Who needs math to settle the issue? So far not a single flattard has answered the question: Do star trails in the southern hemisphere exist in Flattard Land?
I'll look at them and explain why it's flattard bullshit later, but don't you flattards dismiss everything out of NASA?
And how can "math" prove the southern star trails "wrong"? There is no south pole in Flattard Land, but there is on a spherical Earth. This is reality writ large in the night sky.
My Lord, you are misled. You do realize NASA stands for No Such Agency. Hence you are believing in a false agency. Do you realize that?
Then you want to talk about "s[sic]outhern star trails." That fraud of "Southern" even existing when a simple magnet shows you only North exists staggers me. Seriously?
"There is no south pole."
No shit, I just explained that above.
"... but there is on a spherical Earth."
Hence why the Earth is not spherical as explained above. You are getting this on your own. Just think a bit more about it and you'll arrive at the truth. You are almost there.
So I looked at your flattard link, and all it shows are NASA papers describing engineering models that assume a flat nonrotating Earth FOR THE PURPOSE OF THE MODEL. They are not stating that the Earth is actually flat or stationary.
When you're flying in an airplane and get up to walk to the bathroom, do you need to know that the airplane is flying? No, it appears relatively stationary when not taking off or landing, and you just move around as normal. But if you're charting the path of the plane across the ocean, you'd better damn well take into account that the Earth is spherical and rotating.
Flattards gonna flattard. Cherry pick some obscure engineering papers out of context, while ignoring the south pole and the stars that rotate around it.
Of course you don't understand what that means... The flat model is not the same as the globe model. If they used the flat model, what does that tell you? Answer: That the globe model is unacceptable for realistic use.
When you're in a car and you're cruising strait down the road at a fixed speed and direction and you toss a ball up, it doesn't go flying in any direction because your acceleration is near 0. Toss that ball up when you're turning a corner and tell me how it behaves. It doesn't fall directly down anymore does it? It suddenly departs and continues in the same motion it had been set on because of the throw. It seems as though it's curving through the air, but it's the car that's accelerating.
You experience this on a plane when it's moving too.
You DO NOT experience that on earth. Very much like the car example, the earth is supposedly accelerating, constantly turning a corner. You might not think so because you probably don't understand what acceleration is. Acceleration is the rate of change of velocity in both speed and direction. A change in direction alters the vector co-ordinate and results in 'acceleration'.
As the earth is constantly accelerating you would be CONSTANTLY thrown about.
Dishonesty is the foundation of men who care not for others, but only seek for their own enrichment of material interest, in whatever way they can imagine.
As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation. - Stephen Hawking
If they used the flat model, what does that tell you? Answer: That the globe model is unacceptable for realistic use.
No, it tells me that they used a simplifying assumption for a model that doesn't require the real version, just like I don't take into account that the plane is moving at hundreds of miles per hour relative to the Earth when I get up to go to the bathroom. But you're a flattard and will latch on to any piece of straw in the ocean.
Toss that ball up when you're turning a corner and tell me how it behaves.
When you zoom in a curve it flattens out. That's why the flattard cry of 8" per mile squared is only eight inches for an entire mile. That's a deviation of 1 part in 7,920 (63,360 inches in a mile, divided by 8 inches -- some math for you, flattard).
That's for A MILE. How much curve do you think there is on the local scale when calculating the stresses on an airplane? That would be on the order of a couple hundred of feet, as opposed to 5,280 feet in a mile. You're talking millimeters of deviation here at best.
As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation.
Indeed, so where are the southern star trails around the south pole in Flattard Land? Why don't you answer, flattard?
Uh huh... and why wouldn't they need to use the 'globe version'?... Think McFly!
Read and think, flattard! I've already explained it to you: the Earth's curve at the length of an airplane body is on the order of millimeters, so can be ignored.
Yes, now do it correctly for multiple miles, it's per MILE SQUARED... This increases very quickly.
Which doesn't matter, at all, when calculating the local stresses on an airplane.
Hey, When you zoom in on the ball, does the curve flatten out when you're turning around a corner?
Yes, the "corner" is just the curve of the ball, flattard. Would you trouble turning 8 inches over the course of a mile while driving, flattard? Would you even notice?
Read and think, flattard! I've already explained it to you: the Earth's curve at the length of an airplane body is on the order of millimeters, so can be ignored.
You've made up your mind, my guy.
The globe model and flat model aren't compatible. You cannot simply ignore curvature and still insist that you live on a globe. Your inability to comprehend this basic understanding is detrimental to any informed conversation.
I'm sorry for you more than anything, but unfortunately that doesn't fix the situation.
You cannot simply ignore curvature and still insist that you live on a globe.
You can ignore it when it's at millimeter scale and such precision doesn't matter, flattard. But when it does matter, such as when flying internationally, it's the globe model that is used. When star charts are made, it's the globe model that is used. When calculating sunset and sunrise times, it's the globe model that is used. Your inability to comprehend this basic understanding is detrimental to any informed conversation.
I'm sorry for you more than anything, but unfortunately that doesn't fix the situation.
Except we're not. Ever heard of a thing called a gyroscope? They are used to detect changes in motion by using a spinning wheel to keep angular momentum and when an external force is imparted upon it, you can measure the deviation.
The very existence of them tells us that fundamentally, we are on a motionless flat Earth.
Go ahead and show me the grand-unified theory of Gravity that accounts for objects as large as a human and as small as a speck of dust, while simultaneously explaining the motion of the Earth while it somehow doesn't move the gyroscope, yet drags ALL the atmosphere (out to the Moon, because 'scientists' now say that's within the atmosphere) with it.
They are not stating that the Earth is actually flat or stationary.
Of course they aren't that would go against their 71 million a day scam fleecing tax payers.
When you're flying in an airplane and get up to walk to the bathroom, do you need to know that the airplane is flying? No, it appears relatively stationary when not taking off or landing, and you just move around as normal.
Except if the earth was curved the plane would have to correct and tilt down in order to maintain level flight, which is parallel to the ground. You don't have parallel on a ball if you're flying straight without adjusting for the curvature of 8 inches per mile squared.
But if you're charting the path of the plane across the ocean, you'd better damn well take into account that the Earth is spherical and rotating.
A plane flying westwards would have to out pace the earths supposed rotation of 1000mph eastwards. Planes flying east to west and vice versa have virtually the same flight times though.
Cherry pick some obscure engineering papers out of context
They aren't out of context at all, you just don't like the context within so you come up with any excuse.
Except if the earth was curved the plane would have to correct and tilt down in order to maintain level flight, which is parallel to the ground. You don't have parallel on a ball if you're flying straight without adjusting for the curvature of 8 inches per mile squared.
In case you haven't noticed, a plane has controls, and the pilot uses them to maintain the plane level at a given altitude. So imagine this, after flying for a mile, if the plane is off a whopping 8 inches, the pilot could make whatever minute adjustment is needed.
It's like, my god, how do you drive in Flattard Land when the road is curved? Do you actually steer? What a concept!
A plane flying westwards would have to out pace the earths supposed rotation of 1000mph eastwards.
Flattard thinking. Doesn't understand that the plane already is already moving with the Earth when it takes off, and doesn't lose this velocity when it leaves the ground.
Star trails, constellations and celestial navigation only work on a level stationary plane
Then where's the south pole in Flattard Land?
The problem with people that subscribe to heliocentrism is that you guys don't even understand your own model.
The problem is you're a flattard: dumb, ignorant, and obstinate. Southern star trails have nothing to do with a heliocentric model. It's purely the shape of the Earth at play. For the sake of discussion, the Earth could even be stationary, and the stars rotating. Two poles on a spherical Earth, one pole in Flattard Land. That's it.
The so-called "South Pole" and South Pole star "Sigma Octantis" are both myths used to bolster the globetard claim.
Lulz. You know flattards live in places like Australia, right? Don't you think if the southern star trail images were fake, they'd say something? What's going on in this video, flattard? https://www.youtube.com/watch?v=56ZMZtq0qfY
Well for starters having one fixed stationary star that never moves is already impossible with the earth supposedly rotating, orbiting the sun and the sun moving away too. Now add another stationary star to the opposite side. How does this work?
Well for starters having one fixed stationary star that never moves is already impossible with the earth supposedly rotating, orbiting the sun and the sun moving away too.
Since you're going to repeat yourself, I'll repeat the reply: "The problem is you're a flattard: dumb, ignorant, and obstinate. Southern star trails have nothing to do with a heliocentric model. It's purely the shape of the Earth at play. For the sake of discussion, the Earth could even be stationary, and the stars rotating. Two poles on a spherical Earth, one pole in Flattard Land. That's it."
Go ahead and showcase how it is possible to have a fixed star that never moves in the heliocentric model, let alone 2. Are you supposing that both stars on either side of the ball are perfectly keeping up with the earth from trillions of miles away?
These days there's a popular trend when simulating things to simulate every possible mechanism we can imagine. Those who think that way would agree with you. Why would you ever make a flat Earth model when everything is eventually going to make its first flight on a real rotating spherical-ish Earth?
This approach works great until you come across real development or computational limits. The cited paper is from 1988. Computers were much weaker back then. For perspective, the Cray Y-MP was sold that year. Its peak performance was 333 megaflops. She cost \$15 million dollars. Contrast that to today. A Geforce GTX 1070 is capable of 6,500,000 megaflops (6.5 teraflops) and has a price tag of around \$400.
In those days, you didn't waste computational power on frivolities. It turns out that for a vast array of aeronautical problems, the effects of a flat earth vs. round are minimal (much less the effects of rotating vs. not). If you're shooting a shell 15km, and need it to land with pinpoint precision, you need all that extra complexity. However, many aero problems include a guidance unit which would address any error due to Coriolis effects or the spherical ground the same way it would handle any other errors. It'd simply see it wasn't on the right path and make a correction. The other sources of error here, such as winds, play a far larger effect in deviations from a flight plan, so all the rotating and spherical effects can just get lost in the noise.
Even today, we still make flat Earth models. The reason is not computation time, like it was in 1988, but development time. The more things you model, the more things you need to develop, verify, and maintain. If a particular problem does not call for advanced models, why waste budget developing and maintaining them?
A real life example of this shows up in geoids. Quite often we can do all the modeling we need with a spherical Earth. However, sometimes we find that we need to model the Earth with its proper oblate shape, so we them switch to the WGS84 geoid, or any one of its brethren. The price: all sorts of fun complexities. When I say I have a "forward/right/down" body rotation matrix, is the "down" vector towards the center of the earth, or is it perpendicular to the geoid? On a sphere, they're the same. On an oblate spheroid, I have to take the time to figure out which one was intended. If I don't take the time, then I might as well have just used a sphere.
[ + ] Steelerfish
[ - ] Steelerfish 3 points 1 yearApr 16, 2023 09:22:21 ago (+3/-0)
[ + ] RMGoetbbels
[ - ] RMGoetbbels 1 point 1 yearApr 16, 2023 12:18:39 ago (+1/-0)
[ + ] observation1
[ - ] observation1 2 points 1 yearApr 16, 2023 07:06:42 ago (+2/-0)
At least its got that going for them.
[ + ] Thyhorrorcosmic103
[ - ] Thyhorrorcosmic103 2 points 1 yearApr 16, 2023 05:57:22 ago (+2/-0)
[ + ] SecretHitler
[ - ] SecretHitler 2 points 1 yearApr 16, 2023 04:46:11 ago (+2/-0)
[ + ] Monica
[ - ] Monica 1 point 1 yearApr 16, 2023 08:39:16 ago (+1/-0)
[ + ] RMGoetbbels
[ - ] RMGoetbbels 1 point 1 yearApr 16, 2023 09:09:10 ago (+1/-0)
[ + ] chrimony
[ - ] chrimony [op] 0 points 1 yearApr 16, 2023 14:29:36 ago (+0/-0)
[ + ] oyveyo
[ - ] oyveyo 0 points 1 yearApr 16, 2023 11:55:01 ago (+0/-0)
[ + ] RMGoetbbels
[ - ] RMGoetbbels 0 points 1 yearApr 16, 2023 09:08:39 ago (+0/-0)
[ + ] Love240
[ - ] Love240 -1 points 1 yearApr 16, 2023 04:47:08 ago (+1/-2)
https://steemit.com/flat/@slopetester/15-nasa-research-papers-that-admit-flat-and-nonrotating
[ + ] chrimony
[ - ] chrimony [op] 5 points 1 yearApr 16, 2023 05:21:59 ago (+6/-1)
https://www.talk.lol/viewpost?postid=6437476932a5d
[ + ] AryanPrime
[ - ] AryanPrime -1 points 1 yearApr 16, 2023 07:58:44 ago (+1/-2)
stfu faggot
[ + ] Love240
[ - ] Love240 -2 points 1 yearApr 16, 2023 05:23:00 ago (+1/-3)
[ + ] chrimony
[ - ] chrimony [op] 4 points 1 yearApr 16, 2023 05:26:01 ago (+5/-1)
And how can "math" prove the southern star trails "wrong"? There is no south pole in Flattard Land, but there is on a spherical Earth. This is reality writ large in the night sky.
[ + ] GrayDragon
[ - ] GrayDragon -2 points 1 yearApr 16, 2023 06:35:45 ago (+2/-4)
Then you want to talk about "s[sic]outhern star trails." That fraud of "Southern" even existing when a simple magnet shows you only North exists staggers me. Seriously?
"There is no south pole."
No shit, I just explained that above.
"... but there is on a spherical Earth."
Hence why the Earth is not spherical as explained above. You are getting this on your own. Just think a bit more about it and you'll arrive at the truth. You are almost there.
[ + ] chrimony
[ - ] chrimony [op] 4 points 1 yearApr 16, 2023 06:00:33 ago (+4/-0)
When you're flying in an airplane and get up to walk to the bathroom, do you need to know that the airplane is flying? No, it appears relatively stationary when not taking off or landing, and you just move around as normal. But if you're charting the path of the plane across the ocean, you'd better damn well take into account that the Earth is spherical and rotating.
Flattards gonna flattard. Cherry pick some obscure engineering papers out of context, while ignoring the south pole and the stars that rotate around it.
[ + ] Love240
[ - ] Love240 -2 points 1 yearApr 16, 2023 06:29:58 ago (+1/-3)
When you're in a car and you're cruising strait down the road at a fixed speed and direction and you toss a ball up, it doesn't go flying in any direction because your acceleration is near 0. Toss that ball up when you're turning a corner and tell me how it behaves. It doesn't fall directly down anymore does it? It suddenly departs and continues in the same motion it had been set on because of the throw. It seems as though it's curving through the air, but it's the car that's accelerating.
You experience this on a plane when it's moving too.
You DO NOT experience that on earth. Very much like the car example, the earth is supposedly accelerating, constantly turning a corner. You might not think so because you probably don't understand what acceleration is. Acceleration is the rate of change of velocity in both speed and direction. A change in direction alters the vector co-ordinate and results in 'acceleration'.
As the earth is constantly accelerating you would be CONSTANTLY thrown about.
Dishonesty is the foundation of men who care not for others, but only seek for their own enrichment of material interest, in whatever way they can imagine.
- Stephen Hawking
[ + ] chrimony
[ - ] chrimony [op] 3 points 1 yearApr 16, 2023 06:45:28 ago (+4/-1)
No, it tells me that they used a simplifying assumption for a model that doesn't require the real version, just like I don't take into account that the plane is moving at hundreds of miles per hour relative to the Earth when I get up to go to the bathroom. But you're a flattard and will latch on to any piece of straw in the ocean.
When you zoom in a curve it flattens out. That's why the flattard cry of 8" per mile squared is only eight inches for an entire mile. That's a deviation of 1 part in 7,920 (63,360 inches in a mile, divided by 8 inches -- some math for you, flattard).
That's for A MILE. How much curve do you think there is on the local scale when calculating the stresses on an airplane? That would be on the order of a couple hundred of feet, as opposed to 5,280 feet in a mile. You're talking millimeters of deviation here at best.
Indeed, so where are the southern star trails around the south pole in Flattard Land? Why don't you answer, flattard?
[ + ] Love240
[ - ] Love240 -3 points 1 yearApr 16, 2023 06:51:29 ago (+0/-3)
Uh huh... and why wouldn't they need to use the 'globe version'?... Think McFly!
HAHAHA I forgot you were that guy. Hey, When you zoom in on the ball, does the curve flatten out when you're turning around a corner?
There isn't a southern pole to see. The earth's magnetic field is akin to a ring magnet around the central north pole.
Indeed.
[ + ] chrimony
[ - ] chrimony [op] 3 points 1 yearApr 16, 2023 06:59:29 ago (+4/-1)
Read and think, flattard! I've already explained it to you: the Earth's curve at the length of an airplane body is on the order of millimeters, so can be ignored.
Yeah, that's me, Mr. Reality! What's this look like to you?
Zoomed out circle: https://files.catbox.moe/c65vly.png
Zoomed in at point B: https://files.catbox.moe/exdoxf.png
Zoomed in looks pretty flat to me!
Which doesn't matter, at all, when calculating the local stresses on an airplane.
Yes, the "corner" is just the curve of the ball, flattard. Would you trouble turning 8 inches over the course of a mile while driving, flattard? Would you even notice?
Australia exists, flattard: https://www.youtube.com/watch?v=56ZMZtq0qfY
[ + ] Love240
[ - ] Love240 -3 points 1 yearApr 16, 2023 07:07:15 ago (+0/-3)
You've made up your mind, my guy.
The globe model and flat model aren't compatible. You cannot simply ignore curvature and still insist that you live on a globe. Your inability to comprehend this basic understanding is detrimental to any informed conversation.
I'm sorry for you more than anything, but unfortunately that doesn't fix the situation.
[ + ] chrimony
[ - ] chrimony [op] 2 points 1 yearApr 16, 2023 07:14:08 ago (+3/-1)
You can ignore it when it's at millimeter scale and such precision doesn't matter, flattard. But when it does matter, such as when flying internationally, it's the globe model that is used. When star charts are made, it's the globe model that is used. When calculating sunset and sunrise times, it's the globe model that is used. Your inability to comprehend this basic understanding is detrimental to any informed conversation.
I'm sorry for you more than anything, but unfortunately that doesn't fix the situation.
PS: Australia exists.
[ + ] Prairie
[ - ] Prairie 0 points 1 yearApr 16, 2023 08:48:16 ago (+0/-0)
You are. You're something like a fraction of a percent lighter due to this acceleration. It's perpendicular to gravity.
[ + ] Love240
[ - ] Love240 0 points 1 yearApr 16, 2023 08:56:36 ago (+0/-0)
The very existence of them tells us that fundamentally, we are on a motionless flat Earth.
Go ahead and show me the grand-unified theory of Gravity that accounts for objects as large as a human and as small as a speck of dust, while simultaneously explaining the motion of the Earth while it somehow doesn't move the gyroscope, yet drags ALL the atmosphere (out to the Moon, because 'scientists' now say that's within the atmosphere) with it.
[ + ] GetFuckedCunt
[ - ] GetFuckedCunt -3 points 1 yearApr 16, 2023 06:10:30 ago (+1/-4)
Of course they aren't that would go against their 71 million a day scam fleecing tax payers.
Except if the earth was curved the plane would have to correct and tilt down in order to maintain level flight, which is parallel to the ground. You don't have parallel on a ball if you're flying straight without adjusting for the curvature of 8 inches per mile squared.
A plane flying westwards would have to out pace the earths supposed rotation of 1000mph eastwards. Planes flying east to west and vice versa have virtually the same flight times though.
They aren't out of context at all, you just don't like the context within so you come up with any excuse.
[ + ] chrimony
[ - ] chrimony [op] 3 points 1 yearApr 16, 2023 06:31:00 ago (+4/-1)
In case you haven't noticed, a plane has controls, and the pilot uses them to maintain the plane level at a given altitude. So imagine this, after flying for a mile, if the plane is off a whopping 8 inches, the pilot could make whatever minute adjustment is needed.
It's like, my god, how do you drive in Flattard Land when the road is curved? Do you actually steer? What a concept!
Flattard thinking. Doesn't understand that the plane already is already moving with the Earth when it takes off, and doesn't lose this velocity when it leaves the ground.
[ + ] GetFuckedCunt
[ - ] GetFuckedCunt -3 points 1 yearApr 16, 2023 06:02:06 ago (+1/-4)*
https://www.youtube.com/shorts/vQJez9iiS7Y
The problem with people that subscribe to heliocentrism is that you guys don't even understand your own model.
[ + ] chrimony
[ - ] chrimony [op] 4 points 1 yearApr 16, 2023 06:17:08 ago (+4/-0)
Then where's the south pole in Flattard Land?
The problem is you're a flattard: dumb, ignorant, and obstinate. Southern star trails have nothing to do with a heliocentric model. It's purely the shape of the Earth at play. For the sake of discussion, the Earth could even be stationary, and the stars rotating. Two poles on a spherical Earth, one pole in Flattard Land. That's it.
[ + ] GetFuckedCunt
[ - ] GetFuckedCunt -3 points 1 yearApr 16, 2023 06:38:59 ago (+1/-4)
Where is the physical measurement of curvature? 8 inches per mile squared if you suppose a ball with the radius of 3959 as per the heliocentric model.
[ + ] chrimony
[ - ] chrimony [op] 3 points 1 yearApr 16, 2023 06:51:54 ago (+3/-0)
Lulz. You know flattards live in places like Australia, right? Don't you think if the southern star trail images were fake, they'd say something? What's going on in this video, flattard? https://www.youtube.com/watch?v=56ZMZtq0qfY
[ + ] deleted
[ - ] deleted 0 points 1 yearApr 16, 2023 07:54:52 ago (+0/-0)
[ + ] GetFuckedCunt
[ - ] GetFuckedCunt -2 points 1 yearApr 16, 2023 07:53:30 ago (+1/-3)
How does this work?
https://www.youtube.com/shorts/vQJez9iiS7Y
[ + ] chrimony
[ - ] chrimony [op] 0 points 1 yearApr 16, 2023 14:39:05 ago (+0/-0)
Since you're going to repeat yourself, I'll repeat the reply: "The problem is you're a flattard: dumb, ignorant, and obstinate. Southern star trails have nothing to do with a heliocentric model. It's purely the shape of the Earth at play. For the sake of discussion, the Earth could even be stationary, and the stars rotating. Two poles on a spherical Earth, one pole in Flattard Land. That's it."
[ + ] AryanPrime
[ - ] AryanPrime -1 points 1 yearApr 16, 2023 07:59:24 ago (+1/-2)
fucking gaslighting faggots like you should be knocked the fuck out on sight
[ + ] GetFuckedCunt
[ - ] GetFuckedCunt 0 points 1 yearApr 16, 2023 17:01:31 ago (+0/-0)
Learn what has lighting is to ya fucking retard.
[ + ] mikenigger
[ - ] mikenigger 0 points 1 yearApr 16, 2023 08:32:35 ago (+0/-0)
https://www.voat.xyz/viewpost?postid=61f8641f80e51
https://www.voat.xyz/viewpost?postid=61ca7636e0881#comment_61ca7bd063438
[ + ] Love240
[ - ] Love240 0 points 1 yearApr 16, 2023 08:40:03 ago (+0/-0)
It was visible with the naked eye, I've seen it in a reflection.
Good times.
[ + ] Prairie
[ - ] Prairie 0 points 1 yearApr 16, 2023 08:46:15 ago (+0/-0)
These days there's a popular trend when simulating things to simulate every possible mechanism we can imagine. Those who think that way would agree with you. Why would you ever make a flat Earth model when everything is eventually going to make its first flight on a real rotating spherical-ish Earth?
This approach works great until you come across real development or computational limits. The cited paper is from 1988. Computers were much weaker back then. For perspective, the Cray Y-MP was sold that year. Its peak performance was 333 megaflops. She cost \$15 million dollars. Contrast that to today. A Geforce GTX 1070 is capable of 6,500,000 megaflops (6.5 teraflops) and has a price tag of around \$400.
In those days, you didn't waste computational power on frivolities. It turns out that for a vast array of aeronautical problems, the effects of a flat earth vs. round are minimal (much less the effects of rotating vs. not). If you're shooting a shell 15km, and need it to land with pinpoint precision, you need all that extra complexity. However, many aero problems include a guidance unit which would address any error due to Coriolis effects or the spherical ground the same way it would handle any other errors. It'd simply see it wasn't on the right path and make a correction. The other sources of error here, such as winds, play a far larger effect in deviations from a flight plan, so all the rotating and spherical effects can just get lost in the noise.
Even today, we still make flat Earth models. The reason is not computation time, like it was in 1988, but development time. The more things you model, the more things you need to develop, verify, and maintain. If a particular problem does not call for advanced models, why waste budget developing and maintaining them?
A real life example of this shows up in geoids. Quite often we can do all the modeling we need with a spherical Earth. However, sometimes we find that we need to model the Earth with its proper oblate shape, so we them switch to the WGS84 geoid, or any one of its brethren. The price: all sorts of fun complexities. When I say I have a "forward/right/down" body rotation matrix, is the "down" vector towards the center of the earth, or is it perpendicular to the geoid? On a sphere, they're the same. On an oblate spheroid, I have to take the time to figure out which one was intended. If I don't take the time, then I might as well have just used a sphere.