you’ve mis-represented what I wrote, but perhaps my first explanation was over your head. If so, then I apologize for that. I’m simply used to conversing with people who already have some aeronautical knowledge, or understanding of physics. But I’m a sport, so I’ll try to simplify and re-state here.

A conventional altimeter (NOT a radar altimeter) senses only pressure directly, and in this strict sense it doesn’t know or care what the Earth’s shape is. But for the pilot’s benefit, the instrument is designed to extrapolate its pressure-reading into a numerical display of altitude. The display is thus an indirect measure of altitude, and an approximate one at that, albeit a very accurate and extremely useful one. (To measure altitude directly and exactly would require dragging around a very long tape measure over the ocean, and for obvious reasons that’s impractical.)

The aircraft itself, which houses the altimeter, performs exclusively to the atmosphere. In this strict sense, it also doesn’t know or care what the Earth’s shape is. When the pilot configures the aircraft for level flight, the pilot reads the altimeter’s display to do so, but in the direct sense, the pilot is actually trimming the aircraft for a specific atmospheric condition (density altitude, which is governed by barometric pressure) because that’s what the aircraft performs to.

Because the pressure gradient is roughly the same across the globe, an aircraft configured for level flight high above one point will cross another point, thousands of miles away, at very nearly the same altitude—give or take a couple of hundred feet. In other words, because the atmosphere and its pressure gradient follows the Earth’s curvature, so will an aircraft configured for level flight. There’s no need for the pilot to “dip the nose” or execute any other control input, to compensate for the curvature.

I won’t address all of the rest of what you wrote in your latest posts, partly because I don’t understand what you were trying to say in a lot of it. Still, here are a few bullet-point corrections for you.

• Level flight is defined exclusively in relation to the Earth, as a constant altitude over a constant datum—typically, MSL. Your description—“level within the atmosphere”—makes no sense, because the atmosphere contains no frame of reference.
• You misunderstand what a descent is. In aeronautical terms, a descent is relative only to the Earth (MSL or other constant datum). So a level flightpath which follows the Earth’s curvature is NOT a descent, because it does not converge upon that constant datum. The flightpath is LEVEL.
• Instruments do not, as you claim, “measure level flight within the air” because that phrase has no meaning. The altimeter measures atmospheric pressure, which the pilot extrapolates into an approximation of altitude MSL, then uses that approximation to establish a flightpath which is level over the same MSL. Simply put, the aircraft follows the earth’s curvature because the atmosphere does.
• Your emphasis on the VSI is odd. The VSI is a trend/rate instrument only, and pilots use it to gauge their rate of divergence from, or convergence to the Earth. For example, an instrument approach may require a descent of 500 FPM, and the VSI is useful for this. In level flight, the VSI helps to identify deviations as they begin to occur, but the altimeter remains the primary instrument regardless.
• By the way, AngryCymraeg was absolutely correct, in another post to you, in saying that an aircraft at a constant altitude over the curvature is “…flying over level ground, as it measures it.” In response, your repeating the notion of “LEVEL flight within air” is nonsense, because the air contains no frame of reference, and so it doesn’t provide for any up, down, sideways or level. The Earth is needed to define those.
• As a pilot, I’ve flown many aircraft without a VSI. It’s not a required instrument for legal flight, and I can fly level just fine without it.

originally posted by: bobs_uruncle
In this speculative situation of fairy dust and unicorns (lol), it would not be gravity alone but rather centrifugal force. The planet is spinning at about 1000 mph, I haven't done the math, but it might be sufficient to create gravity-like conditions on the inside of the sphere, if it were hollow. It would be something like the spinning of a space station to create artificial gravity. It would be a very odd horizon to be sure.

It sounds like you're talking about centrifugal force. That affects us standing on the outside of Earth's surface at about 1000 mph at lower latitudes where the effect is measurable but small, and diminishes at higher and higher latitudes until it disappears at the poles.

Here's the math:

The centripetal acceleration at the Equator is given by four times pi squared times the radius of the Earth divided by the period of rotation squared (4×π2×R/T^2). Earth's period of rotation is a sidereal day (86164.1 seconds, slightly less than 24 hours), and the equatorial radius of the Earth is about 6378 km. This means that the centripetal acceleration at the Equator is about 0.03 m/s^2 (metres per second squared). Compare this to the acceleration due to gravity which is about 9.8 m/s^2 and you can see how tiny an effect this is - you would weigh about 0.3% less at the equator than at the poles!

So you can calculate how much faster the Earth would have to spin to raise the 0.03 m/s^2 up to 9.8 m/s^2 which means gravity would be effectively "cancelled", then it would need to spin even faster than that to create simulated gravity on the inside of a spinning sphere.

a reply to: Rollie83
I find your detailed explanations interesting but I'm afraid they are probably lost on the flat earth crowd.

Level flight is defined exclusively in relation to the Earth, as a constant altitude over a constant datum—typically, MSL.

Right, so let's say you are flying at 20,000 feet above MSL, over land that is 100 feet above MSL toward a mountain range that peaks at 10,000 feet above MSL. If you keep flying at 20,000 feet above MSL, as you approach the mountain range, the ground will keep getting closer and closer, so this should show that the aircraft is not flying based on distance from the ground, since you are still at 20,000 feet above MSL and your pressure indicator doesn't show a change in pressure as the ground of the mountain range gets closer.

a reply to: Arbitrageur

Arbitrageur, your looming-mountain-range scenario is excellent and correct, and more succinct than my own hyper-wordy explanations are. Will any of our efforts land with the open-minded flatEarther?

A separate question: Will you explain to me how to embed citations from other posts into my own, as you’ve done? I know there’s a “quote” button, but pushing it injects a lot of typographical operators into the text, so I’m yet unsure.

a reply to: Rollie83
I wouldn't hold my breath trying to convince flat earthers, because if you believe in the nearly spherical earth, everything you say is all part of the conspiracy.


To see the exact text used in my post (or any post), click the "quote" button in the upper right, which shows you what are called "ex-tags" for external sources like the gravity math, and "quote tags" for quoting what other people say in posts here. You can actually type your reply at the bottom of that text where the entire thing is inside quote tags, but that is only acceptable if the post is very short, it's against the ATS rules to do that for long posts like yours and my recent long posts, so then we need to "trim" the quote where I just deleted everything but the one line in your post I wanted to focus on.

You can also create those types of tags by clicking the cloud icon for ex-tags or the quote icon for quote tags on the post creation screen, and then copy or paste whatever you have copied from other posts or external sources inside the tags. Sometimes I just type them out manually without clicking those icons.

This link may help, it shows the bbcode for the ex (external) tags, and it works the same way for the quote (internal) tags by using quote instead of ex:
External Source Tags - Please Review This Link.