741

Flat Earth Theory / Re: 2 Simple, Definitive Proofs That the Earth Isn't Flat

« on: April 14, 2016, 04:15:05 PM »

One very simple proof that the earth isn't  fllat is the flat earth definition of the horizon and the distance to the horizon on a flat earth compared with reality.

While I agree this is good evidence against a flat earth, the reason I didn't include it is because it isn't quite as easy to set up a good experiment to verify it. For example, look at all the youtube videos claiming that horizon-distance experiments support a flat earth. Of course, almost all of them are poorly documented, use sloppy math, and don't control for refraction. But that's my point: it is easy to mess up and get the wrong conclusion.

Another simple  reason the horizon is definite proof that the earth isn't flat.:
If the earth was flat the horizon would be at a great distance - where the "dome" meets the "ice wall" - and you would probably just see a blur  because of the thickness of the "atmoplane" in between.

Again, I agree that this is evidence against a flat earth, but I would be hesitant to call it definitive. Especially since you can only guess as to how blurry the horizon would be. Without hard evidence as to what such a horizon would look like, are you surprised that it is routinely dismissed?

All your other points are good, but kind of a derailment from the original point of this thread. Of course, no flat-earthers were responding anyway, so... meh.

742

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 14, 2016, 03:47:23 PM »

Ironic that Flat Earthers will openly, actively, vehemently deny science because they can't see it with their own eyes yet they will rely upon science that they absolutely can't see (special relativity) with their own eyes to attempt to bolster and support their fantasy of what they want the world to be.

What is the frame of reference FES uses to determine the acceleration of the Earth?

Since, as has been stated, velocity/acceleration are meaningless without a frame of reference how did FES come to the conclusion that the Earth is constantly accelerating at 9.8 m/s² and this constant acceleration is what causes the phenomenon we experience as gravity?

We need to be careful when talking about relative acceleration in terms of special relativity. The reason it is called "special" is because it deals with the "special" case of assuming no acceleration. Hence, stuff like the twins' paradox.

The earth's frame of reference is used to determine the earth's acceleration. Just because we can't measure our own velocity without an outside frame of reference doesn't mean we can't measure our own acceleration. How do we measure it? Simple: hold a ball in the air and drop it. What happens? It accelerates down at 9.8m/s². This is easy to measure. Based on this, we can conclude one of 2 things:

1. Our reference frame is accelerating upwards. (Universal Acceleration)
2. The ball is experiencing a downwards force. (gravity)

Since flat-earthers discount the idea of gravity, they choose option 1.

743

Flat Earth Theory / Re: You wouldn't know how fast you're going

« on: April 12, 2016, 08:54:03 PM »

You've missed one important detail about the whole thing though, the twins paradox.
Yes Bob and Earth appear to each other to be moving very fast but only 1 of them is and that's the point I'm making.

Either could be said to be moving, unless you accept the premise of an absolute frame of reference.

Unlike the twins' age, length contraction and relativistic mass are dependent only on the current relative velocity. They are independent of the path taken.

Any observer would have to be travelling close to the speed of light for Earth to appear "normal".

No, any observer would have to be travelling close to 0 m/s relative to the Earth for Earth to appear "normal". Forget about Bob. Bob's frame of reference is arbitrary and unimportant. If you want to measure the relativistic mass or length contraction of an object from our point of view, then the only frame of reference that matters is the Earth's.

You said 3 or 4 times that I didn't mention  that it was to an outside observer. To be honest, I thought it was kinda obvious.

My apologies. I like to be repetitive. I like to be repetitive. I like to be repetitive.

744

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 12, 2016, 08:15:50 PM »

This guy thinks mass = massiveness. Why are yall even wasting your time responding to him.

In general, mass and massiveness refer to the same thing. The distinction he is failing to make is between rest mass and relativistic mass.

745

Flat Earth Theory / Re: You wouldn't know how fast you're going

« on: April 12, 2016, 08:13:10 PM »

As far as I'm concerned, this thread concluded with nametaken graciously accepting Rounder's explanation of relative motion in space. But to clear up the argument that cropped up afterwards...

In simple terms flat earthers are trying to argue that the Earth is travelling close to the speed of light.
E=Mc2 so the mass of everything on Earth is ridiculously huge.

In even simpler terms flat earthers believe they have more mass in the palm of their hand than there is in a black hole.

If you want to talk about velocity, length contraction, and relativistic mass, you need to establish the frame of reference of the observer.

Let's call the observer Bob. Bob can survive in space. Bob is moving at .99 c relative to earth. Bob is pretty darn bored, because he doesn't get Netflix in space, but I digress...

According to Bob, the earth is indeed experiencing length contraction. The earth also has a ridiculously high relativistic mass.

According to the good citizens of earth, Bob is the one experiencing length contraction. Bob is the one with ridiculously high relativistic mass.

According to the good citizens of earth, the earth is not experiencing length contraction, and its total mass is just its normal everyday rest mass.

In conclusion, no one is implying that anyone is holding a black hole in their hand.

BCGreenwood: I don't mind people being wrong. I myself am wrong all the time. Heck, there is a chance I'm wrong about this. But being smug and insulting is a one-way ticket to no-respect land.
junker: You are generally correct about this topic as far as I can tell. But at least try to explain to the poor guy why he is being wrong, instead of being smug and dismissive about everything he says... its no wonder this thread was going nowhere.

746

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 12, 2016, 07:28:37 PM »

I apologise for making you look foolish, as discussed in the other thread.

Be careful about tossing out insults. You never know when you might be wrong. For example...

- After a single year it would be travelling at 309052.8km a second (faster than the speed of light).

Relative to what? Saying "its velocity is such and such" is meaningless without a frame of reference. Regardless of the frame of reference, it won't be faster than the speed of light (see junker's equation).

- Travelling faster than the speed of light is impossible so the only way flat earthers can rectify the glaring problem is if they say the Earth and everything on it is experiencing length contraction.

Again, relative to what? Length contraction happens to objects moving quickly relative to the observer. Since the observers (us) are on earth, the earth and anything moving slowly relative to the earth won't appear to experience significant length contraction.

- Length contraction occurs when an object is travelling close to the speed of light.

Yep! Keep in mind, the object moving quickly can't observe length contraction of itself, because it isn't moving relative to itself.

- E=Mc2 so the mass of everything on Earth would be ridiculously massive because everything is travelling almost as fast as the speed of light

Again, relative to what? Rest mass would remain the same. Relativistic mass would increase relative to some outside fast moving observer, but we wouldn't observe our own relativistic mass increasing.

747

Flat Earth Theory / Re: 2 Simple, Definitive Proofs That the Earth Isn't Flat

« on: April 12, 2016, 03:27:00 PM »

The FE explanations for these observations seems quite bizarre to me. Perspective, somehow makes sun seem to set behind the horizon. Magnification by the "atmoplane" keeps the sun (magically,  exactly) the same size as it moves from noon to sunset.

I didn't bother addressing the perspective explanation, because anyone with any amount of common sense knows that perspective can't cause two objects to appear to be behind each other when they aren't actually behind each other. If a flat-earther comes along to make that argument, I'll gladly address it. Until then, I'll assume they moved on from that silly idea... I hope.

Ditto for the magnification explanation. The picture shown in the wiki in support of the magnification argument is a line of cars with the headlights on. The headlights in front are dim compared to the headlights in back. Of course, the headlights in front aren't even facing the viewer...

Obviously lights get dimmer/smaller as they move away from you.

748

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 12, 2016, 02:52:35 PM »

The situation with the plane is exactly analogous to this. The plane is accelerating upwards with the earth. Relative to the plane and the earth, Bob accelerates downwards as soon as he steps out of the plane.

What is causing the plane to accelerate upwards with the earth?

Good question! Lift. Stick your hand out the car window while driving fast. Palm facing down, fingers together. Now rotate your hand so that your palm is slightly facing forwards. Did you feel your hand pushing upwards? Congratulations, your hand just generated lift like an airplane wing!

Why does this force not apply to Bob when he steps off the plane?

Bob doesn't have wings.

749

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 12, 2016, 06:48:47 AM »

Would I be right in assuming that this "Something" must itself be "pushing on something" (action and reaction, and all that jazz - I didn't see any about SR or GR exempting us from that requirement). 

Yep! Conservation of momentum and all that jazz.

So, please carefully explain what FOR that "something" is in.

It depends. In the case of rocket-like propulsion, the frame of reference would be the earth.

If it is being pushed by something that isn't being accelerated along with the earth, then the relevant reference frame would probably be the outside "something". As the velocity of the earth relative to the "something" approaches c, it would be increasingly difficult for the "something" to continue pushing the earth.

The most plausible scenario would be some theoretical constant stream of massless particles that constantly accelerates the earth. These particles would have to interact with something in the earth, but be virtually undetectable to us (since no one has ever discovered a constant stream of upward particles). This would also probably imply some source of infinite energy... ok, this is getting a bit over my pay grade now. </ramble>

Also, so much seems to be made of the aether (or is it ether or both?) making a "bow wave" (yes, I know it sounds ridiculous to me). Is this aether in its own FOR or the FOR of the "Something" we are being pushed by.

Who knows. Every flat-earther seems to have a different definition of aether/ether. Generally, the concept of ether implies an absolute reference frame, which would make this whole situation... difficult to explain. To say the least.

To be clear, I am not advocating the existence of UA. Dragons indeed.

The bit "uniform force field and a uniform acceleration" you included about EP is telling, because on earth we do not have uniform acceleration.

Indeed. How unfortunate for the theory of UA. Poor thing, it had so much potential...

750

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 12, 2016, 06:02:24 AM »

If this is accepted, however do the rotating celestial bodies explain the above non-time variable gravity variations (not anomalies!)?

This is an excellent point! However, the wording was a bit strange. I would like to try to clarify it, if you don't mind:

We can detect small variations in the strength of gravity. "Celestial Gravitation" is the explanation for this in the UA model.

1. These variations DO NOT change with time.
2. The positions of the heavenly bodies DO change with time.

Therefore, it is extremely unlikely that Celestial Gravitation can account for these variations.

751

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 12, 2016, 05:55:26 AM »

How long has this earth been constantly accelerating at 9.8 m/s?  How fast is this earth actually moving through space after constantly accelerating for all of this time?

How fast is the earth moving through space relative to what? Velocity is relative. There is no absolute frame of reference against which we can measure it.

Lot's of people on this forum seem to toss around the theory of relativity without a decent understanding of it. Contrary to popular belief, the earth can happily accelerate for all eternity, assuming:
1. Something continues to push it.
2. There is no friction in the medium it is travelling through. Or if it isn't travelling through a medium period.

752

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 12, 2016, 05:39:33 AM »

Gravity on the FE is supposedly the effect of the earth rushing upward at some constant speed, keeping everything pinned to the ground.

...

No, it is the effect of the earth accelerating upward at 9.8 m/s². Speed/velocity is different from acceleration. Pretty much everything you say after this is wrong due to this mistake. Especially the stuff about the earth hitting people with a huge amount of force.

All the situations that have been brought up (parachuting, jumping out of a plane, the two objects hanging from a rope) would be affected in the exact same way under gravity and Universal Acceleration. Like SexWarrior said, look up the equivalence principle.

However! That doesn't mean that Universal Acceleration is a perfect replacement for the theory of gravity. The strength of gravity isn't completely constant across the globe. You can measure slight changes in gravity if you climb up a mountain or travel a significant distance north/south. This can't be explained by Universal Acceleration.

How long has this earth been constantly accelerating at 9.8 m/s?  How fast is this earth actually moving through space after constantly accelerating for all of this time?

But let's get back to the discussion at hand.

The equivalence principal.  Your little wiki has a neat little picture of a guy in a rocket and a guy in a room.  Both of which are representative of a respective terra firma for each individual, demonstrating the equivalence principle.

As you will notice from my original comment I was discussing an individual who has jumped out of a plane.  This person is no longer attached to any type of terra firma and is therefore outside the equivalence principle.  He is no longer attached to the plane (analogous to the neat little rocket) and he is no longer attached to the earth (analogous to the neat little box) but is, in fact between the two unaffected by any acceleration.  He is, by FE definition of constant acceleration gravity, in zero gravity and waiting for the earth to catch up to him.

First of all, it's 9.8 m/s². Not 9.8 m/s. I normally dislike being pedantic, but this repeated mistake makes me think you don't understand the difference between velocity and acceleration.

The equivalence principle does not depend on whether someone is touching "terra firma" or not.

First, let's look at an easy example: Bob and Jill are standing on the edge of a cliff. Bob, steps off the cliff! Bob why??? You have so much to live for!!! What happens next according to each theory (gravity, UA)?

1. Gravity: The downward force of gravity is no longer balanced by the upward force exerted by Bob's legs on the earth. Bob accelerates downwards at 9.8 m/s², to Jill's horror.
2. Universal Acceleration: Bob stops accelerating upwards with the earth, but the earth and Jill don't stop accelerating upwards. From the viewpoint of the horrified Jill, Bob is accelerating downwards away from her at 9.8m/s²(even though it's actually her accelerating upwards away from him).

Either way, Bob ends up as a splotch on the rocks below.

The situation with the plane is exactly analogous to this. The plane is accelerating upwards with the earth. Relative to the plane and the earth, Bob accelerates downwards as soon as he steps out of the plane.

The point of the equivalence principle is that it is impossible for someone on the earth to tell the difference between a uniform force field and a uniform acceleration. Relative to someone standing on the earth, objects behave in exactly the same way. By the way, the equivalence principle isn't a flat-earth concept. It was originated by Einstein. I wouldn't trust the wiki on this site for an explanation of it. Look it up on wikipedia or somewhere else.

753

Flat Earth Theory / 2 Simple, Definitive Proofs That the Earth Isn't Flat

« on: April 11, 2016, 06:55:37 PM »

For your consideration, I present two simple proofs that the earth isn't flat. The beauty of these proofs is that they are easy for anyone to verify without expensive equipment or expert knowledge. No faith in NASA/government/scientists required.


The sun sets below the horizon, maintaining its size and shape.

According to most flat-earthers, the sun is a spotlight, rotating in a plane 3000 miles above the earth. Let's make some predictions based on this model:

• The sun should decrease in size as it rotates away from us in the afternoon.

Doesn't happen. The sun stays approximately the same size.

• The sun should not go below 20 degrees from the horizon (based on 3000 miles distance from earth, and 8000 mile diameter of the equator).

It definitely goes below 20 degrees. In fact, it sinks all the way below 0 degrees. In fact, it is possible to see the sun halfway below the horizon, halfway above the horizon, which should absolutely never be possible.

• The sun should appear to always curve north as it travels across the sky. (The point about which it rotates)

This generally happens in the northern hemisphere! Horray! Unfortunately, near the equator, the sun travels in a straight line due west. Bummer. Significantly south of the equator, the sun even curves to the south. Double bummer.

• If the sun is a flat disc, it should appear elliptical as it travels away from us.

Doesn't happen. The sun stays perfectly round.


The existence of the South Celestial Pole

When we are in the Northern Hemisphere, the stars appear to rotate around some point in the North. This is consistent with both a flat earth and spherical earth. Excellent.

When we are near the Equator, the stars appear to travel due west. Again, this is completely consistent with a spherical earth, but on a flat earth, we would expect the stars to still curve north. What gives?

As we continue moving into the Southern Hemisphere, the point in the North about which the stars rotate sets below the horizon, and another point about which the stars rotate rises in the South. The farther south we go, the higher this "South Celestial Pole" rises in the sky. Again, this is completely consistent with a spherical earth, but completely unexplainable on a flat earth.

Some people mention "Celestial Gears" as an explanation for this phenomenon, but I have never seen it actually described. Until there is at least a slightly plausible model explaining the existence of this phenomenon, it is solid evidence against the flat earth model.


Both of these proofs are easy to verify for yourself. The first requires simple observation of the sun on a clear day, preferably near the ocean so that mountains don't obstruct your view. The second only requires travelling to the Southern Hemisphere (unless you already live there) and observing the stars.

754

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 11, 2016, 05:36:55 PM »

The apple falls down to the ground because it is more dense than air. 
The apple floats on water because it is less dense than water but more dense than air. 

This is true! You are referring to the concept of buoyancy.

Less dense matter rises to the top of more dense matter because there is nowhere else to go. 

Why not sideways? or down? or diagonally? Why is "up" preferred?

Buoyancy only works when there is a pressure gradient in a fluid. Pressure gradients are caused by an outside force or an accelerating reference frame (like gravity, or Universal Acceleration). Gravity/UA causes a downward pressure gradient in air and water. (Basically, this means that pressure decreases as you increase your altitude.) Since the pressure below the object is greater than the pressure above the object, light objects will rise against the gradient (up).

TL;DR: Buoyancy would not work without gravity, UA, or some other somewhat constant downward force. Density would not cause objects to rise or fall.

755

Flat Earth Theory / Re: Question about the Gravity of the FE

« on: April 11, 2016, 04:10:49 PM »

Gravity on the FE is supposedly the effect of the earth rushing upward at some constant speed, keeping everything pinned to the ground.

...

No, it is the effect of the earth accelerating upward at 9.8 m/s². Speed/velocity is different from acceleration. Pretty much everything you say after this is wrong due to this mistake. Especially the stuff about the earth hitting people with a huge amount of force.

All the situations that have been brought up (parachuting, jumping out of a plane, the two objects hanging from a rope) would be affected in the exact same way under gravity and Universal Acceleration. Like SexWarrior said, look up the equivalence principle.

However! That doesn't mean that Universal Acceleration is a perfect replacement for the theory of gravity. The strength of gravity isn't completely constant across the globe. You can measure slight changes in gravity if you climb up a mountain or travel a significant distance north/south. This can't be explained by Universal Acceleration.